Urban Stormwater Quality Planning Guidelines December 2010

Transcription

1 Urban Stormwater Quality Planning Guidelines 2010 December 2010

2 Prepared by: Water Quality and Accounting Department of Environment and Resource Management The State of Queensland (Department of Environment and Resource Management) 2010 Copyright inquiries should be addressed to or the Department of Environment and Resource Management, 41 George Street Brisbane QLD 4000 Published by the Queensland Government, December 2010 This document has been prepared with all due diligence and care, based on the best available information at the time of publication. The department holds no responsibility for any errors or omissions within this document. Any decisions made by other parties based on this document are solely the responsibility of those parties. Information contained in this document is from a number of sources and, as such, does not necessarily represent government or departmental policy. This publication can be made available in alternative formats (including large print and audiotape) on request for people with a vision impairment. Contact (07) or <library@derm.qld.gov.au> December 2010 #29581 Cover photo (Shaun Leinster) illustrates a bioretention swale during rainfall. The system is located within a development in South East Queensland and is approximately seven years old. The system was designed to deliver treatment of suspended solids and nutrients as well as provide hydrologic management of run-off from the residential dwellings and road (i.e. dampen stormwater flows). In this case the development layout was carefully considered very early in the design to ensure there was suitable space within the road reserve for the swale bioretention system, driveway crossovers were avoided and the slopes were appropriate. The bioretention swale combines with street trees and pedestrian pathways to form a green linkage through the community.

3 Preface The Queensland Government introduced the Environmental Protection Act 1994 to provide a legislative framework for the protection of Queensland s environment while allowing for development that improves the total quality of life, both now and in the future, in a way that maintains the ecological processes on which life depends. The key objectives of our environmental management strategy are to ensure that Queenslanders and visitors to our state have access to clean and safe waters, and that the environmental and recreational values of our waterway assets are protected for future generations. A cooperative approach is required that includes the community, urban development industry, local government and state agencies. The Department of Environment and Resource Management is committed to protecting the quality of Queensland s waterways through the development of innovative management tools and implementation programs. As a reflection of this commitment, it is releasing these guidelines, for use by local government and industry, to promote consistency and cost-effective catchment-based approaches to stormwater quality planning across Queensland. In particular, these guidelines assist in the application of the State Planning Policy 4/10 for Healthy Waters and its supporting guideline which address urban stormwater quality management in the state planning policy's development assessment code. This code includes criteria to help protect receiving water environmental values from potential development impacts arising from poor urban stormwater quality and altered stormwater flow. This guideline provides ways to better manage development and construction activities in accordance with urban stormwater quality design objectives. It also guides councils in the preparation of urban stormwater quality management plans as part of total water cycle management as required under the Environmental Protection (Water) Policy 2009.

4 Acknowledgements The Urban Stormwater Quality Planning Guidelines 2010 are aimed at improving stormwater quality and stormwater quantity management in Queensland. The precursor to this document was the Draft Urban Stormwater Queensland Best Practice Environmental Management Guidelines Project management The project was managed by the Department of Environment and Resource Management and assisted by funding from the Commonwealth Coastal Catchments Initiative (CCI) program. Figures and photographs Many of the figures and photographs included in the guide have been reproduced, with permission, from a range of sources. The authors wish to thank those publishers and authors concerned. Significant sources include: Victorian EPA (1999) Urban Stormwater: best practice environmental management guidelines, Victoria Stormwater Committee. International Erosion Control Association (Australasia) (2008) Best Practice Erosion and Sediment Control. International Erosion Control Association (Australasia), Picton NSW. Sunshine Coast Regional Council, (2008), Version 1.2, Manual for Erosion and Sediment Control. For further information please contact: Department of Environment and Resource Management Water Quality & Accounting Level 8, Mineral House, 41 George St GPO Box 2454, Brisbane QLD 4001 Fax (07) spphealthywaters@derm.qld.gov.au

5 Abbreviations ARI ARQ Annual recurrence interval Australian Runoff Quality (guideline published by Engineers Australia) AWQ Guidelines Australian and New Zealand Guidelines for Fresh and Marine Water Quality 2000 DEO DERM DO DRO DTMR Desired environmental outcome Department of Environment and Resource Management Design objective Desired regional outcome Department of Transport and Main Roads EP Act Environmental Protection Act 1994 EPP Water Environmental Protection (Water) Policy 2009 ERA ESC ESCP ESD EV FNQ HIA IDAS IECA LGAQ NRM QA QPIF SCMP SCRC SEQ Environmentally relevant activity Erosion and sediment control Erosion and sediment control plan Ecologically sustainable development Environmental value Far North Queensland Housing Industry Association Integrated development assessment system International Erosion Control Association (Australasia) Local Government Association of Queensland Natural resource management Quality assurance Queensland Primary Industries and Fisheries (part of Department of Employment, Economic Development and Innovation) State coastal management plan Sunshine Coast Regional Council South East Queensland SPA Sustainable Planning Act 2009 SPP SQMP State planning policy Site stormwater quality management plan

6 TWCM UDIA USQM USQMP WQ WQIP WQO WSUD Total water cycle management Urban Development Institute of Australia (Queensland) Urban stormwater quality management Urban stormwater quality management plan Water quality Water quality improvement plan Water quality objective Water sensitive urban design

7 Contents Acknowledgements ii Abbreviations iii 1 Introduction What is the purpose of the guidelines? Why do we need the guidelines? Impacts of urbanisation Who should use the guidelines? Local governments Development industry Department of Environment and Resource Management (DERM) Regional natural resource management bodies (NRM bodies) Other infrastructure providers How to use the guidelines Links and references 7 2 Principles and design objectives Introduction 10 Definitions Queensland policy for urban stormwater management Urban stormwater management principles Stormwater management design objectives Determining stormwater quality design objectives Determining stormwater quantity design objectives Application of design objectives 33 Cumulative impacts 33 Achieving the design objectives Further information 33 South East Queensland 33 Other Queensland areas 34 Statewide resource documents 34 3 Stormwater management planning Introduction Urban stormwater quality management plans (USQMPs) 36 Basis of a USQMP The risk management approach 40 i

8 3.4 Development of a USQMP The USQMP process Stage 1 Preliminary activities 43 Framework 43 Inception 43 Document the nature of land use 44 Document the stormwater system Stage 2 Risk assessment 45 Threats and values 45 Workshop 48 Risk assessment Stage 3 Developing a USQMP 49 Management strategies 49 Tasks 49 Source controls 50 Waterway action plans 51 Land use planning links 54 Developing detailed actions 57 Implementation planning Stage 4 Implementing a USQMP 58 Implementation plan tasks 59 Staff training 59 Developing an education program 59 Enforcement 61 Performance review and improvement programs 62 Water quality monitoring and review 63 Management review tasks 64 4 Planning controls Introduction State planning policies Regional planning State USQM framework Land-use planning State planning framework 69 Regional planning Local planning framework 73 Use of zones, overlays and related provisions 78 Local policies 79 ii

9 4.2.3 Development assessment Other controls The importance of an integrated approach 84 5 Water sensitive urban design Introduction Water sensitive urban design and the total water cycle Benefits of water sensitive urban design Site planning Site analysis Site layout plans Concept Design Guidelines for Water Sensitive Urban Design Planning the development phases for long-term benefit Permanent operational phase Construction phase 91 6 Source controls Introduction Preliminary information Council operations Planning of asset construction and maintenance 94 Construction activity planning 94 Maintenance activity planning Source controls for maintenance activities Training and staff awareness Council source control checklist Planning and development erosion and sediment control Strategic planning and legislative issues 98 Development assessment and management issues 99 Material change of use (MCU) and reconfiguration of a lot (ROL) 100 Operational works 100 Water sensitive urban design 101 Construction 101 Site management plan objectives Site stormwater quality management plan checklist 104 Erosion and sediment control plans (ESCPs) Site erosion and sediment control 109 Construction site with disturbance area > 2500 m Erosion risk assessment 112 iii

10 Construction site small scale with disturbance area < 2500m 2 and not part of a larger development 119 Building sites Business surveys Stormwater pollutant surveys Educational programs Developing an education program Enforcement Roles and principles of enforcement Enforcement agencies Enforcement powers of local councils Structural treatment measures Introduction Selecting stormwater quality treatment measures Determine treatment objectives Develop treatment train Undertake site identification Short-list potential treatments Compare potential treatments Primary stormwater treatment Summary of primary treatments Secondary stormwater treatment Summary of secondary treatments Tertiary treatment types Flow management 144 Appendix 1A Example development approval conditions for erosion and sediment control Introduction Use of these provisions Example development approval conditions Development planning and design Construction planning Erosion and sediment control plans Site establishment Site access 156 iv

11 9 Site management Site clearing Soil and stockpile management Drainage control Erosion control Sediment control Site rehabilitation Sediment basin rehabilitation Site monitoring Site maintenance Road works Instream works Works within intertidal areas 177 Appendix 1B Model code of practice provisions erosion and sediment control Introduction Model code of practice 179 Appendix 1B Attachment A Information supporting model code of practice provisions erosion and sediment control Introduction Development planning and design Construction Planning Erosion and sediment control plan (ESCP) Site establishment Site management Land clearing Soil and stockpile management Drainage control Erosion control Sediment control Site stabilisation and rehabilitation 215 v

12 13 Site inspection and monitoring Site maintenance 217 Appendix 2 Model erosion and sediment control plans Introduction Example 1: Construction of university accommodation units 218 Site description 218 Soils information Example 2: Residential subdivision Example 3: Road construction 230 Appendix 3 Development applications stormwater quality management information Development application stormwater quality management Reporting Pre-lodgement stage Lodgement of development applications Document information Executive summary Table of contents Introduction 238 Locality plan 238 Site characteristics 238 Proposed land uses 239 Location conditions Design objectives Strategy description and plan Modelling approach Information request stage Operational works applications 241 List of Figures Figure 2.1 Queensland policy framework for urban stormwater management policy framework for urban stormwater management 11 Figure 2.2 Water quality planning Queensland water guidelines and scheduled EVs and WQOs 12 Figure 2.3 Hierachy of stormwater management control 15 Figure 2.4: Approaches for determining stormwater design objectives and their context in integrated stormwater management for a site 17 vi

13 Figure 2.5: Delineation of regions for application of operational phase design objectives in Table Figure 3.1 Conceptual framework for an urban stormwater quality management plan (USQMP) 38 Figure 3.2: Risk assessment approach 40 Figure 3.3: Design objectives for management of stormwater quantity operational (postconstruction) phase of development 41 Figure 3.4 Process for formulating and implementing a local urban stormwater quality management plan 42 Figure 3.5 Waterway action plan framework 52 Figure 3.6 Land use and development planning framework 55 Figure 4.1 Stormwater management planning and assessment framework 68 Figure 4.2 Queensland stormwater management planning and assessment guideline 70 Figure 4.3 Erosion hazard mapping based on rainfall intensity and slope gradient 78 Figure 4.4 Links between WSUD elements and the urban water cycle. 83 Figure 4.5 Water sensitive urban design and council planning scheme 84 Figure 5.1 Construction site sediment export 87 Figure 5.2 Land use and run-off 89 Figure 6.1 Major staged development cleared then developed in stages over a period of several years. 99 Figure 6.2 : Land development can result in significant vegetation removal, soil disturbance and altered hydrology over large areas 102 Figure 6.3 Planning phase steps for site management 109 Figure 6.4 Reducing the area of disturbance reduces the footprint and cost of erosion and sediment control (SCRC) 111 Figure 6.5 Design phase steps for site management. 112 Figure 6.6 High to extreme erosion hazard 112 Figure 6.7 Construction phase steps for site management 116 Figure 6.8 The communication model 129 Figure 7.1 Desirable design ranges for treatment measures and pollutant sizes 135 Figure 7.2 Outlet and distributed approaches to stormwater treatment location 136 Figure 7.3 Guide to Water by Design Guidelines (current and proposed) as at October vii

14 List of Tables Table 1.1 Common pollutants and likely sources found in urban stormwater 4 Table 1.2 Urban stormwater management topics covered in these guidelines 9 Table 2.1 Summary of design objectives for management of stormwater quality construction phase of development 20 Table 2.2 Summary of design objectives for management of stormwater quality operational (post-construction) phase of development 22 Table 2.3 Application of the operational phase design objectives in Table 2.2 local government area by climatic region. 23 Table 2.4: Design objectives for management of stormwater quantity operational (postconstruction) phase of development 32 Table 3.1 Assessing the values of receiving environments 47 Table 6.1Erosion and sediment control plans for construction and building sites 107 Table 6.2 Monitoring requirements and assessment criteria 118 Table 6.3 Drainage design standard for temporary drainage works 119 Table 6.4 Example Erosion hazard assessment form 122 Table 7.1 Summary of primary treatments 141 Table 7.2 Summary of secondary treatments 143 Table 7.3 Constructed wetlands treatment performance 144 Table A12.1.Drainage design standard for temporary drainage works 162 Table A13.1 Erosion risk rating based on monthly rainfall erosivity 163 Table A13.2 Best practice site clearing and rehabilitation requirements 164 Table A14.1 Sediment control standard based on soil loss rate 168 Table A14.2 Recommended discharge standard for de-watering operations 169 Table A18.1 Maintenance requirements of ESC measures 174 viii

15 1 Introduction 1.1 What is the purpose of the guidelines? These guidelines are to assist urban developers, catchment managers and government decisionmakers to manage urban stormwater quantity and quality to protect the environmental values of waterways under the Environmental Protection (Water) Policy They summarise planning and technical reference material on best practice urban stormwater quality management (USQM). They are intended for persons involved in the planning, design, operation or management of urban land uses or stormwater drainage systems that affect stormwater quality in both metropolitan and regional urban areas (see Section 1.3). The guidelines revise and replace the Model Urban Stormwater Quality Management Plans and Guideline (EPA 2001) and the Stormwater Quality Control Guidelines for Local Government (EPA, DNR 1998). The revised guidelines: describe how best practice urban stormwater quality management can help to achieve water quality objectives for all stages of urban development including planning, design, assessment, approval, construction and operation provide direction on the development of strategies for improved environmental management of urban catchments and waterways, including the preparation of urban stormwater quality management plans as part of the total water cycle management plans required under the Environmental Protection (Water) Policy Five key areas are covered: 1 design objectives defining achievable design objectives (minimum defaults) for managing aspects of urban stormwater consistent with helping to protect environmental values 2 planning controls describing a range of planning methods that can reduce sources of stormwater pollution 3 selection of measures guiding the selection and application of structural treatment measures to suit particular situations to remove pollutants from stormwater 4 best practices raising awareness of best practices for environmental management of stormwater quality 5 urban stormwater quality management plans providing guidance for developing urban stormwater quality management plans for the local area catchment, and site stormwater quality management plans for a development site. The guidelines incorporate existing material (suitably adapted to the Queensland planning system, landscape and climate) to address the following planning and development phases: Local planning phase stormwater management planning for the local government area, urban land capability studies, and locating urban zones scope of studies and information required, water quality modelling, levels of stormwater treatment required, templates of planning scheme codes and policies Development design phase design objectives, regional conditions (soils, storm data, erosivity where available, and conservative design objectives where data is not available) 1

16 design of construction (temporary) and operation phase (permanent, postconstruction) water quality management infrastructure through application of water sensitive urban design Construction phase best practice for delivering nominated stormwater quality during design storm events in the construction phase specification of best practice erosion and sediment control (ESC) Operation phase (post-construction) maintenance requirements, responsibility, management systems, decommissioning and rehabilitation delivering nominated stormwater sediment and nutrient load, and stormwater flow design objectives. These guidelines focus on treatment of stormwater quality, provide limited guidance on drainage/flow (quantity) issues, and are not intended to address stormwater drainage purely for flood mitigation. For further guidance on this subject please refer to the Urban Drainage Manual 2007 available at < Though advice is provided on the selection of components for effective environmental management of stormwater, advice on detailed design of these components is not covered and requires other technical guidance. References to other USQM guidelines include those from: Brisbane City Council Gold Coast City Council Sunshine Coast Regional Council Engineers Australia Local Government Association of Queensland SEQ Healthy Waterways. 1.2 Why do we need the guidelines? The Department of Environment and Resource Management (DERM) as the department responsible for water quality policy in Queensland has a responsibility to ensure that government and stakeholder urban stormwater quality management (USQM) programs are comprehensive, integrated and achieve intended outcomes. DERM through the Environmental Protection (Water) Policy 2009 establishes environmental values (EVs) and water quality objectives (WQOs) for waterways in Queensland through community consultative processes. The WQOs provide planning targets for receiving water quality in ambient conditions. These guidelines advise on best practice urban stormwater management across Queensland and provide regionally-based design objectives to help to achieve the WQOs. The design objectives apply through all phases of regional and local planning, development assessment, construction and operation. Traditionally, urban drainage systems have been developed to meet the community s need to minimise the threat of flooding. The main focus of this development has been on hydraulic capacity and transport of stormwater, rather than protecting the environmental values of waterways. As a result, developers may be faced with uncertainty and differing expectations for designing and operating stormwater quality infrastructure accompanying urban development. The guidelines assist in providing the direction and consistency necessary to help to achieve the WQOs. 2

17 1.2.1 Impacts of urbanisation Poor urban stormwater quality contributes to significant water quality decline within our waterways. Sustained high urban population growth rates in Queensland have led to increasing impacts from urban stormwater. Without improved management, urban development is likely to lead to increased stormwater pollutant loads of sediment, nitrogen and phosphorus. In South East Queensland total loads from urban stormwater are projected to increase by more than 50 per cent by In Great Barrier Reef catchments, sediment loads from urban areas on the coast are predicted to increase by more than 10 per cent in this timeframe. With urbanisation, the area of impervious surfaces within a catchment increases dramatically. Densely developed inner urban areas are highly impervious. A high proportion of sealed area greatly reduces the amount of water infiltrating into the soil and consequently most rainfall is converted to run-off. In addition, urban drainage systems are designed to minimise local flooding by providing smooth and direct pathways for the conveyance of this run-off. The consequences of these physical changes include: reduced stream base flow and an increase in run-off events annually more frequent high flow events in creeks, rivers and receiving waters reduced time lag between rainfall occurring and run-off reaching a waterway because of piping and channelling of flows reduced groundwater inflows to streams during dry weather, with a greater proportion of flows made up from human uses of water in the catchment such as car washing, garden watering and so on. The increased flood volumes, peak discharges and velocities in urban waterways cause a significant increase in the amount of material (contaminant loads) carried by the flow and can cause physical damage to stream channels. Activities such as land development expose soils to water and wind erosion and are major sources of sediment and nutrients. Transportation and industrial activities are sources of many other contaminants. Table 1 lists common pollutant types and their sources. Run-off carries these pollutants into waterways, and although concentrations may be diluted during a run-off event, the total loads can affect the environmental quality of downstream aquatic habitats. Effective management of water bodies requires a systems approach, integrating structural and non-structural measures incorporating water quality objectives, site characteristics, land use, construction erosion and sediment control, urban design, operation, monitoring, and maintenance. Stormwater cannot be adequately managed on a piecemeal basis. 3

18 Table 1.1 Common pollutants and likely sources found in urban stormwater Pollutant Sediment Nutrients Oxygen-demanding substances ph (acidity) Micro-organisms Toxic organics Metals Gross pollutants (litter and debris) Oils and surfactants Increased water temperature Urban source Land surface erosion, including erosion of waterways Pavement and vehicle wear Atmospheric deposition Spillage/illegal discharges Organic matter (e.g. leaf litter, grass) Car washing Weathering of buildings/structures Land surface erosion organic matter Fertiliser Sewer overflows/septic tank leaks Animal/bird faeces Detergents (car washing) Atmospheric deposition Spillage/illegal discharges Organic matter decay Atmospheric deposition Sewer overflows/septic tank leaks Animal/bird faeces Spillage/illegal discharges Atmospheric deposition Spillage/illegal discharges Organic matter decay Erosion of roofing material Disturbance of acid sulfate soils Animal/bird faeces Sewer overflows/septic tank leaks Organic matter decay Pesticides Herbicides Spillage/illegal discharges Sewer overflows/septic tank leaks Atmospheric deposition Vehicle wear Sewer overflows/septic tank leaks Weathering of buildings/structures Spillage/illegal discharges Construction activities, litter pedestrian and vehicular Waste collection systems Organic matter, including leaf-fall from trees Lawn clippings Spills and accidents Asphalt pavements Spillage/illegal discharges Leaks from vehicles Car washing Organic matter Run-off from impervious surfaces Removal of riparian vegetation 4

19 1.3 Who should use the guidelines? There are four main groups responsible for the environmental management of urban stormwater: local governments, the urban development industry, state agencies, and the wider community Local governments Local governments have a significant role in managing stormwater quality as it is responsible for land-use planning, and land and stormwater management. Councils operate many kilometres of constructed drains servicing urban areas across the state. Each local government currently has differing USQM requirements that rely on different (and often generic rather than locally adapted) guidelines sourced from interstate or even overseas. It is expected that this document and any associated legislative requirements will assist in the coordination and review of many of the existing documents used by local governments to create a more consistent and rigorous approach to stormwater quality management and planning suited to the local landscape. Suitable consideration of stormwater quality during the location and broad layout planning of urban areas has the potential to minimise many of the impacts of urbanisation on stormwater. Local government planners and developers can help protect stormwater quality by ensuring the land is capable of sustaining urban development, minimising the extent of impervious surfaces, and providing adequate space for stormwater retention and treatment. New drainage infrastructure should be designed to ensure the impact of urban stormwater on receiving environments is minimal. Local governments are responsible for the management of various parts of the urban environment that discharge directly into the stormwater system. These include roads, reserves, parks and car parks. Adopting an urban stormwater quality planning approach to all phases of development including design, operation and maintenance of infrastructure is an essential element for improved stormwater quality. The guidelines will assist local governments to: assess and plan operational activities which have potential to affect stormwater quality or quantity develop stormwater quality management plans for the local government area plan for new development and assess development applications plan, implement and maintain new drainage infrastructure identify opportunities for upgrading existing infrastructure to improve environmental performance Development industry Urban development affects stormwater quality in many ways, especially during the construction period and at completion when there is a significant increase in the area of impervious surfaces. The management of stormwater discharge is crucial during construction, as soil is often disturbed and left exposed to erosion. High sediment loads reaching receiving waters can be a consequence of poor site management. It is essential that building and construction activities minimise and avoid contaminated run-off being discharged into drains or waterways. The level of impact on stormwater following construction depends on the site s specific land use, specific nature and density of development and layout. By minimising impervious areas and using water sensitive urban design principles, the impact of development on stormwater quality can be minimised. 5

20 Managing urban run-off in a water sensitive manner not only helps resolve problems associated with stormwater, but can enhance the social and environmental amenity of the urban landscape. Urban developers have an important role to play in the adoption of a water sensitive approach to urban planning, design and construction. The guidelines will provide the development industry a basis for implementing their duty of care in the planning, design, construction and maintenance of new urban developments at the suburb or multi-lot scales, as well as any infill or stormwater management retrofit activities Department of Environment and Resource Management (DERM) DERM is responsible for the protection of the quality of Queensland s environment primarily through application of the statutory powers described in the Environmental Protection Act A key objective under this Act is to protect Queensland s waters while allowing for development that is ecologically sustainable. The Environmental Protection (Water) Policy 2009 (EPP Water) provides a framework to achieve this by: identifying EVs for Queensland waters (i.e. aquatic ecosystems, water for drinking, water supply, water for agriculture, industry and recreational use) deciding and stating water quality guidelines and WQOs to enhance or protect the environmental values. DERM aims to provide healthy stream environments that meet the community s needs for recreation, water supply, drainage and flood protection services. The role of DERM in urban stormwater quality policy includes: identifying environmental values and establishing water quality objectives to protect these values for urban waterways and bays through the EPP Water establishing programs for achieving environmental outcomes by encouraging and facilitating best practice including design objectives for urban stormwater quality management facilitating the achievement of water quality objectives using regulatory and non-regulatory (e.g. best practice) means and enforcement where necessary guiding the development of total water cycle management (TWCM) including assessing local planning instruments for consideration of TWCM providing overall direction and strategies for stormwater management including urban stormwater management plans development assessment under the Sustainable Planning Act DERM also provides policy on stormwater management in terms of flood risk. This is primarily through publishing and maintaining the Queensland Urban Drainage Manual (2007). This is a guideline for engineers and designers for planning and designing urban stormwater systems in Queensland (including hydrologic and hydraulic procedures). DERM also provides technical support for flood mitigation subsidy programs and assists with the administration of the State policy on mitigating the impacts of flood (and bushfires and landslides). The guidelines will assist the Department of Environment and Resource Management to provide advice on planning for stormwater quality for healthy waters Regional natural resource management bodies (NRM bodies) Regional NRM bodies have been established in 14 regions of Queensland. These ensure the sustainable development of natural resource-based industries, the protection of land and water resources, and the conservation of natural and cultural heritage. 6

21 NRM bodies provide coordination, investment and implementation services related to integrated waterway and floodplain management. These focus on the maintenance and improvement of river health and achievement of resource condition targets, while preserving the natural functions of the floodplain. These services include: waterway management water quality management management of floodplains management of rural drainage including management of regional drainage schemes (where relevant). The guidelines will assist regional NRM bodies (or their successor bodies) to develop and implement water quality management plans and promote environmental management of urban stormwater Other infrastructure providers Other service providers, such as government and non-government providers of transport, housing and public works, play a role in stormwater management and can use the guidelines as a basis for coordination of existing best practice guidelines in the planning and design of measures to protect the environment from the impact of run-off from infrastructure. 1.4 How to use the guidelines Chapter 2 describes principles and applicable design objectives for the environmental management of urban stormwater. These should provide the basis for the adaptive management and planning of stormwater management programs and the design of new drainage infrastructure. Chapter 3 presents a methodology for preparing stormwater management plans. This approach is intended principally for local government and should provide a basis for implementing best practice. Chapters 4, 5, 6 and 7 describe a range of tools available to meet the design objectives. These include both source controls (such as education programs to reduce pollution sources) and structural controls (such as wetlands or sediment dams to reduce nutrient and total sediment supply loads). Table 2 illustrates the topics covered in these guidelines Links and references The Urban Stormwater Quality Planning Guidelines 2010 support the following documents: Environmental Protection (Water) Policy 2009 Local government planning instruments South East Queensland Regional Plan (Desired Regional Outcomes 2 & 11) Far North Queensland Regional Plan Applicable Queensland Planning Provisions, under the Sustainable Planning Act The guidelines are supported by and referred to in the following documents: South East Queensland Regional Plan Implementation Guideline No. 7 (2009) Far North Queensland Regional Plan Deemed approval standard conditions under the Sustainable Planning Act

22 Temporary State Planning Policy Protecting Wetlands of High Ecological Significance in Great Barrier Reef Catchments a number of local government planning documents. The guidelines refer to a number of existing technical guidelines (see Chapters 3 to 7). 8

23 Table 1.2 Urban stormwater management topics covered in these guidelines Chapter 2 Principles and design objectives 3 Stormwater management planning regional and local 4 Planning controls 5 Water sensitive urban design 6 Source controls 7 Structural controls Urban stormwater topics Urban stormwater management principles Stormwater management objectives Regional and local urban stormwater quality management plans Land use planning strategic statements development plans planning permit applications Urban design development density and subdivision layout open space road system streetscape layout and design drainage design Land management municipal operations construction business operations education and awareness media advertising education community participation Stormwater treatment treatment train approach treatment measures selection criteria flow management channel design storage run-off control 9

24 2 Principles and design objectives Key resource documents Level Document State Environmental Protection (Water) Policy 2009 Queensland Water Quality Guidelines 2009 Urban Stormwater Queensland Best Practice Environmental Management Guidelines 2009 [draft] Technical Note: Derivation of Design Objectives (Jan 2009) (Technical Note: Derivation of Design Objectives) Regional SEQ Healthy Waterways 2006, Water Sensitive Urban Design Developing design objectives for WSUD in SEQ Policy for the Maintenance and Enhancement of Water Quality in Central Queensland (DLGP 2003) Regional plans including: South East Queensland Regional Plan Far North Queensland Regional Plan Local Local government urban stormwater quality management plans (USQMP) within the framework of total water cycle management as required under the Environmental Protection (Water) Policy 2009 Local government planning instruments 2.1 Introduction This chapter presents a regional approach to setting urban stormwater management design objectives based on established best practice stormwater management principles and practices. The regional design objectives provided in Tables 2.1 and 2.2 may be reviewed as further information becomes available (refer to section for further information). Definitions Design objectives are quantifiable and achievable performance outcomes for planning and development to ensure water sensitive urban design (WSUD) and erosion and sediment control is implemented in a regionally consistent way to help achieve water quality objectives and aquatic ecosystem protection in receiving waterways. Site (unless otherwise stated) may mean an individual building site or lot or urban development area such as a new neighbourhood or suburb (grouping of lots). 2.2 Queensland policy for urban stormwater management The role of the State in guiding better planning of urban stormwater management in Queensland was strengthened in The Environmental Protection (Water) Policy 2009 (EPP Water) was amended to place urban stormwater management in a total water cycle management context, and the Draft State Planning Policy for Healthy Waters was released. The final State Planning Policy 4/10 Healthy Waters (SPP Healthy Waters) was approved in October 2010 to commence in early The SPP Healthy Waters provides ways to plan to protect environmental values through better land-use planning and design objectives for development for urban purposes. The SPP Healthy Waters applies to decision-making for community infrastructure and assessable development under the provisions of the Sustainable Planning Act 2009 (SPA) from the date the SPP Healthy Waters becomes effective. 10

25 Figure 2.1 shows the policy framework for urban stormwater management in Queensland together with supporting guidelines and plans. Environmental Protection Act 1994 EPP Water 2009 Sustainable Planning Act 2009 Qld Planning Provisions State Planning Policy for Healthy Waters and its Guideline Urban Stormwater Quality Planning Guidelines 2010 Urban stormwater quality management to help protect EVs Point source water quality management (non-eras) Planning stormwater quality management to help protect EVs Council USQM plan Council planning scheme Landuse zones Stormwater policies Code provisions Development assessment triggers Council corporate plans Capital works Operations Business plans Development assessment Site-based stormwater quality management plans USQM approval conditions for construction and operation Figure 2.1 Queensland policy framework for urban stormwater management policy framework for urban stormwater management The primary water quality management legislation in Queensland is the Environmental Protection Act 1994 (EP Act). The EP Act provides a clear statutory framework for setting and achieving community endorsed environmental values (EVs) and water quality objectives (WQOs). Under the EP Act the EPP Water establishes the EVs of Queensland waterways and WQOs to protect those EVs. The EPP Water contains Schedule 1 with catchment-specific EVs and WQOs currently including: Moreton Bay/South East Queensland waters Mary River Basin/Great Sandy region waters Daintree Basin, Mossman Basins and Trinity Inlet (Cairns). Further catchment EVs and WQOs are under development. The EPP Water and Queensland Water Quality Guidelines 2009 also provide for EVs and WQOs for other freshwater, estuarine and marine waters where no catchment-specific values have been established in Schedule 1. 11

26 Figure 2.2 shows the regions with EVs and WQOs currently in Schedule 1 and the regionalisation of the Queensland Water Quality Guidelines. Figure 2.2 Water quality planning Queensland water guidelines and scheduled EVs and WQOs 12

27 The EPP Water identifies EVs for Queensland s waterways not contained in Schedule 1. These are: a. for high ecological value waters the biological integrity of an aquatic ecosystem that is effectively unmodified or highly valued b. for slightly disturbed waters the biological integrity of an aquatic ecosystem that has effectively unmodified biological indicators, but slightly modified physical, chemical or other indicators c. for moderately disturbed waters the biological integrity of an aquatic ecosystem that is adversely affected by human activity to a relatively small but measurable degree d. for highly disturbed waters the biological integrity of an aquatic ecosystem that is measurably degraded and of lower ecological value than waters mentioned in paragraphs (a) to (c) e. the suitability of the water for producing the foods for human consumption f. the suitability of the water for aquacultural use g. the suitability of the water for agricultural purposes h. for waters that may be used for recreation or aesthetic purposes, the suitability of the water for: (i.) (ii.) (iii.) primary recreational use secondary recreational use visual recreational use i. the suitability of the water for supply as drinking water j. the suitability of the water for industrial use k. the cultural and spiritual values of the water. The EP Act and EPP Water contain general and specific provisions to manage the impacts of run-off from urban and rural areas on the EVs of receiving waters. Urban stormwater has a major influence on the water quality and hydrology of urban waterways. Effective planning of urban stormwater provides a means for minimising the environmental impact from urban stormwater systems. Other sources, such as industrial and sewage point sources, sewer overflows, septic tank losses, and rural and peri-urban run-off can also have significant effects on waterway health. These other sources are beyond the scope of this guide. The application of the design objectives set out in Chapter 2 of this guide will contribute to the protection and achievement of EVs and WQOs in Queensland. 13

28 Environmental Protection (Water) Policy 2009 The purpose of the EPP Water 2009 includes identifying values and management goals for Queensland waters. Schedule 1 details the waters with environmental values across Queensland and their specific water quality objectives. Section 14 states the management intent for waters subject to an activity that involves the release of waste water or contaminants to the waters. The decision to release waste water or contaminant to waters with the below environmental values must ensure the following: for high ecological value waters (HEV) the measures for the indicators for all environmental values (EVs) are maintained for slightly disturbed waters the measures for the slightly modified physical or chemical indicators are progressively improved to achieve the water quality objectives (WQOs) for HEVwaters for moderately disturbed waters (1) if the measures for indicators of the EVs achieve WQOs for the water the measures for the indicators are maintained at levels that achieve the WQOs for the water; or (2) if the measures for indicators of the EVs do not achieve the WQOs for the water the measures for indicators of the EVs are improved to achieve the WQOs. for highly disturbed waters the measures for the indicators of all EVs are progressively improved to achieve the WQOs. 2.3 Urban stormwater management principles Protecting the environmental values and uses of urban waterways requires an integrated or waterway health-based adaptive approach directed at managing the volume and rate of catchment run-off, the quality of the run-off, and protecting the riparian vegetation and the habitats necessary for supporting aquatic ecosystem health. In contrast there is evidence that solely managing stormwater quality using a best practice approach is insufficient to adequately mitigate all the impacts of urbanisation (e.g. Sunshine Coast Regional Council 2008; Maxted and Shaver 1996). Flood management and public safety remain as fundamental objectives of stormwater system planning and design. Stormwater management measures for waterway health enhancement should in no way compromise these objectives. Stormwater management should be based on the following hierarchy of control mechanisms (summarised in Figure 2.3): 1. preservation preserving existing valuable elements of the natural stormwater system, such as natural channels, wetlands and riparian vegetation. Helping to protect EVs through avoiding impacts on urban stormwater quality flow with early and comprehensive forward planning is the first priority (see Chapters 3, 4 and 5). 2. source control limiting changes to the quantity and quality of stormwater at or near the source of potential contaminants or changes to flow such as by using WSUD principles and erosion controls. Managing any remaining impacts after step 1 above, keeping water pollutants on the development site and managing flows adequately, through proper source controls is the next priority (see Chapter 6). 3. structural control using structural measures, such as treatment techniques or retention basins, to improve water quality and control run-off. Applying structural treatment measures (see Chapter 7) on or off site before the run-off enters a waterway is required to capture mobilised pollutants, and mitigate geomorphic stream damage. 14

29 4. receiving waters management as a last line of control, the receiving water should be managed to maintain its EVs in consideration of any residual impacts from stormwater pollutants or flows. Avoid No impacts planning to protect EVs Minimise Source control Minimise In-transit structural control Last resort manage residual impacts Receiving waters management Healthy Waters help protect EVs from urban stormwater impacts Figure 2.3 Hierachy of stormwater management control Preservation and source controls may be used effectively to avoid a number of stormwater impacts. These measures can include land-use planning based on land capability and catchment modelling, education, regulation and operational practices such as erosion controls to limit changes to natural flows and the quality or quantity of urban run-off before it enters the stormwater system. Structural controls involve, as the phrase implies, installing structures to reduce or delay stormwater flow, or to intercept and remove pollutants from urban stormwater run-off. Constructing the structural treatment measures involves the selection and sequential ordering of treatments to achieve optimal pollutant removal and hydrologic management. Different treatments use different processes to remove pollutants, (e.g. depending on the speciation of the pollutant) and manage hydrology. No one treatment can remove all stormwater pollutants. To achieve removal of a range of pollutants, a number of treatments will be required and the selection and order in which they are constructed is a critical consideration. This is the treatment train approach. Pollutant types and size ranges that can be addressed with structural controls are matched with the removal processes that structural treatments employ. Selection of treatment measures should be based on matching the pollutant type with the removal process. Structural controls to manage urban hydrology for healthy waters aim to disconnect impervious surfaces from hydraulically efficient drainage systems. This can be achieved by passing stormwater run-off from impervious surfaces through structural treatments that significantly slow the rate of stormwater run-off and maximise infiltration where possible, reducing the overall volume of stormwater run-off flowing to the receiving waterway. Treatments that target retention of soluble pollutants and pollutants attached to fine colloidal particulates require significant contact time between stormwater run-off and soil and vegetation elements. These types of treatments (such as constructed stormwater wetlands and bioretention systems) will significantly slow the rate of stormwater run-off and can provide a quality of water suitable for a range of re-use options, thus also reducing the volume of stormwater run-off discharged to receiving waterways. Receiving waters management is a last resort. Where pollutant levels or stormwater flow frequencies, volumes and peak flows remain too high (for either new or existing urban development), it may be necessary to manage the receiving environment itself by: 15

30 using bed and bank stabilisation techniques using stormwater quality treatments elsewhere in the catchment to offset local impacts from stormwater implementing a clean-up program for accumulation of major contaminants restricting certain uses of waterways (such as recreation or water supply purposes) in accordance with scheduled EVs. 2.4 Stormwater management design objectives Determining stormwater quality design objectives The EPP (Water) 2009 establishes the EVs in receiving waters. The associated WQOs form the basis for defining the required water quality of urban stormwater entering and mixing in local waterways. There are three ways to estimate the level of stormwater quality improvement necessary for a site to ensure WQOs are taken into account to help protect the EVs for waterways (refer Figure 2.4). For the site scale these are: Monitoring Actual stormwater quality can be compared with receiving water quality to establish the level of treatment necessary to protect EVs, where sufficient monitoring data are available from the same development type in similar landscape conditions. Modelling Stormwater quality and its potential impact on receiving waters can be mathematically modelled to determine treatment requirements (design objectives). Some monitoring data are usually required to validate such models. Best management practices Best available data on the performance efficacy of current best practice treatment technologies can be used to establish minimum standards of performance (typically expressed as minimum average annual pollutant load reductions, or minimum average percentage reductions in pollutant loads see Tables 2.1 and 2.2). In rapidly urbanising catchments, the wet-weather impacts of the construction phase of the land development phase need to be considered as well as the post-development or permanent settlement phase, as the issues and impact assessment methodology are different. Critical impact factors include soil erosion hazard of the landscapes being developed, and increased rainfall run-off coefficients which occur when land is cleared and topsoil removed. 16

31 Is monitoring data available to determine stormwater quality? No Are information & models available to determine stormwater quality during and after construction? No Yes Yes Direct determination of stormwater outcomes Modelled or calculated predictions of stormwater outcomes Stormwater quality outcomes (Tables 2.1 & 2.2 design objectives) Stormwater design objectives Integrated stormwater management for a site Planning Construction Operation Figure 2.4: Approaches for determining stormwater design objectives and their context in integrated stormwater management for a site The preferred method for determining the required level of treatment is by use of monitoring data from a similar development. However, the inherent variability in water quality experienced in waterways and stormwater systems means that an extensive monitoring program is usually required to obtain sufficient data for such assessments. Modelling provides an ability to predict likely changes in water quality associated with proposed urban developments. Such water quality models can be used to establish performance outcomes for stormwater systems. These are limited by the availability of local water quality data and the understanding of the biological and physical processes that influence water quality and the receiving water environment. There are often significant limits on the confidence with which predictions can be made using water quality models at the site scale. Despite the uncertainty of modelling, adopting predictive modelling techniques to quantify estimates of stormwater pollutant concentrations and loads from urban land surfaces and the pollutant removal efficacy of current best practice stormwater treatment infrastructure is an accepted method for establishing best practice stormwater management treatment train design for regions where limited or no monitoring data exists. Further information is available in Technical Note: Derivation of design objectives January 2009 prepared for the Department of Environment and Resource Management. 17

32 Stormwater quality and flow management design objectives for the construction phase of development are provided in Table 2.1 and focus on suspended solids and gross pollutants. The construction phase design objectives were derived from a review of the current design objectives found in local government jurisdictions and review of contemporary literature on erosion and sediment control. The construction phase design objectives for suspended solids will typically differ from the operational phase design objectives because of the risk of exposing large areas of bare soil, timing of the exposure in the context of rainfall, and the relative range of activities on the site. Stormwater quality management design objectives for the operational phase are provided in Table 2.2 with a focus on suspended sediments and nutrients. Stormwater flow management design objectives for the operational phase are provided in Table 2.4 (see also section 2.4.2). The stormwater quality management design objectives for the operational phase were derived from predictive modelling using local climatic data and best available information on: hydrologic characteristics of soils pollutant concentrations generated from different land surfaces pollutant removal efficacy of contemporary stormwater treatment infrastructure designed to current best practice standards, configured in a treatment train and sized to operate at each treatment technology s point of diminishing return1 minimum and interim criteria to reduce the impacts of urbanisation on waterway health. Catchment-specific modelling and local area field studies are always preferred methods to support planning and development design decisions. Where this information is available it should be used to develop site-specific design objectives. The operational phase design objectives in Table 2.2 are: applicable to typical urban developments generally achievable by at least two best practice treatment train solutions effective in helping to protect EVs for the waterway. Table 2.3 and Figure 2.5 shows the local goverment areas and climatic regions for application of the operational phase design objectives in Table 2.2. The delineation of the climatic regions was based on data obtained from the Bureau of Meteorology. Rainfall seasonality, frequency and intensity can influence the portion of annual stormwater run-off able to be treated by stormwater treatment systems. The rainfall statistics used to delineate the climatic regions were therefore: seasonality (mm/month) pattern (rain days/month) mean annual rainfall (mm). Spatial mapping of these rainfall statistics was obtained from the Bureau of Meteorology. Each climatic region contains areas that have a reasonably consistent rainfall characteristic, based on the above statistics. If located on a climatic region boundary as shown in Figure 2.5, or if in doubt about which set of operational phase design objectives in Table 2.2 to apply, the more stringent design objectives should always be adopted (see supporting information in Table 2.3). 1 i.e. any further increase in the size of the treatment technology achieves only a marginal incremental increase in treatment performance 18

33 Table 2.1 is for the construction phase of development for medium and large scale construction sites (defined as disturbance greater than 2500 m2). For small scale construction sites (defined as disturbance area less than 2500 m2) and independent of a larger common development, the implementation of urban stormwater quality management should be in accordance with any guidance provided in local government planning scheme requirements (including any deemed to comply provisions) and Appendix 1 Model provisions for best practice erosion and sediment control, or the Queensland Development Code, Construction phase stormwater design objectives are minimum design objectives. An appropriate mix of measures should aim to achieve all of the design objectives. Measures to meet the design objectives need to reflect site conditions in ways that help protect environmental values for the local waterway. This means that some local councils may impose stronger design objectives, e.g. where there is a potential higher risk to environmental values for the waterway. 19

34 Table 2.1 Summary of design objectives for management of stormwater quality construction phase of development Construction phase stormwater design objectives Notes Drainage control Design life and design storm of temporary drainage works: 1. Disturbed area open for <12 months 1 in 2 ARI 2. Disturbed area open for months 1 in 5 ARI 3. Disturbed area open for > 24 months 1 in 10 ARI Erosion control 1. Minimise exposure of disturbed soils at any time 2. Avoid or minimise large construction activities in the wet season 3. Divert water run-off from undisturbed areas around disturbed areas 4. Use erosion risk ratings to determine appropriate erosion control measures ARI = Average Return Interval (see Engineers Australia document Australian Rainfall and Runoff). Design capacity excludes minimum 150 mm freeboard. A higher drainage design objective may be required for temporary drainage structures upslope of occupied properties. A revised drainage design storm may be required if these design objectives are found to be impracticable (e.g. in North Queensland). Wet season means the high rainfall months, e.g. the four highest rainfall months. For point 4, determine the erosion risk rating using local rainfall erosivity, rainfall depth, or soil loss rate or other acceptable method. A rating scale such as very low, low, moderate, high, extreme should be applied. Such ratings should reflect the local area. Example ratings may be shown in local council guidelines or detailed in best practice guidelines. Sediment control Use soil loss rates to determine appropriate sediment control measures Design storm for sediment control basins should be based on retaining the maximum sediment quantity for the maximum volume of water run-off Site discharge during sediment basin dewatering should not exceed 50 mg/l TSS and ph between For point 1, surrogate determinations may be used such as monthly erosivity or average monthly rainfall. For point 2, a commonly used design storm for basin sizing is 80th% five-day event. Depending on the settling characteristics of local soils, a higher operational design storm can be achieved with chemical dosing operated in flow-through mode in a large storm with rainfall-activated auto-flocculent dosing, and advanced hydraulic efficiency features such as floating offtakes, and a sediment forebay. For example, on the Sunshine Coast operation of the basin can achieve the water quality outcomes in any rainfall event up to 125 mm rainfall depth in any five-day period 2. For point 3, TSS = total suspended solids. Turbidity measurements (e.g. 60 Nephelometric Turbidity Units (NTU)) could be used; however, for accuracy, a sitespecific relationship should be developed between turbidity and total suspended solids. 2 WBM Pty Ltd 2009, Sediment Basin Design Assessment Report to Sunshine Coast Regional Council (SCRC) < 20

35 Water quality outcomes Stormwater drainage/flow management Stormwater flows from undisturbed and disturbed areas manage to help protect environmental values Coarse sediment coarse sediment is retained on site Fine sediment Site discharge during sediment basin dewatering has a TSS concentration less than 50 mg/l Turbidity Site discharge during sediment basin dewatering has a turbidity (NTU) less than 10% above receiving waters turbidity measured immediately upstream of the site Nutrients (N & P) Nitrogen and phosphorus are managed through sediment control. ph Site discharge during sediment basin dewatering has a ph range Litter and other waste Prevent litter/waste entering the site, the stormwater system or watercourses that discharge from the site. Also minimise or sufficiently contain on-site litter and waste production and regularly clear waste bins Hydrocarbons and other contaminants Hydrocarbons and other contaminants are prevented from entering the stormwater system or internal watercourses that discharge from the site Wash down water Wash down water is prevented from entering the stormwater system or internal watercourses that discharge from the site Cations and anions Cations and anions including aluminium, iron and sulfate are managed as required under an approved acid sulfate soil management plan Hydraulics and hydrology Take all reasonable and practicable measures to minimise significant changes to the natural waterway hydraulics and hydrology from: peak flow for the one-year and 100-year ARI event (respectively for aquatic ecosystems and flood protection) run-off frequency and volumes entering receiving waters uncontrolled release of contaminated stormwater As far as is reasonable and practicable, all run-off from disturbed areas is collected and drained to a sediment basin up to the design storm event. Achieve site discharge water quality through, for example, appropriate sediment basin design and operation with flocculation as required. A site-specific relationship should be developed between turbidity and suspended solids, prior to the commencement of construction on large and medium scale construction sites. May be further limited to prevent mobilisation of specific elements. Avoid wind blown litter; remove gross pollutants. See the prescribed water contaminants in schedule 9 of the Environmental Protection Regulation Waste containing contaminants must be disposed of at authorised facilities. Store oil and fuel in accordance with Australian Standard AS1940 no visible oil or grease sheen on released waters. Including making best use of constructed sediment basins to attenuate the discharge rate of stormwater from the site. 21

36 Table 2.2 Summary of design objectives for management of stormwater quality operational (post-construction) phase of development Region (see Figure 2.5) Minimum reductions in mean annual loads from unmitigated development (%) Notes It is expected that application of an appropriately designed and sequenced treatment train will result in operational performance that exceeds the design objectives presented here. Total suspended solids (TSS) Total phosphorus (TP) Total nitrogen (TN) Gross pollutants > 5 mm If a site is adjacent to a regional boundary in Figure 2.5 or if in doubt about which regional design objectives apply, the most stringent regional design objectives should be adopted. Eastern Cape York Central and Western Cape York (north) Central and Western Cape York (south) Wet Tropics Dry Tropics Central Coast (north) Central Coast (south) South East Queensland * 90 * Mackay Regional Council advises that the minimum reduction for TN for the Central Coast (north) to be adopted is 40%, as detailed modelling shows that this is achievable using bioretention systems or wetlands in this local government area Western districts

37 Table 2.3 Application of the operational phase design objectives in Table 2.2 local government area by climatic region. Local government area Regions for stormwater quality design objectives Central and Western Cape York (North) Central and Western Cape York (South) Central Coast (North) Central Coast (South) Dry Tropics (Townsville) East Cape York South East Queensland Western Districts Wet Tropics Aurukun Shire # Balonne Shire # Banana Shire # # Barcaldine Shire # Barcoo Shire # Blackall Tambo Regional # Boulia Shire # Brisbane City # Bulloo Shire # Bundaberg Regional # Burdekin Shire # # Burke Shire # Cairns Regional # Carpentaria Shire # # 23

38 Local government area Regions for stormwater quality design objectives Central and Western Cape York (North) Central and Western Cape York (South) Central Coast (North) Central Coast (South) Dry Tropics (Townsville) East Cape York South East Queensland Western Districts Wet Tropics Cassowary Coast Regional Central Highlands Regional Charters Towers Regional # # # # # # # Cherbourg Shire # Cloncurry Shire # Cook Shire # # # # Croydon Shire # Diamantina Shire Doomadgee Shire # # Etheridge Shire # # Flinders Shire # Fraser Coast Regional Gladstone Regional # # 24

39 Local government area Regions for stormwater quality design objectives Central and Western Cape York (North) Central and Western Cape York (South) Central Coast (North) Central Coast (South) Dry Tropics (Townsville) East Cape York South East Queensland Western Districts Wet Tropics Gold Coast City # Goondiwindi Regional # Gympie Regional Hinchinbrook Shire # # # # Hope Vale Shire # Ipswich City # Isaac Regional # # # Kowanyama Shire # # Lockhart River Shire # Lockyer Valley Regional # Logan City # Longreach Regional # Mackay Regional # 25

40 Local government area Regions for stormwater quality design objectives Central and Western Cape York (North) Central and Western Cape York (South) Central Coast (North) Central Coast (South) Dry Tropics (Townsville) East Cape York South East Queensland Western Districts Wet Tropics Mapoon Shire # Maranoa Regional # McKinlay Shire # Moreton Bay Regional # Mount Isa City # Murweh Shire # Napranum Shire # North Burnett Regional # # Northern Peninsula Area Regional # Paroo Shire # Pormpuraaw Shire # Quilpie Shire # Redland City # Richmond Shire # 26

41 Local government area Regions for stormwater quality design objectives Central and Western Cape York (North) Central and Western Cape York (South) Central Coast (North) Central Coast (South) Dry Tropics (Townsville) East Cape York South East Queensland Western Districts Wet Tropics Rockhampton Regional Scenic Rim Regional Somerset Regional South Burnett Regional Southern Downs Regional Sunshine Coast Regional Tablelands Regional Toowoomba Regional # # # # # # # # # # # # # # Torres Shire # # Townsville Regional Western Downs Regional # # # # # # Whitsunday # # 27

42 Local government area Regions for stormwater quality design objectives Central and Western Cape York (North) Central and Western Cape York (South) Central Coast (North) Central Coast (South) Dry Tropics (Townsville) East Cape York South East Queensland Western Districts Wet Tropics Regional Winton Shire # Woorabinda Shire # # means applicable region. If a local government area is located on a climatic region boundary as shown in Figure 2.5, more than one region may apply. 28

43 Figure 2.5: Delineation of regions for application of operational phase design objectives in Table 2.2 Note that the design objectives for a site may be appropriately based on using local rainfall data (rain gauge records). Modified from Urban Stormwater Queensland Best Practice Environmental Management Guidelines 2009 [draft] Technical Note: Derivation of Design Objectives. 29

44 2.4.2 Determining stormwater quantity design objectives Stormwater quantity management for waterway health enhancement focuses on the management of frequent urban stormwater flows that cause disturbance to aquatic habitats and aquatic ecosystem health, and on waterway geomorphic stability. This is distinct from urban stormwater quantity management for flood management purposes which is concerned with the management of less frequent, more extreme stormwater flows that cause nuisance flooding and potential flood damage. The latter is an important part of integrated stormwater management and should not be compromised in pursuit of the management of frequent flows for waterway health protection. Stormwater management infrastructure can be designed to meet multiple objectives, such as flooding and waterway quality and stability, and thus reduce costs. Construction phase quantity design objective Some Queensland soils have infiltration rates of less than one millimetre per hour and many less than 10 mm/hour. An increase in site surface run-off coefficients begins on most sites when an urban development site is first cleared of vegetation and topsoils removed to expose subsoils. Hence, there is a potential for stream damage through increased flow volume, reduced baseflow, altered stream substrates, and increased frequency of run-off events to waterways during this period, especially if the period of construction is prolonged (in excess of one year from land clearing to end of construction activities). The risk will generally depend on: the relevant EVs of the receiving waters and their sensitivity to impacts climatic region sites in the Western districts (see Figure 2.5 or Table 2.2) will usually not require specific quantity control measures the period that the site has exposed soils, i.e. a high rainfall run-off coefficient compared to the natural condition the area exposed at any one time. Operational (post-construction) phase Two stormwater quantity management design objectives are described in Table 2.4 the frequent flow management design objective and the waterway stability management design objective. Frequent flow management design objective This objective aims to protect in-stream ecosystems from the significant effects of increased run-off frequency, by capturing the initial portion of run-off from impervious areas. This approach ensures that the frequency, duration and severity of hydraulic disturbance to in-stream ecosystems in developed catchments is similar to predevelopment conditions for small flow events. Compliance with this objective may be demonstrated by providing a total stormwater capture volume (m3) calculated as follows: Capture volume (m 3 ) = Impervious area (m²) x target design run-off capture depth (m) The spatial distribution of the required capture volume may be adapted to suit individual site conditions, provided that the required volume from all impervious areas is captured before leaving the site. Implementing the required capture volume will reduce contaminants, providing a synergistic benefit for water quality. Hence there may be opportunity to incorporate frequent flow and stormwater quality treatment measures. Since the objective requires that this capture volume be available each day, the management system (whether infiltration, evaporation, reuse or discharge via bioretention) must be capable of draining the captured stormwater within 24 hours or have extra storage capacity. Waterway stability management design objective This objective aims to prevent accelerated in-stream erosion downstream of urban areas by controlling the magnitude and duration of erosion-generation and sediment-transporting flows. 30

45 Compliance with this design objective can be demonstrated using a run-off routing model. The aim is to ensure the one-year average recurrence interval event is maintained at predevelopment levels. At the discretion of the local authority, the adoption of simplified methods for demonstrating compliance for small developments is acceptable. The document Water sensitive urban design Developing design objectives for water sensitive urban development in South East Queensland (SEQ Healthy Waterways 2006) provides detailed technical discussions on the frequent flow design objective and the waterway stability management design objective, including an outline of possible methods for demonstrating compliance with these two design objectives. 31

46 Table 2.4: Design objectives for management of stormwater quantity operational (post-construction) phase of development Assessment criteria Frequent flow management Waterway stability management Intent Design objective To minimise the frequency of disturbance to aquatic ecosystems from urban development by managing the volume and frequency of surface run-off during small rainfall events. Capture and manage the following design run-off capture depth from all impervious surfaces of the proposed development: a. for total fraction impervious up to 40% capture at least the first 10 mm of run-off from impervious surfaces b. for total fraction impervious >40% capture at least the first 15 mm of run-off from impervious surfaces c. run-off capture capacity replenished within 24 hours of the run-off event; or in accordance with locally developed design objectives which are demonstrated to protect the key hydrologic characteristics of the downstream aquatic ecosystem.. To control the impacts of urban development on channel bed and bank erosion by limiting changes in flow rate and flow duration within the receiving waterway. Limit the post-development peak one-year average recurrence interval (ARI) event discharge within the receiving waterway to the pre-development peak one-year ARI event discharge ( pre-development is defined in Appendix B of Technical Note: Derivation of Design Objectives January 2009). Recommended application Applicable where run-off from or within the site passes through or drains only to unlined channels, or non-tidal waterways or wetlands. Also applicable to subdivisional scale development. It is not necessarily applicable to catchment scale planning where the cumulative drainage impacts of multiple developments and other hydrological impacts may need to be considered. The implications of such specific catchment-scale planning may affect these objectives and the local authority may substitute alternative design objectives. Where a receiving waterway is degraded* the local or regional authority may choose not to require compliance with this objective, on the basis that the receiving waterway and its associated catchment/s have been identified by the authority as having limited potential for future rehabilitation and/or WSUD retrofitting. Management of captured stormwater should include one or more of the following: stormwater evaporation stormwater reuse diversion of flows from receiving environments infiltration to native soils or otherwise filtered through an appropriately designed soil and plant stormwater treatment system, such as bioretention. Applicable where run-off from or within the site passes through or drains only to unlined channels, or non-tidal waterways or wetlands. Where a receiving waterway is significantly degraded*, the local government may choose not to require compliance with this objective, on the basis that the receiving waterway and its associated catchment/s have been identified by the authority as having limited potential for future rehabilitation and/or WSUD retrofitting. Local government may substitute alternative criteria where catchment-scale studies have been undertaken to develop a catchment-specific approach to the management of in-stream erosion impacts. * For the purpose of these guidelines, a waterway is defined as degraded where: the proportion of impervious area within the catchment, prior to the proposed development, is greater than 30 per cent; or the waterway is designated as 'highly disturbed' in Schedule 1 of the Environmental Protection (Water) Policy

47 2.4.3 Application of design objectives It is intended that these design objectives will form part of the statutory requirements for planning and development assessment. The design objectives in Tables 2.1, 2.2 and 2.4 should be considered the minimum necessary for planning new development projects and areas. For the assessment of individual development applications, adoption of the design objectives is regarded as an appropriate method of considering EVs. If future monitoring shows that scheduled EVs for waterways are not being maintained or achieved due to urban development, then further management measures may be required. This approach is consistent with adaptive management and best management practices. For larger-scale strategic land use or catchment planning, protecting EVs would require application of the design objectives to areas of urban development, as well as assessing the combined effects of all catchment activities and land uses on receiving waters. Cumulative impacts Application of the operational phase design objectives to urban development that replaces different land uses will improve the water quality and flow outcomes for a waterway in most cases. Modelling shows that replacing an existing land use such as industrial, agricultural or rural residential with typical water sensitive designs for residential, industrial and commercial development will provide a net decrease in total suspended solid loads and often similar decreases in total phosphorus and nitrogen loads. In any case typical non water sensitive design would result in higher loads. Achieving the design objectives The design objectives can be achieved by employing a variety of structural and non-structural treatment measures. The design objectives have been chosen for their effectiveness in helping to protect EVs, protecting and enhancing waterway health and for their practicality for application to typical developments in the various climatic regions across Queensland. For advice on how to demonstrate compliance with the design objectives, see Technical Note: Derivation of Design Objectives January Local councils may impose more stringent design objectives where deemed necessary. Development of locally relevant design objectives is encouraged. Regionally relevant compliance solutions and design objectives may be developed in regions such as the high rainfall areas of North Queensland. In these areas variations to the nominated design objectives in Tables 2.1, 2.2 and 2.4 may be considered such as dry season application only, restoring capture volume within 72 hours and the capture of the initial 10 mm of run-off. Similarly regions with frequent long dry spells have issues such as maintaining vegetative treatment measures, and high sediment loads in waterways. Alternative design options may be considered including bioretention systems that include a saturation zone at its base, maintaining vegetation through irrigation using greywater, wetlands that comprise a mix of ephemeral zones and deep pools (examples exist in the dry tropics), stormwater storages for later use, and applying offsets where design options are shown to be limited. It is expected that in the future, new science and planning approaches will require the design objectives to be updated. This guideline will be regularly reviewed through a community consultative process Further information South East Queensland Department of Infrastructure and Planning 2009, Implementation Guideline No. 7 Water Sensitive Urban Design Design objectives for urban stormwater management. 33

48 SEQ Healthy Waterways 2006, Water Sensitive Urban Design Developing design objectives for water sensitive urban development in South East Queensland. SEQ Healthy Waterways Partnership 2006, Water Sensitive Urban Design Technical Design Guidelines for South East Queensland (formerly Moreton Bay Waterways and Catchments Partnership). Brisbane City Council 2005, Water Sensitive Urban Design Engineering Guidelines. Gold Coast City Council 2007, Water Sensitive Urban Design Guidelines. Sunshine Coast Regional Council (Maroochy Shire Council 2006) Water Sensitive Urban Design Guidelines; and 2008 Manual for Erosion and Sediment Control. Other Queensland areas Reef Water Quality Improvement Plan (WQIP) actions including: Townsville/Thuringowa WQIP (Ross/Black Catchment) project for development of WSUD Guidelines for the Dry Tropics Mackay Whitsunday NRM Group, Mackay Whitsunday Water Quality Improvement Plan and Urban Stormwater Quality Management Plan Department of Local Government and Planning 2003, Policy for the Maintenance & Enhancement of Water Quality in Central Queensland, DLGP. Mackay Regional Council (Mackay City Council 2006), Stormwater Quality Management Plan for Mackay. Statewide resource documents Department of Environment and Resource Management (DERM) 2009, Technical Note: Derivation of Design Objectives, EDAW Australia January 2009, for Urban stormwater Queensland best practice environmental management guidelines 2009 [draft], DERM Department of Environment and Resource Management 2009, Queensland Water Quality Guidelines, DERM. Department of Natural Resources and Water 2007, Queensland Urban Drainage Manual. Queensland Water Commission 2009, Stormwater Infrastructure Options to Achieve Multiple Water Cycle Outcomes. International Erosion Control Association (Australasia) 2008, Best Practice Erosion and Sediment Control. Engineers Australia 2006, Australian Run-off Quality A guide to Water Sensitive Urban Design. CRC for Catchment Hydrology 2002, MUSIC User Manual. Sunshine Coast Regional Council 2008, Sunshine Coast Regional Council Sediment Basin Design Assessment BMT WBM P/L Hunter, G, Predicting the waterway impacts of urbanisation: modelling considerations pre, during and post urban development, proceedings of Urbanisation and Waterway Health: A forum for Policymakers and Managers, Kawana, Brodie, I and Rosewell, J, Using soil loss models to estimate suspended solids concentrations in stormwater run-off from pre-urban areas, Australian Journal of Water Resources, Vol. 12, No.1, Institution of Engineers Australia, Maxted, J and Shaver, E, Stormwater impacts on aquatic life and the use of retention ponds for mitigation, proceedings of 4th Annual Soil and Water Management for Urban Development Conference, Sydney,

49 3 Stormwater management planning Key resource documents Level Document State Environmental Protection (Water) Policy 2009 Queensland Water Quality Guidelines 2009 Queensland Urban Drainage Manual 2007 Regional Regional plans including: SEQ Regional Plan Far North Queensland Regional Plan Water quality improvement plans Local Local government urban stormwater quality management plans (USQMP) as part of the total water cycle management plan under the Environmental Protection (Water) Policy Introduction In most Queensland communities, urban drainage systems have been designed and built to move stormwater away from developed areas to minimise the threat of flooding. Stormwater makes up most of the discharge entering natural waterways, including both overland flow and piped water from the stormwater system. Licensed discharges from approved environmentally relevant activities (ERAs) under the Environmental Protection Act 1994 (EP Act) are not addressed in these guidelines. Stormwater drains traditionally lead to local creeks and waterways where the stormwater is dispersed without treatment. Unmanaged stormwater systems can result in pollutants such as oil, sediment, nutrients and rubbish entering waterways. Physical changes can also occur, such as waterway channel erosion, due to the reduced stormwater infiltration which typically occurs with urbanisation, and consequent increased velocity and extended duration of flow entering the natural water system. If stormwater is left unmanaged, pollution and physical changes caused by stormwater can cause considerable damage to the environment and, in particular, to waterways. To achieve best practice in the environmental management of stormwater, it is important that catchment management and local government activities are guided by an urban stormwater quality management plan (USQMP). The Environmental Protection (Water) Policy 2009 provides for the development of environmental plans for a local area dealing with total water cycle management including plans about urban stormwater quality management. The USQMP under the EPP (Water) needs to include provisions to improve the quality and flow of urban stormwater in ways that protect the environmental values of waters affected by urban stormwater. These provisions must include consideration of: stormwater quality management needs in accordance with the relevant priority infrastructure plan (PIP) for a local area under the Sustainable Planning Act 2009 (SPA) opportunities for stormwater harvesting, recycling or reuse water sensitive urban design in developed areas within a stated period managing urban stormwater quality and flows for development in the local government area, having regard to any site-specific documents, the Queensland Water Quality Guidelines 2009, and this guideline or other acceptable guidelines monitoring and reporting processes for stormwater quality management. Guidelines on the above matters will be developed in 2010 in consultation with local councils and other stakeholders. This chapter outlines advice on content and process for developing 35

50 suitable USQMPs for a local area. This chapter will be revised once the above detailed guidelines addressing the EPP (Water) provisions are available. 3.2 Urban stormwater quality management plans (USQMPs) This chapter provides advice for the development of regional or local USQMPs. While it is intended mainly for application at local government levels, the process of establishing priorities and actions could also be applied to whole catchments. Improved environmental performance is needed to ensure that the environmental values and beneficial uses of Queensland s waterways are sustained and, if possible, enhanced. The effective management of urban stormwater is a shared responsibility, requiring the effective participation of many state agencies and organisations, local governments, and industry. USQMPs are a way of helping local governments and other catchment managers to recognise and take account of the impacts of activities, strike a balance between social, environmental and economic objectives, and to develop best practice management strategies and programs. This chapter describes a planning process that can be tailored to local needs and to take account of specific social, economic and environmental factors. Local governments and State agencies have many responsibilities which are often seen as more important or of higher priority than stormwater quality management, especially when viewed in the shorter term. However, when the externalities and potential deferred cost to the community of inadequately managed urban development impacts are taken into account (e.g. waterway dredging to remove sediment, loss of tourism and fisheries), better information and overall more cost-effective decisions can be made. Each local government must make its own judgements about balancing priorities, dealing with conflicting objectives and allocating resources. USQMPs provide a transparent framework for making these judgements, recognising the longer term consequences of decisions, and being accountable for performance. A USQMP must identify actions to improve the environmental management of urban stormwater in a way that protects or enhances the environmental values of receiving waters. Technical knowledge is only one obstacle to improved stormwater management. More often, the main constraint is a lack of understanding of cause and effect processes, and consequently a lack of consensus on stormwater management priorities. A key to achieving more effective action lies in establishing consistent priorities across jurisdictions. The USQMP process can: create a shared understanding of the effects of the various stormwater management options identify priorities based on risk assessment develop management strategies and actions generate commitment to a best practice approach establish a basis for ongoing cooperation and coordination between agencies. Commitment is achieved mostly through involvement of a wide cross-section of local government staff and key agency representatives in the planning process and through assignment of accountabilities. Agreed priorities are identified by a consultative process involving local government, Department of Environment and Resource Management (DERM) and other key stakeholders (developer organisations, regional natural resource management (NRM) bodies, water authorities, and transport agencies) in a systematic assessment of environmental risks associated with urban stormwater. It is important for those with a role in stormwater management, engineering and waterway health outcomes work on improving the environmental management of stormwater by sharing 36

51 in the process of developing the USQMP. This means involving representatives from across various functional areas of local government, catchment management (e.g. regional NRM bodies) and agencies such as DERM. This section describes the process that may be undertaken when developing a USQMP to obtain community, industry and council ownership, and identifies the process of reviewing the plan. This section is designed for those involved in the planning, design or management of stormwater systems within Queensland. A conceptual framework for the USQMP is shown in Figure 3.1. Basis of a USQMP Local governments should develop regional or local urban stormwater quality management plans to address the protection of environmental values (EVs) under the Environmental Protection (Water) Policy 2009 (EPP Water). The EPP Water sets out a requirement for development of a USQMP for a local area in the context of total water cycle management planning. A USQMP also fulfils commitments made between DERM and the Local Government Association of Queensland (LGAQ) for implementation of the EPP Water through the protocol Establishing the roles and responsibilities of local and State Government in the Queensland System of Local Government in managing Queensland s environment (DLGP 2006). USQMPs must set out how to improve the quality of urban stormwater consistent with the water quality objectives for waters affected by the system. 37

52 Operation Construct Site Local Regional State planning Reef Water Quality Protection Plan Sustainable Planning Act 2009 SPP for Healthy Waters Council planning scheme: Land-use zones Stormwater policies Code provisions DA triggers National Strategy for ESD 1992 Council corporate planning: Community Plans Capital works Operations Business plans Development assessment: site-based stormwater quality management plans (site SQMP) approval conditions for construction and operation National Water Quality Management Strategy Environmental Protection Act 1994 Environmental Protection Policy (Water) 2009 Regional plans: regional plan Healthy Waters Management Plan regional NRM plan Council water plans USQMP & TWCMP Sub-catchment plans and waterway action plans: WQIPs Healthy Waters Management Plans (HWMP) Figure 3.1 Conceptual framework for an urban stormwater quality management plan (USQMP) Elements of a USQMP A USQMP should consider: measures to minimise the contamination of waters by stormwater in accordance with design objectives for the area (see Chapter 2) maximise the infiltration of water into the ground reduce the velocity of stormwater and remove contaminants from the stormwater. 38

53 measures include, for example: flow rate mitigation, erosion control and infiltration areas grassed or vegetated drainage lines, vegetated water buffers and conservation or restoration of riparian vegetation constructed wetlands, gross pollutant traps, retention basins and trash racks planning and design approaches for its stormwater system that have regard to the needs of the local community. Measures include, for example minimising ecological impacts on waters in the locality acceptable health risks, aesthetics, protection from flooding, public safety and other social concerns making use of stormwater for recycling and water conservation making use of drainage corridors for improved recreational values and open space or landscape areas investigating opportunities to build contaminant control measures and re-establish riparian vegetation and aesthetically pleasing environments in degraded drainage corridors integrating the plan with catchment-based planning and land-use planning addressing the risk areas for acid sulfate soils, particularly in areas of environmental value (see State Planning Policy 2/02 Planning and Management of Development Involving Acid Sulfate Soils) implementing viable alternatives to the release of stormwater through outlets across beaches or into waters with poor circulation the purpose of the EP Act and EPP Water, and how the purpose is to be achieved, so that it reflects the principles and values associated with ecologically sustainable development (ESD). For local governments, the benefits in developing a USQMP include: having a long-term strategic approach to stormwater quality management within council as part of a total water cycle management (TWCM) plan and any healthy waters management plan 3 having strategies in place to improve or maintain the water quality of waterways in the local government area meeting legislative requirements. Regional plans may also carry requirements for urban stormwater quality management including the SEQ Regional Plan , the Water Sensitive Urban Design Implementation Guideline No. 7, and FNQ Regional Plan The USQMP will also be addressed by the priority infrastructure plan (PIP) component of a local planning scheme. The PIP outlines the program of infrastructure required to help deliver orderly and well supported development areas. Well developed PIPs and USQMPs allow a council to allocate or levy appropriate infrastructure charges to assist water quality management. 3 TWCM plans and healthy waters management plans made under the EPP (Water) address rural and urban water quality management issues, and recognise waterway uses, environmental values, water quality objectives and community values (especially important when land-use planning decisions are made). Guidelines are available on the DERM website, see < 39

54 3.3 The risk management approach A risk management approach is used to assess the risk or likelihood of losing values of receiving environments due to the impacts of urban stormwater. Stormwater flows and stormwater pollution are threats to environmental values (including recreational/amenity values) of waterways. The risk of those values being degraded or lost depends on two factors: scale or severity of the stormwater threat sensitivity of the receiving environment to that threat. The aim of risk assessment is to identify areas where the risk of damage is greatest. As a first step we need to assign scores or rankings to the various environments or receiving waters to indicate the risk of damage due to stormwater flows or pollution. If we assign numerical values to indicate the size of the threat and the value of receiving waters, we get a measure of the risk to that environment by multiplying the two as illustrated in Figure 3.2. We then have an objective indication of risk which can be used to assign priorities. Threat from stormwater pollution or flows: scale or severity frequency Value of receiving environment: sensitivity significance Threat x Value Risk of losing environmental values Figure 3.2: Risk assessment approach For example, the aquatic ecosystem value of coastal waters may not be particularly sensitive to stormwater draining over beaches into the surf zone. However, public health may be at significant risk from stormwater outflows and pooling on beaches. Recreational values of beaches are often significant given their level of use, and so amenity may also be greatly affected by accumulating litter..the pollution threat from stormwater and litter at beaches is likely to rank highly in any risk assessment. Any USQMP for this area would therefore need to consider this risk assessment and consequent management actions, in the context of any healthy waters management plan developed for the area. 3.4 Development of a USQMP The most appropriate risk management strategies for achieving improved stormwater management will depend on local circumstances. Most often, risk management will involve a combination of best practice approaches including the following: Planning planning controls should incorporate the potential effects of land-use change and land development on water quality. 40

55 Operations and land management the way works and services such as waste collection are provided by municipalities and the private sector should be reviewed, to ensure that stormwater quality is protected. Education and awareness community and business awareness programs may be instrumental in changing attitudes and the way in which individuals treat their environment. Infrastructure structural treatment measures such as litter traps can be used to capture and retain pollutants. No one approach can be considered as best practice. The achievement of best practice will depend on the successful integration of actions to protect stormwater quality across functional areas within local government and on coordination with other agencies (Figure 3.3). Land-use planning Urban design Planning & design Land management Education/awareness Source controls Best management practices for urban stormwater Stormwater treatment Flow management Structural controls Figure 3.3: Design objectives for management of stormwater quantity operational (post-construction) phase of development When considering the application of a range of proposed approaches to the management of stormwater threats, a number of questions should be asked: Cost-effectiveness Is the cost of measures to avoid or reduce risks high without sufficient benefit? If so, their cost-effectiveness is relatively low.(see A business case for best practice urban stromwater management, Water by Design 2010) Capability Do local governments or others have sufficient resources, expertise or powers to implement the measure? If not, their capability is low. Opportunity Is it practical to implement the measure? There may be no space for installing a structure to treat stormwater, for example. If so, the opportunity is lacking. Potential management strategies should be evaluated on the basis of cost-effectiveness, capability and opportunity. For all practical purposes, a risk-free environment cannot be achieved in existing urban areas. Establishing a shared responsibility for stormwater management involving industry, community, commerce, agencies and local government will help to ensure that risks are addressed by those with the best capacity to do so. 3.5 The USQMP process It is important to carefully plan the process of developing and implementing a USQMP. It is also important to recognise that each region and catchment is different from the next, and that 41

56 individual environmental plans are required to address the characteristics of each catchment. The steps involved are described in the following section. The approach follows the principles of the environmental management system model contained in International Standards (ISO 14000) and includes the need for continual improvement and management involvement. The four-stage process recommended for developing a USQMP is illustrated in Figure 3.4 and described in the text following. Stage 1 Preliminary activities 1. Establish commitment to the project. 2. Agree on project framework and scope including total water cycle management. 3. Define problems and information requirements: catchments, drainage system, receiving environments land-use patterns, land-use activities pollutants total water cycle management. Stage 2 Risk assessment 1. Consider stormwater threats. 2. Identify environmental values and design objectives (WSUD). 3. Produce a list of issues/activities in order of importance (i.e. threat value = priority). Stage 3 Develop the USQMP 1. Consider options for action. 2. Develop a list of recommendations based on cost-effectiveness, capability and opportunity. 3. Establish implementation responsibility, costs, monitoring and review. Stage 4 Implement the USQMP 1. Develop implementation strategy. 2. Establish performance review and improvement programs. 3. Undertake water quality monitoring and review. Figure 3.4 Process for formulating and implementing a local urban stormwater quality management plan Existing USQMPs and related planning processes (such as total water cycle management plans, and healthy waters management plan) include: South East Queensland Regional Water Quality Management Strategy Local government USQMPs, such as Gold Coast City Council, Brisbane City Council, Mackay City Council and Townsville City Council (under development) Regional plans (see South East Queensland, Far North Queensland (FNQ), Central Queensland (CQANM), Central West Queensland, Eastern Downs (EDRPAC), Gulf Region (GRDP), Maranoa and District, North West Queensland, South West Queensland, Townsville Thuringowa (TTSP), Whitsunday, Hinterland and Mackay (WHAM), and Wide Bay Burnett) Water quality improvement plans (WQIPS) for Dry Tropics, Wet Tropics, Mackay Whitsunday, Mary Burnett and SEQ Healthy Waterways Strategy. 42

57 3.5.1 Stage 1 Preliminary activities Framework In this first stage, the commitment of key stakeholders is confirmed, administrative matters agreed and a project schedule formulated. Purpose: To initiate and organise the planning project and obtain commitment of key stakeholders Inputs: Context setting Outputs: Commitment, accountability, schedule Process: Meeting with key stakeholder representatives It is important to obtain the commitment of key stakeholders, especially senior local government managers including the chief executive. The development of the plan will be led by the municipality; a senior council officer should be appointed as project manager of a steering committee to plan the following tasks: Commit resources for developing a plan with a set timeframe for completion. Form a working group and secure agreement on the framework and objectives of the plan. Establish an administrative framework which assigns clear functional responsibilities and resources within council and delegates responsibilities to an appropriate level within the organisation (who does what, when, funding and coordination). Convene a technical working group comprising local government representatives (elected and non-elected) and community stakeholders (including industries and agencies) to ensure broad community support for, and ownership of, the problems and solutions. Undertake a full assessment including modelling of the catchment a specialist in water quality modelling will be needed. The advantage of using a modelling approach is that the links between various activities (land uses), pollutant loads, and receiving water quality is quantified. This enables various management options to be trialled through the model, and their costs and effectiveness assessed, ensuring that the most efficient strategies are chosen. Checklist Key stakeholders committed Project schedule confirmation Project manager appointed Participants in planning process identified Inception This stage involves bringing together participants in the planning process to establish the objectives of the project. It is important for participants to gain an understanding of the process, of organisational arrangements and of the need for their involvement and contribution. Purpose: Inputs: Outputs: Process: To develop participants understanding, highlight key issues and identify information sources Context, outline of the planning process and its objectives Understanding, involvement, issues, information needs, timelines, map of land uses, map of stormwater system ncluding receiving waters Workshop, interviews, field inspections, review of documents 43

58 This is a critical stage in the planning process involving the gathering of information to support the rest of the planning process and ensuring the active involvement of the key participants from local government and other agencies. It is recommended that representatives from council and other agencies be brought together in a workshop. This provides an opportunity to involve participants in a discussion of stormwater management issues in the municipality, including pollution and flow management threats and opportunities for improved performance. Use the workshop as a means to: develop an understanding of the objectives of the project and the planning process reinforce the role of participants in contributing to the development and implementation of the plan identify key people to interview in more detail identify sites for field inspections allocate people to the task of collecting or providing key information required for development of the plan. During the inception stage it is important to begin to gain an understanding of the extent to which existing and potential future activities may be a threat to receiving environments and how well existing management processes within council and other agencies deal with stormwater issues. Examples of typical issues and their origin are given in water quality improvement plans. It is important to use the inception stage to establish how a review of management processes will be undertaken. The review should cover planning, regulation, education, enforcement and operations as well as any existing structural approaches to managing stormwater impacts as outlined below. The relationship between council and other agency activities should also be examined. This information will contribute to the formulation of management strategies later in the planning process. Planning Operations: Regulation: Education: Infrastructure: Regional plans, planning scheme, planning policies, permit conditions :Specifications for service delivery (e.g. waste collections), asset maintenance activities, depot operation Integration between policy, planning controls, local laws and enforcement activities Programs aimed at those involved in activities with potential to affect the stormwater system Incorporation of structural measures into buildings, roads and drainage systems to reduce environmental impacts Document the nature of land use It is useful at this stage to compile an overall picture of land-use activities. This is best represented by the planning scheme zones covering the area; however, local knowledge of differences between land-use types must be applied. For example, there may be a need to distinguish between old and new industrial areas which may differ in the types of industries and the quality or standard of associated infrastructure. The basis of differentiation is the potential of different activities or land uses to generate pollutants. In addition to site-specific activities there are a number of transient activities which must be accounted for. Examples of possible transient activities include land clearing, earthworks, building construction, building maintenance activities, home car servicing and so on. Transient activities can be significant polluters and are difficult to control. Document the stormwater system It is also important to document the stormwater system. This is best presented as a map with physical features showing the catchments (main catchments and subcatchments), the drainage 44

59 system (main drains), and the receiving environments which might include open waterways, wetlands, lakes and coastal waters. A context map which shows adjacent municipalities in the entire catchment is also useful. Checklist Workshop 1 Participants are committed Participants understand planning process and schedule Participants understand nature of stormwater Information requirements have been Responsibility for gathering information has been Key people to be interviewed have been The date of the next workshop has been Checklist Stage 1 outputs A map of the stormwater system has been prepared A map of land-use activities has been prepared Current management processes reviewed and gaps identified, e.g. planning scheme, operations, local laws, integration between functional areas Field inspections have been undertaken Interviews have been undertaken Stage 2 Risk assessment Threats and values This stage involves identifying and confirming: the nature and source of stormwater threats to receiving waters environmental values of receiving waters. It is important to be thorough in the assessment of threats and values to avoid significant later reworking of the results Purpose: To identify and rank the values of receiving environments and the threats posed by stormwater pollutants or flows Inputs: Reports, local knowledge, familiarisation with land-use activities and receiving environments, interviews Outputs: Agreed ratings or rankings of stormwater threats and receiving environment values Process: Review of existing information from stage 1, workshop to present and confirm assessments of threats and values 45

60 Threats A list of major site-specific and transient activities with potential to damage receiving environmental values should be prepared which includes: type of stormwater threat significance rating of the threat. In arriving at a significance rating, consideration should be given to the quantity of pollutant load generated and the frequency of occurrence. There will seldom be data available on the impact of these activities on receiving environments. However, an informed assessment can be based on professional judgement and experience as well as local knowledge, history of spills, complaints, age of infrastructure and so on. Discussions should take place with key people in council, state agencies (DERM), regional NRM body and others. Values The key goal of the USQMP is to protect and enhance the receiving water environmental values. These values can be categorised under a number of headings including: amenity recreational and landscape attributes cultural association with known sites of cultural and heritage significance economic economic benefits derived from water environments environment physical and ecological attributes of waterways hydraulic contribution to protection of property and public safety from the risk of flooding resource urban (potable and non-potable), industrial and agricultural water usage. The values of receiving environments need to be assessed for each of these categories. This can be done qualitatively using the sort of criteria suggested in Table 3.1. For the receiving waters potentially affected by urban stormwater, environmental values (EVs) and water quality objectives (WQOs) should be identified with a description of the existing qualities, characteristics and resilience of the aquatic environment. The intent is to characterise the receiving waters including the required level of ecosystem protection. 46

61 Table 3.1 Assessing the values of receiving environments Value Category Examples of attributes Amenity Cultural Economic Environment Hydraulic Resource Significance Use Direct Indirect Significance Intactness/ Integrity Extent of open space associated with the receiving environment, extent of facilities such as trails, car parks, picnic areas, areas for canoe or boat launching, extent and continuity of public access, visual attractiveness Visitor numbers, level of active water-based recreation or passive non-contact recreation, number of associated recreation events held at a site Sites of cultural and heritage significance Water use, fishing or aquaculture, tourism, transport (e.g. ferry services) Property values Biodiversity, significant species (e.g. rare or threatened), treaties, protection agreements, listings, sites of significance Size of intact area (e.g. continuity of habitat), remnant vegetation, level of invasion by exotic species Extent to which the environment contributes to the protection of property and public safety from flooding Quality of untreated water, degree of treatment required to achieve the required water quality It is important to determine what receiving water quality monitoring data are available and how it compares with the relevant water quality objectives and the policy intent. Water sampling methods are outlined in the Monitoring and Sampling Manual 2009, published by DERM. Assessment methods are also available from the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000). Local or regional ecosystem health monitoring data may be available for the receiving water (e.g. from DERM or local government water quality monitoring programs). The information will be required for comparing the current condition of the receiving waters to the WQOs and must relate to the specific contaminants and risks associated with the stormwater entering the receiving environment. EVs relevant to the receiving waters should be used for incorporation into objectives and action programs in the USQMP. For example, the affected water body might be a bay, an estuary or riverine waters, and different EVs may apply to different parts of the water body. This information may be contained in the documents referenced in Schedule 1 of the EPP Water (also accessible via the DERM website < or from the Queensland Water Quality Guidelines Local information may need to be obtained if these sources do not adequately characterise the waters. For example, water abstraction licences may indicate uses such as stock watering and irrigation. The levels of aquatic ecosystem protection need to be determined as either high ecological value (HEV), slightly disturbed, moderately disturbed, or highly disturbed. Levels of aquatic ecosystems protection may be available from a number of sources including the EPP Water, state and regional coastal management plans (for example, maps of the areas of state significance (natural resources)), the Directory of Important Wetlands in Australia, and marine parks and national parks designations for waters in areas of protected estate. 47

62 Detailed guidance on identifying environmental values is in the DERM guideline: Establishing draft environmental values and water quality objectives. This sets out the process for establishing draft EVs and draft WQOs in line with the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (the Australian Water Quality Guidelines) and the Environmental Protection (Water) Policy Workshop The results of the assessment of threats and values should be presented to stakeholders. This can involve presentation of maps, working through the ranking process used and discussion of the results. Participants should be given the opportunity to question the results and add any information that may have been missed during the assessment process. The aim should be to achieve consensus on the rankings of threat and value. Failure to achieve consensus at this stage may lead to arguments about priorities for action later in the planning process and require a reassessment of values and threats. It may be necessary to follow up individually with some participants to work through the detail of the assessment for particular threats or receiving environment attributes. That is, there is a need to quickly identify what can be agreed upon at the workshop, but to be prepared to spend some time on following up a few outstanding issues later. Checklist Workshop 2 Stormwater threats identified and presented to workshop Values of receiving environments identified and presented to workshop Good representation of stakeholders at the workshop Reasonable consensus achieved Arrangements made to follow up and resolve any significant disagreements Risk assessment This stage involves reviewing stormwater-related threats to determine the potential risks to the environmental values of local waterways. It should take into account: the transmission efficiency of drains carrying the pollution or flow threats the significance of receiving water values the sensitivity of those values to the threats identified. Purpose: Inputs: Outputs: Process: To assess and rank the stormwater risks to receiving environments Rankings or ratings of receiving water values and stormwater threats, knowledge of drainage system pathways to receiving environments Risk ranking of threatening activities Threat x value = risk. A numerical rating system or a simple designation of high, medium or low can be used to rank the potential risks. The results of this ranking can be added to the significance rating. 48

63 Checklist Stormwater threats and receiving water values systematically translated into risk rankings Rankings which seem inappropriate highlighted and explored further Prepared to present and explain the basis of the risk rankings to stakeholder workshop Stage 3 Developing a USQMP Management strategies The USQMP will provide actions and strategies to be undertaken by the council to meet the agreed objectives and values. Strategies may be shire/city-wide, or specific to a catchment, and within the context of a TWCM plan (see EPP Water). The USQMP will provide the framework within which existing industry, developers of urban land, state and local government agencies, and the general public manage their activities and the stormwater system. In most cases, a range of council departments such as operation/works, environment, waterways, stormwater, roads and drainage, sewage and water supply, parks and gardens, planning and environment, waste management and corporate development will have a role in implementing the USQMP. The USQMP should address actions that can be undertaken over differing time periods. The following examples list immediate, medium- and long-term actions: Identify stormwater flows, velocity, outlets, catchments and wetlands (immediate). Implement stormwater treatment such as installing gross pollutant traps/sedimentation basins (medium-term). Implement water quality modelling and prevention measures, e.g. flow detention, retention and polishing wetlands (long-term). The USQMP should address the options councils have to manage and design environmentally effective and cost-effective stormwater systems. The Queensland Urban Drainage Manual provides information for strategic planning (master drainage planning and single development planning) for stormwater management. Tasks The following tasks need to be undertaken: Prepare strategies and catchment-based action plans incorporating a suite of planning, structural, administrative and management practices to address the identified issues. This should be based on a cost-effectiveness ranking, within a specified timeframe. The focus should be on implementing best management practices within a catchment, targeting the priority issues, then monitoring and reviewing performance (see Stage 4). Secure any necessary funding required to implement strategies. Incorporate findings and strategies in the USQMP report, together with an assessment of the social, economic and environmental implications. Secure stakeholder and community input and review the plan if necessary. Review council planning and development control assessment and approval requirements and amend as necessary to ensure that appropriate environmental (water quality) objectives are embodied in strategic planning instruments 49

64 adequate site assessments are carried out, having regard for planning objectives land is zoned for development consistent with land capability subdivisional and building approval requirements reflect best practice land management and pollution control, consistent with land capability and desired environmental objectives Prepare strategies for planning and development, monitoring, education, auditing and enforcement, and area-specific action plans. Develop the plan based on gathered information. Councils with complex significant areas may need to assess the cost-effectiveness of potential control techniques rank control measures in order of cost-effectiveness review alternative catchment land use and management techniques and point source control scenarios. Model various water quality outcomes until a satisfactory balance is achieved between development and required environmental objectives, having regard to social and economic implications. Map present and future land use, environmental and other constraints, land to be set aside for drainage corridors and pollution control infrastructure. Prepare cost strategy, e.g. headworks charges to be levied on future development and infrastructure maintenance. Integrate findings into other strategies, e.g. sewage management, planning schemes and corporate planning. Develop waterway action plans addressing specific waterways (or reaches) and achievement of specific water quality objectives. Source controls Prevention measures or source control may have longer term observable outcomes and may include: designating land use in the planning scheme of environmentally significant or sensitive land, for example, areas that are highly susceptible to erosion, acid sulfate soil hazard, high subsurface groundwater, or flood-prone and environmentally valuable areas (habitat of rare or endangered species) referencing the USQMP as part of planning scheme measures and/or development codes and policies for the local government area. There needs to be recognition that intensification of land use (e.g. from bushland to urban use) inevitably leads to degraded stormwater quality within a catchment. Where development proposals meet the planning performance criteria set to ensure that water quality objectives are met, but are in areas of sensitivity or low land capability, special controls may be introduced requiring a higher level of planning to protect environmental values listed in the plan. Such controls may include special management of stream vegetation and adjacent buffers, or stream rehabilitation proposals assessing the resource value of stormwater (e.g. aquifer recharge or environmental stream flows) as part of the scheme process developing flow control basins, water quality control ponds, polishing wetlands, and aquifer recharge basins. Water flowing from ponds and wetlands may be required to meet quantitative quality targets, particularly in regard to suspended sediments and nutrients identifying the need for litter or oil control devices (e.g. stormwater quality improvement devices (SQIDs)) 50

65 minimising the inflow of stormwater to the sewerage system to reduce hydraulic load and minimise the risk of system overflow, and minimising the inflow of sewer overflows into the stormwater system prohibiting the construction of barriers impassable to native fish providing guidance in planning schemes on design parameters (such as consideration of flood recurrence frequency one in one hundred year annual recurrence interval (ARI) being the most widely used standard). Council should consider more frequent storms in planning schemes for developments due to the higher frequency of impacts of these storms and reduced time for recovery of aquatic ecosystems between events setting conditions on planning approvals to require land developers to prepare and submit site stormwater quality management plans (SQMPs) for specific sites to local governments. Waterway action plans As a component of the USQMP, specific waterway action plans can be applied to individual catchments and should state clearly what it is that council and the community will do to meet the water quality objectives of the USQMP. Taking into account the environmental values for the receiving waters, funding allocated to implement the plan and the level of environmental risk to be managed, the waterway action plans should address the following water management aspects: stormwater quality especially relating to sediments, turbidity, nutrients and litter, and as appropriate, oil, pesticides and coliform count. Design objectives for many of these indicators need to be developed in accordance with Chapter 2. (Table 2.1 provides direction on usable design objectives) stormwater flows as they affect downstream erosion potential, stormwater volume and velocity, environmental flow requirements, or flooding. Design objectives for flow frequency and water way stability should be confirmed (see Chapter 2) local groundwater hydrology, e.g. aquifer storage, quality and use landscape values of local drainage lines, creeks, stormwater control ponds, basins and wetlands aquatic ecosystem habitat including stream and streamside vegetation, stream/basin morphology safety aspects including mosquito breeding potential and accidental drowning. A comprehensive USQMP will address the above factors strategically, with the objective of protecting the environmental values of local and downstream waterways. A waterway action plan may be prepared for each catchment to achieve specific environmental objectives, or they may be applied across the whole local government area. It can provide a mechanism to effectively balance competing needs and interests within a catchment. A conceptual framework for a waterway action plan is shown infigure3.5 51

66 Development planning controls drainage design erosion controls open space education enforcement Water use and riparian management off-stream water use in-stream water use riparian zones Stormwater run-off objectives contaminants and mass load Drainage system objectives discharge rates and volumes run-off frequency flood control environmental flows Objectives water quality objective design objectives hydrology l Figure 3.5 Waterway action plan framework A specific environmental objective for a waterway action plan may be to: Protect waterway health through the minimisation of erosion and sediment discharge during construction, and through implementation of water sensitive urban design features for the built urban environment. Water Sensitive Urban Design (WSUD) aims to retain or replicate natural hydrology and channel design, by encouraging infiltration, flow retention or detention, and by minimising impervious areas and the use of rapid-flow and impervious drainage systems (e.g. pipes). A waterway action plan should address WSUD and other relevant stormwater principles for all new development including: maximising opportunities for using stormwater productively (e.g. water sensitive urban design and constructed stormwater wetlands) maximising opportunities for the enhancement of recreational and visual amenity through the design of drainage corridors and open space adopting water sensitive urban design in conceptualising, aligning, shaping and sizing stormwater facilities in new urban developments pre-treating stormwater prior to discharge to surface water as far as possible minimising hard engineering solutions to riparian management in favour of approaches which preserve natural channel form and riparian vegetation implementing stormwater infrastructure design approaches which are consistent with the planning scheme objectives and principles. Waterway action plans should also address improved stormwater management in existing areas including options for: oil pollution control storage bunding, oil arresters litter capture trash racks sediment capture sediment traps 52

67 nutrient reduction constructed wetlands (can tie in with parkland/open space plans) street sweeping programs targeted source areas industrial land first flush systems for example, collection and reuse of first 20 mm of runoff infiltration techniques for example, construction of grassed swales, infiltration channels/basins stream rehabilitation restoration of naturally vegetated channels and increase the width of riparian corridors labelling and identifying stormwater culverts. Examples of land development controls, as identified by the site assessment report and stormwater management plan include: erosion source control sediment traps wetlands for nutrient control stabilised temporary drainage lines flow control devices rate and volume of run-off to approximate pre-development rates and volumes, including for the one in one year ARI flood recurrence frequency riparian management natural vegetation, channel form, stream substrates, and meanders to be preserved where feasible site rehabilitation. Examples of open space and drainage corridors controls and improvements include: wetlands as landscape features multiple use facilities tennis courts and playing fields as dry sediment basins and flow retardation basins drainage corridors as walking/bicycle/fitness tracks or communication corridors riparian zones and vegetated drainage corridors as wildlife corridors water in a landscape rated among the most desirable features in a recreational/landscape setting and development proposals should be encouraged to reflect this. The waterway action plan should also be developed with consideration of environmental planning and land-use issues. Examples include: inherent features of the catchment that may impose constraints or provide opportunities for land use including topography, soil type and erodibility, water bodies (including both hydrology and water quality), habitats (including aquatic, bushland and wetlands), or any other natural asset information available in relation to the relevant processes and interactions which link features in the catchment. Is this information adequate to enable a reasonably accurate assessment of the environmental impacts of various catchment land-use development scenarios? If it is, what are the likely impacts on such processes and interactions? What trade-offs are acceptable where resource management objectives may be in conflict? Are there issues such as world heritage areas that warrant a precautionary principle approach to development? present river flows and water resource uses and how these have an impact on environmental values and water quality 53

68 land capability and suitability for the proposed use (taking into account stormwater pretreatment measures) council capability to maintain any permanent stormwater pollution control facilities (e.g. flow retention basins, gross pollutant traps and water quality control ponds) which may be necessary to control the long-term environmental impacts of stormwater. Land use planning links Council planning schemes should be informed by and linked to the USQMP for the following reasons: Information gathered in developing the USQMP will support the preparation of planning instruments for local areas and planning scheme amendments or a new planning scheme. Mapping of stormwater infrastructure and catchments will assist in determining the preferred pattern of settlement. Water quality objectives may indicate the need to control the location of certain developments through the planning scheme consistent with design objectives for the area. Water quality objectives can be used to guide the conditions on development approvals. Design objectives may also be relevant (see Chapter 2). Planning policies and codes can be produced based on options for stormwater management developed in waterway action plans (i.e. water sensitive urban design, grassed swales, and porous paving). Planning schemes provide for infrastructure charges on development. If infrastructure charges under the SPA are to be used to fund part or all of the stormwater (and the rest of the water cycle) network, the networks so funded can be designed and costed to achieve the environmental values and water quality objectives established in the USQMP. A conceptual arrangement for the planning and development strategy is shown in Figure 3.6. Land-use planning options have major implications for water quality and flows. Local governments should consider those options that influence environmental and water quality outcomes. These include topography, soil type, local rainfall patterns and other factors which collectively define land capability. High risk sites in terms of cost-effective stormwater quality management may not only comprise steeply sloping land, but also flat sites. This is especially where the groundwater level is high, as it is difficult to direct flows into structural control measures. In areas subject to flooding or infiltration, it is difficult to construct and operate effective sediment basins. Local governments are obliged under the SPA to use planning instruments to address environmental values. The strategic approach in the planning instruments will tie in all development impacts and will set a clear and consistent framework for developers and minimise potential conflict in the community. 54

69 Council corporate plan capital works operational programs business plans priority infrastructure plan Council planning scheme land-use zones based on land capability USQM policies, design objectives USQM code provisions development assessment triggers building site code of practice subdivision design priority infrastructure plan Council USQM plan or USQM strategy and TWCM plan Healthy waters management plan, sub-catchment plans and waterway action plans Development assessment site assessment report erosion hazard rating, risk assessment, land capability information requirements via site stormwater quality management plans implement best practice USQM building design including water sensitive urban design USQM approval conditions for construction and operation Figure 3.6 Land use and development planning framework Local governments need to be clear about the environmental information required in development applications (e.g. land capability assessment or master drainage plan). Common issues include: how to protect EVs of waterways during both construction and post-construction, and specify any likely change to hydrology, and the level or load of sediments and nutrients discharged in stormwater from the development site to any waters as a result of the development the provision of a stormwater site assessment report, and subsequent stormwater management plan which should: conform with principles of ESD demonstrate that the development is occurring on the appropriate land capability class maximise the social value of stormwater and stormwater infrastructure protect riparian zones from disturbance adopt water conservation and recycling principles not cause flooding cost to the council of maintaining permanent stormwater infrastructure provided by the developer or council. USQMP management strategies Developing suitable urban stormwater management strategies involves confirming risk rankings at a workshop of stakeholders and then identifying and evaluating a range of best management practice options for managing the priority risks. These can include measures related to land-use planning, urban design, land management, operations, enforcement, education and awareness, and infrastructure (stormwater treatment). 55

70 Table 3.2: Example presentation of opportunities for implementation of management measures Suggested evaluation Criteria Cost Explanation Use approximate cost categories to compare costs. For example: major cost > $500,000 moderate/high $100 $500 k moderate $50 $100 k low<$50 k Effectiveness Capability & feasbility Assess how well the measure is likely to reduce risk Is it cost-effective and feasible to manage impacts to the extent required to protect EVs? Do we have enough information to be effective? Are the skills readily available? Does the technical ability or understanding exist? Are statutory powers available? What s our track record like? Opportunity Do others need to be involved and will they agree to it? Is space available where structural measures are proposed? Can the measure be included as part of another project which is to be implemented, e.g. drainage system upgrade? Management options should be evaluated against criteria of cost, effectiveness in protecting or enhancing values (reducing risk), opportunities for implementation and capability of the municipal council or other agencies to implement. Table 3.2 provides some examples of how these criteria might be applied. Purpose: To identify and evaluate best practice approaches to managing priority stormwater risks Inputs: Outputs: Priority risk rankings Priority management strategies, tasks, actions and responsibilities Process: Workshop to present and confirm risk rankings, and to identify and evaluate management options For development likely to threaten a particular receiving environment a brief assessment of management measures should be carried out including: land-use planning, urban design, land management, operations, enforcement, education and awareness, and stormwater treatment and infrastructure. As part of this assessment there is a need to compare the effectiveness and feasibility of management options for each priority stormwater risk. 56

71 Developing detailed actions Where particular management measures or options rate highly for feasibility and capability, detailed actions should be formulated. Where relevant these should include: suggested changes to planning schemes, policies and permit conditions suggested changes to specifications for service and asset delivery, e.g. stability of sites on handover, responsibility for operation of subdivision sediment basins during the high risk house-building phase the type, location and indicative cost of structural treatment measures target groups for education programs or enforcement specific locations for targeted programs, e.g. a particular industrial or commercial area or receiving environment the need to further investigate the extent or nature of stormwater threats the need for coordination with others responsibility for leading implementation, i.e. council, regional NRM body, DERM or other suggested performance measures. For each category of management approach, a number of specific actions are available. Priority risk activities for which a similar range of management actions are appropriate can be grouped into broad strategies. For example, an industrial and commercial areas strategy might be an appropriate way of grouping management measures to deal with a range of risk activities related to industrial and commercial land uses in the municipality. A goal or objective should be assigned to each broad strategy. For example: Industrial and commercial areas strategy Goal: To encourage the operations of businesses in the target industrial and commercial activity areas to adopt best practice in relation to the containment of pollutants to stormwater with education as a first priority and enforcement as a last resort, and at the same time to implement effective clean-up procedures and pollutant capture devices where they are necessary. There is also likely to be a need for a corporate strategy to address the inclusion of general policies and objectives into the Council corporate plan and planning scheme. This strategy should also deal with the integration of actions across functional areas within Council and with arrangements for coordination with other agencies such as the DERM. Checklist Management approaches for priority risks evaluated Detailed actions developed for priority risks where feasibility and capability are high Actions grouped into management strategies Responsibilities agreed Strategy developed for integration of actions within Council and coordination with others Final plan circulated for comment 57

72 Implementation planning This stage requires a meeting of senior managers from local government, state agencies, and catchment managers to confirm: commitment to implementing strategies in the plan responsibilities for actions accountability for delivery initial targets and reporting arrangements. Purpose: Inputs: Outputs: Process: To confirm priority actions and implementation arrangements Priority management strategies, tasks, actions and responsibilities Agreement on actions to be implemented and responsibilities Meeting with senior management of council and key stakeholders Successful implementation of the plans will require: clear expression of commitment to improved stormwater quality management incorporation of stormwater quality management objectives (such as design objectives) into the statutory planning framework and other relevant plans, strategies and policies coordination of planning, education, operations, enforcement and infrastructure activities within Council and with other agencies strengthened relationship with State agencies and local Council to deliver coordinated programs and ensure consistent priorities continuous improvement in operational practices particularly to ensure environmental performance objectives are written into specifications for service delivery. Checklist Senior managers in council and state agencies, e.g. DERM have endorsed the plan Responsibilities have been defined Initial actions have been agreed for implementation Ongoing coordination arrangements are agreed and understood and protocols in place Other plans, programs and policies have been modified to incorporate SWMP actions and objectives Stage 4 Implementing a USQMP The successful implementation of stormwater quality management plans will be evaluated by the extent to which objectives, policies and programs for the environmental management of stormwater are incorporated into: council strategic statements and planning schemes operational programs capital works programs annual business plans developer contribution plans. 58

73 Implementation plan tasks The following tasks need to be undertaken: Prepare an implementation plan for agreed control measures, specifying priority, funding, responsibilities and timeframes. Obtain council s endorsement of the plan, values and objectives. Prepare implementation strategy and catchment-based action plans. Implement the USQMP. Raise public awareness and support through effective communication such as brochures, media articles and presentations. Audit management practices, such as on-site erosion and sediment control compliance. Make a copy of the plan available for community access (e.g. library). Having developed the USQMP, it is necessary to implement its strategies and actions. It is essential that council identifies the people responsible for the actions in the environmental plan. These roles and responsibilities must be communicated and documented at each level and/or function. Resources must be available to support an effective environmental plan. This includes financial and technical resources as well as staff. Implementation also includes training staff, community education, and enforcing the actions to achieve the plan s objectives. Staff training Training and education are key components in implementing any program. It is important that all staff have a basic understanding of the stormwater plan and its effects on their everyday roles and responsibilities. As many stormwater plans are implemented by community members as well as council staff, it is imperative that members of the community are informed about the plan and are aware of what actions they can undertake to protect and manage stormwater in their local areas. Education and training are designed to increase knowledge, develop and improve skills and create a more positive attitude about the environment. Education and training programs should be designed to challenge and impact on the practices and behaviours of individuals or groups. There are seven key steps in developing a training and education program: 1. Analyse the problem. 2. Identify stakeholders. 3. Target the program. 4. Develop training and education objectives and outcomes. 5. Design training and education methods and tools. 6. Action the plan 7. Monitor and evaluate. Developing an education program The aim of any education or awareness program is to present information in a way that allows individuals to make informed choices. The fundamental aims of an environmental education program should be to develop, within individuals: an awareness and understanding of the complex, inter-relationships between the individual and the environment, and of the implications of human impacts on the environment an understanding of the need to maintain quality of life with all its variety 59

74 a personal commitment to, and acceptance of, responsibility for the environment and a willingness to participate in improving the environment abilities and attitudes related to solving environmental problems. Community education is an important part of stormwater management. The diffuse-source nature of stormwater means that other approaches such as direct regulation are less likely to be adequate on their own. A community education project would focus on controlling the source of stormwater, quality and quantity. There is a need for ongoing community education programs to support water management infrastructure, regulation and structural solutions. Well-planned and well-conducted community education programs are an essential part of the solution to stormwater problems. Local and more macro projects targeting people s behaviour at work and at home will achieve the desired impact, especially if used strategically with other motivators of behavioural change. Programs must have an impact on the stakeholder s knowledge, skills and attitudes in order to be most effective. Once council has established the aims and objectives of the education and awareness program, it will be important to determine the best ways of promoting and developing the program. This can be done through the following eight-step process. Step 1 Analyse the issue or problem Identify what is causing concern and break this down into the component parts. It is essential that you know the source of the problem and the impacts on that source. For example, there may be a significant number of small industries whose practices are affecting the environment. These people could be targeted, for example, with a workshop through an industry association. Step 2 Identify stakeholders Identify who has a stake in the issue and involve them in project planning and delivery. It is imperative that the training and education plan identifies those individuals or groups which have responsibilities in managing and protecting stormwater. Step 3 Know your target group Clear, precise identification of the target group is essential to quality community education. The more tightly defined the target population, the more chance of success. Knowing your target group means more than just identifying who they are. It requires the development of a full description, including demographic factors like age, gender, socioeconomic status, and level of education. In addition, finding out more precise psycho-social aspects about target group members, such as, their values and motivations, whose opinion they value and the media through which they receive information, is essential to good program design. Often these issues will only be identified when members of the target group are involved. For example, face-toface approaches from a credible source are often the most appropriate educative mechanisms with an industry target. Step 4 Develop objectives and outcomes Determining the results of the training and education program is essential to the scope and design of the program. The goals, objectives and outcomes need to be realistic and targeted to the level of commitment that council has to the stormwater plan. The goal is a broad statement of what you are intending to achieve, the objectives indicate how you will achieve them and the outcomes are the products and services that will be created. Step 5 Design your methods What methods, tools and techniques will be used in the project? Often people start with a method in mind and try to fit it to the target population goals and objectives. This is not appropriate and leads to unsuccessful programs. The educational mechanisms used should flow from each of the preceding steps and be designed in conjunction with the target population. As an example, in one campaign the decision to hold a trade night in a hotel was an approach identified by an industry body. 60

75 Step 6 Consider funding In designing the methods, it is important that budget implications are considered. When costing a project there are a number of factors to be considered and will include the following: What are the possible sources of funding beyond the local government authority? Can we run a cost-shared project? What in-kind opportunities exist? Is sponsorship from the commercial/industrial sector a possibility? What modifications are we prepared to make to the project if funds are insufficient? Step 7 Make an action plan and implement it This plan translates your program into a series of action steps covering the questions when, who, what, where and how. This plan guides all project activity and should be revisited often during the life of the project. Step 8 Monitor and evaluate All projects should be monitored and evaluated to some extent. This is often the most difficult step and it is often omitted. This step requires the collection of information and records to show the progress and achievements of the program. Evaluation against each project objective is essential. The successful implementation of any stormwater management plan will be dependent on people and how they implement it. The education and training program should be focused on targeting key individuals and groups that can influence the community to protect stormwater and get involved. It will be necessary to develop a program that has a number of integrated components that may include mass media, training and community education. These components include television, radio and newspapers, school programs, community meetings, shows and presentations. Staff training and education is critical to the success of the plan and must be integrated into the day-to-day work of each staff member whose job has the potential to impact on stormwater management. Components of internal training include articles in newsletters, development of, and training in, new procedures and induction training. To support the training and education program, a communications plan should be developed for internal and external stakeholders. Consistent and on-going communication ensures that all stakeholders are aware of the issues and progress of the plan. Training and education programs do not have to be expensive or elaborate but they need to be developed and reviewed to meet the needs of each target group. Enforcement Enforcement is one tool for achieving environmental objectives. It is recommended that an education and awareness campaign precede an enforcement campaign. The aim of enforcement should be to meet environmental objectives, not to catch people unaware, especially where an enforcement climate for environmental matters has been non-existent in the past. Following an education and enforcement campaign targeting affected groups, surveillance and enforcement can commence. The following steps are recommended: Clarify the council s regulatory framework. This will include the EPP Water water quality objectives, and the enforceable provisions of any development consent relating to stormwater control. Review the planning and development framework to ensure it is producing clear environmental aims for the local situation through enforceable conditions. Planning and development commitments or requirements, for example, to minimise pollution are of no great value either scientifically or legally. Design objectives as outlined in Chapter 2 of the guidelines are also relevant. Identify activities within the catchment that are not conforming to best environmental outcomes and require attention or investigation in the action plans. This could be done from information on council files or through the relevant industry association. If it has not 61

76 already been done, advise the industry association that an enforcement program is to be implemented and offer to provide additional educational material. Carry out a benchmark survey of the industry to check compliance. The management practices which should be implemented are those which discharge the general environmental duty under the EP Act. This duty means taking all reasonable and practicable measures to minimise the risk of causing environmental harm. A code of practice may be available for a particular industry setting out in detail how the duty can be met for the industry. Inspect problem sites; identify offenders and send either a warning letter or notice. After a short period to allow time for compliance action, carry out follow-up inspections and take enforcement action where appropriate. An infringement notice for sediment pollution will often be appropriate for minor stormwater pollution offences. Where serious or material environmental harm is caused or where a person is a repeat offender, the penal provisions of the EP Act, for example, Section 443, may be brought to bear. After perhaps 12 months, carry out a second survey of control practices, assess the efficacy of the enforcement campaign and review future actions. Performance review and improvement programs Performance review tasks The following tasks need to be undertaken: Survey water quality and compare achievements with targets. This may require a month by month assessment to differentiate wet weather/diffuse source impacts and dry weather/point source impacts. Review comments and feedback from community and other interested parties. Review performance, including the plan and the effectiveness of council, noting areas for improvement. Review implementation strategy and its effectiveness. Assess results of review for improvement program. The preparation of the USQMP and implementation needs to be followed up with a review of how well the USQMP has satisfied the intent of the EP Act and EPP Water. This further step will ensure that the council s processes and structures are appropriate and that there have been improvements to the quality of receiving waters resulting from actions implemented through the waterway action plans. Reporting on the achievements for stormwater management will help meet the requirements of the EPP Water. A stormwater management report could include: audits of ERAs operated by council audits of contractors engaged by council environmental training of employees and stakeholders monitoring environmental conditions against indicators such as the Queensland Water Quality Guidelines 2009 a review of complaints and enforcement actions such as numbers of penalty infringement notices for sediment control breaches a survey of the community and councillors to test awareness of stormwater management practices a review of actions proposed in the USQMP including implementation of actions identified in USQMP action plans 62

77 community education programs undertaken planning and development actions, including numbers of IDAS approvals with appropriate stormwater management conditions and planning scheme provisions addressing stormwater management conduct of council operations such as maintenance of stormwater infrastructure, erosion control practices in place and the existence of guidelines and policies concerning erosion control inclusion of appropriate policies concerning stormwater management in the corporate plan. To ensure the USQMP achieves the best possible outcomes, it is important to review the plan and its impacts for stormwater management. The review will determine any implementation problems and identify areas for improvement and possible expansion to the scope of the USQMP. The results of reviews and proposed improvements to the USQMP are outcomes that can be communicated back to the community. The benefit of this approach is that the USQMP becomes a living document within council and the local community. Improvement program tasks Following a report on the environmental review of the USQMP, council has the option to review results and implement improvement programs. Improvement programs can be used to: fine tune the USQMP update plans to meet legislative requirements improve community perception reduce costs improve planning processes improve financial planning improve communication both within and outside the organisation. Once the USQMP review is completed, council should be able to determine any weaknesses within the plan and the implementation program. When prioritising issues for inclusion into improvement programs, council should consider: objectives and outcomes of the USQMP. If the objectives are not being met, then there could be significant problems with the plan or implementation program environmental risks to stormwater that have not been addressed by the plan problems with implementing action plans. Improvement programs ensure that USQMPs are effective and can continue to meet legislative and community expectations. Refer to the performance indicators decided upon when setting the USQMP objectives. These will generally relate to scientific (physical, chemical and/or biological indicators), as well as best practice compliance indicators. Water quality monitoring and review Water monitoring The scale and complexity of water monitoring aimed at assessing performance of environmental management strategies will depend partly on the environmental values selected, and their indicators. Measuring chemical indicators in a water body, although a useful and common practice, is not always the most appropriate form of monitoring. Because water chemistry can change rapidly, especially with changes in flow, it can be difficult to design and implement a chemical monitoring program which accurately characterises the range of water chemistry changes in space and over time, or measures pollutant loads. 63

78 In some circumstances, measuring physical change might give a more direct and useful indication of the success or otherwise of a land management practice. As an example, a marked increase in the hydraulic radius (i.e. cross-sectional area) of a stream channel following a subdivisional development provides evidence of failure to adequately control stormwater runoff flow rates and volumes. Changes in downstream substrate (e.g. mud infilling of cobble riffle zones) similarly can give direct evidence of poor land management. As ecosystems tend to integrate the effects of longer term fluctuations in water chemistry, an assessment of ecosystem structure and function, compared to the ecosystem prior to development, or at a control location (or preferably both) can be very cost-effective. For further information, refer to the DERM website < for the Queensland Integrated Waterways Monitoring Framework 2010, DERM Monitoring and Sampling Manual 2009, and Queensland Water Quality Guidelines Biological sampling Sampling before development could provide baseline information into the types of animals and plants inhabiting the waterway. This information can be used to design future monitoring and allow an assessment of changes in the natural biological communities through time. Control sampling location(s) will allow an assessment of possible changes over space, that is, the area around the possible impact site. Ecosystem assessment might take the form of a one-off (i.e. one pre- and one postdevelopment) plot assessment of taxa (e.g. number and kind of genera) and biomass of benthic invertebrates. Seasonal and ecological variability should be considered. At the periphery of the impact site, natural variability will generally confound results and ability to draw meaningful conclusions. At least two sites should be selected downstream with at least six plots at each site, plus a control, although a small pilot study would be preferred to properly assess the experimental design. Stream cross-sections through selected sites could provide a basis for plot surveys of mangrove, seagrass or benthic communities, depending on the environmental values to be protected. Plots of data from each site could be examined for information about ecosystem taxa and biomass, and be compared in space and time with control findings, depending on experimental design. Where feasible, the pre-development monitoring exercise should extend for 12 months. Dry season data will generally be more indicative of natural background conditions. Geomorphological change It is recommended that the hydraulic radius of nearby downstream small perennial and nonperennial streams be measured before and after major development as an inexpensive and simple procedure to assess for in-stream changes, e.g. bed scouring caused by any increase in stream power. Monitoring control practices The link between the small but cumulative effects of activities and practices in a catchment and the environmental outcome can take many years to become measurable and obvious. For this reason, various techniques for measuring the effectiveness of environmental management practices, including end of pipe performance, and assessing how well practices are implemented, should be canvassed. Management review tasks Council must review the management of the USQMP at pre-defined times with results of the review to be fed back into the USQMP, incorporating any necessary changes to achieve the objectives. Management review is the last phase of developing and implementing a USQMP before the process loop begins again. At this stage, management review replaces the need for initial review. A comprehensive review of the development and implementation measures for the USQMP and its performance is imperative to the success of the plan. 64

79 This review should be made by top management within the council and should be carried out at defined intervals. This will ensure that continual improvements are being made in overall environmental performance by the council, and that the USQMP is appropriate, adequate and performing effectively. A review of the USQMP includes related policy, objectives and procedures. It would be expected that management would make necessary changes to the USQMP as a consequence of changing circumstances within council, and as a commitment to continuous improvement. The management review should be documented and include observations, conclusions and recommendations for action. The scope of the review should be comprehensive and broad enough to address the environmental obligations and legal requirements of the council. The management review should include: results of audits or performance reviews a review of performance against the set objectives and values the suitability of the USQMP in relation to changing conditions concerns from relevant interested parties the suitability of the Council s environmental policy and need for changes with regard to changing legislation, expectations and requirements of council and the community changes in the political environment or the activities of the council advances in science and technology lessons learned from stormwater or other environmental incidents reporting and communication. Following the completion of the management review, the process of refining the USQMP must continue. As the community and council roles change in response to changes in the use of the council s catchment, so too should the USQMP. 65

80 4 Planning controls Key resource documents Level Document State Sustainable Planning Act 2009 and associated implementation guidelines Environmental Protection (Water) Policy 2009 Queensland Urban Drainage Manual Regional Local Regional plans including: Far North Queensland Regional Plan South East Queensland Regional Plan Implementation Guideline No. 7 Water Sensitive Urban Design: Design Objectives for Urban Stormwater Management (November 2009) South East Queensland Healthy Waterways Strategy and associated guidelines (see Water By Design program) Regional coastal plans Regional natural resource management plans and water quality improvement plans Central Queensland Policy Water Quality Local government planning schemes and local guidelines on water sensitive urban design and erosion and sediment control such as: Gold Coast City Council Maroochy Shire (now part of Sunshine Coast Regional Council) Local government urban stormwater quality management plans such as: Mackay City Council (now Mackay Regional Council) Townsville City Council 4.1 Introduction The Sustainable Planning Act 2009 (SPA) sets out Queensland s planning and development assessment process. For the purposes of urban stormwater quality management, the main elements of the SPA framework are: one system for development assessment the integrated development assessment system (IDAS) local government planning scheme is the main instrument made by a local government that provides an integrated planning policy (including development assessment) for local governments planning scheme area State Planning Policy is a statutory instrument for defining state interests in planning regional plan provides an integrated planning policy for a designated region by identifying outcomes and how to achieve those outcomes Priority Infrastructure Plan (PIP) is the key tool in a planning scheme for integrating landuse planning and infrastructure planning. Most local governments have a planning scheme in place. Many are in the process of preparing a planning instrument under SPA. Council amalgamations now completed involve the eventual assimilation of relevant planning schemes. A summary of the current status of all local government planning schemes can be viewed at the plan making progress register of Queensland local government planning schemes on the SPA website < 66

81 Planning schemes are prepared by local governments under the SPA to manage growth and change in their local government area. Planning schemes must coordinate and integrate state planning policies and the matters they deal with, and also the state and regional dimensions of those matters expressed through regional plans. In this way they are to provide a sound policy basis for subsequent decision making State planning policies A state planning policy (SPP) is an instrument that advances the purpose of SPA by declaring the state s policy on a matter of state interest. SPPs shape planning schemes so that the state s requirements can be incorporated with those of local governments. They also provide for consideration of state interests in development assessment by assessment managers under IDAS. The SPP Healthy Waters is the key SPP that deals with urban stormwater management Regional planning Regional planning provides for those planning issues that involve more than one local government (e.g. significant urban metropolitan growth, major transport and services infrastructure). Local governments can then prepare their planning instruments in the context of the regional planning strategies. Regional planning is undertaken by state and local government in conjunction with the community. A statutory regional plan has been developed for Far North Queensland (FNQ Regional Plan ) to manage the region s high population growth and unique environmental features, as is also the case for the SEQ Regional Plan See the Department of Local Government and Planning for status of regional planning processes State USQM framework Figure 4.1 outlines the current policy and planning framework for urban stormwater management in Queensland. The aim of the framework is to ensure urban stormwater management contributes to protecting EVs through achieving WQOs for Queensland waterways. The current framework comprises state planning instruments acting through local government planning schemes: Environment Protection (Water) Policy 2009 the EPP Water key objectives include protecting and managing urban stormwater in development assessment and associated with state/regional/local planning. The EPP Water and its guidelines establish EVs and WQOs and states how they should be considered in decision making. Managing Queensland s waterways is a joint responsibility between state and local government. Under the EPP Water each local government is required to develop environmental plans for the use and protection of waterways in its council area. State Planning Policy for Healthy Waters the SPP Healthy Waters addresses urban stormwater quality management through SPA planning and development assessment requirements. This guideline links the relevant best practice documents used in planning and urban design via incorporation into the SPP. Section 4.2 includes an outline of the ways regional and local councils can manage achievement of water quality objectives. Chapter 5 provides a range of design tools from which planners and designers can choose those techniques most applicable to their specific area and site conditions. The appropriateness of tools selected is considered during planning and development assessment processes for achieving the design objectives of Chapter 2. Appendix 3 outlines information advice relevant for stormwater quality issues in development applications. Figure 4.1 describes the links among planning processes and the local council planning scheme that incorporates urban development issues described in Chapter 3 and this chapter. 67

82 Figure 4.1 Stormwater management planning and assessment framework 68

83 4.2 Land-use planning State planning framework Developing EVs and WQOs for particular waterways helps achieve the object of the Environmental Protection (Water) Policy 2009 (EPP (Water)). The Department of Environment and Resource Management has established EVs and WQOs for waterways in Queensland through community consultative processes. The WQOs provide planning targets for receiving water quality in ambient conditions. Local government plans are relevant to achieving the WQOs via the management of urban diffuse sources of pollution such as urban stormwater and management of wastewater point sources via development assessment processes. The application of best practice USQM and WSUD principles are a practical means of significantly contributing to the protection and achievement of EVs and WQOs in Queensland waterways. In preparing planning schemes and regulating development, local governments are obliged to seek to achieve ecological sustainability in Queensland waterways. The protection of ecological processes includes conserving, enhancing and restoring the life-supporting capacities of air, ecosystems, soil and water, and protecting biological diversity. Councils should develop a USQM plan within a total water cycle management framework to protect environmental values and any water quality objectives within council s jurisdiction (see Chapter 3). Water is a valuable feature of any local government area. It is ecologically, socially, economically and culturally valuable, and is an important element in maintaining or enhancing amenity. Clean water is necessary to maintain aquatic ecosystems (freshwater and marine), potable water supplies and for recreation, agricultural and industrial purposes. Figure 4.2 outlines the supporting guidelines (notwithstanding these guidelines) available to assist councils with using the USQM framework in planning and development assessment to help achieve WQOs. The SPA, the EPP Water and the SPP Healthy Waters support the effective adoption of water sensitive urban design and total water cycle management planning solutions. 69

84 EPP Water 2009 Environmental Protection Act 1994 State Planning Policy for Healthy Waters Sustainable Planning Act 2009 Urban Stormwater Quality Planning Guidelines 2010 State policy Guidelines o International Erosion Control Assoc. Australasia 2008 Best Practice Erosion & Sediment Control o Department of Transport & Main Roads 2010 Road Drainage Manual o Engineers Australia 2006 Australian Run-off Quality o Engineers Australia 1999 Australian Rainfall & Runoff o Department of Natural Resources and Water 2007 Queensland Urban Drainage Manual o Local Government Association of Queensland 2007 Erosion and Sediment Control Guidelines Regional planning: SEQ Regional Plan Implementation Guide No FNQ Regional Plan Regional NRM Plans Best Management Practice Guides Regional Coastal Plans Implementation Guide Guidelines Regional planning Local planning Council corporate plan: Capital works Operations Business plans Council planning scheme: Land-use zones USQM policies USQM code provisions Development assessment triggers Council Water Sensitive Urban Design Guidelines Council USQM plan Development, planning & assessment Development assessment: Material change of use land use and impact management feasibility issues Reconfiguration development density, layout and character, and impact management feasibility issues Operational works site stormwater quality management plans Stormwater approval conditions for best practice construction and operation Figure 4.2 Queensland stormwater management planning and assessment guideline 70

85 Regional planning Urban stormwater quality management is addressed in the various statutory and non-statutory regional planning processes. These are summarised as follows: Regional natural resource management (NRM) plans and investment strategies The Queensland Government has implemented the community-based regional NRM program through Australian Government s Caring for our Country program and the State Q2 Coasts and Country program. Regional delivery of NRM is through14 community-based regional NRM bodies. These bodies receive funding and in-kind support from the Australian and Queensland Governments to develop and implement regional NRM plans and investment strategies. The plans address critical regional issues such as salinity, water quality, biodiversity and vegetation management. Urban stormwater management is an issue addressed in many of the regional NRM plans. Regional investment strategies provide details on the specific actions, costs and timeframes that are required to implement a regional plan and achieve targets. Water Quality Improvement Plans (WQIPs) have also been developed in most regions. WQIPs in Douglas Shire, Great Barrier Reef catchments and Moreton Bay are finalised. The outcomes of WQIPs will be supported by planning and development assessment in planning schemes, and state planning and management mechanisms. Far North Queensland A statutory regional plan for Far North Queensland (FNQ) has been developed. The FNQ Regional Plan was prepared in consultation with councils, community and business groups. Infrastructure programs, investment in natural resources and environmental programs, and policies of Queensland Government agencies and regional and local councils will be required to align with the FNQ regional plan. Urban stormwater management is addressed. The FNQ region covers some km² around the regional city of Cairns and extends north to Cape Tribulation, west to Herberton and south to Cardwell. It includes the local government areas of the Tablelands, Cairns, Cassowary Coast and the Aboriginal local governments of Yarrabah and Wujal Wujal. Cairns City is the major urban centre. Central Queensland The Policy for the Maintenance and Enhancement of Water Quality in Central Queensland (the policy) is consistent with various state and Commonwealth statutory requirements, and recognises that these form critical parts of its implementation framework, together with relevant regional, catchment-based and local initiatives. Chapter 1 of the document Developing a Water Quality Policy for Central Queensland (Department of Local Government and Planning) discusses the regional and local planning initiatives, and state and Commonwealth policies and legislation that influence the policy. This chapter briefly outlines those aspects of the statutory context that have direct relevance to the role of local government planning schemes in dealing with river health and water quality, and those aspects of the policy that planning schemes need to consider. The Central Queensland regional plan (Central Queensland Regional Growth Management Framework) (RGMF) sets out stormwater quality management provisions that should be reflected in local government planning schemes. The policy is directly linked to the RGMF as the policy was developed as a priority action identified within the RGMF. Local governments are therefore required to reflect in their planning schemes, where appropriate, the regional recommendations of the policy. It is also desirable, though not required by legislation, that, where possible, local government planning schemes reflect the regional dimensions of other regional plans such as Fitzroy Basin Association s Central Queensland Strategy for Sustainability 2004 and beyond. 71

86 South East Queensland The South East Queensland Regional Plan (SEQ regional plan) recognises that management of the natural water cycle is required to achieve environmental, social and economic sustainability of the South East Queensland (SEQ) region. Through the principles and policies of Desired Regional Outcome (DRO) 11 Water management, and DRO 2 Natural environment, the SEQ regional plan adopts a total water cycle management approach as the framework for managing urban water quality in SEQ. As part of this approach, the SEQ regional plan endorses the adoption of water sensitive urban design. Any plans, policies and codes being prepared or amended by state agencies must reflect and align with the SEQ regional plan. Performance standards or design objectives regionally adapted to climate, landscape and soils are essential for effective WSUD implementation. Design objectives for improved stormwater management have been developed in SEQ. These design objectives are reflected in the SEQ Regional Plan Implementation Guideline for WSUD and establish minimum outcomes to be met by urban development in the region (also see SEQ Healthy Waters water sensitive urban design technical design guidelines for SEQ). To support a total water cycle management approach, design objectives for other aspects of the water cycle (e.g. water conservation and reuse, and minimisation of sewage treatment plant effluent discharged to waterways) can be considered. SEQ Healthy Waterways Strategy The SEQ Healthy Waterways Partnership was established as the Moreton Bay Waterways and Catchments Partnership (MBWCP) in July 2001 and is a special collaboration between government, industry, researchers and the community. These partners work together to improve catchment management and waterway health in the eastward-draining rivers of South East Queensland (between Noosa and the Queensland New South Wales border) and Moreton Bay. The South East Queensland Healthy Waterways Strategy (SEQHWS) includes 12 action plans presented in a series of separate documents. The SEQHWS has been developed through an extensive consultation process with partners and the community. Urban stormwater management is addressed in the Water Sensitive Urban Design Action Plan. Actions include legislative amendments by state agencies, planning scheme amendments, guidelines and education programs all designed to collectively achieve the management action goal: By 2026, all developed urban land in SEQ will meet consistent regional standards for water sensitive urban design. The action plan addresses five major issues that need to be tackled in order to achieve the action plan target. These are: legislation, policy and planning achieving best practice WSUD standards in existing urban catchments best WSUD practices awareness and capacity building erosion and sediment control. The WSUD action plan is focused on overcoming barriers to enable all developed urban land in SEQ to meet consistent regional standards for water sensitive urban design. 72

87 4.2.2 Local planning framework Councils use several planning processes to effectively manage urban stormwater quality including: the corporate plan 4 the local area urban stormwater management plan planning schemes. Planning schemes are a significant opportunity for implementing and achieving urban stormwater management goals for new urban development in a council area. Figure 4.2 outlines the relationship of these processes. A SPA planning scheme: outlines the strategic outcomes sought for the local government area as a whole and for particular localities allocates land for different uses, including residential growth areas, having regard to a range of considerations coordinates and integrates infrastructure and land-use planning, and indicates the location of existing and proposed community infrastructure identifies areas or places that constrain the use of land due to their environmental value, resource value or their adverse effects on development identifies the kind of development that requires approval (assessable development) or that can be carried out without approval if certain requirements are met (self-assessable development) specifies the development standards or criteria for assessing the suitability of a development proposal. A SPA planning scheme carries out these functions using the following key elements: Strategic outcomes provide the foundation of the scheme and express the purpose of the planning scheme and what it seeks to achieve. They cover a broad range of issues such as community needs, economic activity and nature conservation. Planning scheme maps identify land-use allocations, areas with special attributes, and major infrastructure. Planning schemes are also intended to include plans for growth and infrastructure provision. Zone is a common term given to the broad land-use allocations in the planning scheme, e.g. residential, business, recreation. The term overlay is often used for identified special attributes of land that are sensitive to the effects of development or may constrain development due to an environmental hazard or the value of a resource. Development assessment tables identify: the assessment category (assessable, development requiring compliance assessment, self-assessable or exempt) that applies to development in a particular zone or affected by an overlay the assessment criteria, including applicable codes, that are relevant to particular development whether code assessment or impact assessment is required for assessable development. 4 The Local Government Act 2009 introduced new terminology and requirements for the preparation of corporate planning documents. 73

88 Development assessment criteria, mostly contained in codes, are the criteria or standards for achieving the outcomes sought from self-assessable development, development requiring compliance assessment or assessable development. Codes may address a specific type of development (e.g. reconfiguring a lot), a type of use (e.g. home business), or may relate to an identified zone or overlay. Priority infrastructure plans (PIPs) are the key tool in a planning scheme for integrating land-use planning and infrastructure planning. PIPs assist in planning infrastructure in a coordinated, efficient and orderly way that encourages urban growth in areas where adequate infrastructure exists or can be provided efficiently. This ensures all new development is supplied with essential infrastructure such as water supply, sewerage, stormwater, roads and public parks. PIPs provide a mechanism for determining and charging for trunk infrastructure. Council s corporate plan should recognise the role of infrastructure planning in achieving overall municipal goals for urban stormwater quality management. The corporate vision will recognise the wider relationship between any local drainage network and the rest of the catchment, the key features of the drainage infrastructure that are to be protected and the ways in which the drainage system can, in turn, contribute to the achievement of other municipal goals. Fundamental requirements for the content of a corporate plan are set out in the Local Government Act As Chapter 3 of this guideline indicates, the preparation of a regional or local area urban stormwater quality management plan (USQMP) involves: identifying threats to receiving water environments from urban stormwater identifying strategies for managing urban stormwater to protect receiving environments identifying responsibilities for implementing strategies and actions to improve the environmental management of stormwater identifying opportunities to incorporate into all council management and operations activities actions and strategies to improve the environmental management of stormwater. This is a model process for the identification of issues and objectives for inclusion in council s corporate plan and to develop local policies and statutory controls in the planning scheme for the achievement of these objectives. Land-use planning and urban capability Land-use planning is of high importance in the protection of environmental values of waterways. The available evidence suggests an inexorable adverse linkage between urban land use and the health of downstream waters notwithstanding best efforts to date. Urban stormwater quality management therefore is only an adjunct to catchment-based land-use planning, especially in the protection of high value ecosystems which, once modified, are extremely difficult to rehabilitate back to their original state. Many modified systems stabilise at the changed state. Land capability assessment Land capability in Queensland has been traditionally associated with land suitability for agricultural production; however, in relation to urban land use, it is the capacity of an area to sustain a proposed land use without having a significant impact on the health of aquatic ecosystems or exceeding the physical capability of the land to support the development. If an assessment of these factors is not carried out, the opportunity to mitigate many of the impacts of a development may be lost or may only be overcome at significant cost to the developer initially, and governments later. 74

89 A full assessment of land capability may consider: depth to water table productive arable land dieback rockfall hazard drainage rock outcrop engineering hazard run-on fire hazard salinity (dryland/irrigation induced) flood hazard seasonal water logging groundwater geochemistry seepage scald inherent erosion risk shallow soils mass movement hazard sheet erosion risk permanently high watertable soil qualities (especially acid sulphate, erodibility, and sodicity/dispersibility) poor moisture availability steep slopes potential/known discharge area wetland and buffers wind erosion risk groundwater recharge areas It is not usually cost-effective to look at all these factors when consent authorities are making land-use decisions for example, urban footprint investigations or regional plans. Critical factors at this stage are those where there may not be cost-effective means for overcoming them for example, but not limited to, arable land, steep slopes/erosion hazard, flooding, mass movement and watertable. The results of an urban capability assessment can be presented in a map form within the planning scheme. These maps indicate the features of the water environment and any limitations imposed by the environmental characteristics of the site. The maps may be presented as a series of overlays, each containing a different suite of features or constraints, along with maps showing other planning needs for example, landscape scenic value and biodiversity conservation. Urban capability planning Urban capability planning and mapping is developed from an assessment of the interaction between the constraint factors, and a consideration of the implications of such assessment on the likely impacts, and their manageability. The urban land capability approach as developed by Hannam and Hicks (1980) 5 is used here, and can be accessed at the website of the New South Wales Department of Environment and Climate Change (DECC) 6 for greater detail. 5 Hannam, I.D. and Hicks, R.W. (1980). Soil Conservation and Urban Land Use Planning. Journal of the Soil Conservation Service of New South Wales 36: DECC (1998). Managing Urban Stormwater: Source Control, Part D Urban land capability assessment (draft), at < 75

90 NSW DECC, Land-use planning and urban capability < In this document, urban capability is considered as the capacity of an area to sustain a proposed land use without having a significant impact on the health of aquatic ecosystems or exceeding the physical capability of the land to support the development. Urban capability assessment is an important part of stormwater management. If an assessment is not carried out, the opportunity to mitigate many of the impacts of development may be lost or may only be overcome at significant cost to the developer or community. It is important that each development is tailored to the characteristics of a development site. The optimal time for assessing urban capability in the development process is at the land-use planning stage. Assessments can be undertaken as part of regional and local environmental studies, which provide the framework for regional environmental plans (REPs) and local environmental plans (LEPs) respectively. A broad assessment can be undertaken when regional studies are being prepared, with a more detailed assessment occurring for local studies. Urban capability mapping is developed from an assessment of the interaction between the landform, soils and hydrological features of proposed urban lands. It is designed to assist responsible planning and management in developing urban lands. Urban capability planning entails: establishing management objectives for example, as contained in any water quality improvement plan or healthy waterways management plan (as required in the EPP Water) preparing a land-use constraints table which sets out the qualitative and quantitative criteria for allocating the degree of constraint (e.g. slope gradient <15 per cent) delineating land units that is, tracts of land that can be treated separately for meaningful land assessment which can be expected to have the same rating for the proposed specific land use collecting data on soils, erosion hazard, nutrient hazardous areas, landform, drainage and geology establishing land units for urban capability This involves relating the soil and landscape data to the specific land-use constraints tables for each land unit. The degree of constraint for each unit is then determined by the most limiting land attribute. These maps will initially assign broad categories as indicated in Table 4.1 below producing urban capability maps The resultant map indicates physical constraints to conventional urban development and, in light of these, the maximum intensities of urban use the different areas will accept and the management and protective measures required to prevent degradation. 76

91 Table 4.21: Urban capability classes Class Description The particular land use is acceptable, with any land, soil or water constraints occurring only at a low degree. The particular land use is acceptable. However, one or more land, soil or water constraints exist at a moderate (but not high) degree and which require specialised management and/or construction techniques. The particular land use may not be acceptable. However, one or more land, soil or water constraints occur at a high degree and should be subject to special approval by the development consent authority. Usually such constraints are dependent on further specialised geotechnical/engineering, soil or water conservation advice. This special class includes areas with a very high variability of land, soil or water constraints which are unable to be delineated adequately at the scale of mapping and/or where further detailed site investigations are necessary. Land capability and land development Land capability factors are equally important later when land is proposed for complying development (material change of use, reconfiguration, and operational works) as they affect the design, intensity and management of development. A hierarchy of investigation levels is therefore warranted. Once urban land use is allocated based on the highest priority constraints, developers and landowners are usually obliged to provide information on the detailed biophysical and other impacts of development to ensure: the design and scale of the development (material change of use, and reconfiguration applications) is compatible with the site constraints and opportunities, and for operational works applications best management practice measures take account of the site constraints and opportunities during construction (erosion and sediment control), and post-construction (water sensitive urban design). A planning scheme code and or policy may be used to codify the constraints to, and management of, development based on land capability maps. For example, in Figure 4.3 below, setting out the degree of erosion hazard based on rainfall intensity (R-factor) and gradient might influence the design and intensity of development as well as scale of control measures. In this (formerly) Maroochy Shire Council (MSC) 2007 scheme, sites which are shown on the diagram as falling above the A line may be constrained in terms of lot layout and permitted cut and fill (slab on ground) construction. Those sites above the B line may also require significant reduction in development density and/or specialist investigations where a proposal is consistent with the planning scheme land use for the area, and a review of feasibility against the environmental objectives where it is not. It should be understood that it may not be costeffective to reliably control impacts on such sites by structural measures. 77

92 40 35 Slope (%) Medium to Low Erosion Hazard High to Very High Erosion Hazard D-line C-line Extreme Erosion Hazard B-line A-line R-factor Figure 4.3 Erosion hazard mapping based on rainfall intensity and slope gradient Use of zones, overlays and related provisions A range of spatial planning tools is available through the Sustainable Planning Act 2009 planning schemes to contribute to the achievement of water quality objectives. The following are examples of planning techniques with a spatial base: Urban floodway zone applied to land in urban areas identified as part of the active floodway High erosion hazard land overlay applied within the development footprint Land subject to inundation overlay applied to land in rural or urban areas subject to inundation, but not part of the primary floodway Special building overlay applied to land in urban areas subject to inundation, but not part of the primary floodway Incorporated plan overlay may identify specific areas where more detailed planning is necessary and include specific policy measures in a document which is incorporated in the planning scheme Development plan overlay may indicate areas of land where a detailed development plan is essential before development can be approved Development contributions overlay may illustrate areas where a development contributions plan is in place or proposed. Each zone or overlay has a clearly identified range of matters for consideration in making a decision. USQM plans should therefore consider the opportunities available to interlink with the techniques above. 78

93 Local policies Local policies can be based on issues or geography. The following is an example of an issuebased policy for stormwater: Stormwater drainage policy This policy applies to all land in the local government area. Policy basis Planning scheme policies Urban Stormwater Provisions and Waterways Overlay Code Queensland government legislative requirements (EPP Water, SPP Healthy Waters, regional plan) Requirements as signatory to the National Water Quality Management Strategy. Objectives Ensure that land-use activities potentially discharging contaminated run-off or wastes to waterways during construction and operation phases are sited and managed to minimise such discharges and to protect the quality of surface water and groundwater resources, rivers, streams, wetlands, estuaries and marine environments. Policy It is policy that: urban zones are designated in accordance with avoiding and minimising stormwater quality impacts urban development is designed in accordance with the planning scheme policies Urban Stormwater Provisions and Waterways Overlay Code, and consider the Urban Stormwater Quality Planning Guidelines. Local policies can also apply to a specific area or feature and may be multi-functional in character. The following example as a hypothetical scenario demonstrates this. 79

94 Local Rivers Council This policy applies to waterways with stream health class A and B (see Map 1). Policy basis Local River is the second major watercourse in the council area. The river is identified in the planning scheme as a key environmental feature. Urban development is encroaching as part of residential expansion. Action to manage the impact of development on the river s environmental values is required. The river is also listed in Schedule 1 of the EPP (Water) and identified as an aquatic ecosystem. The regional plan also identifies the riparian areas of the river as a major open space link. Objectives Establish Local River as a major open space link. Protect environmental values and water quality objectives. Protect conservation assets. Ensure that nearby urban development is sympathetic to the river environment. Policy It is policy that: urban development is prohibited outside the urban zone site management plans will be prepared for all development in the urban zone in the catchment of Local River development in the area must comply with the council s Local Rivers Management Plan development consider DERM s Urban Stormwater Quality Planning Guidelines Development assessment The state and local planning requirements contain the long-term direction and outcomes sought by the community and government. Figure 4.2 illustrates the way in which a development assessment decision derives its policy input from the state and local planning requirements. The relevant zone or overlay in the planning scheme determines the land-use outcomes. Information requirements for a development application may also be stated (see Appendix 3 for advice on this issue). These guidelines identify the relevant legislation, plans, strategies and guidelines which councils should give effect to under planning schemes via the majority of development assessment decisions. In a minority of development assessment decisions the decision-maker is a state agency in accordance with provisions in the Sustainable Planning Act 2009 and related legislation. Councils develop appropriate stormwater development approval conditions for a development as part of the development assessment process and implementation of local area stormwater management plans. These conditions can impose requirements related to a particular development or use of land both during construction and ongoing operational use of the site. There are, therefore, standard conditions that should appear on most development approvals which involve stormwater quality considerations. For example, development in the policy area must reflect the council s adopted local area stormwater management plan and/or planning scheme provisions; or, if a plan has not been adopted, development must reflect the SPP for Healthy Waters Appendix 1 - Development Assessment Code and the Urban Stormwater Quality Planning Guidelines As well as this, the owner of the land must enter into an 80

95 agreement with the relevant authority for the provision of drainage to the site in accordance with the authority s requirements and relevant legislation at the time. (This may form part of the general servicing condition normally placed on subdivision but should also apply to development where there is no subdivision.) Examples of other more specific conditions are set out below: Example: Development assessment conditions for stormwater protection Ensure that water containing oil, foam, grease, scum or litter is not discharged to the stormwater drainage system from the site. Ensure that all stored wastes are kept in designated areas or covered containers that prevent escape into the stormwater system. Ensure that all reasonable and practical measures are taken to minimise the amount of contaminants deposited by vehicles on the abutting roads when vehicles are leaving the premises. Ensure that no contaminants are washed into or allowed to enter the stormwater drainage system. Ensure that the site is developed and managed to minimise the risks of hydrologic damage to waters, and stormwater pollution through the contamination of run-off by chemicals, sediments, animal wastes or gross pollutants in accordance with current best management practices Other controls Other controls arising from development assessment processes may address the remaining elements of water sensitive urban design (WSUD) including: groundwater management groundwater quality groundwater quantity water conservation demand management stormwater harvesting and reuse greywater reuse recycling wastewater minimisation demand management infiltration management stormwater harvesting. Figure 4.5 summarises the WSUD elements. Many WSUD elements are addressed in Queensland through the existing work of various regional and local planning processes (e.g. the SEQ Healthy Waterways Strategy, regional NRM plans and implementation actions, and local council policies). However, not all of these are relevant to development assessment. To be effective, the design process for permanent stormwater management controls should be integrated with the elements for WSUD outlined above for the overall design for the site. 81

96 Development approval conditions will need to address construction and permanent phase controls. Parts 4.2 (Water Savings Targets) and 4.3 (Alternative Water Sources Commercial Buildings) of the Queensland Development Code include requirements for water savings targets and alternative water sources. The Water Act 2000, and the Water Supply (Safety & Reliability) Act 2008 which DERM implements, may impose requirements upon councils and developers on stormwater quantity (and in some cases, quality) management matters including: certain requirements for service areas of water service providers regulating certain levee banks regulating extraction of quarry materials from a watercourse or lake destruction of native vegetation, excavation, or placement of fill from a watercourse, lake or spring authorisation to take, and to interfere with, water from watercourse, lake or spring authorisation to take, or to interfere with, overland flow water (i.e. this may include stormwater harvesting in limited cases). Development assessment under the Sustainable Planning Act 2009 includes processes to identify all state and local government controls relevant to the proposed development (through the Integrated Development Assessment System (IDAS)). Councils may also impose conditions for stormwater quality management by entering into an agreement with a landowner. An agreement may be required as part of the planning control process for new urban subdivisions. It may provide for the: prohibition, restriction or regulation of the use or development of the land conditions subject to which the land may be used for specified purposes matters intended to advance the objectives of planning in Queensland. An advantage of some agreements is that they may be registered on title to bind future purchasers of the land. 82

97 Urban water cycle Total water cycle management Water sensitive urban design Potable water conservation Wastewater minimisation Stormwater management Groundwater management Demand management Rainwater reuse water reuse greywater reclaimed. Demand management Stormwater reuse Water reuse greywater reclaimed Infiltration inflow reduction Wastewater quality. Rain/stormwater harvesting Stormwater quality improvement Stormwater quality management Hydrologic environmental controls. Groundwater quality management Groundwater quantity management. Figure 4.4 Links between WSUD elements and the urban water cycle. The State Planning Policy for Healthy Waters deals with wastewater minimisation and stormwater management components (in bold). 83

98 4.2.5 The importance of an integrated approach The important linkage between land-use planning and operational activities of council is recognised in the Sustainable Planning Act 2009 plan-making process and the Local Government Act 2009 provisions. These provisions create the opportunity for the desired environmental outcomes contained in the planning scheme to be realised through the complementary policies of all council departments and service providers. This is of major significance for stormwater management, where other activities such as infrastructure planning and development, parks and recreation and conservation planning can play key roles in achieving improved stormwater quality. It is the integration of these processes that is the main approach to regional planning, planning schemes and development assessment in Queensland. These guidelines support the development of an integrated approach to the environmental management of stormwater within local government. Figure 4.6 outlines the links between WSUD and council planning schemes. Chapter 5 details WSUD principles, policy basis, and implementation tools. Figure 4.5 Water sensitive urban design and council planning scheme State interest (EPP Water) Desired environmental outcomes 5.1 Water Sensitive Urban Design (WSUD) Local scheme policies Zones 5.2 Site planning WSUD Chapter 5 Overlays Assessment codes & development approval conditions Design implementation tools 5.3 Planning the development phases for long-term benefit 84

99 5 Water sensitive urban design Key resource documents Level State Document Environmental Protection (Water) Policy 2009 Engineers Australia 2006, Australian Run-off Quality A Guide to WSUD International Erosion Control Association, Australia 2008 Best Practice Erosion and Sediment Control. International Erosion Control Association (Australia), Department of Natural Resources and Water 2007 Queensland Urban Drainage Manual Department of Transport & Main Roads 2010, Road Design Manual: A Guide to the Planning, Design, Operation and maintenance of Road Drainage Infrastructure 2nd Edition Regional specific Water Sensitive Urban Design (WSUD) policies and guidelines including: SEQ Regional Plan and Implementation Guideline No. 7 Water Sensitive Urban Design Objectives for Urban Stormwater Management (November 2009) Concept Design Guidelines for Water Sensitive Urban Design Version 1, Water by Design. South East Queensland Healthy Waterways Partnership, Brisbane, March 2009 Water Sensitive Urban Design Technical Design Guidelines for South East Queensland, South East Queensland Healthy Waterways Partnership 2006 Regional Deemed to Comply Solutions Stormwater Quality Management (South East Queensland), Water by Design, South East Queensland Healthy Waterways Partnership Construction and Establishment Guidelines: Swales, Bioretention Systems and Wetlands Version 1.1, Water by Design 2010 Asset Handover Guideline, Water by Design 2010 Asset Management Guideline, Water by Design (proposed) Far North Queensland Regional Plan Regional NRM Plans and Water Quality Improvement Plans Townsville/Thuringowa (WSUD Guidelines) Mackay Whitsunday (WQIP) Local government planning schemes and local guidelines on WSUD, erosion and sediment control, e.g. Local Sunshine Coast Regional Council 2008, Manual for Erosion and Sediment Control Gold Coast City Council 2007, WSUD Guidelines and WSUD Design Manual Brisbane City Council 2005, WSUD Engineering Guidelines 5.1 Introduction Chapter 5 introduces Water Sensitive Urban Design (WSUD) principles and presents techniques for incorporating WSUD principles into residential and commercial design as well as site planning. (Chapter 6 details source controls in the construction phase of site development and Chapter 7 deals with source controls in the permanent operation or post construction phase of site development.) 85

100 5.1.1 Water sensitive urban design and the total water cycle WSUD is an holistic approach to the planning and design of urban development that aims to minimise impacts on the natural water cycle and protect the health of aquatic ecosystems and environmental values. WSUD requires inter-disciplinary cooperation among the fields of water supply, wastewater (including sewage), groundwater and stormwater management. WSUD is applicable to new urban development such as residential estates, multiple unit dwellings, commercial and industrial and individual lot building sites. WSUD is also applicable to existing urban development as an infill or urban redevelopment program. It promotes the integration of water supply considerations and stormwater and wastewater management for urban development. The principles of WSUD are to: protect existing natural features of the natural drainage system including waterways and water bodies and ecological processes integrate public open space with stormwater drainage corridors to maximise public access, recreation activities, visual amenity while preserving waterway habitats and wildlife corridors maintain natural hydrologic behaviour of catchments and preserve the natural water cycle via minimising changes to the natural frequency, duration, volume and peak discharge of urban stormwater protect water quality environmental values of surface and groundwaters minimise demand on the reticulated water supply system and utilise stormwater as a valued resource minimise capital and maintenance costs of stormwater infrastructure and minimise sewage discharges to the natural environment integrate water into the landscape to enhance visual, social, cultural and ecological values. WSUD is a nationally recognised term, and may be viewed as integrating the holistic management of the urban water cycle into the planning and design of the built form of development. WSUD adopts a planning and design approach that integrates multiple opportunities into the built form of individual allotments, streets, suburbs and even masterplanned communities and precincts. Total water cycle management (TWCM) can be described as the integrated management of water resources to ensure their equitable and sustainable use by the built and natural environments or water catchment. To this end, TWCM provides a system or framework for decision making within organisations. It shares many of the same principles as WSUD. TWCM is therefore concerned with all aspects of the water cycle, normally on a broad strategic basis from a regional or local authority level to a neighbourhood or local plan level. TWCM is also concerned with the whole water cycle from catchment management issues, to water recycling and treatment, through to the specific aspects of WSUD at the neighbourhood or site specific levels. WSUD provides the framework, principles and practices to promote and support integration of total water cycle management into the planning and design of the built urban environment. Integrating WSUD outcomes into the urban built form is an essential aspect of achieving a total water cycle management philosophy. Techniques which emphasise addressing stormwater where it falls, infiltrating it, preserving natural drainage patterns, and preserving natural vegetation, offer the best opportunity to protect the environmental values of nearby creeks, rivers, lakes, wetlands, and coastal waters. Incorporating these ideas and concepts into the project design before it is built also offers the opportunity to reduce capital infrastructure and long-term maintenance costs. At the neighbourhood or even at the catchment scale, these techniques can help design neighbourhoods that minimise impacts on water quality and improve the quality of life. 86

101 These guidelines seek to achieve a consistent approach to the planning and design of both the construction and permanent phases of urban land development in accordance with water sensitive design principles that, with respect to stormwater management, include those WSUD principles listed above. Urban land development usually involves major earthworks potentially resulting in significant contamination of stormwater by eroding soils and building waste pollutants. During the construction phase, hundreds of tonnes per hectare of soil plus adsorbed pollutants can be eroded from disturbed areas and deposited into downstream waterways, potentially overwhelming the future benefits of water sensitive urban design implemented in the subsequent permanent phase of urban land development. The implementation of best management practices during urban land development minimises the risk of causing environmental harm to the environmental values of the receiving waters. During the construction and permanent phases the following impacts can occur: construction phase (as depicted in Figure 5.1) from major soil disturbance, alteration of natural drainage lines, increased run-off volume with exposure of subsoils, and the removal of essential soil-stabilising vegetation, potentially resulting in major discharge of sediment, nutrients and other pollutants (e.g. litter, rubble, cement and concrete wash-off, paints, plaster, brick-sand, cleaning products and imported soils) to receiving waters permanent phase from increased imperviousness, decreased water infiltration and changes to stormwater run-off characteristics, potentially aggravating downstream flooding and increasing pollutant inflows to receiving waters. Maroochy Shire Council Figure 5.1 Construction site sediment export WSUD offers an alternative to the traditional conveyance approach to stormwater management. It seeks to minimise the impact of urban land development on the natural water cycle, integrating the design of the urban form (for example, housing density, degree of imperviousness, and landscaping) with stormwater source (including erosion and sediment control at the construction phase and structural controls). 87

102 5.1.2 Benefits of water sensitive urban design WSUD emphasises the benefit of stormwater and waterways as a resource and an asset, rather than the conventional view of stormwater merely as a nuisance. It provides many opportunities to integrate water features in urban design and to enhance the social and environmental amenity of urban developments. The economic benefits and constraints of applying the WSUD techniques to achieve the urban stormwater design objectives of the State Planning Policy for Healthy Waters are summarised in the Water by Design publication, A Business case for Best Practice Urban Stromwater Management Version 1.1 (2010) published by the South East Queensland Healthy Waterways Partnership. Its findings are that the benefits of using WSUD to achieve the stormwater management objectives on typical residential, commercial and industrial development in Queensland are likely to significantly exceed the costs. 5.2 Site planning The processes used to develop site layout plans are fundamental to achieving the principles of WSUD and good environmental management of stormwater. The following describes key areas where developers can incorporate these principles at the site planning stage Site analysis The purpose of a site analysis is to identify the natural features that need to be considered during planning and design. These include the area s topography, drainage patterns, soils, geology, ground cover and sensitive regions, along with significant natural attributes such as wetlands, waterways, remnant vegetation and wildlife corridors. There should also be an assessment of the area s stormwater and drainage requirements and constraints. This should include flood control (for example the 100-year ARI flood limit), the potential maintenance of natural waterway corridors and the provision of stormwater management structures and treatment measures. As part of the drainage strategy, developers need to demonstrate that the proposed construction phase erosion, sediment and drainage controls and the permanent phase stormwater treatment train measures, developed in accordance with the respective treatment guidelines, or design objectives, will sufficiently mitigate potential water quality and quantity impacts to protect the environmental values of receiving waters. The physical ability of the site to sustain specific uses determines the scale and arrangement of development that is most consistent with WSUD principles Site layout plans Site layout plans determine the scale and arrangement of the proposed development that is most consistent with WSUD principles for managing the drainage system. Using the site analysis which identifies and protects those areas of environmental significance, the areas of developable land can be identified. Site layout plans address where the development should occur within the site to produce the least overall impact on the environment. The plans should ensure there is adequate land area in appropriate locations designated for the purpose of temporary and permanent stormwater management. The assessment of potential areas for development should consider the site locations of stormwater treatment measures such as constructed wetlands, sediment basins, gross sediment traps and infiltration/retention basins. It is important to minimise the areas of the site which do not drain to treatment measures essential for protection of the EVs, for example, sediment basins during land development. 88

103 Figure 5.2 Land use and run-off Preferred conceptual design options and details of cost-effectiveness practices should be prepared that: are most appropriate for retaining or detaining stormwater locally, given the particular conditions of soil, geology and topography involved and the anticipated land use ensure pollution mobilisation and conveyance within and from the site are minimised increase public amenity through landscaping and the provision of wetlands and wildlife habitats, where possible and appropriate. Preliminary layout plans would be required for pre-lodgement conferencing with the assessment manager prior to lodging the detailed design with the development application. These matters are detailed for both the construction phase and the permanent phase of urban land development in the following sections. The construction phase controls in Figure 5.2 have not been adequate to protect local EVs notwithstanding implementation of a range of typical control measures. It is very important that construction phase sediment movement does not ruin WSUD measures. The site layout will also have implications for water quality during land development, especially on moderate to extreme erosion hazard land. For example, roads which are laid out parallel to the contours will increase site disturbance by maximising cut and fill, while roads perpendicular to the contours will increase slope length and hence, if uncontrolled, concentrate flows and increase run-off velocities. Roads diagonal to the contours tend to reduce the erosion risk. 89

104 5.2.3 Concept Design Guidelines for Water Sensitive Urban Design The Concept Design Guidelines for Water Sensitive Urban Design (Water by Design 2009, South East Queensland Healthy Waterways Partnership, Brisbane) assist interdisciplinary teams to conceptualise and develop design solutions that integrate best practice sustainable urban water management with the urban form. Further information on design tools or best planning practices of WSUD for different types of urban development can be found in section 4 of that guideline. The term water sensitive urban design for urban planning and design sets the context for these guidelines. The guidelines can be used by all practitioners involved in the conceptual design phase of urban development. Although the content of these guidelines is tailored for specific application in South East Queensland, they are also relevant and applicable for areas outside South East Queensland. 5.3 Planning the development phases for long-term benefit The development phases include the permanent operational phase and the construction phase. The two phases are discussed in more detail in the following sections. Effectively managing stormwater over the long term, long after the construction process is over, is a significant challenge. To be most effective, the design process for permanent stormwater controls should be integrated into the overall design for the site. Planning for permanent stormwater controls could affect decisions about site design, location of buildings and other structures, grading, and preserving natural features. By preserving natural drainage patterns, trees, native vegetation, riparian buffers, and wetlands, it might be possible to construct fewer or smaller structural stormwater controls to cope with run-off from the site. Permanent stormwater controls should be designed with two important goals in mind: 1. reduction of the volume and velocity of run-off 2. reduction of the pollutants contained within stormwater leaving the site Permanent operational phase Stormwater treatment measures may be applied to lot, street, subdivision and commercial or industrial scale. Measures include gross pollutant traps, sediment basins, vegetated swales, buffer strips, infiltration devices, porous paving, bio-retention systems, constructed wetlands and rainwater tanks. At an appropriate development scale, stormwater treatment measures can be combined to develop a stormwater treatment train to remove pollutants, manage flow and conserve/re-use stormwater, in accordance with the stormwater treatment guidelines (design objectives) for permanent phase development in Table 2.2 and Table 2.4 (see Chapter 2). Design and construction of stormwater treatment measures are described in Chapter 7 Structural treatment measures. Stormwater treatment train design information and layout drawings should be included in the technical information submitted with the development application. Supporting technical information should include equipment selection, sizing and calculations (or model outputs) that quantify the design performance in accordance with the permanent phase stormwater treatment guidelines (design objectives). Site layout drawings should include stormwater treatment train equipment identification and location. Best management practices that support the principles of WSUD for smaller scale housing, commercial/industrial developments include the treatment of stormwater run-off from impervious areas. Possible stormwater treatment measures include gross pollutant traps, litter/trash racks and bio-retention systems. The type and scale of the development will 90

105 determine the adopted treatment measures, as deemed to comply solutions. 7 Deemed to comply solutions, rather than individually modelled and designed treatment train solutions, are likely to be the most effective and efficient way of addressing stormwater design objectives for many smaller developments. For many smaller development types the SEQ Healthy Waterways Partnership guideline Water Sensitive Urban Design Deemed to Comply Solutions for Queensland Stormwater Quality Management 2009 outlines straightforward measures for storm water quality management. The deemed to comply solutions are designed to meet the stormwater quality management design objectives (see Chapter 2) without the need for a site stormwater quality management plan. (Note that an erosion and sediment control plan may still be required.) The Queensland Urban Drainage Manual (NRW, 2007) provides design guidelines for the hard-engineering components of WSUD (for example, pipe drainage) and the design of open channels, but does not provide specific design information on WSUD. It details technical and regulatory aspects to be considered during the planning of urban stormwater drainage works, and includes design and computational procedures. Information on WSUD is available at state, regional and local levels from the key resource documents listed at the beginning of this chapter. Stormwater conservation/reuse measures under the Queensland Development Code MP 4.2 (Water Savings Targets) include water savings targets of 70 kl/year for new detached houses and 42 kl/year for terraces/townhouses. Water savings targets must be achieved by means other than the use of the reticulated water supply. The water savings targets apply statewide in accordance with the commencements dates therein. Acceptable solutions include rainwater tanks: for detached houses a minimum capacity of 5000 L, and for semi-detached houses a minimum capacity of 3000 L. Tanks must be plumbed to toilets and washing machines Construction phase Eroded soils and litter are major pollutant sources during construction activity. There is also potential for hydro-modification of streams due to increased run-off coefficients when subsoils are exposed, for longer term major developments. WSUD principles and reducing erosion during construction are fundamental to achieving water quality objectives in relevant waterways. Significant reductions in pollutants can be achieved by using a combination of improved construction practices, structural and vegetation measures and soil stabilisation techniques. A site management plan should be prepared, incorporating a range of control measures. Chapter 6 details source controls in the two development phases: construction phase site development permanent operation phase (post-construction) residential development. 7 Deemed to comply solutions means that the implementation of specified practices is deemed to comply with the stormwater design objectives. 91

106 6 Source controls Key resource documents Level State Document Engineers Australia (2006), Australian Run-off Quality, A Guide to Water Sensitive Urban Design International Erosion Control Association (Australasia) (2008) Best Practice Erosion and Sediment Control Department of Natural Resources and Water (2007), Queensland Urban Drainage Manual Department of Transport and Main Roads (2010), Road Drainage Manual A Guide to the Planning, Design, Operation and Maintenance of Road Drainage Infrastructure 2 nd Edition Urban Development Institute of Australia (Queensland), EnviroDevelopment Standards Version 2 Region-specific source control policies and guidelines including: South East Queensland (SEQ) Regional Plan and Implementation Guideline No. 7 Water Sensitive Urban Design Objectives Regional SEQ Healthy Waterways Strategy & supporting guidelines South East Queensland Healthy Waterways Partnership (2006) Water Sensitive Urban Design Technical Design Guidelines for South East Queensland Water by Design (2009) Concept Design Guidelines for Water Sensitive Urban Design Version 1, South East Queensland Healthy Waterways Partnership. Far North Queensland Regional Organisation of Councils Development Manual Operational Works Design Guidelines D5. Stormwater Quality Management Version No. 11/06 Regional NRM Plans and Water Quality Improvement Plans (WQIP) Townsville/Thuringowa (Water Sensitive Urban Design Guidelines) Mackay Whitsunday (WQIP) Local and regional council planning schemes and local guidelines: Sunshine Coast Regional Council 2008, Manual for Erosion and Sediment Control Local Gold Coast City Council 2007, Water Sensitive Urban Design (WSUD) Guidelines and WSUD Design Manual Brisbane City Council 2005, WSUD Engineering Guidelines Local Government Association of Queensland 2006, Introductory Erosion and Sediment Control Guidelines for Queensland Councils 92

107 6.1 Introduction Preliminary information This chapter may be revised where new urban stormwater policies and guidelines relevant to Queensland are further developed. This chapter does not attempt to interpret all legal requirements for erosion and sediment control for all jurisdictions. At the time of writing, this policy area was under further development within South East Queensland. Therefore the following advice is to be used as a guide only. This chapter is based on the framework and content of Victoria Stormwater Committee VIC EPA 1999, Best Practice Environmental Management Guidelines Urban Stormwater, CSIRO Publishing. Dealing with pollution at source is the most effective means of protecting stormwater quality. This chapter describes tools available to councils and other agencies to help manage stormwater pollution resulting from council operations and household, business and construction activities in urban areas. These include: council operations source control measures for local and regional council activities that may affect stormwater quality construction activity developing site management plans and best practices to implement the plan planning and development putting in place the planning framework and institutional processes for management of land development and building activities with water catchments to protect the environmental values of the waters business surveys performing surveys to determine the nature and extent of business activities likely to cause stormwater pollution education programs ways to prepare and deliver education programs to reduce stormwater pollution from council, industry and household activities enforcement measures that can be taken to complement education and other management programs. Elements of source control dealing with managing the quantity of run-off from urban areas are covered in sections describing Water Sensitive Urban Design and land use planning (Chapter 5). The pollution-generating activities of business and industry are not addressed in any detail by this guide. Major waste management activities of industry are dealt with by the Department of Environment and Resource Management and local/regional councils through conditions of environmental authorities and waste management agreements. However, there are many wastegenerating activities not part of major industrial processes that are not subject directly to such licensing or regulation and which have significant collective potential to pollute stormwater. Responsibility for dealing with these pollution-generating activities rests with managers of the business enterprises and councils. The business survey section (section 6.4) provides a method for self-assessment or independent appraisal of business activities and their pollution potential to enable better targeting of education and enforcement programs. For further information see the Department of Environment and Resource Management s website for its Compliance Strategy and Annual Compliance Plan. SPP for Healthy Waters contains provisions on how local governments protect receiving water EVs from the impacts of the release of wastewater (other than contaminated stormwater and sewage) from these non-era developments. Part B of the Development Assessment Code (Appendix 1) provides interim preformance outcomes until local planning schemes incorporate locally appropriate Codes. 93

108 6.2 Council operations Through their operations in areas such as road and pipeline construction and maintenance, street cleaning, sewerage reticulation and pump stations, and waste collection, local and regional councils directly influence the quality of stormwater within a catchment. By managing stormwater in its operational activities, local and regional councils can significantly improve the quality of urban stormwater run-off. There are three main areas of local and regional council activity that can affect stormwater quality. These are: planning of asset construction and maintenance maintenance operations staff training to improve practices. To help ensure project managers, council staff and contractors consider all aspects of water quality in their activities, a simple checklist is provided in section Planning of asset construction and maintenance Stormwater quality is an essential consideration during the planning of asset construction and maintenance activities. An analysis of each activity s potential to pollute should be undertaken and improved methods designed into the activity to minimise pollutant generation. Construction activity planning The construction of buildings, roads, drains and open spaces all have the potential to produce pollutants that may enter the stormwater system. Eroded soils with associated adsorbed pollutants and litter are major pollutant sources during construction activity. Significant reductions in these pollutants can be achieved by using a combination of improved construction practices, structural and vegetation measures, and soil stabilisation techniques. A site management plan should be prepared, incorporating a range of control measures that are complementary to the construction plans (see section below on site management plans). Fundamental to reducing erosion is restricting activities in areas prone to erosion to minimise disturbance and exposure of the soil. Careful planning and siting of works will reduce the opportunity for erosion to occur. Much council construction and maintenance work is performed by contractors. When developing an asset construction and maintenance specification or brief, the specification should contain a clause that stipulates the need for consideration of stormwater quality. For example: Example clause The impact of XXX Road must take into consideration the issue of stormwater quality and include an erosion and sediment control plan with appropriate treatments and operational features to minimise stormwater pollution and meet the design objectives for release off-site as set out in the Urban Stormwater Quality Planning Guidelines, Department of Environment and Resource Management. For all construction activities council should ensure that works are planned to minimise erosion and sediment generation. For major construction activities a site management plan should be required. To help council staff assess any construction activity for its pollutant potential and evaluate a site management plan, a checklist is presented in Section

109 Maintenance activity planning Sensible planning of operational procedures for each maintenance activity is the key to minimising their impact on stormwater. Inspections to identify those activities that are significant sources of pollution are an essential component of this planning process. Information from inspections can be used to change operational activities to improve stormwater quality. Ongoing monitoring of these activities is required to ensure stormwater pollution is minimised. Monitoring may be carried out through inspections, reviewing the number and type of complaints, and through contract reporting mechanisms. As in all survey schemes, good record keeping is vital Source controls for maintenance activities There are a number of simple and practical changes to maintenance activities that local and regional councils can implement at minimal cost and achieve significant improvement in the quality of stormwater run-off. In performing maintenance activities, the goal is to prevent waste material entering the stormwater drainage system. The maintenance activities listed below provide a starting point. Guidelines are available from various sources including the South East Queensland Healthy Waterways Partnership website and the Local Government Association of Queensland (see also start of chapter section on key resource documents). Possible maintenance activities include: street cleaning drain maintenance domestic waste and recycling collection council bin design and cleaning pavement repairs and resurfacing unsealed roads parks, reserves, golf courses and medians material storage plant and equipment unloading and loading areas building maintenance and construction graffiti removal emergency response stormwater quality treatment assets Training and staff awareness Improved stormwater quality is largely dependent on the comprehension, acceptance and adoption of best practices by council staff. Staff training in these practices will assist implementation. The following systems can be developed to establish and maintain staff knowledge and awareness: 95

110 staff work groups these provide effective forums for the review of current work practices and the development of appropriate new work practices performance indicators develop a range of key work practice performance indicators to be used in work group reviews routine monitoring programs train staff to routinely check activity procedures and their effect on stormwater pollution work practice audits and training periodically audit employee work practices and regularly review work performance and implement training contract inclusions write contracts that clearly instruct sub-contractors to work in accordance with this guide Council source control checklist The following checklist can assist council staff to identify and address any aspects of council operational activities that may affect stormwater quality. The checklist can be used to refer back to the relevant sections within this guide which provide further information on individual issues. The checklist is divided into two parts: Part A deals with the planning of construction and maintenance activities. This should be completed at the planning stage of each project/contract and can be referred to when writing specifications. Part B describes maintenance activities that potentially impact on stormwater quality. Choose the section that is relevant to a particular activity and use the checklist to ensure that all aspects of the activity that may affect stormwater quality are considered. Part A: Planning asset construction and maintenance Do the works have the potential to affect stormwater quality? If yes: Maintenance planning Can alternative measures be used (e.g. grass cutting: use alternative species, use grass catchers)? Can clean-up measures be employed during the works (e.g. street sweepers following grass mowers)? Has a suitable site been identified for disposal of removed sediment and vegetation? Such material should not be left on or adjacent to the banks of watercourses. Construction planning Is the site larger than one hectare or in a high risk erosion area? If yes: You need to develop site management plan. See the checklist in section If no: Are mitigation measures required on-site (e.g. open bin or skip, or sediment fences on boundary, prompt revegetation of site, prevent sediment export from vehicles)? Are the suggested measures appropriate? 96

111 Part B: Maintenance activities Pavement repairs measures are taken to prevent pavement material from entering the stormwater system all materials are removed from the site when work is completed. Unsealed roads measures are taken to minimise erosion and sedimentation suitable road material is used thorough compaction of road material is performed works are timed to reduce the risk of erosion and sedimentation Street cleaning programs have been developed to cater for hot spots an auditing program is implemented to allow revision of cleaning schedules the cleaning program is coordinated with other council activities operators of street cleaning machinery and equipment are well trained refuelling, loading, vehicle maintenance and wash-down areas are equipped with structures to prevent pollutants from entering the stormwater system routine inspections and maintenance are performed for all equipment and plant training procedures are put into place for staff in regard to accidental spills and disposal of waste from cleaning equipment Drainage maintenance regular inspection and maintenance programs are performed auditing programs are in place to assess if the maintenance schedule is being followed appropriate machinery is being used refuelling, loading and vehicle maintenance areas are equipped with structures to prevent pollutants from entering the stormwater system routine inspection and maintenance programs for equipment and plant are implemented staff are trained to deal with accidental spills and maintenance of the drainage system staff are trained in environmentally sound procedures when carrying out works in and around natural watercourses and wetlands 97

112 Domestic waste, recycling and council bin collection appropriate vehicles and receptacles are being used for waste collection to minimise pollutants/waste materials entering the stormwater system staff are trained in appropriate best practice techniques to minimise spillages collections are frequent enough to minimise spillages/loss of materials entering the stormwater system an auditing process is established to ensure that collection frequency is maintained as specified on schedules and spillages, or other losses are minimised local laws have been developed to discourage illegal dumping or poor litter management by local businesses and residents (e.g. building sites, commercial areas) refuelling, loading and vehicle maintenance areas are equipped with structures to prevent pollutants from entering the stormwater system an inspection and maintenance schedule for equipment and plant is implemented Parks, reserves, golf course and median strips appropriate management practices are conducted to minimise grass leaves and prunings from entering the stormwater system the type of vegetation planted increases infiltration appropriate fertilisers are used and operators are trained in appropriate application techniques refuelling, loading and vehicle maintenance areas are equipped with structures to prevent pollutants from entering the stormwater system routine inspections and maintenance are performed on all equipment and plant staff are trained so their actions minimise the impact on stormwater quality Building maintenance and construction materials are stored under cover building and cleaning wastes are not disposed of into the stormwater system staff are trained in stormwater quality best practice techniques Graffiti removal no toxicants are washed into the stormwater system staff are trained in stormwater quality best practice techniques 6.3 Planning and development erosion and sediment control Strategic planning and legislative issues This section informs planning and decision making on land development activities that may result in stormwater erosion of disturbed soil and sediment transport to land and waters, potentially having an impact on receiving waters environmental values under the Environmental Protection (Water) Policy 2009 (the EPP Water). 98

113 The environmental values established under the EPP Water need to be protected, in part, by: providing natural water infiltration and flows using water sensitive urban design principles (WSUD) and effective erosion and sediment control using best practice urban stormwater quality and quantity management. Development assessment and management issues The effective management of stormwater quality and quantity during the land development phase minimises the risk of causing environmental harm 8 to the receiving waters. In a single storm event, 25 mm depth of soil can be washed from a single hectare amounting to 250 cubic metres of soil (around ten to fifteen dump truck loads). Construction activities therefore involving major soil disturbance, alteration of natural drainage lines, or the removal of essential soil stabilising vegetation can potentially result in many hundreds of tonnes of sediment being deposited in receiving waters. With the sediment are associated soil nutrients, and potentially other pollutants (e.g. litter, rubble, concrete-mixer waste, petro-chemicals, paints and cleaning products). As larger greenfield sites may be entirely cleared initially but not stabilised for two years or more, during which smaller stages are on-sold and progressively brought onto the market (see Figure 6.1), the adverse impact on the receiving environment from storms during these years can completely overwhelm the future benefits of WSUD implemented in the permanent phase. Figure 6.1 Major staged development cleared then developed in stages over a period of several years. These impacts need to be considered separately from the post-development or permanent settlement phase as the issues and impact assessment methodology are different. The critical impact factors are site erosion hazard (including the timing of development with respect to wet seasons) and the duration and areal extent of exposed soil until final site stabilisation after the end of major house-building activities. 8 See section 14 of the Environmental Protection Act

114 Stormwater quality management technology has its limitations because: control measures are usually aimed at managing risk, engineering practicality, and costeffectiveness on individual sites, rather than managing cumulative impacts at catchment scale industry compliance performance levels rely on complex and often imperfect contractual arrangements between the many involved parties owner, consultants, contractors and subcontractors. Protection of environmental values will therefore usually require a catchment-based approach to allocation of land use, land capability, catchment hydrology and the environmental values to be protected. The aim is to ensure that these cumulative risk-failure impacts do not over time result in unintended and unacceptable consequences to the environmental values. If modelling is used for this purpose, it should take account of the construction phases of development, including both the increased run-off coefficients, and sediment and nutrient exports accompanying land clearing and subsoil exposure. Councils also need to have in place effective institutional processes to manage land developments. This includes processes for development assessment, auditing and compliance, and for long-term management of permanent stormwater quality treatment assets such as biofiltration basins and wetlands. Material change of use (MCU) and reconfiguration of a lot (ROL) The overall potential impacts of both the construction and permanent phases, and the feasibility and cost-effectiveness of control measures on each site (given, for example, site constraints, and nature and scale of the development) need to be considered first when a change in land use is proposed, and subsequently as the development unfolds. Potentially serious land capability constraints affecting the cost-effectiveness and hence the feasibility of a development include: flood prone areas sediment basins are often located at the low point of a development and they may not be stable or able to be properly installed or operated if subject to flooding steep terrain high erosion risk, difficulty in preventing erosion, and in installing a stable and adequately sized sediment basin flat terrain with high groundwater levels difficulty in collecting and directing surface flows, coupled with difficulty of installing a sediment basin in the presence of high groundwater, which is sometimes geochemically contaminated. A conceptual erosion and sediment control plan should be submitted for MCU and ROL applications to demonstrate that there are feasible measures available to adequately manage the impacts of development as they are understood and relevant to those stages, to the degree required to protect the environmental values. This also informs the developer of the economic consequences of impact management at the outset of the development process. As site constraints increase, the cost-effectiveness of best practice control measures decrease. Where the conceptual plan cannot substantiate that best practice control measures are feasible and still achieve the environmental performance objectives, the proposed nature, layout and intensity of development should be reconsidered, for example by fitting the development more to the terrain, rather than fitting the terrain to the development, to reduce the need for clearing and earthworks. Operational works Development approvals for operational works should be contingent on prior submission of a detailed erosion and sediment control plan (ESCP) which complies with this guide or any further council requirements as a minimum technical standard. The initial ESCP should be prepared having regard for the earthworks plan, and provides a basis for subsequent civil tendering, so that the principal contractor can more accurately assess the likely costs of the project, and reduce the need later for variations to contract. The primary ESCP may later be 100

115 followed by a series of secondary ESCPs for the various stages of the project in collaboration with the principal contractor. However, best practice design as set out in an ESCP is only the first step to development compliance. Subsequent installation, operation maintenance and monitoring of structural controls and their works programming and coordination requires ongoing adaptive management, and this must be carried out in compliance with the general environmental duty under the Environmental Protection Act , that is, taking all reasonable and practicable measures to protect the environmental values of receiving waters from environmental harm. Water sensitive urban design Water sensitive urban design (WSUD) approaches to water management during development and its construction aim to minimise impacts on the natural water cycle, avoid or minimise offsite pollutant discharge, limit changes to the volume, rate, duration and frequency of stormwater discharge, and protect the environmental values of receiving waters. WSUD approaches are described in Chapter 5 of this guideline (see also key resource documents for this chapter). WSUD applied to the construction phase of land development is primarily concerned with drainage, erosion and sediment control. WSUD at the construction stage needs to take account of the final layout of permanent stormwater controls that will be constructed. Temporary erosion and sediment controls need to be incorporated into stormwater management plans for areas where permanent stormwater controls such as wet ponds, swales, and bio-retention cells are to be constructed. Poor erosion and sediment controls can lead to waterway damage, and the permanent controls being overwhelmed with sediment, and not performing as designed once the development is completed. WSUD principles should be incorporated into construction phase planning and design, in accordance with the stormwater design objectives in Table 2.1 or acceptable local design objectives of at equal or greater effect. Construction There are a number of simple ways to minimise pollution from construction sites. Significant improvements can be achieved with careful planning and coordination between construction activities and control measures. A key reference document, Best Practice Erosion and Sediment Control, International Erosion Control Association (Australasia), (IECA 2008) should be consulted for information on the main concepts for reducing pollution from construction sites. Construction activity can be divided into two phases the land development stage and the building stage. Both of these phases are known to result in serious stormwater pollution unless appropriately managed. Land development stage Land development involves making undeveloped land suitable for urban uses through vegetation clearing, land forming and provision of services such as roads, drainage, water supply, sewers, electricity and gas. Land development usually involves major earthworks resulting in significant potential for contamination of stormwater by eroding soils (Figure 6.2). Building stage Building construction can result in significant soil disturbance as well as the contamination of stormwater with building wastes. Pollutants can include litter, rubble, concrete-mixer waste, paints, plaster, brick sand, cleaning products and imported soils, etc. It should be noted that conventional allotment sediment control practices for a building site are largely ineffective at turbidity control. Therefore, for greenfield developments, subdivision-scale controls may be needed. 9 See section 319 of the Environmental Protection Act

116 Effective source control measures employed during construction can greatly minimise the impact of both phases of construction activity on stormwater quality. Site management plans (may also be known as erosion and sediment control plans or include such provisions) are an effective means of planning and implementing measures to minimise the generation of pollutants from construction activities. Best management practices This section discusses the issues involved with both phases of construction and outlines some best practice measures that can reduce pollutants reaching the stormwater system. Guidelines for developing a site management plan or erosion and sediment control plan are also included. However, in implementing the guidelines, there should always be regard for particular site conditions, and for complying with the general environmental duty (GED) under the Environmental Protection Act However, this guideline does not attempt to cover all the potential requirements under this Act for the GED as it is a planning guideline and not a compliance and enforcement guideline that would apply for all situations and jurisdictions. Where a particular combination of best practice measures does not result in the desired environmental or design objective, those management measures should be reviewed to see if a different combination of measures, or additional measures are necessary in accordance with local government requirements and the GED. Figure 6.2 : Land development can result in significant vegetation removal, soil disturbance and altered hydrology over large areas Urban land development usually involves major earthworks potentially resulting in significant contamination of stormwater by eroding soils and building waste pollutants. Best management practices for urban stormwater minimises the risk of causing environmental harm to the environmental values of receiving waters. Principles Stormwater quality control during the construction phase involves: planning The nature and scale of development must be consistent with the constraints and opportunities of the site and stormwater quality management integrated into the works schedule not prepared as an after-thought. They also need to: provide continuous and cost-effective protection integrate and synchronise the various measures for the construction, building and permanent phases to provide continuous protection for the site source control Preventing erosion in the first place is fundamental to stormwater quality management on construction sites. This initially involves: 102

117 preservation of essential or protected vegetation such as riparian vegetation, and vegetation which does not need to be removed for construction purposes. Construction needs aside, where there is a need to show the customer what they re buying, concentrate on thinning undergrowth and brush, while minimising grubbing, topsoil removal, and tree removal. Vegetation helps keep the soil in place project works scheduling to minimise site activity in areas prone to erosion (e.g. in and around drainage lines) minimising both the area and the duration of disturbance careful planning and scheduling of operational works Avoiding exposure of disturbed areas during peak rainfall periods will significantly reduce the potential for erosion and stream hydro-modification to occur. While it is generally recommended that larger sites are cleared and developed in manageable smaller stages, this may sometimes conflict with the need to quickly complete and stabilise a large development prior to the wet season. Where larger sites are not staged, however, there should be a progressive revegetation (or other effective stabilisation measure) program implemented following commencement of clearing (not at the end) so that no part of the site is left exposed and unstable for extended periods in the high rainfall coastal regions. Even temporary grass vegetation or synthetic covers can reduce erosion levels to less than 1 per cent of the level expected if the site is left with soils exposed sediment control through structural measures such as sediment fences and sediment retention basins hydrologic control Specific control measures to meet the design objectives of Chapter 2 may not be necessary for smaller, well managed developments which are quickly stabilised, especially in inland areas and if avoiding the wet season in the coastal zone. However, a larger greenfield site presents a significant risk of causing stream hydro-modification if it is in the coastal zone, and there are proposed to be large areas of exposed soil on the site at any one time over a period of 12 months or longer (from the time of clearing to completion of house building). In such cases, the risk should be quantified and the justification for management measures considered in terms of their cost-effectiveness, balanced against the risk to the environmental values of the receiving waters. Site management plan objectives Site management plans 10 aim to minimise the generation and export of sediment and other pollutants resulting from construction activities. Generally this can be achieved through: the project manager ensuring that the contractual lines of responsibility for all measures are clearly set out to contractors and sub-contractors from commencement of works until final site stabilisation. Where there is failure critical to environmental performance by a contractor, the project manager should ensure there is a system in place for this to be discovered and promptly remedied coordination of erosion controls with construction activities, including the staging of works minimising soil exposure during construction hasty and extensive revegetation and/or land stabilisation works effective management of water to, within and from a site provision of suitable access tracks and loading, unloading, maintenance and wash-down areas effective litter management and house-keeping practices 10 Site management plans may also be termed or include erosion and sediment control plans(escp) or site Stormwater Quality Management Plan (SQMP). 103

118 employing sediment capture techniques a flexible plan that can incorporate unexpected changes in the design, site or weather conditions. It is recommended that all site management plans have, as a minimum, the following features: 1. a set of drawings clearly showing the site layout and features and locations of erosion control works and other measures to minimise pollution 2. a narrative accompanying the plans to describe how erosion and sediment control measures were chosen and their maintenance requirements 3. background information including site boundaries, contour maps, existing vegetation, location of site access and other impervious areas and existing and proposed drainage pathways with discharge points also shown 4. program of works containing details on the nature and specific location of works (revegetation, cut and fills, run-off diversions, stockpile management, access protection), timing of measures to be implemented, and maintenance requirements (extent and frequency) 5. engineering details outlining methodologies for each control measure, with supporting engineering calculations for all proposed sediment basins, constructed wetlands, gross pollutant traps etc. Details should include procedures for construction and maintenance requirements as well as the predicted performance of each measure Site stormwater quality management plan checklist The following checklist can be used to help develop a site stormwater quality management plan or to assess that adequate measures for stormwater protection will be implemented on a proposed development. The checklist highlights the key components and considerations that a site management plan should incorporate. 104

119 Site management plans checklist Construction activity or section number General Is the site larger than 2500m 2? Or does it pose a higher erosion risk? If yes: You need to develop a site management plan. If no: Use building best practices to reduce pollution threats (e.g. open bin or skip, or sediment fences on boundary, prompt revegetation of site, prevention of sediment export by vehicles). Section Presentation of site management plans Will the works require soil to be exposed? If yes, have adequate site management plans been prepared with: plans in scale of at least 1:2000 accompanying documents that explain the rationale for proposed actions. Details of site management plans Do the plans have adequate information on the following? Section Section Location of features such as: site boundaries vegetation type and areas to be protected drainage pathways including contours and discharge points impervious surfaces (access roads and parking areas) natural features to be protected (e.g. streams and wetlands) limits of vegetation clearing areas for storage including hazardous materials and stockpiles areas of grading, cutting and filling access tracks to be installed collection and diversion drain dimensions and lining dimensions of sediment basin 2. Coordination with construction plans: major milestones in construction and how the erosion and sediment control measures relate to these 3. Proposed control measures including where appropriate: Section 6.3 diversion of water from construction areas erosion control measures connection of roof downpipes to subdivision trunk drainage as soon as roofs and gutters are finished 105

120 sediment retention measures provision for stockpile location and management plans for vegetation removal and revegetation adequate access provisions to and from the site measures and actions for unexpected events (e.g. storms, work stoppages) maintenance requirements for each measures recommended timing of measures in relation to the construction program. Review construction plan Is the construction plan integrated with the site management plan and does it provide for the following? Section implementation of erosion and control measures within the construction plan coordination with site management plans flexibility for unforeseen events any other issues not otherwise covered that could affect stormwater quality Construction site best practices Are there procedures in place to deal with the following? litter control on-site and from the site refuelling and maintenance of vehicles and equipment unloading and loading to minimise spillages training for staff in procedures for accidental spills Section wash-out and wash-down for painting, concrete works, grouting, etc storage of materials on-site 106

121 Erosion and sediment control plans (ESCPs) Table 6.1 summarises ESCP requirements for all sites. Table 6.1Erosion and sediment control plans for construction and building sites Development Construction site medium to large scale Disturbance area greater than 2500 m² (medium scale) or greater than 1 hectare (large scale) Note: a high erosion hazard assessment (see Table 6.4) would lower these area thresholds. Note: A site greater than 2500 m² (medium scale) with a low erosion hazard assessment (see Table 6.4) may suit the application of deemed to comply solutions See section Construction site small scale with disturbance area <2500m 2 Construction site small scale Disturbance area less than 2500 m² and not part of a larger common development Building sites Type of ESCP High erosion risk see section Construction site with disturbance area >2500m 2 Development is in accordance with an approved ESCP that addresses best practice erosion and sediment control and demonstrates compliance with the stormwater design objectives (see Table 2.1). Lower erosion risk see section Construction site small scale with disturbance area <2500m 2 Development is in accordance with an approved ESCP. Planning, design and implementation of best management practices is deemed to comply with the stormwater design objectives. Note: the general environmental duty under the Environmental Protection Act 1994 continues to apply. See section Building sites Building work should comply with the Queensland Development Code draft, Part 16 Erosion and sediment control or replacement. 11 A site erosion and sediment control plan (ESCP) for all assessable development which involves vegetation clearing and soil disturbance should be a standard requirement. The ESCP should incorporate a range of best practice control measures that are complementary to, and integrated with, site construction plans. There should be measures for: preservation of vegetation (vegetated areas to be protected need to be physically delineated to prevent vehicle access). 11 At the time of printing, the QDC Draft Part 16 Erosion and Sediment Control was not accessable on the DLGP website. 107

122 drainage control (diverting clean up-slope water away from the works, and managing the flow of muddy water through and off the site without causing on-site or in-stream erosion) erosion control (keeping soil in place e.g. revegetation) sediment capture (will involve different measures for different aspects of the problem e.g. sheet flow and concentrated flow). For building and development works on areas equal to or greater than 2500 m 2 an ESCP is recommended. The plan should include: a description of a suite of measures which address different aspects of the problem, and which collectively result in optimal and cost-effective performance measures to mitigate pollution threats to stormwater recommendations that can be followed easily and used on site (usually including A1-size plans) a commentary that describes the development of the plan (i.e. relationship to other plans including stormwater plans and expertise used in developing the plan). The purpose of the plan is to ensure that effective soil, water and vegetation management is an integral part of construction works. For small sites (i.e. less than 2500 m 2 ), the objective of stormwater quality protection remains the same. Most of the pollution control tools are equally applicable to small sites, although more emphasis on building waste management is necessary. The checklist in section can be used to ensure that adequate provision has been given to pollution control on-site. Note: subsequent iterations of ESCP may or may not be required to be approved by the local government. In summary, development should be in accordance with an approved ESCP that: applies to all aspects of the construction phase, from concept planning to asset hand over outlines to tenderers exactly what is to happen, having regard for the earthworks/cut and fill plan, so they are aware of what it is they are responsible for, and can assess cost implications explains to on-site contractors what they are to do, and how, when and where they are to do it on-site provides protection of the environmental values of receiving waters, in accordance with the stormwater treatment guidelines that inform site planning, design and management comprises drawing(s) and supporting information that delineate the operational works at a level of detail and design standard, for erosion and sediment control measures, commensurate with the proposed site disturbance and environmental risk (including erosion hazard) comprises measures that manage stormwater movement, mitigate soil erosion and control the discharge of sediment, nutrients and other pollutants to receiving waters provides for stability of temporary drainage structures up to the design storm event (e.g. see Table 2.1) and provides for the limitation of sediment discharge by the collection of run-off from disturbed areas and drainage to a sediment basin(s) includes consideration of the final layout of permanent stormwater controls that will be constructed along with the buildings, roads, parking lots, and other structures. Construction phase erosion and sediment controls need to be incorporated into stormwater management plans for areas where permanent stormwater controls, such as wet ponds, swales, and bioretention cells are to be constructed. 108

123 6.3.3 Site erosion and sediment control There are broadly three categories of development based on disturbance area and location that should be addressed in making an effective ESCP. These are: high erosion risk development with disturbance greater than 2500 m 2 (medium and large scale) (see section ) lower erosion risk development with disturbance less than 2500 m 2 (see section ) building sites (see section ). Where the downstream or receiving waters are of high ecological value, under the Environmental Protection (Water) Policy 2009, the assessment manager or referral agency may require enhanced source controls including avoidance of construction during the wet season (especially works in stream channels, floodplains or riparian zones) as necessary to protect the environmental values. Confirmation should be sought at pre-lodgement conferencing. Construction site with disturbance area > 2500 m 2 Typical development types in this category may include residential subdivision, medium/large scale high-density housing projects and medium/large scale commercial and industrial works involving site disturbance greater than 1 hectare and/or a high erosion hazard assessment. Development conditions should include compliance with an ESCP for high erosion hazard sites during the construction phase in line with the best practice objectives outlined in Table 2.1. There are three stages to development of an appropriate ESCP for high environmental risk (including high erosion risk) developments. These are: planning phase design phase construction. Each stage is addressed as described in the following diagram (Figure 6.3): Figure 6.3 Planning phase steps for site management Appendix 1A, section 3 outlines best practice site planning. Data collection can be required at two levels to: 1. support the assessment of site constraints. Data collection and mapping should focus on the collection of soil, water, vegetation and topographical information. Site data from field or 109

124 laboratory testing should include soils characterisation 12 and mapping (1:5000). Site mapping should include highly erodible soils (type-d and type-f soils, see technical note below), steeply sloping areas (>15 per cent), riparian and existing vegetation, existing site contours, watercourses/drainage lines, groundwater table, areas subject to flooding, wetlands and downstream waters, existing and adjacent land uses 2. support site assessment and the impact on the adjacent environment. Supplementary information should include soil erosion susceptibility data, vegetation and acid sulfate soils mapping, environmental values and water quality objectives for receiving waters, levels of aquatic ecosystems protection, existing wet and dry weather water quality and ecosystem health monitoring data, wetlands and protected estate mapping, rainfall data and rainfall erosivity estimation. Assessments should include biodiversity, soils erodibility, groundwater, flooding, potential water quality pollutants and water quality impacts and flow volume and run-off frequency impacts on receiving waters. Technical note Type-C soil: A soil that contains a significant proportion of coarse-grained particles (less than 33 per cent, finer than 0.02 mm) and will settle relatively quickly without the need for flocculation. Type-D soil: A soil that contains a significant proportion (>10 per cent) of fine (<0.005 mm) dispersible materials that will never settle unless flocculated or coagulated. That is, a soil where the percentage of clay plus half the percentage of silt (roughly the fraction <0.005 mm) multiplied by the dispersion percentage is equal to or greater than 10. Type-F soil: A soil that contains a significant proportion of fine-grained particles (33 per cent or more, finer than 0.02 mm) and requires extended settlement periods to achieve efficient settlement that may or may not benefit from chemical flocculation. Site Erosion risk level is determined through a Site erosion hazard assessment (See Table 6.4). A Site erosion hazard assessment is required to be included in the information for prelodgement conferencing with the assessment manager. Effective planning is fundamentally important to the subsequent detailed design of erosion and sediment control measures. These measures should be commensurate with the complexity and degree of environmental risk associated with the proposed works. Site planning should minimise the area and time of disturbance (see Figure 6.4) and address control factors such as slope gradient and length. Planning should be integrated with overall site planning, including the layout of lots, roads, open space and the provision of services. The layout should minimise the amount of cut and fill over the site. Preliminary site design and layout should determine the scale and arrangement of the proposed development that is most consistent with water sensitive urban design principles. 12 Soils analysis should include ph, electrical conductivity, organic carbon, total nitrogen, nitrite nitrogen, sulfur, exchangeable basic and acidic cations, cation exchange capacity, plant available phosphorus and potassium, particle size analysis, textural description, and Emerson dispersion class number. 110

125 Figure 6.4 Reducing the area of disturbance reduces the footprint and cost of erosion and sediment control (SCRC) Where more effective permanent measures can be applied in place of less effective temporary measures, such as for watercourse crossings, permanent measures may be able to be advanced in the works schedule to reduce risk. Similarly critical landscaping elements such as revegetation should not be planned to commence at the end of the civil works, but be progressively applied as soon as civil works in a workable area are complete. Pre-lodgement conferencing with the assessment manager is an essential step to discuss preliminary design and layout proposal(s) and to ensure that lodged development applications contain the requisite information to enable a decision to be made. Matters for clarification should include the specific information requirements and the level of supporting technical detail for inclusion in the development application.. For medium-scale developments on sites with a low assessed erosion hazard, confirmation should be sought from the assessment manager on the type of erosion and sediment control plan to be prepared and the required level of supporting technical detail Where the downstream or receiving waters are of high ecological value, under the Environmental Protection (Water) Policy 2009, the Assessment Manager or Referral Agency may require enhanced source controls including avoidance of construction during the wet season (especially works in stream channels, floodplains or riparian zones) as necessary to protect the environmental values. Confirmation should be sought at pre-lodgement conferencing. 111

126 Design Phase Design sto rm ARI Rain fall erosivity Erosion Risk Assessment Drainage control standard Erosion control standard Sediment control standard Selection of ESC measures Prepa ration of ESCP Design of ESC measures Monthly soil loss analysis (if necessa ry) to dete rmine the all owable disturbance period based on achi evable sediment control standard Review of ESCP Construction Phase Plan appr oval and setting of development conditions Figure 6.5 Design phase steps for site management. (Note that the control standards shown in the diagram are equivalent to the design objectives in Chapter 2, Table 2.1.) Following pre-lodgement conferencing, layout of the preferred site option, detailed design (consistent with the stormwater treatment guidelines or design objectives) and the underpinning calculations should be completed as part of the preparation of the development application. Erosion risk assessment Erosion risk assessment calculations should be undertaken once the concept design is finalised. The Revised Universal Soil Loss Equation (RUSLE) method is recommended for application to subcatchment plans to predict the annual soil loss rates from sheet and rill erosion of the proposed areas of soil disturbance. Technical details, including the derivation of rainfall erosivity and soil erodibility factors, are provided in Best Practice Soil and Erosion Control, International Erosion Control Association (IECA) (Australasia) Figure 6.6 High to extreme erosion hazard Erosion hazard and site constraints (SCRC) 112

127 The results should be used to identify the various zones of erosion risk within the site and the detailed design and selection of control measures. Disturbance of land identified as extreme erosion risk, for example Figure 6.6, should be avoided. It may not be feasible or cost-effective to develop such land, and still protect the environmental values, depending on the nature, layout and density of development and this should be decided by councils at the material change of use and reconfiguration stages of development assessment. If any development is approved, it should be of low impact character, for example, pole housing, with minimal cut and fill, and should be subject to intensified erosion and sediment controls. Areas of disturbed/exposed soil should be protected, when not actively worked, with a synthetic cover if necessary, and activity scheduled to avoid high rainfall periods. High or very high erosion risk land may necessitate a similar approach, again depending on the nature, layout and density of development. Another major constraint when assessing likely impacts for all proposed developments, except on low erosion hazard situations, is the feasibility of installing any sediment basin which is necessary to achieve the environmental performance objectives. Constrained sites are those which have flat terrain with high groundwater levels (difficulty in collecting and directing surface flows, coupled with difficulty of installing a sediment basin in the presence of high, sometimes acid-sulfate, groundwater), and also steeply sloping sites (greater than 15 per cent). Note StatePlanning Policy 1/03 Mitigating the adverse Impacts of flood, Bushfire and Landslide may also need to be considered on sites greater that 15 per cent slope Sediment basin design Sediment basin installation is required if, on either a subcatchment or whole-of-development basis, the calculated uncontrolled soil loss rate is greater than 150 m 3 per hectare per year. Sediment laden stormwater run-off, after the installation of source erosion and sediment control measures, should be drained to a sediment basin(s) constructed upstream of any wetlands or final ponds before discharging to downstream waters. In constrained sites or corridors a risk assessment should be undertaken including the implications of acquiring land for a temporary sediment basin. Sediment basins for both coarse grained soils (type-c) and for dispersive and fine grained soils (type-d and type-f respectively) should be generally designed, operated and maintained in accordance with the IECA 2008 publication, Best Practice Erosion and Sediment Control, or an equivalent current guideline issued by a local government or appropriate professional organisation such as Engineers Australia. In particular, note: impervious clay is to be used in construction of the embankments embankments are to meet required compaction levels 95 per cent MMD (Maximum Dry Density) collection drains, and basins and their outlets, should be designed to be stable in the peak flow from at least the 10-year ARI critical time of concentration event. Sediment basin design must address the stormwater treatment guidelines (design objectives) in Table 2.1 and meet structural integrity and stability requirements. Note that in aiming to meet the design objectives, type-c soil basins may only adequately control turbidity for sites on aeolian (wind-blown) sandy soils, due to significant clay content in many type-c soils. Note also that some soils which are essentially coarse-grained can be type-d, always requiring flocculation. Simple bench settling tests are recommended in doubtful cases, as part of the design process. The design of sediment basin settling zones should normally adopt the five-day rainfall depth for type-d and type-f soils. The 80th percentile storm depth should be used for sites where soil disturbance (from land clearing to site stabilisation, equal to 70 per cent grass coverage over at least 90 per cent of the site) is less than six months duration, and the 85th percentile if longer 113

128 than six months. This assumes flocculation, settling and discharge are achieved within five days. In the wet season, the cycle may need to be significantly shorter, having regard for the three-day weather forecast. Any requirement for rain activated flocculation dosing systems should be assessed during soils properties determination. During sediment basin de-watering, release water quality monitoring is required, and the total suspended solids concentration should be less than 50 mg/l in any grab sample during any event up to the design storm event. Where there is in place an approved monitoring program which produces and records a reliable wet weather basin outflow dataset representative of the pollutograph, the 50 mg/l objective applies as a 90th percentile. Where the objective is exceeded, the control measures on site should be promptly reviewed to ensure that all reasonable and practicable measures are being taken in respect of both basin operation, and the hydrologic and sediment loading on the basin. All reasonable and practicable measures should also be taken for storm events beyond the design event. This includes attending the site during and immediately after wet weather, including outside normal working hours, and initiating remedial action where control measures have failed, additional measures are necessary, or maintenance is required. Where development sites have a low erosion hazard assessment, best practice may be deemed to comply 13 with the performance objectives in Table 2.1 by the assessment manager in accordance with any local guidelines. Potential drainage, erosion and sediment source control measures which could be used to reduce stormwater pollution include: temporary structures installed during the construction phase permanent structures to be built during the construction phase permanent structures that may be suitable for retrofitting to existing urban development. The planning and design of permanent road drainage structures and associated erosion and sediment controls should be in accordance with the Interim Guide to Road Planning and Design Practice and Road Drainage Manual (Department of Transport and Main Roads) or Queensland Urban Drainage Manual, Department of Natural Resources and Water (now Department of Environment and Resource Management), where appropriate. Engineering guidelines for the planning, design and management of permanent hardengineering drainage systems, to be built during the construction phase, are detailed in the Queensland Urban Drainage Manual. This information must be supplemented with appropriate WSUD guidelines. Appendixes 1A and 1B include best practice design for land disturbing activities that may or may not drain to a sediment basin including erosion and sediment control measures and drainage systems. Erosion and sediment control plan preparation ESCPs should comprise a report, accompanying mapping and engineering drawings. Plans should be certified by a suitably qualified and accredited professional in erosion and sediment control (CPESC) and submitted with the development application. Authors must have appropriate experience, demonstrated skills in erosion and sediment control and completed an advanced specialised training course in erosion and sediment control (for example, as provided by bodies such as the IECA (Australasia) or the Australian Society of Soil Science. For large sites (greater than 2500 m 2 ), a registered professional such as a Registered Professional Engineer of Queensland (RPEQ) under the Professional Engineers Act 2002 must certify the hydrology and hydraulics components of ESCPs. Appendix 1A, section 6 outlines ESCP principles and content. Example model erosion and sediment control plans are presented in Appendix 2. Development application and decision 13 Deemed to comply solutions has the meaning that the implementation of best management practices is deemed to comply with the stormwater treatment guidelines (Table 2.1 design objectives) provided the duty of care is met for proper installation, maintenance, operation and monitoring. 114

129 The completed development application with the appropriate lodgement forms and requisite information, including the site erosion and sediment control plan, should be lodged for assessment and decision. In deciding the application, the precautionary principle 14 should be applied where there are threats of serious or irreversible environmental damage, and scientific information on the resilience of the system is unknown or limited. In such circumstances the assessment manager should be guided by careful evaluation to avoid, wherever practicable, serious or irreversible damage to the environment and an assessment of the risk-weighted consequences of various options. Once the decision is made, the decision notice must state if the application is approved, subject to conditions, and if the approval is a combined or separate preliminary approval and development permit. A development permit authorises the assessable development to occur, subject to conditions. Decision notice conditions may include, for example, that: the quality of stormwater run-off leaving the site should meet the design objectives in Table 2.1 in Chapter 2 of Urban Stormwater Quality Planning Guidelines 2010 an erosion and sediment control plan setting out best management practices of current works on the site is to be displayed in the construction site office erosion and sediment controls are installed and functional, before other site disturbance commences a person is to be nominated as carrying managerial responsibility for compliance with the conditions of approval, and their contact details, including after-hours details, provided in writing prior to the pre-start meeting. Written advice is to be given in advance where the person changes stated frequency of water quality monitoring of upstream waters and the approved site discharge conducted during and after each storm event. Ecosystem health monitoring of downstream waters is monitored in accordance with Table 6.2 below. Written reports should be submitted to local and regional councils every six months third-party site inspection and external auditing for compliance assessment, against the approved erosion and sediment control plan, is undertaken at four-weekly intervals during the construction period management systems are to be in effect to action inspection or compliance reports all erosion and sediment control measures are to be in a fully effective operating condition at the end of each day s work sediment basins are retained and maintained by the developer or through some other arrangement by negotiation with council until the site is finally stabilised after house building, equivalent to 70 per cent grass coverage on more than 90 per cent of the contributing catchment. Construction phase 14 Intergovernmental Agreement on the Environment s

130 Construction Phase Review of Stormwater Management Plan by Contractor Construction Site Management Site Inspection & Water Quality Monitoring External Audit Figure 6.7 Construction phase steps for site management Operational works may commence subject to the development permit. The measures stipulated in the ESCP should be reflected in the tendering arrangements (Bill of Quantities and Schedule of Rates) so that fair allowance is made for the cost of compliance and reduce the need for variations to contracts. Construction site management should involve: site clearing site establishment site access soil and stockpile management site management drainage control erosion control sediment control site rehabilitation site monitoring. Daily maintenance checks should be completed by the site supervisor/manager and an erosion and sediment control checklist records maintained until project completion. A management system should be in place to implement site inspection recommendations for modification or enhancement of erosion and sediment control measures. Site inspection should be completed by competent and suitably trained persons, having undertaken short course training in erosion and sediment control to local and regional council requirements. External compliance auditors should have qualifications and experience to the satisfaction of local and regional councils, for example, attending IECA (Australasia) accredited courses. Appendix 1A, sections 4 to 17 outline best practice for site establishment, construction, inspection, maintenance and monitoring activities. 116

131 Water quality monitoring The following is adapted from South Australian Transport Water Quality Monitoring Manual for Construction Sites, 2001 Water quality monitoring is a tool to assist in managing construction sites, evaluating project impacts and ensuring legislative compliance. A risk assessment approach is used for determining what intensity of monitoring is appropriate on each project. Four levels of monitoring apply, with each level building on the one before. A brief description of each level follows: Level one monitoring represents the simplest form of monitoring and involves visual inspections of the work site and potential receiving waters. This applies to sites of low erosion risk (see Chapter 2). Level two monitoring requires visual inspections plus water quality readings to be taken using handheld field equipment. This level is applicable to most sites where a discharge is expected but is considered unlikely to have a serious impact on the aquatic environment. It is expected that level two monitoring will be the most common form of monitoring utilised. Level three monitoring involves visual inspections plus the installation of automated water sampling and monitoring equipment. It should be undertaken for higher risk sites. Level four monitoring involves visual inspections, water quality sampling and biological monitoring for higher risk sites in high environmental value catchments. Monitoring levels three and four will both require the input of professional advice to assist with the design and implementation of the monitoring programs.the procedures provide guidance on the selection of locations for monitoring, the frequency of sampling and the type of equipment that should be used. In addition to the specified turbidity sampling, total suspended solids should also be monitored as required in the development permit. See Table 6.2 Monitoring requirements and assessment criteria for each level, but refer to development permit for specific requirements. Note the 50 NTU 15 turbidity criteria shown are intended as a simple, easy to measure internal guide for operators to assess how well their treatment train is working. Exceeding this limit should trigger investigation to determine whether there is any control system failure; or whether additional measures are necessary. They do not replace the design objectives set out in Chapter 2 or a development approval. 15 NTU Nephelometric turbidity units 117

132 Table 6.2 Monitoring requirements and assessment criteria Level one Level two Level three Level four Visual inspection of site erosion and drainage management measures Visual inspection of drainage discharge points As for level one, plus: record of colour of site water discharge and receiving water upstream and downstream of site As for level two, plus: fixed in-situ automated sampling on main watercourses with manual sampling at minor discharge points to record: As for level three, plus: biological monitoring below site at a control site, (or at an approved reference site) Photo points Temperature and rainfall from nearest Bureau of Meteorology station manual turbidity recordings turbidity water depth site rainfall May also require: suspended sediment samples Method sediment grading analysis streamflow recordings Frequency Weekly and during rainfall events Weekly and during rainfall events Continuous recording by insitu probe when watercourse flowing. Turbidity recording interval to be set to suit flow conditions but typically should not exceed 15 minutes between recordings. Manual recordings should be taken daily and during rainfall events. Monitoring could start before site works commence and consist of one sample set during spring and autumn. Sampling should continue for 12 months following completion of site works. Criteria Sediment traps clear and available for trapping sediment. No visible sediment discharge in receiving waters. Discharge <50 NTU and/or no greater than 10% more than turbidity in receiving water. Discharge <50 NTU and/or no greater than 10% more than turbidity in receiving water. Results should indicate no statistical change in environmental health, and site should maintain healthy rivers classification. Digital or single-lens reflex 50 mm camera. Kodak standard colour chart. Fully automated recording equipment. Specialist sampling equipment is required. Portable turbidity meter. Portable turbidity meter. Equipment Sample containers for laboratory analyses or if turbidity meter fixed in office. Sample containers for laboratory analyses or if using a desktop turbidity meter. Expertise Staff with good observational skills and ability to reliably assess and record site conditions. As for level one, plus staff trained in water quality monitoring. As for level two, plus monitoring program to be developed and overseen by a qualified hydrologist. Manual measurements can be taken by staff trained in water quality monitoring. As for level three, plus biological samples must be collected and analysed by a skilled freshwater ecologist. 118

133 Construction site small scale with disturbance area < 2500m 2 and not part of a larger development Intent Development, involving site disturbance of less than 2500 m 2 and not part of a larger common development, should comply with a site ESCP. The implementation of best management practices to achieve design objectives in Table 2.1 can be codified for low erosion risk development types. Typical development examples may include multi-lot development, high rise development, small to medium scale housing, and commercial and industrial developments. Erosion hazard assessment If the site is assessed as a high to extreme erosion hazard (see Table 6.4) then erosion control measures should be critically assessed by the assessment manager. Temporary sediment basin installation may be required or portable settling/flocculation tanks may need to be procured, especially if de-watering operations are necessary. For smaller scale sites with space limitations, erosion prone areas should be protected;, the activity should be scheduled to avoid high rainfall periods and, where practical, developed to final design, as shown in Table 6.3. For land disturbing activities that do not drain to a sediment basin, erosion and sediment control measures should be designed to be effective during a design storm of 0.5 times the critical 1-in- 1 year ARI design storm 16 (within the limits of available technology) and drainage systems designed in accordance with Table 6.3. Table 6.3 Drainage design standard for temporary drainage works (Source: International Erosion Control Association (Australasia) (2008) Best Practice Erosion and Sediment Control and Appendix A1.1 ) Drainage structure Anticipated design life < 12 months months > 24 months Temporary drainage structures [1] 1-in-2 years 1-in-5 years 1-in-10 years Temporary drainage structures (e.g. catch drain, flow diversion bank) located immediately up-slope of an occupied property that would be adversely affected by the failure or overtopping of the structure. [1], [2] 1-in-10 years 1-in-10 years 1-in-10 years Temporary culvert crossing Minimum 1-in-1 year ARI hydraulic capacity wherever reasonable and practicable. Notes: [1] Design capacity excludes minimum 150 mm freeboard. [2] Design flow rate based on up-slope drainage structures operating in accordance with their design capacity excluding freeboard, i.e. any constructed freeboard is assumed to have been washed away or otherwise deactivated. [3] Design life includes the total period from commencement of work until final stabilisation. Note: Due allowance must be made for channel flow obstructions such as rock check dams. All reasonable and practical measures should be taken to prevent, or at least minimise, environmental harm during storm events beyond the design event. 16 The critical storm duration or the design storm event that produces the peak flows. All hydrological calculations shall be in accordance with the procedures in Australian Rainfall and Run-off, Engineers Australia, 2001, or the locally adopted manual/guideline (e.g. Sunshine Coast Regional Council has adopted a 1-in-10 y ARI event for all temporary catch drains). 119

134 This includes attending the site after hours in wet weather and taking all reasonable and practicable measures to reduce hydrologic and sediment loadings on sediment basins, such as reinstating damaged diversion drains. Lower risk erosion and sediment control plans should consist of a layout plan(s) showing the proposed erosion and sediment control measures and the supporting documentation, typically as follows: Layout plan(s) should include: north point, plan scale (not larger than 1:1000); author s name, signature and date the use of standard drawing symbols for drainage, erosion and sediment controls property boundaries, adjoining roads, approximate site grades and direction of fall approximate location of trees and vegetation, showing items for removal and location of land where protective cover will be maintained location of site access, proposed roads and impervious areas existing and proposed drainage patterns, with stormwater discharge points location and protection of local and regional council stormwater drain inlets location of buildings and activity areas, including soil and other stockpiles, and washdown areas disturbed areas potentially erosion prone undisturbed areas where ground cover will be maintained location, type and identification of erosion, sediment and drainage controls, including: stabilised access controls sediment fencing and other perimeter controls the diversion of run-off from up-slope lands around disturbed areas barrier fencing to protect undisturbed areas. Supporting documentation should include: a completed erosion hazard assessment form information on the program of works, including timing, duration and installation sequencing of site activity nature and extent of earthworks, including cut and fill volume maintenance responsibilities, including daily site checklist. Decision notice conditioning If the development application is approved, decision notice conditions should include that: operational works comply with the approved erosion and sediment control plan erosion and sediment controls are installed and functional before operational works start. Appendix 2 contains Example model ESCPs. Other examples may be may be accessed at the Brisbane City Council website and the NSW Government Landcom website. An example daily site checklist is at the Brisbane City Council website. 120

135 Building sites Intent In areas of high erosion risk, some building works should comply with a site ESCP that addresses best practice erosion and sediment control. Erosion and sediment control plan (ESCP) The ESCP should be a stand-alone drawing with explanatory comments. It should be prepared and submitted for approval and communicated to builders, sub-contractors, private certifiers and home owners. A completed erosion hazard assessment form should be attached to the ESCP. If the building site is assessed as a potential high erosion hazard that is if the average slope for the site is >15 per cent and/or the site has dispersive soils exposed during November to March then erosion control measures and the nature and layout of the development, especially the amount of cut and fill (e.g. slab on ground or pole house) should be critically assessed by the assessment manager. Considerations should include the protective covering of erosion prone areas at the end of daily work, and prior to predicted rainfall, scheduling the activity to avoid the highest rainfall risk periods or, if practical, initially developed to final design. The ESCP should include an annotated drawing that addresses: site layout; and stabilised site entry and exit points control of up-slope stormwater location/management of topsoil and other stockpiles control of erosion from disturbed areas location of sediment and barrier fencing road drainage protection location/containment of clean-up and wash-down effluent controls control of litter and building waste (provision of on-site bin) installation sequence and daily site checklist. Further information on controlling building site stormwater pollution is available at < 121

136 Table 6.4 Example Erosion hazard assessment form 17 Controlling factor Points Score Average slope of the whole site prior to operational works Slope < 2% 0 More than or equal to 2% but < 5% 1 More than or equal to 5% but < 10% 2 More than or equal to 10% but < 15% More than or equal to 15% Soil type (to be disturbed) Gravels and sandy soils High risk Sandy loam 2 Clays on flood plains 3 Shallow soils on slopes Clays on slopes >5% / imported fill or untested 4 5 High risk Anticipated duration of site disturbance Duration < 2 weeks 0 More than 2 weeks but < 3 months 2 More than 3 months but < 6 months More than 6 months Anticipated erosive rainfall risk during site disturbance Low (monthly average rainfall <45 mm) 0 Moderate (monthly average rainfall mm) 1 High (monthly average rainfall mm) 2 Very high (monthly average rainfall mm) Extreme (monthly average rainfall >1500 mm) Off-site sediment control (down-slope of the soil disturbance) Score 1 point if there is no purpose-built sediment trap 1 (e.g. sediment basin, gross pollutant trap or purpose-built wetland) Run-off entering the site 4 5 High risk 4 5 High risk Score 1 point if stormwater run-off not diverted from entering the site or away from soil disturbance. 1 Extent of site disturbance Score 2 points if building works requires reshaping of the ground surface. Total Score High erosion risk if score 11 or greater, or five for any factor Several local Governments have already developed their own Erosion Hazard Assessment forms. This Erosion Hazard Asssessment form is adapted from the Best Practice Erosion and Sediment Control, International Erosion Control Association (Australasia), IECA 2008 Appendix H - Building Sites, the Brisbane City Council Erosion Hazard Assessment Form and Attachment 2 to the QDC Draft Part 16 Erosion and Sediment Control. 122

137 A checklist illustrates the steps involved in the planning process and a range of controls are described that can be applied in site management plans. More detailed design guides for site control measures can be found in Best Practice Erosion and Sediment Control, International Erosion Control Association (Australasia), IECA Business surveys Some business activities have significant potential to pollute the stormwater system. For example: commercial areas are known to generate high levels of litter industry can contaminate stormwater through poor control of industrial processes, or the transport, handling and storage of goods food preparation businesses may have poor facilities for waste handling and disposal the motor vehicle repair industry uses and produces many materials with potential to seriously contaminate stormwater and pollute waterways. Responsibility for dealing with these pollution-generating activities rests with the owners and managers of the business enterprise, as well as everyone that conducts work for or within these businesses. When it comes to protecting our environment, everyone has a role, and appropriate steps should be taken to follow best practice to achieve water quality objectives. Education backed up by enforcement is the best means of ensuring businesses are aware of their potential to pollute and have knowledge of the measures available to minimise pollution risks. Surveying business operations is an effective means for determining the extent and nature of activities with the potential to pollute and therefore targeting education and enforcement programs appropriately. The remainder of this section presents a methodology and checklist for conducting surveys of businesses that have the potential to pollute urban stormwater. Such surveys may be either internal reviews or external third-party audits. Education is a key tool for addressing stormwater pollution generated by business. Methods for developing education programs, a range of educational tools and examples of proven programs are presented in section Stormwater pollutant surveys The purpose of a survey is to identify business activities that are potentially generating pollutants likely to affect stormwater quality. This might include businesses servicing the construction industry such as concrete batching and asphalt plants, motor garages and other light industry. Surveys can be used to help target pollution reduction programs (for example, to locate a treatment measure or target an education program) or can be used to assess the performance of a program to improve business practices. The survey process itself can also be used to raise awareness amongst business operators of their potential to pollute. Survey types Business surveys are a useful tool for determining the nature and extent of activities with the potential to pollute local waterways. A survey can be carried out by face-to-face or telephone interview, or mailed question sheets. Surveys can be targeted (specific area or industry), random (a certain number of enterprises within an area), or representative (enterprises selected as being representative of a broader group). The checklists in the next section can form the basis of a survey questionnaire. Development of a survey program should be carried out in conjunction with the local operations group of the Department of Environment and Resource Management. Local groups or other community groups may also be able to assist carrying out surveys. 123

138 Water quality assessment Another way of surveying activities that affect stormwater quality is through water quality monitoring. Data collected from water quality monitoring can be used to isolate catchments that contribute high concentrations of pollutants. Some pollutants are indicative of specific problems and these data can be used to isolate the problem and then perform a detailed investigation to locate the source. For example, high turbidity levels in wet weather, and high levels of E. coli in drains which indicate the presence of faecal contamination and an illegal sewer connection or sewer pump station surcharging to the stormwater system are possible causes. Water quality monitoring data are collected by the Department of Environment and Resource Management as well as some local governments, schools and natural resource management (NRM) groups. These organisations can provide data and also advise on water quality monitoring methods and equipment. Such programs involve the community with water quality monitoring. More detailed investigations can involve remote videos or plumbing inspections in the drainage network to identify pollution sources. However, these methods are costly and time consuming. Before considering such investigations it is recommended that an initial survey (using the checklists) of problem areas is undertaken to appreciate the extent and nature of the problem and to assess whether a more detailed investigation is warranted. Stormwater quality checklists for businesses The checklist presented in this section is designed to evaluate a range of business-related activities for their potential to pollute and can be used as the basis for questionnaires. Use of the checklists will help identify the nature and extent of those activities. This will assist the development and targeting of management programs. Stormwater quality checklist for businesses Introductory questions: 1. Are paved areas ever cleaned? 2. Are any materials stored outside? 3. Is material delivered onto the premises? 4. Can packaging become litter? 5. Does the business produce waste? If yes, go to: Section 1 Section 2 Section 3 Section 4 Section 5 1. Pavement cleaning/ wash-down areas Notes Are wastes from paved areas (including footpath, entrance, loading dock and car park) swept and picked up for disposal? Are paved areas cleaned with hoses or blowers? Are appropriate chemicals used for cleaning? Are wastes prevented from entering gutters/drains/ stormwater system? Is litter the only waste likely to be generated on pavements? Do site personnel consider organic matter (fallen leafs, cut grass) not to be a pollutant? Are there designated equipment wash-down areas? Is all plant maintenance performed in contained areas? 2. Material storage and spill control Notes 124

139 Are storage containers regularly checked for leakages and storage levels? Are outside storage areas contained (e.g. bunding) to prevent any materials reaching the stormwater system? Are they protected from vandals/pests/water? Are there contingency plans for spills/escape of stored materials? Are there sufficient supplies of clean-up and spill containment materials? Are staff trained in spill procedures regularly? Are high-risk areas isolated from the drainage system? 3. Delivery and transfer Notes Are there designated delivery areas? Are delivery areas under cover and protected from run-off? Are delivery areas regularly inspected and cleaned? Are spill capture boxes used to contain spills on-site? Are loads covered when leaving the premises? Are there spill control procedures in place, and are staff trained? Are there spill containment systems fully operational and readily available? 4. Litter management Notes Are areas that generate litter regularly cleaned? Are bins provided for customers/staff? Are the areas surrounding the premises regularly cleaned, and wastes collected and disposed of? Have sources of litter been identified? Have litter management measures been reviewed recently 5. Waste storage and disposal Notes Waste storage and collection: Are stored wastes protected from escape during high winds or rain? Is the storage area isolated from the stormwater system? Should material escape the storage container, will it be contained on-site? Are waste containers always emptied before reaching capacity? Are waste collections regularly monitored to ensure no escape? Is the waste collection contractor required to clean up after collection? Are storage containers protected from vandals and pests? Waste discharges: Are all wastes prevented from entering the stormwater system? Are there diversion or containment systems to prevent stormwater contamination, including in the event of a leak or spill? Are systems regularly inspected or tested? Are staff trained in their operation? Is a trade waste agreement required for discharge to sewer? 125

140 6.5 Educational programs Education is a key source control tool for dealing with activities carried out within residential households and business premises which have the potential to contaminate stormwater run-off. Individually these activities may seem insignificant. Given the number of households in urban areas the total impact on stormwater quality can be very significant. In many cases simple changes in attitude and behaviour can vastly reduce pollution of stormwater from domestic activities. This section describes a methodology for developing effective education and awareness programs for stormwater pollution. This includes a number of education tools and examples of successful programs Developing an education program Why education programs are appropriate Education is a most appropriate and effective strategy for minimising stormwater pollution for many reasons, including: targeting diffuse sources the diffuse source nature of the stormwater pollution problem means that structural solutions are often less effective than education targeting the individual the behaviour of individuals at home and work greatly influences stormwater quality. By targeting home and work practices, great improvements can be made targeting whole community education has the capacity to mobilise the whole community and can therefore have a major effect on stormwater quality linking opportunity education provides the opportunity to clearly link individual behaviour and water quality motivating behaviour simple messages such as stormwater flows untreated into our rivers and oceans is a major motivator for appropriate behaviour. While these are benefits of an education strategy, there are also some cautionary issues. Education has a short half-life and it is quite costly. It is essential that the education strategy is well targeted and well planned. Education should be focussed on changing attitudes. Education should be an integral part of any stormwater management program. Best results will be achieved when education is used to support a range of regulatory, policy and economic mechanisms. An education program is not an isolated set of activities; it is a number of integrated activities targeting different people for particular purposes. Developing an education program Effective community education requires a thorough understanding of: environmental issues audience behaviours targeted best ways to achieve an improved environment. Objectives When planning an education program, consideration should be given to both short- and longterm objectives. For example, short-term objectives may be: to improve the understanding of: how the streets, the stormwater system, creeks, rivers and oceans are interconnected 126

141 how daily activities affect stormwater quality. Long term objectives may be: to encourage a true sense of responsibility for, and appreciation of, urban waterways to instil a change in community attitude to litter, pollution and its impact on our waterways. Lasting change comes first from a change in one s thinking. The development process There are seven key steps in planning an effective community education program. Step 1: Define and analyse the problem This is best achieved by breaking the stormwater pollution problem down into component parts. It is essential to first determine which are the key pollutants within a given drainage catchment, the sources of such pollutants, and who has an impact on these sources. Remember that the key pollutants may not always be visible to the naked eye (e.g. garden chemicals). Step 2: Identifying stakeholders The stakeholders in the issues need to be identified and involved in the project planning and delivery. Stakeholders can be defined according to many criteria. These can include geographical region, ethnic background, socioeconomic group, age group, occupational group, special interest groups or behavioural or attitudinal sectors within the broader community. There are a number of stakeholders that may affect stormwater quality. These include: commercial businesses and industry for example, shopping centres, the construction industry and the car repair industry. Many of these businesses are represented by industry associations and professional bodies land holders and residents for example, local residents, farmers and local environmental and community groups school/youth groups council staff. Step 3: Know your target group Precise identification of the target group is essential in developing a quality community education program. Knowing the target group means much more than simple identification. It requires development of a complete profile, so that the most effective communication methods can be identified. This can include demographic information such as age, gender, socioeconomic status and level of education. Step 4: Set objectives Once the issues and the target groups are identified, specific program objectives can be set. The objectives indicate the awareness, understanding or attitudes that are targeted. Identify one or two simple key messages to communicate these objectives to the target audience. These messages can be categorised as follows: Informative messages convey facts for example, Each year the volume of dog faeces produced in public places in Brisbane would fill one and a half Olympic-sized swimming pools. Feeling messages get people emotionally involved in an issue for example, Plastic bags in waterways can kill or injure animals. Attitude messages are important for the need to simply change a person s attitude to what they may have accepted in the past for example, the accepted practice of throwing away cigarette butts; the accepted practice of continuing to place litter into a public rubbish bin 127

142 even if it is full; and the general acceptance of litter within a so-called drain, when such litter would not be accepted within the creek into which the drain discharges. Responsibility messages appeal to a person s sense of what is right or proper for example, People in the car industry should minimise release of car wash effluent to the road drain. Empowering messages empower people to act for example, Individual actions, no matter how small, do make a difference. Action messages advise people of how they can become directly involved for example, Don t wash paint brushes in the sink. Dispose of excess paint by wiping it on newspaper, wash the brush with water then pour the water on your lawn or garden. Step 5: Design your methods The most successful programs use techniques specifically designed for the target audience. Determine which education tools and techniques are likely to work most effectively with a particular target group. A mixture of techniques may increase the chances of success. Finally, you will need to check that there is an appropriate balance between tools which inform and those which facilitate action. Educational tools and techniques are explained in more detail later in this chapter. Step 6: Form action plans and timelines Planning the education program requires consideration of costing, timelines, distribution, approvals and briefs. The plan guides all project activity and should be revisited often during the project. Costing Identify initial and recurrent costs including staff, ongoing costs and the possibility of any potential income. There are a number of factors to consider when costing a project including: funding sources What possible sources of funding are there beyond one organisation? Are there any in-kind opportunities? sponsorship Is sponsorship from the commercial/ industrial sector possible? trim-to-fit How can the project be modified if sufficient funds are not found? Step 7: Monitor and evaluate This requires the collection of information and records to show the effectiveness of the project. This is often the most difficult step and is too often neglected. Audit review questions might include: 1. Did the message(s) reach the audience to the extent expected? How is this known? 2. Were the messages understood? 3. Were the expected outcomes reached? Did behaviour change? Linking programs A broad infrastructure of stormwater and environmental education programs and resources exists to help in program development. 1. Local programs integrate stormwater quality programs into existing local programs run by council or other agencies. 2. External programs link in with existing programs in other councils around the state or country. 3. Advisory groups involve focus or advisory groups in the development of education programs. 128

143 Figure 6.8 The communication model Tips for effective communication Community education messages need to be communicated clearly from the outset. The following are suggestions for effective communication: 1. Be clear and concise Provide a clear, concise and consistent message describing how the target audience contributes to storm water quality programs and how it can reduce its impacts. 2. Use plain English Use everyday language. Use external reviewers to reduce the use of technical terms, acronyms and jargon. 3. Deliver simple messages Break up complicated subjects into smaller and simpler concepts. Present these concepts in a metered and organised way, to avoid overloading and confusing the audience. 4. Link messages Ensure each message clearly relates to the last in the sequence. 5. Provide language translations Translate your messages into the foreign languages within your community. Ensure that cultural differences are considered when messages are translated. 6. Check correctness Make sure all messages have a sound, up-to-date technical basis. The communication model shown in Figure 6.8 illustrates how behavioural changes are best achieved through two-way, collaborative communication. Educational tools and techniques: index Most individuals require exposure to the same message many times before becoming conscious of it. Given limited resources, the question therefore is not which one medium is best, but which mixture of media can deliver optimal results. The following is a list of tools that can be used to develop educational programs: printed material media signs community programs 129

144 display community water quality monitoring programs launches local action committees and groups consumer programs business programs school education programs. Examples of education programs Examples of education programs in Queensland that use the tools above include: EcoBiz: < Water Watch: < Sunshine Coast Regional Council: < Townsville City Council: < Mackay City Council: < South East Queensland Healthy Waterways Partnership, Ecosystem Health Monitoring Program Report Card: < Keep Australia Beautiful: < 6.6 Enforcement Roles and principles of enforcement Enforcement should be seen as a complement to management and education strategies. Councils have a variety of enforcement responsibilities and powers which are supported by those of other authorities, including DERM. Enforcement may involve a warning or service of a notice requiring the recipient to carry out specified actions or imposing financial penalties. Enforcement should be fair, predictable and consistent and should be blind to whether the party involved is an individual, company or government agency. The primary purpose of enforcement should be to prevent future problems by making polluters accountable. This acts to improve the polluter s practices and deter others from carrying out polluting activities. A non-disclosed, outof-court settlement may not achieve the desired wider outcomes Enforcement agencies To protect the environment and ensure clean rivers, fresh air and suitable disposal of hazardous and toxic wastes, the Environmental Protection Act 1994 makes individuals, industry, state agencies and local governments accountable for their actions, and encourages good environmental practice. A range of enforcement measures are available to authorities administering this Act. The measure to be used when a breach is discovered depends on factors including: the seriousness of the breach the extent of cooperation from those involved their willingness to correct the problems so the environment is not harmed again. In some cases, no enforcement action will be taken. Measures available include: infringement notices 130

145 injunctions to cease an activity orders to carry out specified works or clean up damage cancellation or suspension of licence prosecution. For further information on compliance and enforcement see the DERM s website Enforcement powers of local councils Planning controls Enforcement powers are detailed under the Sustainable Planning Act 2009 for offences including: Self-assesable development must comply with codes with applicable codes Carrying out developmenr without compliance permit or compliance Certificate Compliance with compliance permit or compliance certificate Carrying out assessable development without permit Assessable development must comply with code; and Compliance with development approval; See < for further information. Local laws Under the Local Government Act 2009, a council may make local laws. The intention of this provision is to link a council s local law-making power to its functions and powers conferred elsewhere. A local law cannot be inconsistent with an Act or regulation and to the extent that it is, it will not comply. This does not necessarily mean, however, that it cannot duplicate an existing law. Local laws can protect many aspects of the environment. Councils have the power to introduce local laws to protect stormwater quality which is fundamentally related to councils environmental protection function. See < for further information. 131

146 7 Structural treatment measures Key resource documents Level Document State Engineers Australia 2006, Australian Run-off Quality, A Guide to WSUD IECA 2008, Best Practice Erosion and Sediment Control, International Erosion Control Association (Australasia), NSW Department of Natural Resources and Water (2007) Queensland Urban Drainage Manual Department of Transport and Main Roads (2010), Road Drainage Manual A Guide to the Planning, Design, Operation and Maintenance of Road Drainage Infrastructure 2 nd Edition Regional Regional specific structural treatment guidelines including: SEQ Healthy Waterways 2006, Water Sensitive Urban Design, Technical Design Guidelines for South East Queensland Water by Design Construction and Establishment Guidelines: Swales, Bioretention Systems and Wetlands Version 1.1 (2010) Water by Design Asset Handover Guideline 2010 Water by Design Rectification Guideline 2010 Water by Design Maintenance Guideline 2010 Water by Design Data Capture Guideline 2010 Water by Design Asset Management Guideline (proposed) Regional NRM Plans and Water Quality Improvement Plans Townsville/Thuringowa (WSUD Guidelines) Mackay Whitsunday (WSUD Guidelines) Local Local and regional councils planning schemes and local guidelines on structural treatment measures e.g.: Gold Coast City Council 2007, WSUD Guidelines and WSUD Design Manual Brisbane City Council 2005, WSUD Engineering Guidelines This chapter is based on the content of the Best Practice Environmental Management Guidelines Urban Stormwater, Victoria Stormwater Committee VIC EPA 1999, CSIRO Publishing. It provides a general overview of urban stormwater structural treatment measures. The chapter may be further revised when additional guidelines on these measures relevant to Queensland are developed.. In South East Queensland, Water by Design has developed a suite of stormwater-related guidelines for both pre-construction and construction phases (Chapter 6) and the postconstruction phase (this chapter). These have general application across Queensland. Figure 7.3 is an outline of Water by Design guidelines, available and proposed. 132

147 7.1 Introduction Stormwater structural treatment measures in this chapter deal with the post construction, operational phase of development. Measures dealing with the construction phase are described in Chapter 6 Source controls. Stormwater structural treatment measures can be grouped into four categories: primary, secondary, tertiary, and flow management. Primary treatment Physical screening or rapid sedimentation techniques. Typical retained contaminants include gross pollutants and coarse sediments (see section 7.3). Secondary treatment Finer particle sedimentation and filtration techniques. Typical retained contaminants include fine particles and attached pollutants (see section 7.4). Tertiary treatment Enhanced sedimentation and filtration, biological uptake, adsorption onto sediments. Typical retained contaminants include nutrients and metals (see section 7.5). Flow management This aims to protect waterway stability, and manage frequency of run-off events to mimic natural conditions (see section 7.6). Many of the treatment measures described in this chapter may be the subject of field testing for suitability in various Queensland regions. Monitoring of structural treatments used in other states may also provide useful advice. There is a need for further long-term performance monitoring of the applicable techniques some may demonstrate incidental environmental impacts not yet recognised. Ongoing performance monitoring and the complexity of the pollutant retention processes involved make estimating pollutant retention an imprecise science. As a result, refinements to treatment design parameters over time should be regarded as part of an adaptive (best practice) management process. 7.2 Selecting stormwater quality treatment measures The selection and implementation of structural treatment measures involves six steps: 1. Determine treatment objectives Establish the pollutants of concern in the catchment (e.g. litter, sediments, nutrients) and the level of pollutant retention required (see section 7.2.1). 2. Develop the treatment train Assess the treatment processes required and appropriate measures and ordering, including flow retention and detention, and any pre-treatment requirements, for example, screening of coarse sediments or flow control (see section 7.2.2). 3. Undertake site identification Identify potential sites and site constraints, for example, slopes and soil types (see section 7.2.3). 4. Short-list potential treatments Identify all applicable treatments (see section 7.2.4). 5. Compare potential treatments Compare all potential treatments for removal efficiency, maintenance requirements, social impacts, integration with construction phase stormwater quality controls, and costs (see section 7.2.5). 6. Complete detailed design Complete detailed design of the optimal treatment train. This chapter reviews the first five steps of this process and outlines a methodology for selecting and ranking treatment options using various pollutants and design objectives as the target. The detailed design process (step 6) requires further, more site-specific information and is outside the scope of this guide. Detailed design guidance is available in the key references listed in the beginning of this chapter. 133

148 7.2.1 Determine treatment objectives The stormwater pollutant profile of any catchment area is determined largely by the area s land use and stormwater management. For example, human-derived litter can be a problem in commercial areas, whereas sediment run-off is often more prevalent in developing urban areas (that is, during the construction phase). To isolate the pollutants of concern in any catchment, designers need to closely examine receiving water degradation in light of the area s land use and current management practices. The design objectives set out in Chapter 2 are a guide to the typical pollutant load reductions required to help contribute to protecting environmental values set out in the Environment Protection (Water) Policy 2009 (EPP Water). In order to protect receiving waters, treatments may be required to reduce the impact of one or more of the following pollutant categories: gross pollutants trash, litter and vegetation larger than 5 mm coarse sediment contaminant particles between 5 mm and 0.5 mm medium sediment contaminant particles between 0.5 mm and mm fine sediments contaminant particles smaller than mm pollutants that are attached to fine sediments specifically nutrients, metals, toxicants and hydrocarbons dissolved pollutants typically nutrients, metals and salts. The treatment measures considered should be assessed according to their trapping efficiency for each pollutant category. The overall treatment effectiveness of a measure is a function of its pollutant removal rate and the volume of run-off treated. A high-flow by-pass is generally designed into treatment measures for protection from large flood flows that could damage the device or scour and transport previously collected pollutants downstream. The maximum flow rate at which a treatment measure is designed to operate in an efficient manner is termed the design flow. Selecting the design flow is a trade-off between the cost and space requirements of the device (a higher design flow will generally require a larger facility with additional costs) and the volume of water that could potentially by-pass the measure and avoid treatment Develop treatment train Many pollutant treatments, particularly those targeting fine pollutants, require a number of measures used in sequence to be effective. There is a clear relationship between pollutant size (from gross particle sizes down to dissolved) and the appropriate process that can be employed to retain the pollutant. The treatment types in Figure 7.1 show the size range of pollutants that each treats effectively. By knowing the target pollutants appropriate treatment measures can be selected. 134

149 Figure 7.1 Desirable design ranges for treatment measures and pollutant sizes Figure 7.1 also illustrates the approximate hydraulic loading rate for effective operation of the various treatments. The hydraulic loading rate is a function of the treatment process (either screening, sedimentation, enhanced sedimentation, filtration or biological uptake) and can be used to approximate the area required to install a facility given the design flow. This is useful to assess the space requirements for the various treatments. The treatment train approach is particularly important when a measure requires pre-treatments to remove pollutants that may affect the performance of the treatment measure. For example, wetland systems are often employed to protect receiving environments from the impact of excessive nutrients and metals. However, wetlands will perform poorly if gross pollutants and coarse sediments are not removed prior to the wetland treatment. It is therefore important to select and order treatment measures appropriately to ensure that wetland systems are protected from gross pollutants and coarse sediments. By taking this treatment train approach, as described in Chapter 2, the most effective sequence of the treatments can be determined. Possible further research on design objectives and treatment trains Much of the water sensitive urban design (and erosion and sediment control) stormwater controls remove mostly coarse sediment and trash from run-off (that is, most of the mass in accordance with the proposed design objectives). Removing clay/turbidity is not well addressed as current stormwater models do not deal directly with turbidity. In well-treated urban stormwater run-off from catchments widely fitted with treatment trains, lower mass loads with a greater proportion of clay/turbidity entering the stream will likely result. Natural stormwater quality has a much greater proportion of mass as coarse particles. Streams carry a natural sediment load which is in equilibrium with other stream processes. So mass load reduction, ignoring particle size, can starve a stream of its natural sediment load and it may erode its own bed and banks to return to an equilibrium condition. Using treatment trains to control turbidity as opposed to total suspended solids is one area of USQM that needs to be further investigated. Turbidity data is only just being collected. For further information: Geoff Hunter, Predicting the Waterway Impacts of Urbanisation: modeling considerations pre, during and post urban development, proceedings of Urbanisation and Waterway Health: A Forum for Policymakers and Managers, Kawana, Turbidity in urban stormwater can be addressed in the land use and catchment planning stages. 135

150 7.2.3 Undertake site identification Locating a treatment When determining the location for stormwater treatment measures, many factors must be considered. One fundamental question is whether to adopt an outlet or a distributed approach. Figure 7.2 Outlet and distributed approaches to stormwater treatment location The traditional outlet approach involves constructing a single large treatment at the catchment s outlet. Although this single site approach offers obvious maintenance advantages, it has the disadvantage of needing to treat very large volumes of water at a location sometimes far from the pollutant s source. An alternative is the distributed approach. Here, a number of smaller and potentially different treatments are installed throughout a catchment. A distributed approach to stormwater pollution treatment has many advantages over the outlet approach. These include: improved protection Water quality protection may be distributed along a greater length of the waterway. localised treatment Specific targeting of treatments may be directed at highly polluted sites. distributed risk The distributed approach has a lower risk of overall system failure, as the failure of any single treatment will not usually significantly impact on the total treatment system performance. improved removal efficiencies Distributed treatments are typically located in areas of lower flow. Lower flow velocities and volumes and high pollutant concentrations in stormwater at these sites lead to higher operating efficiencies. staged implementation Individual sites may be brought into operation in stages. Typically, a distributed treatment scheme will incorporate a range of structural treatment types. To ensure optimal pollutant removal efficiency, a treatment train approach should be considered during each step of the design process particularly where pre-treatment may be an issue. Site constraints The characteristics of a particular site can limit the choice of treatment measures suited to the area. These constraints fall broadly into two categories physical and social. Physical site constraints can make construction difficult or impossible and maintenance expensive. Factors to consider include: topography e.g. steep slopes soils and geology e.g. erosivity, dispersibility, porosity, depth to bedrock or instability 136

151 groundwater e.g. geochemistry and depth to water table space limited open space, proximity to underground services e.g. gas, power. Social constraints include issues of health and safety, aesthetics and impacts on recreation facilities. Factors to consider include: odour problems visual impacts noise physical injury resulting from unauthorised access to structures contamination infection, poisoning or injury caused by trapped pollutants or algal blooms vermin e.g. mosquitoes, rats. Many social issues can be addressed simply during the treatment design stage. This may involve development of occupational health and safety procedures for operations and maintenance staff, installation of warning signs, fencing around dangerous areas and so on Short-list potential treatments A short list of potential treatment techniques that meet the requirements for the target pollutants and site constraints should be developed. Various primary, secondary and tertiary treatment techniques are listed in Tables 7.1, 7.2 and 7.3 respectively, along with their pollutant retention efficiencies for a range of contaminants. Specific pollutant retentions can be compared to the performance objectives set in Table 2.1. The pollutant retention efficiencies are based on the desirable hydraulic loading rate and are listed for all six pollutant categories: gross pollutants, coarse sediments, medium sediments, fine sediments, attached pollutants and dissolved pollutants. Pollutant retention efficiencies are graded as follows: very high (VH) 80 per cent to 100 per cent of total pollutant load retained high (H) 60 per cent to 80 per cent of total pollutant load retained moderate (M) 40 per cent to 60 per cent of total pollutant load retained low (L) 10 per cent to 40 per cent of total pollutant load retained negligible (N) less than 10 per cent of total pollutant load retained. These efficiency classifications allow the designer to quickly reject those techniques which have little impact on the target contaminants. For example, primary and secondary treatments would not be short-listed when specifically targeting dissolved nutrient or metal contamination only tertiary treatments will have an impact in this case. However, it should be remembered that the effective operation of many tertiary systems will rely on the existence of primary and/or secondary pre-treatment Compare potential treatments Having established a short list, the treatment measures should be reviewed in detail to determine the best options. Factors to consider include maintenance requirements and operation ability, pollutant retention, head requirements, cost and secondary benefits. These considerations are further described below. Various references describe a wide range of treatment types. Each description should present a review of the treatment measure s operation, advantages, limitations, performance, costs and maintenance requirements. 137

152 Maintenance and operation A poorly maintained treatment measure may not only perform badly, it may become a flood hazard, a source of pollution itself or worse, convert low-risk (e.g. particulate) pollutants into high-risk (e.g. dissolved) pollutants. Treatment measure operation and maintenance requirements vary widely. When assessing the treatment measure s maintenance requirements and operational ability, consideration should be given to the following issues: ease of maintenance and operation The selected treatment should be easy and safe to maintain and operate. extent of maintenance Ensure the maintenance requirements are within the operator s capability. access to the treatment site Consider the ease of site access when reviewing the treatment s maintenance requirements. frequency of maintenance Ensure that resources are available to carry out maintenance at the required frequency. debris and pollutant clearing During clearing, the treatment should not require direct human contact with debris and trapped pollutants (automated clearing facilities are preferred). disposal Consider the disposal of any waste from the treatment process. Pollutant retention A closer look at the treatment measure s pollutant retention is required at this stage. Depending on maintenance requirements, operational ability, cost and head requirements, the overall pollutant retention efficiency for each specific target pollutant should preferably be as high as possible. Head requirements Some treatments require large amounts of hydraulic head for operation. These are obviously not suitable for use in low lying areas with mild drain slopes. Tables 7.1, 7.2 and 7.3 list the hydraulic head requirements for primary, secondary and tertiary treatment types respectively. These have been classified as follows: high more than 1 metre moderate between 0.5 metre and 1 metre low less than 0.5 metre. Cost Relative capital and maintenance costs for treatments are presented in Tables 7.1, 7.2 and 7.3. These are indicative rankings only; costs will vary according to catchment characteristics and rainfall. Capital costs are based on the treatment s total installed cost per hectare of catchment. Broad approximations to give the reader a starting point are categorised as: high (H) greater than $1500 per hectare of catchment moderate (M) between $500 and $1500 per hectare of catchment low (L) less than $500 per hectare of catchment. Maintenance costs are based on the cost per hectare per annum of the particular treatment type. Once again, broad estimates are categorised as: high (H) greater than $250 per hectare of catchment per annum moderate (M) between $100 and $250 per hectare of catchment per annum low (L) less than $100 per hectare of catchment per annum. 138

153 Maintenance costs in this section include inspections and routine maintenance and cleaning operations, but do not include any disposal costs associated with removed pollutants. Detailed cost information can be obtained from the treatment designers or suppliers. Secondary benefits Certain treatment measures provide incidental benefits beyond the primary goal of removing the target pollutants. Some treatment measures demonstrate the potential to remove pollutants other than the primary targets, for example, a litter trap that also removes sediment. Other treatment types provide added benefits such as aiding flood control, ecological enhancement or provision of an educational resource. All such benefits need to be considered when selecting a treatment measure. 7.3 Primary stormwater treatment There is a wide choice of primary treatment measures available, with an increasingly diverse range of treatment types being used throughout Australia. Primary treatment measures vary in size, cost and trapping performance by orders of magnitude. New designs are evolving rapidly. There is generally a shortage of data relating to the trapping performance of the newer methods, making treatment comparisons difficult. Table 7.1 lists 17 types of primary treatments identified at the time of publication. These have either been used extensively in Australia, or are becoming more frequently used and show promise for efficient pollutant removal. The primary treatment measures listed fall into one of five operating types: 1. drainage entrance treatments grate entrance systems, side entry pit traps and baffled pits 2. in-line methods litter collection baskets, boom diversion systems, release nets, trash racks, gross pollutant traps, return flow litter baskets, and hydraulically operated trash racks 3. self-cleaning screens circular screens, downwardly inclined screens 4. floating traps flexible floating booms, floating debris traps 5. sediment traps sediment settling basins and ponds, circular settling tanks, hydrodynamic separators. Drainage entrance treatments Drainage entrance treatments involve either preventing the pollutants entry into the stormwater drainage system, or capturing the pollutants at drainage entrance points. This can be achieved by either restricting the stormwater entrance size, capturing the pollutants as stormwater falls into the drainage system, or retaining the pollutants in the entrance pit. Entrance treatments are generally located close to the pollutant source allowing the most polluted areas to be targeted. Use of entrance treatments can also help to reduce downstream pipe blockages. In-line devices In-line methods use direct screening to retain gross solids by passing flow through a grid or mesh barrier assembly. As pollutants build up at the barrier, smaller material may also be retained due to the reduced effective pore size. There are various trapping methods using either baskets, prongs, racks or perforated bags. These systems are generally simple to install and can retain large quantities of material. One limitation is the possibility of blockage. If the pores in the barrier are blocked, water levels may rise and spill collected pollutants downstream. 139

154 In-line non-screening devices direct stormwater into off-line chambers that collect pollutants by altering the hydraulics in the chamber. The systems divert flow and pollutants by means of a boom that is capable of rising during times of high discharge. Self-cleaning screens The tendency of in-line screens to block is their main limitation. To improve in-line screen performance, there have been numerous attempts to design a self-cleaning trash screen. Two self-cleaning designs have been used successfully: circular screens and downwardly inclined screens. Developed in Victoria, circular screens induce a vortex that keeps pollutants continually in motion and this keeps the screen free of debris. The second process, downwardly inclined screens, has been developed independently in New South Wales and South Africa. It nvolves angling a trash rack downstream. Gravity and the force of the water push the pollutants down the screen and onto a holding shelf. Floating traps Floating traps are generally intended to remove highly buoyant and visible pollutants such as plastic bottles. These are typically installed in the lower reaches of waterways where velocities are lowest. The earliest boom designs were based on those used for oil slick retention. Floating traps generally consist of a partly submerged floating barrier fitted across the waterway, which either retains the pollutants or deflects them into a retention chamber. Floating traps have been employed for some time in Australia s major cities. More recent developments incorporate pollutant retention chambers and advanced trap clearing methods. Sediment traps There are a number of sediment traps available, ranging from simple hydraulic settling pond designs to complex structures using vortices and secondary flows for sediment separation. Each trapping system aims to create favourable flow conditions for sedimentation. The hydraulic settling pond-type sediment traps can be either concrete basins or more natural ponds constructed with site soils. They retain sediments by simply enlarging the channel so that water velocities are reduced. More complex sediment traps generate vortex flows, which enhance sedimentation through secondary flows. Sediment traps are ideal for pre-treatment of larger sediment particles prior to a constructed wetland system. However, relevant regional or catchment plans should be consulted as the implications of widespread adoption of sediment basins and wetlands may have been considered. The natural sediment load is in equilibrium with other stream processes. Catchment studies may examine mass load reduction, particle size, and a stream s natural sediment load and an equilibrium condition. Recommendations on use of sediment dams in a catchment may result. See IECA 2008 for further information Summary of primary treatments Table 7.1 presents a summary of the primary treatments listed in the guidelines. It presents relative estimates of the trapping performances, installation and maintenance costs per hectare, head requirements and approximate catchment area per unit treatment 140

155 Table 7.1 Summary of primary treatments Device Catchment area (ha) gross pollutants coarse sediment Trapping efficiency medium sediment fine sediment attached pollutant dissolved pollutants Cleaning frequencies Head requirements Installation costs Grate and entrance screens L N N N N N weekly L/M Side entry pit traps M/H L N N N N monthly L/M M/H Baffled pits L M L/M L N N monthly L/M L/M Litter collection baskets M/H L/M N N N N weekly/mont M/H M/H M/H Boom diversion systems M L/M N/L N N N monthly L M M/H N N weekly/mont L L L/M Trash racks L N/L N/L N N N monthly L/M M L/M Gross pollutant traps L/M M/H M L N N monthly/qua H H M/H Return flow litter baskets M/H M L N N N monthly L M/H L/M Hydraulically operated trash racks >10 H/VH L/M N N N N weekly L L/M M/H Circular screens VH H M L/M L N quarterly L H M Downwardly inclined screens H/VH N N N N N monthly/qua H M/H L/M Flexible floating boom >100 N/L N N N N N weekly/mont L M Floating debris traps >100 L N N N N N weekly/mont L L M Sediment settling basins N M/H M L N/L N half-yearly L L/M L/M Circular settling tanks 1-20 L/M H M/H M L/M N monthly L H M Hydrodynamic separation L/M M/H M M L/M N monthly L H L/M N = negligible, L = low, M = moderate, H = High, VH = very high Maintenance costs 141

156 7.4 Secondary stormwater treatment Secondary treatments are used to retain or remove coarse, medium and fine sediments from stormwater and can be divided into two broad categories: pre-entrance treatments filter strips, grass swales, triple interceptor pits, porous pavements and infiltration trenches in-transit treatments infiltration basins, extended detention basins and sand filters. Pre-entrance treatments Pre-entrance treatments either use infiltration techniques to separate out entrained sediments from stormwater before it enters the drainage network, or use enhanced sedimentation to contain contaminants. Infiltration can be achieved in one of two ways either by discharging the stormwater over vegetated land to encourage infiltration, or by using purpose built infiltration structures. Filter strips and grass swales are typical examples of flowing water over vegetation. Purpose built infiltration structures include infiltration trenches and porous pavements. These methods have the advantage of separating out pollutants close to the source, thereby avoiding the difficulties of entrained flow pollutant removal. In-transit treatments In-transit secondary treatments target entrained pollutants flowing through the stormwater system. These either use reduced water velocities to encourage sedimentation or direct filtration through a porous medium. Reduced velocities are typically achieved using storage ponds, such as infiltration and detention basins. The direct filtration methods use sand filters to screen stormwater as it flows through the sand grains, leaving the pollutant in the sand. These can remove large quantities of pollutants, but require regular maintenance Summary of secondary treatments Table 7.2 presents a summary of the secondary treatments listed within this guide. It shows relative estimates of the trapping performances, installation and maintenance costs per hectare, head requirements and approximate catchment area per unit treatment. Urban stormwater Queensland best practice environmental management guidelines

157 Table 7.2 Summary of secondary treatments Device Catchment area (ha) Trapping efficiency Head requirements Installation costs Maintenance costs gross pollutants coarse sediment medium sediment fine sediment attached pollutants dissolved pollutants Filter strips L/M H M/H L/M L/M L L L L Grass swales L M/H M L/M L/M L L L L Triple interceptor pits L/M M L/M L L N L/M M H Porous pavements L H M/H M M L L M L/M Infiltration trenches L M/H M L/M L/M L L L M/H Infiltration basins N M/H M M M L L L/M H Extended detention basins L M/H M L/M L/M L L L/M M/H Sand filters 1-50 L M/H M/H M M L H M/H M/H N = negligible, L = low, M = moderate, H = High, VH = very high 143

158 7.5 Tertiary treatment types Constructed wetland systems are generally the only treatment technique used for removal or retention of nutrients and fine sediments. Key reference documents describe and summarise the pollutant retention performance of constructed wetlands and provide some basic design information. Sufficient design information is presented to enable preliminary sizing of a wetland system to meet the design objectives set in Chapter 2. The detailed design is an involved process requiring the input of several disciplines such as hydrology, aquatic biology and landscape planning. Table 7.3 Constructed wetlands treatment performance Criteria Catchment area (hectares) Trapping efficiency: gross pollutants Trapping efficiency: coarse sediments Trapping efficiency: medium sediments Trapping efficiency: fine sediments Trapping efficiency: attached pollutants Trapping efficiency: dissolved pollutants Head requirements Installation costs Maintenance costs Value/ranking >10 L/M H M/H L/M M/H L/M L/M H M N = negligible, L = low, M = moderate, H = high, VH = very high Sand filters that include a media layer with an adsorption capacity (for example, peat or humus) could also be classified as tertiary treatment measures. This is a relatively recent innovation in sand filter design until recently, sand filters have been classified as secondary treatment measures. More detailed description of sand filters is included in SEQ Healthy Waterways publications. 7.6 Flow management Urbanisation has significant impacts on catchment hydrology, which in turn affects the physical and biological characteristics of waterways. Recent initiatives in integrated stormwater management have recognised the importance of water quality. However, the importance of managing the impact of changes in flows on receiving waterways must also be taken into account. The two main characteristics of urban development that alter flow regimes in waterways are: removed vegetation and increased impervious area in the catchment increased hydraulic efficiency within drainage lines and receiving waterways. These characteristics increase both the magnitude and frequency of peak discharges, with the greatest impact resulting from increased hydraulic efficiency. There are opportunities to integrate both hydraulic capacity and waterway health objectives within a stormwater system. This is particularly so, as limiting changes in peak discharge is a critical component of protecting aquatic ecosystems as well as reducing the incidence of flooding. 144

159 Urban Stormwater Quality Planning Guidelines The key resource documents outline the objectives of effective flow management and present a range of flow management techniques. Table 2.1 outlines stormwater run-off flow frequency and stormwater quality design objectives for Queensland. 145

160 Urban Stormwater Quality Planning Guidelines Figure 7.3 Guide to Water by Design Guidelines (current and proposed) as at October

161 Urban Stormwater Quality Planning Guidelines Appendix 1A Example development approval conditions for erosion and sediment control Contents Appendix 1A 1. Introduction Use of these provisions Example development approval conditions / Site planning checklist Development planning and design Construction planning Erosion and Sediment Control Plans (ESCP) Site establishment Site access Site management Site clearing Soil and stockpile management Drainage control Erosion control Sediment control Site rehabilitation Sediment basin rehabilitation Site monitoring Site maintenance Road works Instream works Works within intertidal areas

162 Urban Stormwater Quality Planning Guidelines 1 Introduction These best practice provisions inform both local government assessment managers or other assessing authority and applicants when considering or preparing development applications involving urban land development. The provisions are set out in the following sections 1 to 20. This appendix is based on Appendix G Model code of practice of IECA 2008, Best Practice Erosion and Sediment Control, International Erosion Control Association (Australasia), Picton NSW. 2 Use of these provisions Local government assessment managers: may use this information when considering erosion and sediment control issues in development applications may adopt some or all of these provisions in developing their own requirements Applicants may use this information in considering best practice erosion and sediment control. 3 Example development approval conditions The following development approval conditions (sections 4 to 20) have been provided as a guide only. Project managers and regulatory authorities should review the following example conditions to determine which conditions will be applicable to a particular region or development application. The conditions are based on development approval by a local government state and federal agencies must make appropriate modifications to the wording of each clause. It is recognised that it is neither reasonable nor practicable for all of the following development conditions to be applied on all sites. Discretion needs to be applied by regulators in the selection and application of these conditions. If contradiction exists between any of the conditions, then those conditions that best achieve the aims or intent of the erosion and sediment control plan (ESCP) will apply. Site planning checklist: erosion hazard assessment completed on the site erosion risk mapping completed on site on-site and off-site environmental values identified. High ecological values receiving waters or wetlands identified potential impacts of the development on environmental values identified potential site limitation with respect to soils, topography, water supply and vegetation identified areas of potential acid sulfate soils identified proposed works have been appropriately integrated into the site's topography, protected vegetation and environmental values location and size of major construction site sediment identified sufficient useable land made available for construction of major sediment basins 148

163 Urban Stormwater Quality Planning Guidelines sufficient useable land made available for stockpiling construction materials development layout does not interfere with the construction and operation of the major sediment basins development layout allows up-slope stormwater to be temporarily diverted around construction activities soil testing and soil mapping has been completed vegetation mapping completed. 4 Development planning and design 1. Land use of a proposed development must be compatible with the capability of the land to sustain it without degrading the environmental values of waterways having regard to the limitations of control technology and practices. 2. All reasonable and practicable measures must be taken to minimise changes to the volume, frequency, duration and velocity of stormwater run-off so that changes to the natural water cycle and the risk of causing, or contributing to, accelerated erosion within downstream waterways are minimised. 3. Where increased stormwater run-off from a proposed development (including land subdivision) is likely to accelerate erosion of any watercourse, appropriate measures must be taken to prevent or minimise this erosion. 4. Erosion and sediment control (ESC) measures must be an integral component of the project's planning, design and costing. 5. The location and design of the proposed works must take appropriate consideration of the need to minimise potential erosion problems during the construction and operational phases of the project (for example, by fitting the development to the terrain, reducing cut and fill, minimising watercourse crossings, and avoiding high erosion hazard areas). 6. Where site constraints are such that best practice control measures may not be costeffective or difficult to implement (such as high erosion hazard, flooding and high groundwater), the design of the development must be reviewed to reduce its potential for harm. 7. To the maximum degree reasonable and practicable, the development layout must aim to minimise the duration that any and all areas of soil will be required to be exposed to the erosive effects of wind, rain and surface run-off during the construction period. 8. The staging and/or layout of the works must not cause unnecessary soil disturbance if an acceptable alternative staging/layout is available that achieves the same or equivalent project outcomes at no unreasonable additional cost. 9. Adequate site data, including soil data, flooding and groundwater levels must be obtained prior to, or during, the planning phase to identify potential site constraints (for example,dispersible or acid sulfate soils) and to appropriately recognise and integrate these constraints into site planning. 10. A conceptual ESCP must be submitted to the assessing authority if: in accordance with that authority's erosion hazard assessment procedures, the site is classified as high-risk or represents a high or extreme erosion hazard; or there may be impediments to implementation of control measures to adequately protect environmental values, such as flooding (submergence of control measures) high groundwater (water infiltration to sediment basins) or flat land (no hydraulic head). 149

164 Urban Stormwater Quality Planning Guidelines 11. The development must adopt best practice erosion and sediment control techniques and practices. 5 Construction planning 12. To the maximum degree reasonable and practicable, the construction site layout and construction program must aim to minimise the duration that any and all areas of soil will be exposed to the erosive effects of wind, rain and surface run-off during the construction period. 13. The construction site layout, methodology, staging and programming must not cause unnecessary environmental harm if an alternative layout, methodology, staging or program (which reduces unnecessary soil disturbance and/or potential environmental harm) is available that achieves the same or equivalent project outcomes at a reasonable cost. 14. The construction site layout and construction program must take appropriate consideration of the need to minimise potential erosion problems during the construction and operational phases of the project (for example, through minimisation of temporary watercourse crossings and the avoidance of high erosion hazard areas and construction practices). 15. Soil disturbances must be staged into manageably sized areas of no greater than 3.5 hectares to ensure adequate ESC management and progressive stabilisation of disturbed surfaces. 16. To the maximum degree reasonable and practicable, all necessary soil sampling and analysis must be completed prior to commencement of bulk earthworks. 17. An ESCP must be prepared by suitably trained and experienced personnel and submitted to [insert organisation] prior to commencement of construction. 18. An ESCP must be prepared by suitably trained and experienced personnel and approved by the assessing authority prior to commencement of construction. (alternative to above). 19. An ESCP must be prepared by suitably trained and experienced personnel and approved by [insert organisation] prior to access to the site being granted for commencement of construction. (alternative to above). 20. On sites with a soil disturbance greater than 2500 square metres, a site stabilisation plan, landscape plan, and/or vegetation management plan must be prepared and approved by the assessing authority prior to initial land clearing or bulk earthworks. Such a plan(s) must show progressive stabilisation of exposed soil for erosion control purposes including, but not limited to all of the following: i. schedule for stabilisation of exposed soil areas ii. specifications for subsoil and topsoil preparation and application iii. specification of stabilisation by mulching or other appropriate surface treatment (note that grass seeding without adequate mulching is not permitted) iv. details on the type and application rate of any tackifiers to be used in the application of mulches (including hydromulch, bonded fibre matrix, and compost blankets). 21. On sites with a soil disturbance greater than 2500 square metres, a monitoring and maintenance program is prepared by, or under the supervision of, suitably qualified and experienced personnel. 22. On sites with a soil disturbance greater than 2500 square metres, an event-based water quality monitoring program must be prepared and approved by council prior to initial land clearing or bulk earthworks. Such a program must document proposed water quality monitoring, and include: i. location of instream water quality monitoring stations 150

165 Urban Stormwater Quality Planning Guidelines ii. water quality monitoring, sampling and analysis procedures and standards. 23. A performance bond in the form of a bank guarantee must be submitted to the assessing authority prior to commencement of construction to ensure effective erosion mitigation, sediment control and site rehabilitation measures are implemented. 6 Erosion and sediment control plans 24. Adequate site data, including soil data, must be obtained to allow the preparation of an appropriate ESCP, and allow the selection, design and specification of required ESC measures. 25. Prior to development of the ESCP, the site must be assessed from a hydrological, hydrogeological, hydraulic, vegetation, soils and geological perspective to determine relevant site constraints that may affect the focus or detail of the plan. 26. A conceptual ESCP must include plan(s) (no larger than 1:1000), and must address the following issues: i. identify the likely need for the construction of sediment basins on the site ii. identify that adequate space has been made available for the construction and operation of major sediment traps and essential flow diversion systems iii. demonstrate that there is a feasible means of constructing the project while still protecting key environmental values iv. identify problem soil areas including, dispersive soils, acid sulfate soils, areas of potential mass movement v. identify key environmental features on the site such as protected vegetation. 27. Preparation of an ESCP as part of the development application/approval process is required for the following types of land-disturbing activities: i. development which increases site impermeability by more than 15 per cent, involves site excavation or filling exceeding 100 m 3 or site disturbance greater than 250 m 2 ii. re-configuration of an allotment involving land disturbance, multi-unit dwellings, commercial and industrial developments iii. any land-disturbing development subject to code assessment (such as, multi-unit dwellings, commercial and industrial developments, filling and excavation) where such activities are deemed to be high or extreme risk in accordance with council's erosion hazard assessment procedures iv. any other land-disturbing development that is deemed to be high or extreme risk by council or other creditable source. 28. If an ESCP is required by an assessing authority, then this plan must be prepared by the applicant or owner, and approved by the assessing authority prior to the commencement of any work or activity, including land clearing, except as allowed under for the purposes of ground survey, geotechnical investigation, or other recognised essential purposes, provided the work is: i. consistent with state and council vegetation protection and/or preservation requirements and/or policies; and ii. undertaken so that the ground surface is not disturbed and at least 150 mm stubble remains on the surface (where such a stubble exists prior to clearing); or iii. to provide site access via the minimum practicable number of site access corridors. 151

166 Urban Stormwater Quality Planning Guidelines 29. The level of detail supplied in the ESCP must be commensurate with the complexity of the proposal and the assessed environmental risk. 30. The ESCP must include plan(s) (no larger than 1:1000), supporting documentation, and construction specifications that can be readily understood and applied on-site. The plan(s) must include all aspects of proposed site disturbance, temporary drainage works, erosion and sediment control measures, installation sequence, and site rehabilitation for the duration of the project, including (where appropriate) the nominated maintenance period. 31. On sites with a soil disturbance greater than 2500 square metres, the ESCP (including supporting documentation) must include: i. north point and plan scale ii. site and easement boundaries and adjoining roadways iii. construction access points iv. site office, car park and location of material stockpiles v. limits of disturbance vi. retained vegetation including protected trees vii. general soil information and location of problematic soils viii. groundwater, and flood-affected areas (2-year ARI) ix. location of critical environmental values (where appropriate) x. existing site contours (unless the provision of these contours adversely impacts the clarity of the ESCP) xi. final site contours including locations of cut and fill xii. construction drainage plans for each stage of earthworks, including land contours for that stage of construction, sub-catchment boundaries and location of watercourses xiii. general layout and staging of proposed works xiv. location of all drainage, erosion and sediment control measures xv. full design and construction details (such as, cross-sections, minimum channel grades, channel linings) for all drainage and sediment control devices, including diversion channels and sediment basins xvi. site revegetation requirements (if not contained on a separate plan submitted to the assessing authority) xvii. site monitoring and maintenance program, including the location of proposed water quality monitoring stations xviii. technical notes relating to: A. site preparation and land clearing B. extent, timing and application of erosion control measures C. temporary ESC measures installed at end of working day D. temporary ESC measure in case of impending storms, or emergency situations E. installation sequence for ESC measures F. site revegetation and rehabilitation requirements G. application rates (or at least the minimum application rates) for mulching and revegetation measures 152

167 Urban Stormwater Quality Planning Guidelines H. legend of standard symbols used within the plans I. sediment basin operation and flocculent dosing xix. calculation sheets for the sizing of ESC measures xx. completed ESCP checklist xxi. any other relevant information council may require to properly assess the ESCP. 32. If the timing of the proposed construction activities are not known during development of the ESCP, and if rainfall erosivity varies significantly throughout the year, then the erosion control specifications placed on the ESCP must specify appropriate erosion control measures for each level of rainfall erosivity. 33. On sites with a soil disturbance greater than one hectare, the ESCP must include: i. individual ESCPs for: the bulk earthworks phase, roadworks and drainage phase and the practical completion/on-maintenance phases of construction. Each phase above must be documented graphically on a dedicated ESCP, or detail shown on an ESCP, and supported by a clearly documented construction sequence, or ESC installation sequence, which describes the timing of key ESC actions on the site ii. procedures for the temporary shutdown of the site, whether a planned or unplanned shutdown. 34. The ESCP must clearly state that no land-disturbing activities on the site shall occur until all perimeter ESC measures, sediment basins, and associated temporary drainage controls, have been constructed in accordance with best practice erosion and sediment control. 35. On sites with a soil disturbance greater than 2500 square metres, ESCPs must be signed-off by a suitably qualified and experienced professional. A suitably qualified and experienced professional is defined as a person with all of the following: i. training and/or qualifications in erosion and sediment control that are recognised by the council ii. professional affiliations with an engineering, environmental engineering, soil science, and/or scientific organisation (for example, the International Erosion Control Association, Engineers Australia, Environment Institute of Australia and New Zealand, and the Australian Society of Soil Science Inc.) iii. at least two years experience in the management of erosion and sediment control which can be verified by an independent third party. 36. When signing-off on an ESCP, the signatory is deemed to be making the following statements: i. the ESCP satisfies the intent and design/performance standards established by all relevant local, state and federal policies relating to erosion and sediment control ii. the ESCP has been reviewed and approved by personnel suitably trained and experienced (to a degree appropriate for the given type and size of the land disturbance) in each of the following categories: construction, soil science, hydrology/hydraulics, and site revegetation/rehabilitation iii. the ESCP is both reasonable and practicable iv. the ESCP contains sufficient information to allow the appropriate application of the plans. 37. ESCPs prepared for developments in excess of one hectare, or where the ESCP incorporates a sediment basin, must be signed-off by an engineer experienced in hydrology and hydraulics. 153

168 Urban Stormwater Quality Planning Guidelines 38. ESCPs that incorporate a sediment basin with a constructed earth embankment with a height greater than one metre, must be signed-off by a geotechnical specialist. 39. The approved ESCP must be available on-site for inspection by council officers while work activities are occurring. 40. Should the development be commenced and not completed within twelve months of approval of the ESCP, a revised ESCP must be prepared, with further revisions thereafter at half-yearly intervals. 41. Addition erosion and sediment control measures are implemented, and a revised ESCP is submitted for approval (within five business days of any such amendments) in the event that: i. there is a high probability that serious or material environmental harm may occur as a result of sediment leaving the site ii. the implemented works fail to achieve the local government ESC standard/code, or state environmental protection requirements iii. site conditions significantly change iv. site inspections indicate that the implemented works are failing to achieve the objective of the ESCP. 42. In circumstances where it is considered necessary to prepare an amended ESCP, and the preparation of the amended ESCP is not imminent, then all necessary new or modified erosion and sediment control measures must be implemented in accordance with current best pratice. In circumstances where there is significant risk of environmental harm, then upon receipt of the amended ESCP, all works must be implemented in accordance with the revised plan. Otherwise, only upon approval of the amended ESCP by the assessing authority shall works be implemented in accordance with the amended plan. 43. A copy of the amended ESCP must be forwarded to council [insert officer] within five business days of any such amendments. 44. The design standard of erosion and sediment control must be commensurate with the degree of environmental risk associated to the proposed works. 45. All ESC measures are to be designed to a standard commensurate with the site's environmental risk, and as a minimum, to a design standard approved by the assessing authority. (alternative to above) 46. All erosion and sediment control measures, including temporary drainage control measures, must be designed in accordance with the design standards presented in [insert publication]. 47. The ESCP must incorporate hold points (where appropriate) detailing critical performance indicators of the various elements of the ESCP. The development must not be allowed to proceed without adherence to designated hold points at specified times. 7 Site establishment 48. The applicant must ensure that a copy of the development approval conditions, development permit, ESCP, monitoring and maintenance program, landscape and/or site rehabilitation plan, and any other documents required for the management of soil erosion and sediment control, are provided to the principal contractor prior to the commencement of land-disturbing activities. 49. On sites with a soil disturbance greater than one hectare, a vegetation management plan is provided to the principal contractor prior to the commencement of land disturbing activities. 154

169 Urban Stormwater Quality Planning Guidelines 50. On sites with a soil disturbance greater than one hectare, procedures for conducting a site shutdown (whether programmed or un-programmed) are provided to the principal contractor prior to the commencement of land disturbing activities. 51. Prior to the commencement of any construction activities, or soil disturbance (excluding that reasonably required for site investigation, survey or data collection) the applicant must engage and nominate (in writing to council) appropriately trained and experienced personnel to undertake regular ESC audits of the site, directly after a run-off-producing rainfall, and at no greater than fourteen calendar day intervals, from the commencement of site disturbance until acceptance of the site by the assessing authority under onmaintenance conditions. Such personnel must, collectively, have the following capabilities: i. an understanding of the local environmental values that could potentially be affected by the proposed works ii. a good working knowledge of the site s ESC issues, and potential environmental impacts, that is commensurate with the complexity of the site and the degree of environmental risk iii. a good working knowledge of current best practice ESC measures appropriate for the given site conditions and type of works iv. ability to appropriately monitor, interpret, and report on the site's ESC performance, including the ability to recognise poor performance and potential ESC problems v. ability to provide advice and guidance on appropriate measures and procedures to maintain the site at all times in a condition representative of current best practice, and that is reasonably likely to achieve the required ESC standard vi. a good working knowledge of the correct installation, operational and maintenance procedures for the full range of ESC measures used on the site. 52. Prior to the commencement of site works, the applicant must document a specific list of personnel that details the chain of command in relation to the implementation, modification, and maintenance of site erosion and sediment control measures. This document will, as a minimum, detail the ESC-related responsibilities and accountabilities of personnel, and must be updated to reflect any changes in staffing arrangements. This document will be provided to council officers at the site pre-start meeting. (alternative to above) 53. Prior to the commencement of any construction activity, or soil disturbance (excluding that reasonably required for site investigation, survey or data collection), the applicant must engage and nominate at the pre-start meeting, a site representative (other than the principal contractor) to undertake regular ESC audits of the site, directly after a runoff-producing rainfall, and at no greater than fourteen calendar day intervals, from the commencement of site disturbance until acceptance of the site by council under on-maintenance conditions. (alternative to above) 54. Prior to the commencement of any construction activity, or soil disturbance (excluding that reasonably required for site investigation, survey, or data collection), the applicant must nominate (in writing) a representative(s) to council who has authority to ensure compliance with the development conditions with respect to erosion and sediment control. (alternative to above) 55. Prior to the commencement of construction, the applicant is to provide a detailed program to the assessing authority showing the proposed timing for all works associated with the project, including the installation of erosion and sediment control measures. 56. A detailed landscape and rehabilitation plan for the site must be submitted to council for approval prior to initial land clearing or bulk earthworks. 155

170 Urban Stormwater Quality Planning Guidelines 57. A permit must be provided by the applicant to council that entitles officers of the assessing authority, or their representatives, to enter onto the land at any time to carry out additional erosion mitigation and sediment control works required as a result of the development. The cost of any such works shall be fully recouped from the developer prior to any further works proceeding. 58. All office facilities and operational activities must be located such that any effluent, including wash-down water, can be totally contained and treated within the site. 59. Adequate waste collection bins must be provided on-site and maintained such that potential and actual environmental harm is minimised. 8 Site access 60. Prior to the commencement of site works, the location of all site access point(s) must be verified with the local government. 61. Site access must be stabilised and confined to the minimum practicable number of locations. 62. Vehicular access into the site must be appropriately managed to minimise the risk of sediment being tracked or washed onto adjoining sealed roadways. 63. All reasonable and practicable measures must be taken to ensure stormwater run-off from access roads and stabilised entry/exit systems drains to an appropriate sediment control device. 9 Site management 64. All land-disturbing activities must be conducted in accordance with the requirements of relevant legislation. 65. Any works that cause significant soil disturbance that is ancillary to any purpose for which external approval is required, must not commence before the issue of that approval. 66. The applicant must ensure on-site soil erosion and the release of sediment and sedimentladen stormwater from the site is minimised at all times through compliance with an approved ESCP (as amended from time to time). 67. The applicant must take all necessary actions to ensure that all land-disturbing activities are undertaken at all times in accordance with the current ESCP and the conditions of development approval. (alternative to above) 68. In circumstances where addition or alternative erosion and sediment control measures are required on a site, or a revised ESCP needs to be prepared, then only those works necessary to minimise or prevent environmental harm must be conducted on-site prior to preparation of a revised ESCP. 69. All ESC measures are to be constructed, operated and maintained in a manner that is commensurate with the site's environmental risk and/or erosion hazard assessment. 70. All erosion and sediment control measures must constructed, operated and maintained to the standards and specifications contained in either: i. the approved ESCP (as amended from time to time) and associated supporting documentation ii. the latest version of [insert document] if such standards and specifications are not contained in the approved ESCP. 156

171 Urban Stormwater Quality Planning Guidelines 71. All works subject to an approved ESCP must be carried out in accordance with the approved ESCP (as amended from time to time) unless circumstances arise where: i. compliance with the ESCP would increase the potential for environmental harm as assessed by an authority recognised by the assessing authority in which case the person(s) responsible may be required to take additional, or alternative protective measures ii. the assessing authority or its representative determines that unacceptable off-site sedimentation is occurring as a result of a land-disturbing activity in which case the person(s) responsible may be required to take additional, or alternative protective action, and/or undertake reasonable restoration works within the timeframe specified by the assessing authority. 72. Land disturbing activities, other than [insert items or relevant clause] may only be undertaken without approval of an ESCP provided the land on which this work is undertaken: i. is not within 40 metres of a river, stream, watercourse, lake, estuarine, lagoon, wetland or ridge line ii. has less than 10 per cent of its area steeper than 4:1 (H:V) iii. is not designated by council, or other creditable source, as being geotechnically unstable iv. the height/depth of cut and/or fill does not exceed one metre v. the area of land affected is not greater than 250 square metres vi. uncontaminated up-site stormwater run-off is diverted around the earthworks (where appropriate and lawful) vii. erosion and sediment control measures are adopted which minimise the release of sediment from the site viii. the site is appropriately rehabilitated/revegetated on completion. 73. The applicant must ensure an adequate supply of erosion control, sediment control, and appropriate pollution clean-up materials are available on-site during the construction period. 74. Land-disturbing activities must be undertaken in such a manner that allows all reasonable and practicable measures to be undertaken to: i. allow stormwater to pass through the site in a controlled manner and at nonerosive flow velocities ii. minimise soil erosion resulting from wind, rain and flowing water iii. minimises the duration that disturbed soils are exposed to the erosive forces of wind, rain and flowing water iv. minimise adverse effects of sediment run-off (including safety issues) v. minimise or prevent environmental harm resulting from work-related soil erosion and sediment run-off vi. ensure that the value and use of land/properties adjacent to the development (including roads) are not diminished as a result of the adopted ESC measures. 75. Whenever the council or its representative determines that unacceptable off-site sedimentation is occurring as a result of a land-disturbing activity, the person(s) responsible may be required to take additional, or alternative protective action, and/or undertake reasonable restoration works within the timeframe specified by the council. (alternative to above) 157

172 Urban Stormwater Quality Planning Guidelines 76. Where circumstances change during construction and those circumstances could not have been foreseen, the assessing authority may require erosion and sediment control measures/works to be carried out in addition to, or instead of, those measures/works specified in the approved plan and/or specifications. In such cases these works must be completed within the timeframe specified by the assessing authority. 77. The construction schedule must aim to minimise the duration that any and all areas of soil are exposed to the erosive effects of wind, rain and flowing water. 78. Land disturbing activities must not cause unnecessary soil disturbance if an acceptable alternative construction process is available that achieves the same or equivalent outcomes at a reasonable cost. 79. Sediment, including clay, silt, sand, gravel, soil, mud, cement and ceramic waste, deposited off the site as a direct result of on-site activities, must be collected and the area cleaned/rehabilitated as soon as reasonable and practicable, with appropriate consideration given to both the safety and environmental risk associated with the sediment deposition. 80. Concrete waste and chemical products, including petroleum and oil-based products, must be prevented from entering any internal or external water body, or any external drainage system, excluding those on-site water bodies specifically designed to contain and/or treat such material. 81. All flammable and combustible liquids, including all liquid chemicals if such chemicals could potentially be washed or discharged from the site, must be stored and handled on-site in accordance with relevant standards such as AS-1940 The storage and handling of flammable and combustible liquids. 82. Impervious bunds must be constructed around all storage areas containing more than one cubic metre of petroleum and oil-based products such that the enclosed volume is large enough to contain 110 per cent of the volume held in the largest, individual storage tank. 83. On-site personnel involved in the handling and storage of flammable and combustible liquids, including all liquid chemicals, must be appropriately trained and/or supervised, as required in order to allow such personnel to appropriately perform such activities. 84. Wherever reasonable and practicable, brick, tile or masonry cutting must be carried out on a pervious surface (for example, grass or open soil), or in such a manner that any resulting liquid run-off is prevented from discharging into a gutter, drain or water. 85. All reasonable and practicable measures must be taken to prevent the discharge of any cement-laden run-off (such as resulting from the formation of exposed aggregate surfaces) into stormwater drains or waterways. 86. Newly sealed hard-stand areas (such as, roads, driveways and car parks) must be swept thoroughly as soon as practicable after sealing/surfacing to minimise the risk of components of the surfacing compound entering stormwater drains. 87. Trenches not located within roadways must be backfilled, capped with topsoil and compacted to a level at least 75 mm above adjoining ground level and appropriately stabilised. 88. All stormwater, sewer line and other service trenches not located within roadways are to be mulched and seeded, other otherwise appropriately stabilised, within seven days after backfill, or otherwise rehabilitated in accordance with the vegetation management plan. 89. No more than 150 metres of stormwater, sewer line and services trenches not located within roadways shall be open at any one time. 90. Site spoil must be lawfully disposed of in a manner that does not result in ongoing soil erosion or environmental harm. 91. All fill material placed on site shall comprise only natural earth and rock, and is to be free of contaminants, be free draining, and be compacted in layers not exceeding 300 mm to

173 Urban Stormwater Quality Planning Guidelines per cent modified maximum dry density in accordance with relevant standards such as AS The development must not be allowed to proceed without adherence to designated hold points contained within the ESCP. 10 Site clearing 93. All site clearing must be conducted in accordance with state and local government vegetation protection and/or preservation requirements and/or policies. 94. No site clearing, land-disturbing activities, or earthworks shall be undertaken prior to approval of a vegetation management plan. 95. Prior to the commencement of general site clearing, all areas of protected vegetation, and significant areas of retained vegetation, must be clearly identified as necessary to minimise the risk of disturbance to these areas. 96. No site clearing, other than provided for in [insert clauses], land-disturbing activities, or earthworks, shall be undertaken prior to approval of engineering plans and/or an associated ESCP. 97. Land clearing must be delayed as long as reasonable and practicable and must be undertaken in conjunction with development of each stage of works, unless otherwise approved by the assessing authority. 98. All reasonable and practicable efforts must be taken to delay the removal of, or disturbance to, existing ground cover (organic or inorganic) prior to land-disturbing activities. 99. Bulk tree-clearing and grubbing of the site must be immediately followed by specified temporary erosion control measures (for example, temporary grassing, or mulching) prior to commencement of each stage of construction works Site clearing for the purposes of ground survey, geotechnical investigation, or other recognised essential purposes can be undertaken without development consent or approval, provided the work is: i. consistent with state and local government vegetation protection and/or preservation requirements and/or policies; and ii. undertaken so that the ground surface is not disturbed and at least 150 mm stubble remains on the surface (where such a stubble exists prior to clearing); or iii. to provide site access via the minimum practicable number of site access corridors Site clearing must be limited to five metres from the edge of proposed constructed works, two metres of essential construction traffic routes, and a total of 10 metres width for construction access, unless supported by an approved written proposal Land clearing must not extend beyond that necessary to provide up to eight weeks of site activity during those months when the expected rainfall erosivity is less than 100, six weeks if between 100 and 285, four weeks if between 285 and 1500, and two weeks if greater than Land clearing must not extend beyond that necessary to provide up to eight weeks of site activity during those months when the actual or average rainfall is less than 45 mm, six weeks if between 45 mm and 100 mm, four weeks if between 100 mm and 225 mm, and two weeks if greater than 225 mm. (alternative to above) 104. Land clearing is limited to the minimum practicable during those periods when soil erosion due to wind, rain or surface water is possible. (alternative to above) 159

174 Urban Stormwater Quality Planning Guidelines 105. Site clearing must be staged into manageably-sized areas of no greater than 3.5 ha to ensure adequate ESC management and progressive stabilisation of disturbed surfaces. (alternative to above) 106. Initial land-disturbing activities must be strictly limited to the establishment of the site compound, site entry/exit points, temporary drainage crossings and diversions (including stabilisation measures), haul road(s), perimeter sediment controls, and sediment basins (including emergency spillways). No catchment area shall be grubbed of vegetation or stripped of topsoil until the associated sediment basin/trap(s) are constructed and fully operational Trails and tracks for the purpose of bush fire prevention and control may be constructed without consent, provide they comply with state and local government relevant bush fire control and vegetation protection policies Disturbance to natural watercourses (including bed and banks) and their associated riparian zones must be limited to the minimum necessary to complete the approved works No land clearing shall be undertaken unless preceded or accompanied by installation of adequate drainage and sediment control measures unless such clearing is required for the purpose of installing such measures, in which case, only the minimum clearing required to install such measures shall occur All reasonable measures must be undertaken to protect retained vegetation from damage to roots, trunk and branches. 160

175 Urban Stormwater Quality Planning Guidelines 11 Soil and stockpile management 111. All reasonable and practicable measures must be taken to obtained the maximum benefit from existing topsoil, including: i. where the proposed area of soil disturbance does not exceed 2500 square metres and the topsoil does not contain undesirable weed seed, the top 100 mm of topsoil (excluding material best described as subsoil) located within areas of proposed soil disturbance (including stockpile areas) must be stripped and stockpiled separately from the remaining soil; and ii. where the proposed area of soil disturbance exceeds 2500 square metres and the topsoil does not contain undesirable weed seed, the top 50 mm of topsoil (excluding material best described as subsoil) must be stripped and stockpiled separately from the remaining soil, and spread as a final surface soil; and iii. in areas where the topsoil contains undesirable weed seed, the topsoil must be suitably buried, treated or removed from the site; or iv. alternatively, topsoil is managed (that is, stripped, stockpiled and reused) in accordance with the recommendations of an approved vegetation management plan Stockpiles of erodible material must be: i. appropriately protected from wind, rain, concentrated surface flow, and excessive up-slope stormwater surface flows; and ii. located at least two metres from any hazardous area, retained vegetation, or concentrated drainage line; and iii. located up-slope of an appropriate sediment control system; and iv. provided with an appropriate protective cover (synthetic or organic) if the materials are likely to be stockpiled for more than four weeks; or v. provided with an appropriate protective cover (synthetic or organic) if the materials are likely to be stockpiled for more than ten days during months of high erosion risk (defined by clause [insert clause]); or vi. provided with an appropriate protective cover (synthetic or organic) if the materials are likely to be stockpiled for more than five days during months of extreme erosion risk (defined by clause [insert clause]). 12 Drainage control 113. All temporary drainage control measures must be designed, installed, operated and maintained in accordance with the latest version of [insert publication], or other approved publication All temporary drainage control measures must be designed to have a minimum non-erosive hydraulic capacity (excluding 150 mm freeboard) in accordance with Table A1.1. Note: Table A1.1 is equivalent to Table 6.3 contained in Chapter 6 of the USMPG 161

176 Urban Stormwater Quality Planning Guidelines Table A12.1.Drainage design standard for temporary drainage works Drainage structure Anticipated design life [3] < 12 months months Temporary drainage structures [1] 1-in-2 year 1- in-5 year > 24 months 1-in-10 year Temporary drainage structures (e.g. catch drain, flow diversion bank) located immediately up-slope of an occupied property that would be adversely affected by the failure or overtopping of the [1], [2] structure. 1-in-10 year 1- in- 10 year 1-in-10 year Temporary culvert crossing Minimum 1-in-1 year hydraulic capacity wherever reasonable and practicable. [1] Design capacity excludes minimum 150 mm freeboard. [2] Design flow rate based on up-slope drainage structures operating in accordance with their design capacity excluding freeboard, that is, any constructed freeboard is assumed to have been washed away or otherwise deactivated. [3] Design life includes the total period from commencement of work until final stabilisation. Note: Due allowance must be made for channel flow obstructions such as rock check dams Where the overtopping or failure of a temporary drainage system would likely cause detrimental flooding or nuisance to existing residential or commercial properties, or failure of a sediment basin collection and diversion system, the drainage system must have a minimum hydraulic capacity (excluding freeboard) equal to the 1-in-10 year ARI design storm Wherever reasonable and practicable, stormwater run-off entering the site from external areas, and non-sediment laden (clean) stormwater run-off entering a work area or area of soil disturbance, must be diverted around or through that area in a manner that minimises soil erosion and contamination of that water for all discharges up to the specified design storm discharge If the drainage area up-slope of a soil disturbance exceeds 1500 square metres and the average monthly rainfall exceeds 45 mm, then all reasonable and practicable measures must be taken to divert this stormwater, up to the design storm, around or through the soil disturbance in a manner that minimises soil erosion and contamination of the water During construction, all reasonable and practicable measures must be implemented to control flow velocities in such a manner than prevents soil erosion along drainage paths and at the entrance and exit of all drains and drainage structures during all storms up to the relevant design storm discharge To the maximum degree reasonable and practicable, all waters discharged during the construction phase must discharge onto stable land, in a non-erosive manner, and at a legal point of discharge. 162

177 Urban Stormwater Quality Planning Guidelines 120. Appropriate drainage controls must be installed above batters to prevent up-slope stormwater eroding the batter face Wherever reasonable and practicable, clean surface waters must be diverted away from sediment control devices During the construction period, roof water must be managed in a manner that minimises site wetness within active work areas, and soil erosion Stormwater from roofed areas must be connected to a council approved stormwater disposal system immediately after placement of the roof. 13 Erosion control 124. Wherever reasonable and practicable, priority must be given to the prevention, or at least the minimisation, of soil erosion, rather than the trapping of displaced sediment. Such a clause shall not reduce the responsibility to apply and maintain, at all times, all necessary sediment control measures Wherever reasonable and practicable, priority must be given to the prevention, or at least the minimisation, of soil erosion (i.e. drainage and erosion control measures), rather than allowing the erosion to occur and trying to trap the resulting sediment. Where this is not reasonable or practicable, then all reasonable and practicable measures must be taken to minimise soil erosion even if the adopted sediment control measures comply with the required treatment standard. (alternative to above) 126. Appropriate erosion control measures must be incorporated into all stages of a development, including each phase of earthworks All erosion control measures must be designed, installed, operated and maintained in accordance with current best practice as outlined by the latest version of [insert publication], or other approved publication Within the limits of the current technology, erosion control measures used to control wind erosion must be commensurate with the expected seasonal wind conditions in terms of wind speed and direction The potential erosion risk shall be based on the rating outlined in Table A13.1. [Table A13.1 presented as a default Authorities may choose to select an alternative rating in preference to that outlined in Section 4.4 or Appendix F of IECA 2008, Best Practice Erosion and Sediment Control, International Erosion Control Association (Australasia), Picton NSW] Table A13.1 Erosion risk rating based on monthly rainfall erosivity Erosion risk rating Average monthly erosivity (Rfactor) Very Low 0 to 60 Low 60+ to 100 Moderate 100+ to 285 High 285+ to 1500 Extreme > All erosion control measures must be designed to satisfy, as a minimum, the design standard outlined in Table A

178 Urban Stormwater Quality Planning Guidelines Table A13.2 Best practice site clearing and rehabilitation requirements Risk All cases Very low Low Moderate High Extreme Best practice requirements All reasonable and practicable steps taken to apply best practice erosion control measures to completed earth works, or otherwise stabilise such works, prior to anticipated rainfall including existing unstable, undisturbed, soil surfaces under the management or control of the building/construction works. Land clearing limited to eight weeks of work if rainfall is reasonably possible Disturbed soil surfaces stabilised with minimum 60 per cent cover [2] within 30 days of completion of works if rainfall is reasonably possible Unfinished earthworks are suitably stabilised if rainfall is reasonably possible, and disturbance is expected to be suspended for a period exceeding 30 days. Land clearing limited to maximum eight weeks of work Disturbed soil surfaces stabilised with minimum 70 per cent cover [2 ] within 30 days of completion of works within any area of a work site Unfinished earthworks are suitably stabilised if rainfall is reasonably possible, and disturbance is expected to be suspended for a period exceeding 30 days Appropriate protection of all planned garden beds is strongly recommended. Land clearing limited to maximum six weeks of work Disturbed soil surfaces stabilised with minimum 70 per cent cover [2] within 20 days of completion of works within any area of a work site All planned garden beds protected with a minimum 75 mm layer of organic mulching, heavy erosion control blanket, rock mulching, or the equivalent Staged construction and stabilisation of earth batters (steeper than 6H:1V) in maximum 3 metre vertical increments wherever reasonable and practicable Unfinished earthworks are suitably stabilised if rainfall is reasonably possible, and disturbance is expected to be suspended for a period exceeding 20 days. Land clearing limited to maximum four weeks of work Disturbed soil surfaces stabilised with minimum 75 per cent cover [2] within 10 days of completion of works within any area of a work site All planned garden beds protected with a minimum 75 mm layer of organic mulching, heavy erosion control blanket, rock mulching, or the equivalent Staged construction and stabilisation of earth batters (steeper than 6H:1V) in maximum 3 metre vertical increments wherever reasonable and practicable The use of turf to form grassed surfaces given appropriate consideration Soil stockpiles and unfinished earthworks are suitably stabilised if disturbance is expected to be suspended for a period exceeding 10 days. Land clearing limited to maximum twoweeks of work Disturbed soil surfaces stabilised with minimum 80 per cent cover [2] within five days of completion of works within any area of a work site All planned garden beds protected with a minimum 75 mm layer of organic mulching, heavy erosion control blanket, rock mulching, or the equivalent Staged construction and stabilisation of earth batters (steeper than 6H:1V) in maximum 2 m vertical increments wherever reasonable and practicable High priority given to the use of turf to form grassed surfaces Soil stockpiles and unfinished earthworks are suitably stabilised if disturbance is expected to be suspended for a period exceeding five days. 164

179 Urban Stormwater Quality Planning Guidelines 131. All temporary earth banks, flow diversion systems, and sediment basin embankments are to be machine-compacted, seeded and mulched within ten days of formation for the purpose of establishing a vegetative cover, unless otherwise stated within an approved vegetation management plan Unprotected slope lengths must not exceed 80 metres, or an equivalent vertical fall of three metres prior to shutdown periods, (and during the period [insert date/month] and [insert date/month]) Unprotected slope lengths must not exceed 80m and an equivalent vertical fall of three metres prior to specified shutdown periods or when rainfall is expected to exceed [insert value] within a 24-hour period, or the monthly rainfall is expected to exceed [insert value]. (alternative to above) 134. Construction and stabilisation of earth batters steeper than 6:1 (H:V) must be staged such that no more than three vertical metres of any batter is exposed to run-off-producing rainfall at any instant The application of liquid or chemical-based dust suppression measures must ensure that sediment-laden run-off resulting from such measures (such as, run-off of excess water) does not create a traffic or environmental hazard The potential erosion risk for works within drainage channels and waterways shall be based on the rating outlined in Table A13.4 or Table A13.5 as appropriate for the site conditions. [Tables A13.3 and A13.4 presented as a default Authorities may choose to select an alternative rating in reference to that outlined in Section 4.4 or Appendix F of IECA 2008, Best Practice Erosion and Sediment Control, International Erosion Control Association (Australasia), Picton NSW] Table A13.3 Erosion risk rating based on expected channel flow conditions Erosion risk rating Expected flow conditions [1] Very Low Low Moderate High Extreme No rainfall or channel flow expected during plant establishment. Light local rainfall is expected which is likely to result in only a minor increase in channel flow above the normal dry weather flow rate. Heavy local rainfall is expected which is likely to cause stormwater inflows into the channel and a minor increase in channel flow above the normal dry weather flow rate. Medium to high-velocity in-bank flows are expected during the plant establishment period that are likely to inundate unstable, disturbed or recently revegetated channel surfaces. Medium to high-velocity overbank or near bankfull channel flows are expected during the plant establishment period that are likely to inundate unstable, disturbed or recently revegetated channel surfaces. Note: [1] Erosion risk rating based on worst-case of the expected flow conditions. 165

180 Urban Stormwater Quality Planning Guidelines Table A13.4 Erosion risk rating based on expected daily and average monthly rainfalltable Erosion risk rating [1] Expected 24hour rainfall Average monthly rainfall Very Low 0 to 2 mm 0 to 30 mm Low 2+ to 10 mm 30+ to 45 mm Moderate 10+ to 25mm 45+ to 100 mm High 25+ to 100 mm 100+ to 225 mm Extreme > 100 mm > 225 mm Note: [1] Erosion risk rating based on worst case of expected rainfall within any 24-hour period or average monthly rainfall All erosion control measures for works within drainage channels and waterways must be designed to satisfy, as a minimum, the design standard outlined in Table A

181 Urban Stormwater Quality Planning Guidelines Table A13.5 Best practice channel clearing and stabilisation requirements Risk [1] All cases Very low Low Moderate High Extreme Best practice requirements All reasonable and practicable steps taken to apply best practice erosion control measures to completed channel works, or otherwise stabilise such works, prior to an anticipated increase in stream flow. Channel clearing limited to maximum eight weeks of programmed work Disturbed soil surfaces stabilised with minimum 70 per cent cover [2] within 30 days of completion of works within any area of a work site Non-completed works stabilised if exposed, or expected to be exposed, for a period exceeding 30 days. Channel clearing limited to maximum six weeks of programmed work Disturbed soil surfaces stabilised with minimum 70 per cent cover [2] within 30 days of completion of works within any area of a work site Non-completed works stabilised if exposed, or expected to be exposed, for a period exceeding 30 days. Channel clearing limited to maximum four weeks of programmed work Disturbed soil surfaces stabilised with minimum 80 per cent cover [2] within 10 days of completion of works within any area of a work site Appropriate consideration given to the use of rock protection, biodegradable erosion control mesh or the equivalent, on all erodible stream banks subject to high velocity flows Non-completed works stabilised if exposed, or expected to be exposed, for a period exceeding 20 days. Channel clearing limited to maximum two weeks of programmed work Disturbed soil surfaces stabilised with minimum 90 per cent cover [2] within five days of completion of works within any area of a work site Appropriate consideration given to the use of rock protection, biodegradable erosion control mesh or the equivalent, on all erodible stream banks subject to high velocity flows Non-completed works stabilised if exposed, or expected to be exposed, for a period exceeding 10 days. Channel clearing limited to maximum 1 week of programmed work Disturbed soil surfaces stabilised with minimum 90 per cent cover [2] within five days of completion of works within any area of a work site Appropriate consideration given to the use of rock protection, biodegradable erosion control mesh or the equivalent, on all erodible stream banks subject to high velocity flows Non-completed works stabilised if exposed, or expected to be exposed, for a period exceeding five days. Notes: [1] Erosion risk based on channel flow conditions (Table A13.4), or daily/monthly rainfall depth (Table A13.5) as directed by the relevant regulatory authority. [2] Minimum cover requirement may be reduced if the natural cover of the immediate land is less than the nominated value, for example, in arid and semi-arid areas. 167

182 Urban Stormwater Quality Planning Guidelines 14 Sediment control 138. The potential safety risk of a proposed sediment trap to site workers and the public must be given appropriate consideration, especially those sediment traps located within publicly accessible areas All reasonable and practicable measures must be taken to prevent or minimise the release of sediment from the site All sediment control measures must be designed, installed, operated and maintained in accordance with current best practice All reasonable and practicable measures must be taken to trap sediment as close to its source as is possible The applicant must ensure that sediment-laden run-off from the site is directed to an appropriate sediment control device in accordance with the required treatment standard All sediment traps must be designed, installed, operated and maintained to collect and retain the maximum quantity of sediment appropriate to the type of sediment trap Wherever reasonable and practicable, all sediment control measures (excluding dewatering and instream sediment control measures) must be designed to be effective during a minimum design storm of 0.5 times the critical 1-in-1 year ARI design storm All instream sediment control measures must be designed to be effective during those flow conditions considered appropriate by the council All sediment control measures must be designed to satisfy, as a minimum, the design standard outlined in Table A14.1. Table A14.1 Sediment control standard based on soil loss rate Area limit (m2) [1] Soil loss rate limit (t/ha/yr) [2] Soil loss rate limit (t/ha/month) [3] Type-1 Type-2 Type-3 Type-1 Type-2 Type N/A N/A [4] N/A N/A [4] 1000 N/A N/A All cases N/A N/A All cases 2500 N/A > N/A > >2500 > > Notes: [1] Area is defined by the catchment area draining to a given location. The area does not include any clean water catchment that bypasses the sediment trap. [2] Soil loss rate limit defines the maximum allowable soil loss rate from a given catchment area draining to a given sediment trap at any given point in time within the construction phase. [3] Soil loss rate limit defines the maximum allowable soil loss rate from a given catchment area draining to a given sediment trap at any given point in time within a given month in those cases where the time of construction can be specified. [4] Refer to the regulating authority for assessment procedures. The default is a type-3 sediment trap The classification of sediment control measures (that is, type 1, type 2, type 3 or supplementary) shall be in accordance with [insert document]. 168

183 Urban Stormwater Quality Planning Guidelines 148. All sediment control measures implemented for the control of sediment-laden discharge from de-watering activities must be designed to satisfy, as a minimum, the discharge standard outlined in Table A14.2. Table A14.2 Recommended discharge standard for de-watering operations Site conditions All cases Soil disturbances exceeding 2500 m 2 Projects exceeding $500,000 expenditure Post-storm de-watering of sediment basins Discharge water quality standard Take all reasonable and practicable measures to achieve a 90 percentile total suspended solids concentration not exceeding 50 mg/l 90 percentile total suspended solids (TSS) concentration not exceeding 50 mg/l Water ph between 6.5 and Prior to the controlled discharge (for example,. de-watering activities from excavations and sediment basins) of any water from the site during construction, the following water quality objectives must be achieved: total suspended solids (maximum 50mg/L, TSS) turbidity (measured in NTUs maximum of 60 NTU) water ph between 6.5 and 8.5 unless otherwise required by the council. (alternative to above) 150. All type-f or type-d sediment basins must be maintained at a minimum water level between rainfall events A minimum stockpile of flocculating agents must be securely stored on-site to provide for at least three complete treatments of all chemically treated sediment basins The Applicant must ensure that on each occasion a type-f or type-d basin cannot be dewatered prior to being surcharged by a following rainfall event, a report is presented to the assessing authority identifying the circumstances and proposed amendments, if any, to the basin's operating procedures As-constructed plans must be prepared for all for constructed sediment basins and associated emergency spillways. Such plans must appropriately verify the basin s dimensions, levels and volumes comply with the approved design drawings. These plans must be submitted to the assessing authority within 14 calendar days of the construction of each basin All sediment basins must remain fully operational at all times until the basin's design catchment achieves the required ground coverage, or surface stabilisation, in accordance with the erosion control standard An appropriately marked (for example, painted) de-silting marker post must be installed in each sediment basin to clearly indicate the top of the sediment storage zone Settled sediment must be removed as soon as reasonable and practicable from any sediment basin if: i. it is anticipated that the next storm event is likely to cause sediment to settle above the basin's sediment storage zone 169

184 Urban Stormwater Quality Planning Guidelines ii. the elevation of settled sediment is above the top of the basin's sediment storage zone iii. the elevation of settled sediment is above the basins sediment marker line Scour protection measures placed on sediment basin emergency spillways must appropriately protect the spillway chute and its side batters from scour, and must extend a minimum of three metres beyond the downstream toe of the basin's embankment Suitable all-weather maintenance access must be provided to all sediment control devices All sediment control devices (other than sediment basins) must be de-silted and made fully operational as soon as reasonable and practicable after run-off-producing rainfall, or if the sediment retention capacity of the device falls below 75 per cent of the design retention capacity All material removed from a sediment control device during maintenance or decommissioning, whether solid or liquid, must be disposed of in a manner that does not cause ongoing soil erosion or environmental harm. 15 Site rehabilitation 161. No site revegetation shall be undertaken prior to approval of a vegetation management plan No site revegetation, excluding temporary revegetation conducted for purposes of erosion control, shall be undertaken prior to approval of a vegetation management plan. (alternative to above) 163. Adequate site data, including soil data, must be obtained to appropriately plan, design, implement, and maintain site revegetation and stabilisation works A detailed landscape and rehabilitation plan for the site must be submitted to council for approval prior to initial land clearing or bulk earthworks A minimum 60 per cent ground cover must be achieved on all non-completed earthworks exposed to accelerated soil erosion if further construction activities or soil disturbances are likely to be suspended for more than 30 days during those months when the expected rainfall erosivity is less than 60; minimum 70 per cent cover within 30 days if between 60 and 100; minimum 70 per cent cover within 20 days if between 100 and 285; minimum 75 per cent cover within 10 days if between 285 and 1500; and minimum 80 per cent cover within 5 days if greater than (alternative to conditions contained in Tables A13.3 and A13.6) 166. A minimum 60 per cent ground cover must be achieved on all non-completed earthworks exposed to accelerated soil erosion if further construction activities or soil disturbances are likely to be suspended for more than 30 days during those months when the expected rainfall is less than 30 mm; minimum 70 per cent cover within 30 days if between 30 and 45 mm; minimum 70 per cent cover within 20 days if between 45 and 100 mm; minimum 75 per cent cover within 10 days if between 100 and 225 mm; and minimum 80 per cent cover within five days if greater than 225 mm. (alternative to above) 167. All unstable or disturbed soil surfaces must be adequately stabilised against erosion (minimum 70 per cent) prior to commencement of use, or survey plan endorsement All disturbed areas must be rendered erosion resistant by turfing, mulching, paving or otherwise suitably stabilised within [insert number of days] days of completion of earthworks within any given area or sub-area No completed earthwork surface shall remain denuded for longer than 60 days. 170

185 Urban Stormwater Quality Planning Guidelines 170. Unless otherwise directed within an approved landscape plan or vegetation management plan, topsoil must be placed at a minimum depth of 75 mm on slopes 4:1 (H:V) or flatter, and 50 mm on slopes steeper than 4: All cut and fill earth batters less than three metres in elevation must be topsoiled, and grass seeded/hydromulched within 10 days of completion of grading All cut and fill earth batters greater than three metres in elevation must be topsoiled, and grass seeded/hydromulched in stages not exceeding three vertical-metres The ph level of topsoil must be appropriate to enable establishment and growth of specified vegetation prior to initiating the establishment of vegetation Soil ameliorants must be added to the soil in accordance with an approved landscape plan, vegetation management plan, and/or soil analysis Surface soil density, compaction and surface roughness must be adjusted prior to seeding/planting in accordance with an approved landscape plan, vegetation management plan, and/or soil analysis Procedures for initiating a site shutdown, whether programmed or un-programmed, must incorporate revegetation of all soil disturbances unless otherwise approved by council. The stabilisation works must not rely upon the longevity of non vegetated erosion control blankets, or temporary soil binders Revegetation procedures associated with a programmed site shutdown must commence at least 30 days prior to the nominated shutdown time. 16 Sediment basin rehabilitation 178. Procedures for the staged rehabilitation of all sediment basins must be provided within the supporting documentation of the ESCP and/or as technical notes within the ESCP In all cases where a construction phase sediment basin is to be transformed into a permanent component of the site s stormwater management system (for example, detention/retention basin, wetland or bioretention/biofiltration system), then the required protection of the permanent system from sedimentation during the construction and maintenance phases of the development must be resolved in consultation with the proposed long-term asset owner/manager In all cases where a construction phase sediment basin is to be transformed into a permanent component of the site s stormwater management system (e.g. detention/retention basin, wetland or bioretention/biofiltration system), then the required protection of the permanent system from sedimentation during the construction, maintenance, and building phases of the development must be resolved in consultation with the proposed long-term asset owner/manager. (alternative to above) 181. Required drainage, erosion and sediment control measures during the decommissioning and rehabilitation or a sediment basin must comply with same standards specified for the normal construction works Upon decommissioning of a sediment basin, all water and sediment must be removed from the basin prior to removal of the embankment (if any). Any such material, liquid or solid, must be dispose of in a manner that will not create an erosion or pollution hazard A basin s catchment conditions associated with the staged decommissioning of the basin from a type 1 to a type 2 sediment trap must comply with the specified sediment control standard If an alternative, permanent, outlet structure is to be constructed prior to stabilisation of the up-slope catchment area, then this outlet structure must not be made operational if it will adversely affect the required operation of the sediment basin. 171

186 Urban Stormwater Quality Planning Guidelines 185. The permanent stormwater treatment features (for example, vegetation and filtration media) must be appropriately protected from the adverse effects of sediment runoff in accordance with the requirements of the proposed asset manager A sediment basin must not be decommissioned until all up-slope site stabilisation measures have been implemented and are appropriately working to control soil erosion and sediment runoff in accordance with the specified ESC standard Immediately prior to the construction of the permanent stormwater treatment device, appropriate flow bypass conditions must be established to prevent sediment-laden water entering the device Immediately following the construction of the filter media of the permanent stormwater treatment device, the filter media must be covered by heavy-duty filter cloth (minimum bidum A44 or equivalent) and a minimum 200 mm layer of earth or sacrificial filter media. Such earth and filter cloth must not be removed from the device until suitable surface conditions being achieved within the basin s catchment area The minimum sediment control standard for the protection of the permanent stormwater treatment device during the construction phase is a type 2 sediment trap The minimum sediment control standard for the protection of the permanent stormwater treatment device during the construction and maintenance phases is a type 2 sediment trap. (alternative to above) 191. Plant establishment within the permanent stormwater treatment device must be delayed until sediment intrusion into the device is suitably under control Upon suitable conditions being achieved within the basin s catchment area, the operational features of the permanent stormwater treatment system must be made fully operational (that is, maintenance and/or reconstruction as required) The permanent stormwater treatment features of the rehabilitated basin must not be made operational until all up-slope site stabilisation measures have been implemented and are appropriately working to control soil erosion and sediment runoff in accordance with the specified ESC standard. (alternative to above) 194. Upon the approval of [insert authority], the newly constructed permanent stormwater treatment features of the basin may be made operational if such actions do not prevent the site from operating at the required sediment control standard. (alternative to above) 17 Site monitoring 195. The applicant must ensure that appropriate procedures and personnel are engaged to plan and conduct site inspections and water quality monitoring throughout the construction and maintenance phase (including as appropriate, pre-construction monitoring) that is commensurate with the site's environmental risk All ESC measures must be inspected: i. at least daily (when work is occurring on-site) ii. at least weekly (when work is not occurring on-site) iii. within 24 hours of expected rainfall iv. within 18 hours of a rainfall event of sufficient intensity and duration to cause run-off on the site During period of water discharge from the site, water quality samples must be collected at each monitoring station at least once on each calendar day until such discharge stops. 172

187 Urban Stormwater Quality Planning Guidelines 198. All site monitoring data including rainfall records, dates of water quality testing, testing results and records of controlled water releases for the site, must be kept in an on-site register. The register is to be maintained up to date for the duration of the approved works and be available on-site for inspection by the assessing authority on request At nominated instream water monitoring stations, a minimum of three water samples must be taken and analysed, and the average result being used to determine quality Sediment basin water quality samples must be taken at a depth no greater than 200 mm above the top surface of the settled sediment within the basin The applicant must ensure the implementation and maintenance of a system that monitors and records site compliance and non-compliance with the ESC approval requirements. This system must as a minimum incorporate regular site audits. Such audits must be: i. undertaken by a person suitably qualified and experienced in erosion and sediment control that can be verified by an independent third party. This person must not be an employee or agent of the principal contractor ii. conducted on the next business day following a rainfall event in which greater than 10 mm of rainfall has been recorded by the Bureau of Meteorology rain gauge nearest to the site iii. conducted at intervals of not more than one calendar month commencing from the day of site disturbance until all disturbed areas have been adequately stabilised against erosion to the acceptance of the assessing authority iv. conducted using an approved site inspection checklist presenting in [insert publication] as amended from time to time The applicant must provide the assessing authority with a report at intervals of no less than least every two months, starting from the commencement of site works, and up until all disturbed areas have been adequately stabilised against erosion to the acceptance of the assessing authority. The report must include as a minimum for that review period: i. copies of all original site inspection checklists ii. non-conformance and corrective action reports iii. sediment basin water quality and site discharge water quality monitoring results iv. plan showing the areas of completed soil stabilisation v. rainfall records including date and rainfall depth Within fourteen days of completing each hydromulch, bonded fibre matrix or compost blanket application, the applicant must obtain in writing from the mulching contractor, certification that the application complies with current best practice All environmental incidents must be recorded in a field log which must remain accessible to all relevant regulatory authorities on request. 18 Site maintenance 205. All ESC measures must be maintained in proper working order at all times during their required operational life, including hydraulic capacity and operational effectiveness All necessary ESC measures must be maintained in proper working order at all times during the project's maintenance period All temporary ESC measures must be removed after the satisfactory completion of an offmaintenance inspection by council and prior to formal acceptance of off-maintenance by council. 173

188 Urban Stormwater Quality Planning Guidelines 208. Maintenance of ESC measures must occur in accordance with Table A18.1. Table A18.1 Maintenance requirements of ESC measures ESC Measure Maintenance trigger Timeframe Sediment basins Other ESC measures When settled sediment exceeds the volume of the sediment storage zone The capacity of ESC measures falls below 75 per cent Within seven days of the inspection By end of the day during any stay in rainfall 209. All materials removed from ESC devices during maintenance, whether solid or liquid, must be disposed of in a manner that does not cause ongoing soil erosion or environmental harm Poisoning of excess vegetation in drainage lines must not be undertaken, except under the specific approval of the assessing authority Washing/flushing of streets shall only occur where sweeping has failed to remove sufficient sediment and there is a compelling need to remove the remaining sediment ( for example, for safety reasons). In such circumstances, all reasonable and practicable sediment control measures must be used to prevent, or at least minimise, the release of sediment into receiving waters. Only those measures that will not cause safety issues or adverse property flooding to third parties shall be employed Where it is necessary to clear excess vegetation in order to restore the water carrying capacity of open drains, the vegetation must be selectively cut and trimmed so as to leave a short, dense, live ground cover for the purpose of minimising soil erosion Maintenance mowing of all road shoulders, table drains, batters and other surfaces likely to experience accelerated soil erosion must aim to leave the grass length no shorter than 50 mm where reasonable and practicable Maintenance mowing must be done in a manner that will not damage the profile of formed, soft edges, such as the crest of earth embankments The applicant must ensure that it is clearly define and document who is the responsible person for maintaining those ESC measures installed during the subdivision phase but are required to be operational during the subsequent building phase. Where there is no documented description of who is responsible, responsibility for maintenance shall rest with the applicant Responsibility for maintenance for ESC measures that the assessing authority has accepted on maintenance shall remain with the applicant up until the works are declared to be off maintenance by the assessing authority The applicant must ensure that the principal contractor keeps written records of ESC monitoring and maintenance activities conducted during the construction and maintenance periods, and be able to present and/or provide original copies of such records to the assessing authority on request. 19 Road works 218. Vegetation removed during road works must be re-used to the maximum possible extent to minimise short and long-term soil erosion. Non-salvageable debris must be disposed of in a manner that does not cause ongoing environmental harm. 174

189 Urban Stormwater Quality Planning Guidelines 219. Soil disturbances must be staged into manageably-sized areas of no greater than 10 hectares to ensure adequate ESC management and progressive stabilisation of disturbed surfaces Newly constructed spray-sealed roads must be swept thoroughly as soon as possible after gravelling to prevent excess gravel entering stormwater drains or waterways During the construction period, all unstable fill embankments are to be left with a lip (windrow) at the top of the slope at the end of each day's operation, or other appropriate drainage control measures, to prevent bank erosion All cut and fill earth batters are to be topsoiled, grass seeded/hydromulched within 10 days of completion of grading. 20 Instream works 223. The applicant must ensure that all necessary state government licences and permits are obtained prior to commencing instream works, including licences/permits for the disturbance to native vegetation Design must take due account of potential for environmental harm, for example, bridging is preferred to arch culverts, and arch culverts are preferred to pipe culverts Prior to the commencement of any construction activity, or soil disturbance, the applicant must prepare, and make available to the assessing authority, written procedures of dealing with incident, emergency and complaints Prior to the commencement of any construction activity, or soil disturbance, the applicant must prepare, and make available to the assessing authority, written procedures for the management of wildlife, terrestrial and aquatic passage Terrestrial and aquatic passage must be maintained along the waterway at all times and in accordance with state and assessing authority guidelines The design of instream structures must give appropriate consideration to the aim of reducing the potential impact of associated instream maintenance activities Disturbance to natural watercourses (including bed and banks) and their associated riparian zones must be limited to the minimum necessary to complete the approved works To the maximum degree reasonable and practicable, all instream disturbances must be programmed to occur during the least erosive periods of the year To the maximum degree reasonable and practicable, all instream disturbances must be programmed to occur during periods of least impact to fish migration Priority must be given to the safe and effective diversion of instream flows around instream disturbances rather than the use of instream sediment control measures The Applicant must ensure an adequate supply of erosion control, sediment control, and appropriate pollution clean-up materials are available on-site during the construction period The number, width and extent of temporary watercourse crossings must be reduced to the absolute minimum necessary to complete the works The choice of temporary watercourse crossing must be of a type, location and size that causes the least overall damage to the environment given appropriate consideration to its installation, operation and removal All temporary watercourse crossings, including their approach roads, must employ appropriate drainage, erosion and sediment controls to minimise sediment inflow into the watercourse. 175

190 Urban Stormwater Quality Planning Guidelines 237. To the maximum degree reasonable and practicable, access tracks, whether temporary or permanent, must be located a distance from the top of bank of at least 30 metres, or the width of the stream (measured at the top of the bank), whichever is the lesser No erodible material shall be stockpiled within 40 metres of the top of bank, unless approved by the assessing authority All petroleum-based equipment (such as, vehicles and motors) located within bed and bank regions of the waters must be inspected on a daily basis All materials blown onto the water surface must be collected and secured as soon as practicable All site activities must be inspected prior to forecast rain, daily during extended periods of rainfall, after run-off-producing rain, and at least weekly throughout the construction and maintenance periods Synthetic reinforced erosion control mats and blankets must not be placed within, or adjacent to, riparian zones and watercourses if such materials are likely to cause environmental harm to wildlife or wildlife habitat. 176

191 Urban Stormwater Quality Planning Guidelines 21 Works within intertidal areas 243. The applicant must ensure that all necessary state government licences and permits are obtained prior to commencing instream works, including licences/permits for the disturbance to marine vegetation To the maximum degree reasonable and practicable, the applicant must ensure disturbance to aquatic vegetation, particularly seagrasses and mangroves, is minimised No erodible material shall be stockpiled within 40 metres from the high tide mark, unless approved by the assessing authority The applicant shall take all appropriate steps to ensure sediment deposition within the voids between natural and introduced rock located within the tidal zone is minimised The applicant shall take all appropriate steps to ensure that all equipment is washed down (cleaned) well away from the water s edge, and in a manner that prevents sediment-laden water entering the waterway All waste receptors must be sealed and/or covered outside working hours to prevent the entry of water and vermin, or wind disturbance of the contained material Drip pans must be placed under all vehicles and motorised equipment placed on docks, barges, or other structures that extend over water bodies if the vehicle or equipment is expected to be idle for more than one hour All barges must be fitted with watertight curbs or toe boards to contain spills and prevent materials, tools, and debris from leaving the barge The applicant must take all reasonable and practicable measures to ensure that vehicle (amphibious or terrestrial) damage to seawalls (for example, due to wave and wash conditions) is minimised The applicant must ensure all appropriate measures are deployed to provide secondary containment for any spills while materials and/or equipment are being transferred on and off barges to (for example, floating sediment curtains) The applicant must ensure all materials being transported by boats or barges are adequately secured during transportation. 177

192 Urban Stormwater Quality Planning Guidelines Appendix 1B Model code of practice provisions erosion and sediment control Contents Appendix 1B Attachment A 1. Introduction / use of these provisions Model code of practice Development planning and design Construction planning Erosion and sediment control plans (ESCP) Site establishment Site management Land clearing Soil and stockpile management Drainage control Erosion control Sediment control Site stabilisation and rehabilitation Site inspection and monitoring Site maintenance Attachment A ~ Information supporting model code of practice provisions erosion and sediment control

193 Urban Stormwater Quality Planning Guidelines 1 Introduction This appendix presents model code of practice provisions for erosion and sediment control on construction sites. Government bodies are encouraged to either adopt these provisions or develop their own regional-based code of practice using this model code as a template. The following model code provisions have been provided as a guide only. Project managers and regulatory authorities should review the relevant code provisions for adoption into applicable codes. 2 Model code of practice Compliance with a given performance criterion can only be achieved by: i. complying with the acceptable solution ii. formulating an alternative solution which complies with the performance criterion, or is shown to be at least equivalent to the acceptable solutions iii. a combination of (i) and (ii). Unless otherwise indicated, all outcomes listed within the acceptable solution must be satisfied in order to comply with the acceptable solution. Attachment A to Appendix 1B forms part of this code. The attachment provides essential information and requirements not otherwise provided within the code. Note that where Appendix H and Appendix I are mentioned in this appendix, they refer to the IECA 2008, Best Practice Erosion and Sediment Control, International Erosion Control Association (Australasia), Picton NSW. If the scheduled works incorporate building activities, then the model code of practice provided in Appendix H (Building sites) shall apply. If the scheduled works incorporate instream soil disturbances, then the model code of practice provided in Appendix I (Instream works) shall apply. In the event of a conflict over the desired outcome of a performance criterion or an acceptable solution, then the outcome shall be that which best achieves the objective of the code, that being: To protect the environment while allowing for development that improves the total quality of life, both now and in the future, in a way that maintains the ecological processes on which life depends. To achieve this objective a person must not carry out any activity that causes, or is likely to cause, environmental harm unless the person takes all reasonable and practicable measures to prevent or minimise the harm.(s319 Environmental Protection Act 1994) In assessing all reasonable and practicable measures, appropriate consideration must be given to: i. the nature of the potential harm ii. the sensitivity of the receiving environment iii. the current state of technical knowledge for the activity iv. the likelihood of successful application of the various measures that might be undertaken v. the financial implications of the various measures relative to the type of activity. 179

194 Urban Stormwater Quality Planning Guidelines The various recommendations presented in this guideline are an indication of what may be considered reasonable and practicable for the construction industry. This model code of practice does not provide all the information necessary to adequately control soil erosion and sediment run-off in all situations. Users of the code should always make their own site-specific evaluation, testing and design, and refer to their own advisers and consultants as appropriate. Specifically, the adoption of this model code of practice will not necessarily guarantee: i. compliance with any statutory obligation ii. avoidance of all environmental harm or nuisance. Development planning and design Performance criteria Acceptable solution P1 P2 P3 P4 Adequate data is obtained to allow appropriate site planning and design. The design and layout of the development does not cause unnecessary soil disturbance. The design and layout of the development minimise the risk of environmental harm occurring during the construction phase. The design and layout of the A1 a. The extent and complexity of data collection is commensurate with the potential environmental risk, and the extent and complexity of the proposed soil disturbance. A2 b. Potential site constraints and zones of high or extreme erosion hazard are identified early in the planning phase. c. A conceptual ESCP is prepared if the construction activities are deemed to represent a high to extreme erosion hazard. a. The development is appropriately integrated into the existing site conditions, including the existing topography, such that the need for extensive land reshaping and surface modifications is minimised. b. Wherever reasonable and practicable, cut and fill and slab-on-ground construction practices are not employed on land slopes equal to, or steeper than 15 per cent. c. The design, staging, and layout of the development do not cause unnecessary soil disturbance if an alternative design, staging or layout (which reduces the potential environmental harm) is available that achieves the same or equivalent project outcomes at a reasonable cost. A3 a. Potential high-risk construction activities are identified during development planning. A4 b. Essential ESC control measures are appropriately integrated into the project s planning, design and financial analysis. c. Adequate space is provided for the construction and maintenance of essential ESC measures. d. The development layout avoids the placement of critical structures or buildings within the region of the lowest land elevation within any sub-catchment if such a structure would prevent the construction and effective operation of essential ESC measures throughout the construction period. e. The development s design and layout do not cause unnecessary delays to the initiation and satisfactory completion of site stabilisation and final rehabilitation activities. a. The development is designed to appropriate drainage standards (permanent drainage works). b. Ongoing erosion problems at the inlet and outlet of 180

195 Urban Stormwater Quality Planning Guidelines development minimise the risk of environmental harm occurring during the operational phase of the development. permanent drainage systems (pipes or channels) are minimised. c. The development incorporates current best practice stormwater quality controls for the operational phase of the development. d. The development design and layout appropriately recognises and integrates identified site constraints. e. To the maximum degree reasonable and practicable, disturbance to deep-rooted vegetation on slopes susceptible to mass movement is minimised, if not totally avoided. a. All reasonable and practicable measures are taken to minimise changes to the natural water cycle (including volume, frequency, duration and velocity of stormwater run-off) during the operational phase of the development. b. The number of temporary and permanent watercourses crossing is reduced to the minimum necessary. P5 The design and layout of the development minimise the risk of environmental harm to downstream waterways. A5 Construction planning Performance criteria Acceptable solution P6 Adequate site data is obtained to allow appropriate construction planning. A6 a. Zones of high to extreme erosion hazard are identified prior to construction planning. b. The extent and complexity of site data, including soil mapping, is commensurate with the potential environmental risk, and the extent and complexity of the soil disturbance. a. Development of the ESCP is an integral part of construction planning. b. High-risk construction activities are identified during construction planning. c. High-risk construction activities and disturbances of high to extreme erosion hazard areas are minimised, if no totally avoided, especially during periods of high to extreme erosion potential. d. All reasonable and practicable measures are taken to design/plan the construction layout, programming, staging and methodology to minimise environmental risks associated with high-risk construction activities. e. Construction planning minimises the duration that any and all areas of soil will be exposed to the erosive effects of wind, rain and flowing water, in part through the progressive and prompt stabilisation of disturbed areas. P7 Construction planning aims to minimise the risk of environmental harm occurring during the construction phase. A7 f. Construction site layout, methodology, staging and programming do not cause unnecessary environmental harm if an alternative layout, methodology, staging or program (which reduces unnecessary soil disturbance and/or potential environmental harm) is available that achieves the same or equivalent project outcomes at a reasonable cost. g. On sites with a soil disturbance greater than 2500 m2, a water quality monitoring program, and site stabilisation plan, landscape plan, and/or vegetation management plan is prepared and approved by the relevant regulatory authority prior to site establishment. P8 Construction planning aims to minimise the risk of environmental A8 a. To the maximum degree reasonable and practicable, instream disturbances are programmed to occur during the least erosive and environmentally damaging periods of the year. 181

196 Urban Stormwater Quality Planning Guidelines harm to downstream waterways. b. The number of temporary watercourse crossings is minimised. Erosion and sediment control plan (ESCP) Performance criteria Acceptable solution P9 An ESCP is prepared prior to site disturbance that provides sufficient information to achieve the required environmental protection. A9 a. The design standard of drainage, erosion and sediment controls comply with the requirements of the relevant regulatory authority, or where such a standard does not exist, are designed in accordance with current best practice. b. As a minimum, the ESC design standard applied to a site at any given instant is commensurate with the degree of environmental risk, and the type, cost, and scope of the proposed works. c. The level of information and detail supplied in the ESCP is commensurate with the potential environmental risk and the complexity of the proposed works; and of sufficient clarity to allow on-site personnel to appropriately implement the plan. a. The qualifications and experience of the personnel preparing and/or supervising the preparation of the ESCP is commensurate with the potential environmental risk, and the extent and complexity of the soil disturbance. b. The design of each sediment basin is signed off by a suitably qualified and experienced professional. c. On sites with a soil disturbance greater than 2500 m2, the ESCP is signed off by a suitably qualified and experienced professional. d. On sites with a soil disturbance greater than one hectare, or where the ESCP incorporates a sediment basin, the ESCP is signed off by an engineer experienced in hydrology and hydraulics. e. Where the ESCP incorporates a sediment basin with a constructed earth embankment with a height greater than one metre, the ESCP is signed off by an appropriate geotechnical specialist. a. The extent and complexity of data collected prior to finalisation of the ESCP is commensurate with the potential environmental risk, and the extent and complexity of the soil disturbance. b. In preparation of the ESCP, priority is given to the prevention, or at least the minimisation, of soil erosion, rather than just the trapping of displaced sediment. c. The stormwater drainage requirements of the construction phase are appropriately integrated into the ESCP through the use of best-practice drainage control measures and design standards. P10 The ESCP is prepared by, or under the supervision of, suitably qualified and experienced personnel. A10 P11 The ESCP is appropriate for the site conditions and the potential environmental risk. A11 182

197 Urban Stormwater Quality Planning Guidelines P12 The ESCP remains relevant, at all times, to the current site conditions. A12 a. The ESCP remains both effective and flexible, and is based on anticipated soil, weather, and construction conditions (as may vary from time to time). b. The ESCP is appropriately amended if the implemented works fail to achieve the objective of the ESCP, the required performance standard, or the State s environmental protection requirements. c. Once the works commence, a revised ESCP is prepared should the works not be completed within 12 months, with further reviews undertaken thereafter at half-yearly intervals. d. All amended ESCPs are prepared by, or under the supervision of, suitably qualified and experienced personnel. P13 Potential harm to wildlife as a result of ESC measures is minimised. A13 Synthetic (plastic) reinforced fabrics are not specified within, or adjacent to, bushland areas, riparian zones and watercourses if such materials are likely to cause harm to wildlife or wildlife habitats. Site establishment Performance criteria Acceptable solution P14 Site personnel are provided with all necessary information prior to site establishment. A14 a. The development approval conditions, development permit, ESCP, monitoring and maintenance program, landscape and/or site rehabilitation plan, and any other document required for the management of soil erosion and sediment control, are provided to the principal contractor prior to the commencement of land disturbing activities. b. On sites with a soil disturbance greater than one hectare, a vegetation management plan, and procedures for conducting a site shutdown (whether programmed or unprogrammed), are provided to the principal contractor prior to the commencement of land disturbing activities. a. Prior to the commencement of any construction activities or soil disturbance, appropriately trained and experienced personnel are engaged to undertake regular ESC audits of the site. b. Prior to commencement of site works, a chain of command in relation to the implementation, modification, and maintenance of ESC measures is established. P15 Appropriate personnel are engaged to implement and monitor all necessary ESC measures prior to commencement of site disturbance. A15 P16 Site establishment does not cause unnecessary soil disturbance or environmental harm. A16 a. No land-disturbing activities occur on the site until all perimeter ESC measures, sediment traps, and associated temporary drainage controls, have been constructed in accordance with the ESCP and best practice erosion and sediment control. b. All site office facilities and operational activities are located such that all effluent, including wash-down water, can be totally contained and treated within the site. c. Adequate waste collection areas/bins are provided on-site and maintained such that environmental harm is minimised. a. Authorised site access is confined to the minimum practicable number of locations. b. Access onto the site, where authorised or unauthorised, is appropriately managed to minimise the risk of sediment being tracked onto adjoining sealed roadways. c. All reasonable and practicable measures are taken to ensure stormwater run-off from access roads and P17 Site access is appropriately managed to minimise the risk of environmental harm. A17 183

198 Urban Stormwater Quality Planning Guidelines stabilised entry/exit systems, drains to an appropriate sediment control device. Site management Performance criteria P18 The work site is managed such that environmental harm is minimised. Acceptable solution A18 a. No land-disturbing activities are undertaken prior to appropriate consideration being given to erosion and sediment control issues. b. All works subject to an ESCP are carried out in accordance with the ESCP (as amended from time to time) unless circumstances arise where compliance with the ESCP would increase the potential for environmental harm as assessed by a recognised authority. c. All ESC measures are installed, operated and maintained in accordance with current best management practice. d. Land-disturbing activities are undertaken in such a manner that allows all reasonable and practicable measures to be undertaken to: i. allow stormwater to pass through the site in a controlled manner and at non-erosive flow velocities ii. iii. iv. minimise soil erosion resulting from wind, rain and flowing water minimise the duration that disturbed soils are exposed to the erosive forces of wind, rain and flowing water prevent, or at least minimise, environmental harm (including public nuisance and safety issues) resulting from work-related soil erosion and sediment run-off. e. Site spoil is lawfully disposed of in a manner that does not result in ongoing soil erosion or environmental harm. P19 Those responsible for erosion and sediment control are appropriately trained and equipped. A19 Site managers and/or the nominated responsible ESC personnel achieve and maintain a good working knowledge of the correct installation and operational procedures of all ESC measures used on the site. P20 P21 Disturbance to ESC measures by on-site personnel is minimised. The adopted ESC measures remain relevant at all times to the current site conditions. A20 a. On-site personnel are appropriately instructed and educated as to the purpose and operation of adopted drainage, ESC measures, and the need to maintain such measures in proper working order at all times. b. Unnecessary disturbance to ESC measures by on-site personnel, sub-contractors and construction traffic (including site management and material delivery vehicles) is minimised. A21 a. Performance of the site s ESC measures is monitored in accordance with the site s monitoring and maintenance program. b. The adopted erosion and sediment control measures are appropriately amended if site conditions significantly change, or are expected to significantly change, from those conditions assumed during development of the ESCP. c. The adopted erosion and sediment control measures are 184

199 Urban Stormwater Quality Planning Guidelines appropriately amended if the implemented works fail to achieve the objective of the ESCP, or the required performance standard, or the State s environmental protection requirements, or unacceptable environmental harm is occurring or is likely to occur. d. In circumstances where addition or alternative erosion and sediment control measures are required on a site, and a revised ESCP needs to be prepared, then only those works necessary to minimise environmental harm are conducted prior to preparation of the revised ESCP. P22 The work site is appropriately prepared for imminent construction activities and weather conditions. A22 a. Adequate supplies of drainage, erosion and sediment control, and relevant pollution clean-up materials, are retained on-site during the construction period. b. Appropriate short-term drainage control measures (e.g. flow diversion around recently opened trenches and excavations) are installed and operational prior to impending storms. c. A minimum stockpile of flocculating agents is securely stored on-site to provide for at least three complete treatments of all chemically treated sediment traps. P23 P24 P25 Land disturbing activities do not cause unnecessary soil disturbance. Damage to retained or protected vegetation is minimised. Adopted work practices minimise the release of pollutants into receiving waters. A23 a. Land-disturbing activities do not cause unnecessary soil disturbance if an alternative construction process (that reduces potential environmental harm) is available that achieves the same or equivalent project outcomes at a reasonable cost. b. The extent of unnecessary soil disturbance, including disturbances outside the designated work area, is minimised. A24 a. Prior to the commencement of land disturbing activities within any given area, all protected vegetation and significant areas of retained vegetation within that area, are appropriately identified to minimise the risk of disturbance to such areas. A25 b. No damage is allowed to occur to roots, trunk or branches of retained vegetation, unless under the direction of an appropriate vegetation management plan. a. Emergency and pollution control procedures are commensurate with the site conditions, local environmental values, and the type, cost, scope and complexity of the works. b. All liquid chemicals, including petroleum products, that could potentially be washed or discharged from the site in association with sediment, are stored and handled on-site in accordance with relevant standards such as AS1940. c. Cement-laden run-off, concrete waste, and chemical products (including petroleum and oil-based products), are managed on-site in accordance with current best management practice. d. Brick-, tile- and masonry-cutting activities are carried out in accordance with current best management practice. e. Washing of tools and painting equipment is carried out in accordance with current best management practice. f. Newly sealed hard-stand areas (e.g. roads, driveways and car parks) are swept thoroughly as soon as practicable after surfacing to minimise the risk of components of the surfacing compound (e.g. bitumen and gravel) entering stormwater drains. g. All pollutants washed or blown from the site are collected 185

200 Urban Stormwater Quality Planning Guidelines and secured as soon as practicable. P26 The application of liquid or chemicalbased dust suppression measures does not cause an environmental hazard. A26 a. The application of dust suppression measures complies with state-approved environmental controls and manufacturer s instructions (whichever is the most restrictive or environmentally conservative). b. Vegetation watering and dust suppression activities are conducted in a manner that ensures sediment-laden runoff from such activities does not create a traffic or safety hazard. P27 Environmental harm, safety issues, and nuisance or damage to public and private property resulting from off-site sediment deposits, material spills, and/or the adopted ESC measures is minimised. A27 a. Sediment and other material originating from the work area, or as a result of the transportation of materials to or from the work area, that collects on sealed roads, or within gutters, drains or waterways outside the immediate work area, is removed: i. immediately if rain is occurring or imminent ii. iii. immediately if considered a safety hazard if items (i) or (ii) do not apply, as soon as practicable, but before completion of the day s work. iv. Washing/flushing of sealed surfaces only occurs where sweeping has failed to remove sufficient sediment, and there is a compelling need to remove the remaining sediment (e.g. for safety reasons). b. Sediment deposits that cause nuisance to, or adversely affect the use or value of, neighbouring properties are removed and the area rehabilitated as soon as practicable. c. The adopted ESC measures do not adversely affect drainage or flooding conditions within neighbouring properties. P28 Potential safety risks to site workers and the public as a result of ESC measures are minimised. A28 a. Operational safety issues (public and site personnel) are given appropriate consideration during the installation, operation, maintenance and removal of ESC measures. b. Publicly accessible sediment basins are fenced (i.e. exclusion fencing) where there is considered to be an unacceptable safety risk. P29 Potential harm to wildlife as a result of ESC measures is minimised. A29 a. Disturbance to wildlife habitats is limited to the minimum necessary to complete the approved works. b. Large sediment traps allow appropriate egress of wildlife where such wildlife could enter the trap. c. Synthetic (plastic) reinforced fabrics are not placed within, or adjacent to, bushland areas, riparian zones, and watercourses if such materials are likely to cause harm to wildlife or wildlife habitats. P30 Disturbance to natural watercourses is minimised. A30 a. Instream works are conducted in accordance with an approved code of practice for instream works. b. No instream land-disturbing activities are undertaken prior to development of a vegetation management plan. c. Disturbance to natural watercourses (including bed and bank vegetation) and their associated riparian zones is limited to the minimum necessary to complete the approved works. d. The number, location, type, and size of temporary watercourse crossing are such that the overall adverse impact on the environment is minimised. e. All temporary watercourse crossings, including their approach roads, employ appropriate drainage, erosion and 186

201 Urban Stormwater Quality Planning Guidelines sediment controls to minimise sediment inflow into the watercourse. P31 Site shutdowns are conducted in a manner that minimises potential environmental harm. A31 a. Procedures for initiating a site shutdown incorporate appropriate revegetation of all soil disturbances unless otherwise stipulated within an approved site management plan. b. Revegetation procedures associated with a programmed site shutdown commence at least 30 days prior to the nominated shutdown time. c. Adopted site stabilisation measures do not rely upon the longevity of non-vegetated erosion control blankets and short-term soil binders. Land clearing Performance criteria P32 P33 P34 P35 Potential environmental harm resulting from land clearing is minimised. Land clearing is limited to the minimum necessary. Soil erosion during and following land clearing is minimised. Sediment releases to receiving water (within or outside the site) are minimised during land clearing operations. Acceptable solution A32 A33 A34 A35 a. All land clearing is conducted in accordance with State and local government vegetation protection and/or preservation requirements and/or policies. b. On sites with a soil disturbance greater than one hectare, no land clearing is undertaken prior to approval of a vegetation management plan. c. Limits on the extent and duration of soil disturbance are commensurate with the potential erosion risk and/or erosion hazard. d. Compliance with performance criterion P24. a. Land clearing does not cause unnecessary soil disturbance if an alternative process (which reduces the potential environmental harm) is available that achieves the same or equivalent project outcomes at a reasonable cost. b. Land clearing at any given time during periods of potential soil erosion is restricted to only those areas required for the current stage of works. c. Wherever reasonable and practicable, land clearing is limited to five metres from the edge of proposed constructed works, two metres of essential construction traffic routes, and a total of 10 metres width for construction access. a. Land clearing within any sub-area is delayed as long as reasonable and practicable. b. Land clearing and site rehabilitation are staged to minimise the extent and duration that any and all areas of soil are exposed to the erosive effects of wind, rain and flowing water. c. If tree clearing is required well in advance of future earthworks, then tree clearing methods that will minimise potential soil erosion are employed, especially in areas of high to extreme erosion risk. a. No land clearing is undertaken unless preceded or accompanied by the installation of adequate drainage and sediment control measures. b. No part of a sediment basin catchment area is grubbed of vegetation, or stripped of topsoil, until the basin is constructed and fully operational. 187

202 Urban Stormwater Quality Planning Guidelines Soil and stockpile management Performance criteria Acceptable solution P36 The soil structure of soils that are to be revegetated is not unnecessarily damaged. A36 Soils that are to be revegetated are not unnecessarily disturbed when they are either too wet, or too dry. P37 Maximum benefit is obtained from existing topsoil. A37 a. The topsoil is managed (i.e. stripped, treated, stockpiled and reused) in accordance with the recommendations of an approved vegetation management plan or similar. OR b. Topsoil is stripped, stockpiled, placed, and where necessary treated, in accordance with current best practice. AND c. Topsoil originating from the site is respread as the topsoil to maximise erosion control and revegetation, except where it has been assessed that such soil will not improve erosion control and/or revegetation on the site. P38 Environmental harm caused by the temporary stockpiling of erodible material is minimised. A38 Stockpiles of erodible material are: i. located fully within the relevant property; ii. appropriately protected from wind, rain and excessive surface flows in accordance with current best practice; and iii. located at least two metres from hazardous areas, retained vegetation, and overland flow paths; and iv. located up-slope of an appropriate sediment control system. P39 Exposed dispersive soils are managed such that the risk of ongoing soil erosion is minimised. A39 Construction details for drainage systems and bank stabilisation works within dispersive soil areas clearly demonstrate how these soils will be managed to prevent future erosion problems. P40 Exposed potential acid sulfate soils are appropriately managed. A40 a. If acid sulfate soils conditions exist on site, then appropriate warnings are placed on the ESCP. b. All exposed actual or potential acid sulfate soils are managed in accordance with current best practice. c. On-site personnel involved in the disturbance of actual or potential acid sulfate soils are appropriately trained and/or supervised. Drainage control Performance criteria Acceptable solution P41 Temporary drainage control measures are designed, constructed and maintained to an appropriate A41 a. The standard of drainage control complies with the requirements of the relevant regulatory authority, or where such a standard does not exist, drainage controls are designed in accordance with current best practice. b. Stormwater drainage during each stage of earth works is managed in accordance with the appropriate ESCP or construction drainage plan (as amended from time to 188

203 Urban Stormwater Quality Planning Guidelines standard. time). c. All drainage channels, whether temporary or permanent, are constructed and maintained (at all times) with sufficient size, gradient and surface conditions to maintain their required hydraulic capacity. d. The adopted drainage control measures remain relevant, at all times, to the current and imminent site conditions. P42 Stormwater movement through the site is appropriately managed to minimise soil erosion. A42 a. If the drainage area up-slope of a soil disturbance exceeds 1500 m 2, and the average monthly rainfall exceeds 45 mm, all stormwater discharged from this area (up to the design storm) is diverted around or through the soil disturbance in a manner that minimises soil erosion. b. Appropriate drainage controls are installed above an exposed earth batter to minimise soil erosion on the batter. c. The spacing of cross-slope drainage systems down long exposed, non-vegetated or recently seeded slopes, does not exceed that standard set by the relevant regulatory authority, or in the absence of such standard, are designed in accordance with current best practice. d. Flow velocities within drainage channels and at the entrance and exit of all drainage structures (including chutes, slope drains, and spillways) are controlled in such a manner that prevents soil erosion during all discharges up to the relevant design discharge. P43 P44 P45 Stormwater movement through the site is appropriately managed to minimise environmental harm. Stormwater movement through the site is appropriately managed to minimise site wetness within active work areas. Stormwater entering into, or discharged from, the site is appropriately A43 a. All temporary and permanent drainage systems are installed as soon a practicable. A44 A45 b. Clean water is diverted around sediment traps in a manner that maximises the sediment trapping efficiency of the sediment trap. c. All reasonable and practicable measures are taken to ensure stormwater run-off entering an area of soil disturbance is diverted around or through that area in a manner that minimises soil erosion and contamination of that water for all discharges up to the specified design discharge. d. Adequate drainage controls (e.g. cross drainage systems and/or longitudinal drainage) are applied to all unsealed roads and tracks to minimise erosion on, and sediment run-off from, such surfaces. e. All reasonable and practicable measures are taken to ensure sediment-laden run-off from access roads and stabilised entry/exit systems drains to an appropriate sediment control device. f. All reasonable and practicable measures are taken to divert stormwater around excavations and trenches. a. Roof water does not unreasonably increase soil wetness within work areas. b. Roof water drainage systems are installed prior to placement of the roof. c. Roof water drainage systems are connected to an approved stormwater drainage system immediately after placement of the roof. a. All waters discharged during the construction phase are discharged onto stable land, in a non-erosive manner, and at a legal point of discharge. b. All drainage channels up-slope of neighbouring properties are constructed and maintained with sufficient size, 189

204 Urban Stormwater Quality Planning Guidelines managed to minimise flooding, damage and nuisance to neighbouring properties. gradient and surface conditions to maintain the required hydraulic capacity. c. Stormwater is not unlawfully diverted into neighbouring properties. Erosion control Performance criteria Acceptable solution P46 P47 P48 P49 Erosion control measures are designed, installed and maintained to an appropriate standard. The control of soil erosion is given appropriate priority. Soil erosion is minimised. Soil erosion resulting from rainfall is minimised. A46 a. The standard of erosion control complies with the requirements of the relevant regulatory authority, or where such a standard does not exist, erosion controls are designed in accordance with current best practice. A47 A48 A49 b. As a minimum, the type and degree of erosion control are commensurate with the expected site conditions, soil type, potential environmental risk, and the type, cost, and scope of the works. c. The adopted erosion control measures remain relevant, at all times, to the current and imminent site conditions. a. Wherever reasonable and practicable, priority is given to the prevention, or at least minimisation, of soil erosion, rather than allowing soil erosion to occur and trying to trap the resulting sediment. b. The existence of best practice sediment control measures within a given sub-catchment does not diminish the need for the application of best-practice erosion control measures. a. Appropriate erosion control measures are incorporated into all stages of a development, including each phase of earthworks. b. Site activities are carried out in a manner that minimises the duration that any and all disturbed soil surfaces are exposed to the erosive forces of wind, rain and flowing water. c. Erosion control measures are applied to exposed soils as soon as practicable after earthworks have been completed within each sub-area. d. The application of necessary erosion control measures is not unnecessarily delayed for the purpose of coordinating such activities with final site rehabilitation/revegetation. e. Appropriate drainage and erosion control measures are implemented and maintained around the site office area and on temporary access roads to minimise raindrop impact erosion and the generation of mud. a. Soil disturbing activities are programmed to minimise soil exposure during periods when: i. the monthly rainfall erosivity is expected to exceed 1500, or ii. the monthly rainfall is expected to exceed 225 mm. b. Existing ground covers are protected from damage and retained as long as practicable. c. Exposed dispersible soils are either treated or covered with a layer of non-dispersible soil before being covered with vegetation, mulch or erosion control blankets. 190

205 Urban Stormwater Quality Planning Guidelines P50 Soil erosion resulting from surface water flow is minimised. A50 Service trenches are backfilled, compacted and rehabilitated in a manner that prevents undesirable water flow and soil erosion along the trench. P51 Soil erosion resulting from wind erosion is minimised. A51 a. Erosion control measures used to control wind erosion are commensurate with soil exposure and the expected wind conditions in terms of speed and direction. b. Stockpiles of erodible material are covered during periods of strong wind or when strong winds are imminent. 191

206 Urban Stormwater Quality Planning Guidelines Sediment control Performance criteria P52 P53 P54 Sediment control measures are designed, installed, operated and maintained to an appropriate standard. The on-site retention of sediment is maximised. Sediment displaced off-site by vehicular traffic is minimised. Acceptable solution A52 A53 A54 a. The standard of sediment control complies with the requirements of the relevant regulatory authority, or where such a standard does not exist, sediment controls are designed in accordance with current best practice. b. As a minimum, the type and degree of sediment controls are commensurate with the site conditions, soil type, potential environmental risk, and the type, cost, and scope of the works. c. No sub-catchment relies solely on supplementary sediment traps unless site conditions prevent the use of other more appropriate sediment control systems. d. As-constructed plans are prepared for all constructed sediment basins and associated emergency spillways. e. The adopted sediment control measures remain relevant at all times to the current and imminent site conditions. a. All reasonable and practicable measures are taken to prevent, or at least minimise, the release of sediment from the site, or into water where it is likely to cause environmental harm. b. Appropriate sediment controls are installed and made operational before any up-slope soil disturbance occurs. c. All sediment-laden run-off from the site is directed to an appropriate sediment control device in accordance with the required treatment standard. d. The site s sediment control standard does not rely on operation of off-site sediment control systems. e. Optimum benefit is made of every opportunity to trap sediment within the work site. f. Sediment is trapped as close to its source as possible. g. Appropriate sediment control measures are applied to all temporary building and construction works, including the site office, car park, stockpile areas and watercourse crossings. h. Sediment traps are designed, constructed, maintained and operated to collect and retain sediment. i. All type F and type D sediment basins are maintained at a minimum achievable water level between rainfall events. a. Number of site entry/exit points is limited to the minimum practical number. b. Site entry/exit points are appropriately designed and stabilised to minimise sediment being washed off the site by stormwater and/or being transported off the site by vehicles. c. All reasonable and practicable measures are taken to ensure sediment-laden stormwater run-off from access roads and stabilised entry/exit systems drains to an appropriate sediment control device. 192

207 Urban Stormwater Quality Planning Guidelines P55 Sediment-related environmental harm resulting from de-watering activities is minimised. A55 a. Flow diversion barriers, or other appropriate systems, are used to minimise the quantity of watering entering excavations and trenches. b. All sediment control measures implemented for the control of sediment-laden discharge from de-watering activities are designed to satisfy, as a minimum, current best practice discharge standards. c. As a minimum, the type and degree of sediment controls utilised during de-watering operations are commensurate with the site conditions, soil type, potential environmental risk, and the type, cost, and scope of the works. P56 Sediment control measures are located within the property boundary. A56 All sediment control measures are located within the property boundary, unless: i. it is that portion of the entry/exit pad located between the property boundary and the sealed road; or ii. the sediment control measure is required to collect sediment wash-off from building works located along the property boundary; and iii. approval has been obtained from the relevant regulatory authority and the relevant landowner or asset manager. Site stabilisation and rehabilitation Performance criteria Acceptable solution P57 Site rehabilitation, including site revegetation, is designed, installed and maintained to an appropriate standard. A57 a. The standard of site rehabilitation complies with the requirements of the relevant regulatory authority or, where such a standard does not exist, complies with current best practice. b. As a minimum, the type and degree of site rehabilitation is commensurate with the expected site conditions, soil type, potential environmental risk, and the type, cost and scope of the works. c. Site rehabilitation, including site revegetation, remains, at all times during the construction and specified maintenance period, relevant to the current and imminent site conditions. P58 Adequate site data is obtained to allow the appropriate design of site rehabilitation measures. A58 All necessary site data, including soil data, is obtained to appropriately plan, design, implement and maintain site revegetation and stabilisation. 193

208 Urban Stormwater Quality Planning Guidelines P59 P60 P61 Site rehabilitation methods and procedures minimise the risk of environmental harm. Optimum soil conditions are achieved prior to revegetation. Site rehabilitation methods, procedures, and outcomes are compatible with site conditions and local environmental values. A59 a. Site revegetation, excluding temporary revegetation conducted for purposes of erosion control, is conducted in accordance with a site stabilisation plan, landscape plan, revegetation plan, or vegetation management plan, where such a plan exists. b. Disturbed soil surfaces are appropriately stabilised to minimise the risk of short-term soil erosion. c. Site stabilisation and/or revegetation are commenced as soon as practicable after earthworks are completed within any given manageable drainage area. d. The construction schedule and/or ESC installation sequence clearly indicates the staging of site stabilisation and revegetation measures. e. All temporary ESC measures are removed and the land rehabilitated as soon as practicable after they are no longer needed. A60 a. Soil surfaces that are to be vegetated, are left in an appropriate roughened state, and an appropriate physical and chemical condition, to encourage rapid revegetation. b. Required adjusts to the soil condition are made prior to seeding/planting. A61 a. The qualifications and experience of the personnel preparing and/or supervising the preparation of any site stabilisation plan, vegetation management plan, or similar, are commensurate with the potential environmental risk, and the extent and complexity of the works. b. Plant selection and landscape design are compatible with identified environmental values. Site inspection and monitoring Performance criteria Acceptable solution P62 A monitoring and maintenance program is prepared by, or under the supervision of, suitably qualified and experienced personnel. A62 The qualifications and experience of the personnel preparing and/or supervising the preparation of the monitoring and maintenance program is commensurate with the potential environmental risk, and the extent and complexity of the works. P63 The performance of the site s drainage, erosion and sediment control measures is regularly monitored. A63 a. The extent and complexity of site monitoring (including water quality monitoring) is commensurate with the potential environmental risk, and the extent and complexity of the works. b. A record is maintained of the site s compliance and non-compliance with erosion and sediment control approval requirements. c. All site monitoring data including environmental incidents, rainfall records, dates of water quality testing, testing results, and records of controlled water releases 194

209 Urban Stormwater Quality Planning Guidelines for the site, are kept in an on-site register. P64 The site s drainage, erosion and sediment control measures remain relevant at all times to the current site conditions. A64 All ESC measures are inspected by site personnel: i. at least daily (when work is occurring on-site); ii. at least weekly (when work is not occurring on-site); iii. within 24 hours of expected rainfall; and iv. within 18-hours of a rainfall event of sufficient intensity and duration to cause run-off on the site. Site maintenance Performance criteria Acceptable solution P65 P66 All ESC measures are maintained in proper working order at all times during their required operational life. The maintenance of ESC measures does not increase the risk of soil erosion. A65 a. All ESC measures are maintained in proper working order for the duration of the period in which their operation is required in order to satisfy the required treatment standard, and/or the objective of the ESCP. b. All sediment control measures are maintained in accordance with the requirements of the relevant regulatory authority, or where such a standard does not exist, in accordance with current best practice. c. As a minimum, the maintenance of all ESC measures is commensurate with the expected site conditions, and potential environmental risk. d. Suitable access is provided to allow the proper installation and maintenance of sediment traps. e. The ESCP clearly indicates what degree of site stabilisation is required prior to the decommissioning of any ESC measure. A66 a. Excess vegetation cleared for the purpose of restoring the hydraulic capacity of open drains is selectively cut and trimmed so as to leave a short, dense, live ground cover with a grass length no shorter than 50 mm. b. Maintenance mowing is done in a manner that does not damage the profile of formed, soft edges, such as the crest of earth embankments. P67 The maintenance of ESC measures does not cause environmental harm. A67 All materials removed from ESC devices during maintenance or decommissioning, whether solid or liquid, is lawfully disposed of in a manner that does not cause ongoing soil erosion or environmental harm. 195

210 Urban Stormwater Quality Planning Guidelines Appendix 1B Attachment A Information supporting model code of practice provisions erosion and sediment control Contents ~ Attachment A supporting information 1. Introduction Development planning and design Construction planning Erosion and sediment control plans (ESCP) Site establishment Site management Land clearing Soil and stockpile management Drainage control Erosion control Sediment control Site stabilisation and rehabilitation Site inspection and monitoring Site maintenance

211 Urban Stormwater Quality Planning Guidelines 1 Introduction This Attachment A forms part of the Code and provides essential information and requirements not otherwise provided within the Code. Note: For various appendices, chapters and tables mentioned throughout this attachment, refer to the Best Practice Erosion and Sediment Control. International Erosion Control Association (Australasia) Picton, NSW Development planning and design The intent of the development planning and design section is to: enable erosion and sediment control issues to appropriately influence the planning and design of developments and other land disturbing activities for the purpose of minimising their overall adverse environmental impact enable development planners to recognise that along with consideration of the operational phase of a development, appropriate consideration must be given to how something is to be constructed, and the potential adverse impacts of this construction phase recognise the limitations of control measures on constrained sites, e.g. flood prone land. Acceptable Solution A1(a) Data collection may include soil testing, identification of potential site constraints, and development of a conceptual erosion and sediment control plan (where such data and/or plans are considered reasonably necessary to enable appropriate site planning and design). Appropriate site planning and design refers to the aim of minimising the potential environmental harm (both during the construction and operational phases) of the development. The extent and complexity of data collection is discussed further in Chapter 3 Site planning. Sufficient soil data must be obtained on the site to: reasonable identify the location of dispersive soils reasonable identify the location of potential acid sulfate soils allow the appropriate selection, design, and specification of ESC measures maximise the erosion control benefits of the proposed site revegetation and stabilisation works. The potential environmental risk relates to the potential of a land-disturbing activity to cause harm, whether material, serious, reversible or irreversible, to an environmental value, including nuisance to a neighbouring property or person. The potential environmental risk is related, in part, to the assessed Erosion Hazard (refer to Appendix F Erosion hazard assessment). Acceptable Solution A1(b) Potential site constraints are discussed within Chapter 3 Site planning, and include: limitations of the supply of water problematic soils and soil conditions, including: acid sulfate soils, dispersive or sodic soils, expansive/reactive soils (cracking clays), soils of extreme ph (less than 5.5 or greater than 8.5), soils of low wet-bearing strength, saline soils, toxic soils, and any other soil that could result in ongoing erosion or environmental harm topographic limitations, including: coastal and intertidal areas, drainage problem areas, existing erosion problems, flood prone land, high groundwater, land prone to mass movement, local microclimates, rock outcrops, steep slope, waterways and wetlands. 197

212 Urban Stormwater Quality Planning Guidelines Problematic soils are discussed in more detail in Section 3.4 of Chapter 3, and Section C11 of Appendix C Soils and revegetation. Zones of high or extreme erosion hazard may be identified through the application of an appropriate Erosion Hazard Assessment scheme such as those discussed in Chapter 3 Site planning, and Appendix F Erosion hazard assessment. Acceptable Solution A1(c) A conceptual erosion and sediment control plan incorporates plan(s) (no larger than 1:1000) that: 1. identify the likely need for the construction of sediment basins on the site 2. identify that adequate space has been made available for the construction and operation of major sediment traps and essential flow diversion systems 3. demonstrate that there is a feasible means of constructing the project while still protecting key environmental values 4. identify problem soil areas including, dispersive soils, acid sulfate soils, and areas of potential mass movement 5. identify key environmental features on the site such as protected vegetation. The preparation of erosion and sediment control plans (ESCPs), including conceptual ESCPs is discussed in Chapter 5 Preparation of plans. Environmental risk, project cost, and safety issues must be given appropriate consideration when determining the development layout and construction process. Construction activities that are deemed to represent a high to extreme erosion hazard include: any disturbance of high to extreme hazard areas, or a problematic soil that could result in unmanageable soil erosion and/or environmental harm any construction or building activity, or procedure, that could potentially cause serious environmental harm any soil disturbance that could cause the transformation of significant quantities of potential acid sulfate soils (PASS) into actual acid sulfate soils (AASS), such as to cause material or serious environmental harm. Acceptable Solution A2(b) The development design must aim to minimise, if not totally avoid, disturbance to high or extreme erosion hazard areas, including dispersive soils, acid sulfate soils, and slopes steeper than 20 per cent, wherever reasonable and practicable. Acceptable Solution A3(a) Refer to A1(c) for discussion on high-risk construction activities. Acceptable Solution A3(b) Essential ESC control measures include any drainage, erosion or sediment control measures that are considered critical in regards to the protection of environmental values. Such measures usually include: all Type 1 sediment traps, including sediment basins all Type 2 sediment traps located within subcatchments that do not incorporate a Type 1 sediment trap all Type 3 sediment traps located within subcatchments that do not incorporate a Type 1 or Type 2 sediment trap drainage control measures that allow the diversion of up-slope catchment areas in excess of 2500 m 198

213 Urban Stormwater Quality Planning Guidelines any instream sediment control or flow diversion system. Acceptable Solution A3(c) & (d) The most critical issue is ensuring sufficient space is available to construct and maintain all sediment basins, including associated settling ponds, embankments and spillways. Acceptable Solution A3(e) If erosion control practices are reliant on final site revegetation, then to the maximum degree practicable, such activities must be allowed to occur in close association with the staging of soil disturbance for the purpose of minimising the duration that any and all soil surfaces are exposed to the erosive force of wind, rain and flowing water. Acceptable Solution A4(a) Reference is to drainage design standards suitable for the operational phase of developments, not the drainage standards presented within this document, which focuses on the construction phase. Acceptable Solution A4(b) Ongoing erosion problems can result from any of the following: changes to the volume, duration, frequency, or rate of stormwater runoff excessive (i.e. erosive) flow velocities inappropriate distribution of flow velocities throughout the depth and width of flow discharged from a stormwater drain into a receiving water inappropriate direction of flow discharged from a stormwater drain into a receiving water. Acceptable Solution A4(d) Refer to A1(b) for discussion on site constraints. Acceptable Solution A4(e) The full impact of the removal of deep-rooted vegetation from steep slopes may not be evident for 5 to 10 years, or until such time as the plant root system begins to fail (assuming that the root system remains within the soil profile after removal of the upper portion of the plant). Planners and designers must appreciate that plants provide many essential roles besides the provision of scenery. Acceptable Solution A5(b) Temporary watercourse crossings referring to those crossings constructed for use only during the construction phase. 199

214 Urban Stormwater Quality Planning Guidelines 3 Construction Planning The intent of the construction planning section is to: take all reasonable and practicable measures to actively avoid foreseeable soil erosion problems and associated environmental hazards during the construction phase ensure that those involved in construction planning do not assume that the environmental impact of such hazards can be totally resolved (irrespective of the site s layout, methodology, staging, and programming) through applying best practice erosion and sediment control. Construction planning refers to planning the layout, methodology, staging, and programming (timing and scheduling) of the construction phase. Acceptable Solution A6(a) Refer to A1(b) for discussion on zones of high and extreme erosion hazard. Acceptable Solution A6(b) Refer to A1(a) for discussion on potential environmental risk. Acceptable Solution A7(a) Ideally, ESCPs should be developed in close association with construction planning because the needs and limitations of the construction process represent an important component of the ESCP. In theory, a construction process cannot be finalised without reference to an ESCP, and an ESCP cannot be finalised without knowledge of the construction process. Acceptable Solution A7(b) & (c) Refer to A1(c) for discussion on high-risk construction activities. Refer to A1(b) for discussion on zones of high and extreme erosion hazard. Periods of high and extreme erosion potential refers to the variation in the erosion hazard throughout a calendar year based on variations in the rainfall erosivity as described in Appendix E Soil loss estimation. Periods of high to extreme erosion potential include: periods of high to extreme erosion risk as defined in Section 4.4 of Chapter 4 Design standards and technique selection periods of strong winds sufficient to cause significant dust problems. Acceptable Solution A7(f) Reference is made to the extent of unnecessary soil disturbance that can be influenced by the construction planning process. The extent of any unnecessary soil disturbance, including disturbances outside the designated work area, must be minimised in order to minimise the risk of environmental harm. Minimising the potential environmental harm can be achieved, in part, by scheduling major land disturbances, and disturbances to high and extreme erosion risk areas, for the least erosive periods of the year. Acceptable Solution A7(g) Site stabilisation plans, landscape plans, and/or vegetation management plans must show progressive stabilisation of exposed soil for the purposes of erosion control, including but not limited to, all of the following: 200

215 Urban Stormwater Quality Planning Guidelines 1. schedule for stabilisation of exposed soil area 2. specifications for subsoil and topsoil preparation and application 3. specification of stabilisation by mulching or other appropriate surface treatment (note, grass seeding without adequate mulching is generally not considered best-practice) 4. details on the type and application rate of any tackifiers to be used in the application of mulches (including hydromulch, bonded fibre matrix, and compost blankets). Water quality monitoring programs must document proposed water quality monitoring, and include: 1. location of all instream water quality monitoring stations 2. water quality monitoring, sampling, and analysis procedures and standards. 4 Erosion and sediment control plan (ESCP) The intent of this section is to ensure ESCPs are: 1. appropriate for the site conditions, which may vary from time to time 2. prepared by, or under the supervision of, suitable personnel 3. able to achieve the required design standard and environmental protection. Acceptable Solution A9(a) Such a clause shall not reduce the responsibility of applying and maintaining, at all times, all necessary sediment control measures in accordance with the sediment control standard. Acceptable Solution A9(b) Refer to A1(a) for discussion on environmental risk. It is recognised that the degree of erosion and sediment control is related to the type, cost and scope of works in addition to the environmental risk. This association is acknowledged within the terms of current best practice erosion and sediment control as defined within this document (2008 conditions). Acceptable Solution A9(c) On very minor works, such as regular council maintenance activities, or the installation of minor services, the ESCP may be represented by standard drawings prepared by the principle company/organisation as part of an in-house Code of Practice. The key intent is to ensure that appropriate consideration is given to erosion and sediment control requirements before works commence. On sites with a soil disturbance greater than 2500 m 2, the ESCP (including supporting documentation and construction specifications) must include: 1. north point and plan scale 2. site and easement boundaries and adjoining roadways 3. construction access points 4. site office, car park and location of stockpiles 5. proposed construction activities and limits of disturbance 6. retained vegetation including protected trees 7. general soil information and location of problem soil 8. location of critical environmental values (where appropriate) 201

216 Urban Stormwater Quality Planning Guidelines 9. existing site contours (unless the provision of these contours adversely impacts the clarity of the ESCP) 10. final site contours including locations of cut and fill 11. construction drainage plans for each stage of earthworks, including land contours for that stage of construction, subcatchment boundaries and location of watercourses 12. general layout and staging of proposed works 13. location of all drainage, erosion and sediment control measures 14. full design and construction details (e.g. cross-sections, minimum channel grades, channel linings) for all drainage and sediment control devices, including diversion channels and sediment basins 15. construction specifications for adopted ESC measures (as appropriate) 16. site revegetation requirements (if not contained within separate plans) 17. site monitoring and maintenance program, including the location of proposed water quality monitoring stations 18. technical notes relating to: i. site preparation and land clearing ii. extent, timing and application of erosion control measures iii. temporary ESC measures installed at end of working day iv. temporary ESC measure in case of impending storms, or emergency situations v. installation sequence for ESC measures vi. site revegetation and rehabilitation requirements vii. application rates (or at least the minimum application rates) for mulching and revegetation measures viii. legend of standard symbols used within the plans ix. chemical flocculation procedures 19. calculation sheets for the sizing of ESC measures 20. a completed ESCP checklist such as presented in [insert publication] 21. any other relevant information the regulatory authority may require to properly assess the ESCP. Site-specific ESCPs must address all aspects of proposed site disturbance, temporary drainage works, erosion and sediment control measures, installation sequence, and site rehabilitation for the duration of the construction phase, including (where appropriate) the nominated maintenance period. If the timing of the proposed construction activity is not known during development of the ESCP, and if rainfall erosivity varies significantly throughout the year, then the erosion control specifications placed on the ESCP must specify appropriate erosion control measures for each level of rainfall erosivity. For example, light mulching may be appropriate during periods of light rainfall, hydromulching during periods of light to moderate rainfall, and erosion control blankets or bonded fibre matrix during those periods of the year when moderate to heavy rainfall is either occurring or expected to occur. The ESCP must clearly state that no land-disturbing activities shall occur on the site until all associated perimeter ESC measures, including sediment basins and temporary drainage controls, have been constructed in accordance with the ESCP and best practice erosion and sediment control procedures. Sufficient information and detail includes the provision of sufficient long-sections and crosssection of all Type 1 and Type 2 sediment traps (e.g. sediment basins) relative to existing and/or final ground levels to allow their construction. 202

217 Urban Stormwater Quality Planning Guidelines On sites with a soil disturbance greater than one (1) hectare, the ESCP must include: individual ESCPs for the bulk earthworks phase, roadworks and drainage phase and the practical completion/on-maintenance phases of construction. Each phase above must be documented graphically on a dedicated ESCP, or detail shown on an ESCP, and supported by a clearly documented construction sequence, or ESC installation sequence, which describes the timing of key ESC actions on the site procedures for the temporary shutdown of the site, whether a planned or unplanned shutdown. Acceptable Solution A10(b) & (c) A suitably qualified and experienced professional is defined as a person with all of the following: 1. training and/or qualifications in erosion and sediment control that are recognised by the regulatory authority 2. professional affiliations with an engineering, environmental engineering, soil science, and/or scientific organisation (e.g. the International Erosion Control Association; Engineers Australia; Environment Institute of Australia and New Zealand; or the Australian Society of Soil Science Inc 3. at least two years experience in the management of erosion and sediment control which can be verified by an independent third party. ESCPs for high-risk sites should be reviewed by a suitably qualified and experienced third party reviewer prior to its implementation. The assessment and categorisation of high-risk sites may be defined by the relevant Regulatory authority; otherwise, refer to the discussion in Chapter 3 Site planning, and Appendix F Erosion hazard assessment. Acceptable Solution A10(d) The intent is to ensure the adoption of an appropriate design discharge for sizing the basin and associated emergency spillway, and to ensure the appropriate hydraulic design of the basin s, including the spillway s location, sizing and scour protection. Acceptable Solution A10(e) The intent is to ensure the appropriate design and construction specification of the embankment with regard to its structural stability. Acceptable Solution A11(a) It is sufficient for the extent and complexity of data collection to be determined by a suitably qualified and experienced professional as defined in A10(c) above. On sites with a soil disturbance greater than one (1) hectare, the site needs to be assessed from a hydrological, hydraulic, vegetation, soils, and geological perspective to determine relevant site constraints that may affect the focus or detail of the ESCP. Acceptable Solution A11(b) Typically the drainage standard is based on a specified design storm average recurrence interval (ARI), the erosion standard is based on the expected rainfall erosivity, and the sediment control standard is based on the expected soil loss rate. Refer to Chapter 4 Design standards and technique selection for selection of design standards. Acceptable Solution A11(c) On disturbances exceeding 2500 m, construction drainage plans need to be prepared for each stage of earth works. The intent of construction drainage plans is to show: 203

218 Urban Stormwater Quality Planning Guidelines 1. flow entry and exit points 2. areas of sheet flow and path lines of concentrated flow 3. subcatchment boundaries 4. all permanent and temporary roads 5. all temporary and permanent drainage control measures expected to exist during the given stage of works. Acceptable Solution A12(a) The timing and degree of ESC specified in the ESCP(s) needs to be appropriate for the given soil properties, expected weather conditions, and susceptibility of the receiving waters to environmental harm resulting from sediment-laden runoff. Current (2008) best practice design standard of the drainage, erosion and sediment control measures are outlined in Chapter 4 Design standards and technique selection. Acceptable Solution A12(b) Additional and/or alternative erosion and sediment control measures must be implemented, and a revised ESCP must be prepared and submitted to relevant Regulatory authority for approval (where required) in the event that any of the following apply: 1. site conditions significantly change from those previously anticipated 2. there is a high probability that serious or material environmental harm might occur as a result of sediment leaving the site 3. the implemented works fail to achieve the adopted ESC standard, or the State s environmental protection requirements 4. site inspections indicate that the implemented works are failing to achieve the objective of this ESCP. Acceptable Solution A12(d) A suitably qualified and experienced professional is defined in A10(c) above. Acceptable Solution A13 Synthetic reinforced fabrics include plastic reinforced erosion control blankets, mats and meshes. 5 Site establishment The intent of this section is to ensure that during site establishment: 1. on-site personnel are provided with all necessary information to fully comply with all legal requirements, minimise environmental harm, and achieve the objective of the ESCP 2. land-disturbing activities proceed in a manner consistent with the objective of the ESCP. Acceptable Solution A14(a) Supply of such material is relevant only to that material that exists, or is required to exist. Acceptable Solution A14(b) A discussion on site shutdown procedures is provided in Section 6.15 of Chapter 6 Site management. Acceptable Solution A15(a) On low-risk sites, ESC audits (including site inspections and water quality monitoring) may be performed by site personnel; however, as the risk of environmental harm increases, the need for third-party site inspections and water quality monitoring increases. Personnel undertaking ESC audits of a site must, collectively, have the following capabilities: 204

219 Urban Stormwater Quality Planning Guidelines 1. an understanding of the local environmental values that could potentially be affected by the proposed works 2. a good working knowledge of the site s Erosion and Sediment Control (ESC) issues, and potential environmental impacts, that is commensurate with the complexity of the site and the degree of environmental risk 3. a good working knowledge of current best practice ESC measures for the given site conditions and type of works 4. ability to appropriately monitor, interpret, and report on the site s ESC performance, including the ability to recognise poor performance and potential ESC problems 5. ability to provide advice and guidance on appropriate measures and procedures to maintain the site at all times in a condition representative of current best practice, and that is reasonably likely to achieve the required ESC standard 6. a good working knowledge of the correct installation, operational and maintenance procedures for the full range of ESC measures used on the site. Acceptable Solution A15(b) The construction industry s dealing of work place safety issues provides a good model for the development of an appropriate chain of command for the protection of environmental values. The aim is to produce a fair, reasonable and practicable approach based on environmental risk. As in workplace safety, the responsibility of environmental protection, and therefore erosion and sediment control, rests with all site personnel, whether or not the work site is the normal place of work of any and all personnel. Establishing a chain of command does not diminish the responsibility of each and every person to take all reasonable and practicable measures to minimise environmental harm resulting from their actions as per their environmental duty of care. Acceptable Solution A16(a) The exception to this clause is land disturbance necessary to provide access and allow the installation the initial ESC measures. In general, initial land-disturbing activities should be limited to the establishment of the site compound, site entry/exit points, temporary drainage controls (including drain stabilisation measures), haul road(s), perimeter sediment controls, and any sediment basins/traps required for the first stage of works. Acceptable Solution A16(b) Operational activities include such things as material stockpiles, storage areas, vehicle maintenance facilities, cleaning stations and concrete waste receptors. Acceptable Solution A16(c) Waste collection areas include litter bins and receptors for waste concrete. Acceptable Solution A17(b) Within the limits of what is considered reasonable and practicable, site managers should take appropriate actions (such as fencing) to minimise the potential environmental harm cause by both authorised and unauthorised access onto the site. Acceptable Solution A17(c) It is recognised that it may not be practicable for all stormwater runoff from all areas of site entry/exit paths to be directed to a sediment trap; however, such areas must be limited to the minimum practicable. 205

220 Urban Stormwater Quality Planning Guidelines 6 Site management Acceptable Solution A18(a) Where appropriate, an ESCP is prepared (in accordance with Appendix 1A, section 6), and where necessary approved by a relevant Regulatory authority, prior to commencing any landdisturbing activities. Acceptable Solution A18(b) The potential for environmental harm must be assessed by a recognised expert or authority. Acceptable Solution A18(c) Refer to A1(a) for discussion on potential environmental risk. Acceptable Solution A18(d) Applies to all land-disturbing activities, whether planned or unplanned, and especially to any works that are required to be conducted without an associated ESCP. Acceptable Solution A18(d)(iv) Includes ensuring that the value and use of land/properties adjacent to the development (including roads) are not diminished as a result of work-related soil erosion and sediment runoff. Acceptable Solution A19 Responsible ESC personnel are those persons employed or contracted by the land owner and/or developer as the principal officer(s) responsible for ensuring appropriate application of the planned ESC measures and for the provision of advice in response to unplanned ESC issues. Acceptable Solution A20(a) Recommended training requirements are discussed in Section 6.19 of Chapter 6 Site management. Acceptable Solution A20(b) Necessary disturbance to ESC measures would include the short-term removal of an ESC measure to allow the installation of services under the ESC measure, or to allow vehicular or material access. Performance Criterion P21 Performance Criteria P21 and P22 require work sites to be appropriately prepared for both current and imminent site conditions. Compliance with these criteria requires ESCPs to be living documents that remain both effective and flexible, and thus are able to appropriately adapt to changing site conditions. Acceptable Solution A21(b) A significant change in site conditions includes: 1. unseasonable weather conditions 2. exposure of problematic soil conditions not previously anticipated 3. significant change in construction methodology, staging or programming of earthworks and/or site stabilisation activities 4. significant change in the development design or layout 5. an unprogrammed site shutdown. Performance Criterion P22 Performance Criteria P21 and P22 require work sites to be appropriately prepared for both current and imminent site conditions. Compliance with these criteria requires ESCPs to be 206

221 Urban Stormwater Quality Planning Guidelines living documents that remain both effective and flexible, and thus are able to appropriately adapt to changing site conditions. Acceptable Solution A24(a) Appropriate identification depends on the level of risk of damage to protected or retained vegetation. Appropriate identification does not necessarily mean markers, signs or fencing; however, such measures may be appropriate in some areas. Acceptable Solution A25(b) AS1940 The storage and handling of flammable and combustible liquids (as amended from time to time). In addition to the above: Impervious bunds must be constructed around all storage areas containing more than 1m of petroleum and oil-based products such that the enclosed volume is large enough to contain 110 per cent of the volume held in the largest, individual storage tank. On-site personnel involved in the handling and storage of flammable and combustible liquids, including all liquid chemicals, must be appropriately trained and/or supervised, as required in order to allow such personnel to appropriately perform such activities. Acceptable Solution A25(c) Current (2008) best practice requires that all reasonable and practicable measures are taken to: 6. prevent the release of cement-laden runoff, concrete waste, and chemical products (including petroleum and oil-based products), into an internal or external water body, completed internal drainage systems, or any external drainage system, excluding those onsite drains and water bodies specifically designed to contain and/or treat such material 7. ensure all solid and liquid waste from concrete production, and concreting equipment (including delivery and placement vehicles), is fully contained within the property 8. ensure cement residue from work activities is: retained on a pervious surface (e.g. a grassed or open soil area, or excavated trench); or filtered through a fine-grained, porous earth embankment; or collected and disposed of in a manner that minimises ongoing environmental harm. Acceptable Solution A25(d) Current (2008) best practice requires that wherever practicable, the cutting of bricks, concrete, ceramics, and other slurry-producing materials must be carried out in a manner that: 1. complies with current State guidelines, policies, and legislation; and 2. fully contains any contaminated waste water for later treatment and/or lawful disposal; or 3. appropriately filters (e.g. through a fine-grained, porous earth embankment) any contaminated slurry/water prior to its release from the immediate work area. Acceptable Solution A25(e) Current (2008) best practice requires that wherever practicable, the washing of tools and painting equipment is carried out in a manner that: 1. complies with current State guidelines, policies and legislation; and 2. fully contains any contaminated waste water for later treatment and/or lawful disposal; or 3. appropriately filters (e.g. through a fine-grained, porous, earth embankment) any contaminated liquid prior to its release from the immediate work area; or 4. appropriately infiltrates all contaminated liquid matter into an area of porous grass or open soil. 207

222 Urban Stormwater Quality Planning Guidelines Acceptable Solution A26(b) Sediment and sediment-laden runoff must not settle or collect on public roadways where such material could result in a traffic or safety hazard. Acceptable Solution A27(a) Sediment and other material includes clay, silt, sand, gravel, soil, mud, cement and fineceramic waste. Acceptable Solution A27(b) Sealed surfaces include sealed roads and car parks. In circumstances where the washing/flushing of sealed surfaces is required, all reasonable and practicable sediment control measures must be employed to prevent, or at least minimise, the release of sediment into receiving waters. Only those measures that will not cause safety issues or adverse property flooding to third parties shall be employed. Acceptable Solution A28(a) Appropriate consideration includes taking all reasonable and practicable measures to minimise safety risks. As a general rule, safety issues take a higher priority than ESC issues; however, this does not mean that the existence of potential safety issues diminishes the ESC standard required of a work site. Public safety risks include potential damage to public vehicles resulting from the use of inappropriate kerb-inlet sediment traps on public roads. The potential safety risk of a proposed sediment trap to site workers and the public must be given appropriate consideration before its installation, especially those sediment traps located within publicly accessible areas. Performance Criterion P29 The protection of wildlife does not diminish the required ESC standard, or the need to take all reasonable and practicable measures to minimise environmental harm resulting from soil erosion and displaced sediment. Performance Criterion P30 Further discussion on the protection of waterways and the conducting of instream works is provided in Appendix I Instream works. Performance Criterion P31 A discussion on site shutdown procedures is provided in Section 6.15 of Chapter 6 Site management. 7 Land clearing Acceptable Solution A32(c) Operational restrictions on the extent and duration of land disturbance, including land clearing (as presented by Performance Criteria P32 to P35) only apply when such land disturbance is at risk, or potentially at risk, of erosion by wind, rain, or flowing water. The potential erosion risk is related (in part) to the potential rainfall erosivity as defined in Section 4.4 of Chapter 4 Design standards and technique selection. The potential erosion hazard may be identified through the application of an appropriate erosion hazard assessment scheme such as those discussed in Chapter 3 Site planning, and Appendix F Erosion hazard assessment. Acceptable Solution A33(b) The extent of unnecessary soil disturbance, including disturbances outside the designated work area, must be minimised at all times. 208

223 Urban Stormwater Quality Planning Guidelines Wherever reasonable and practicable, land clearing must be limited to the current stage of works. Current (2008) best practice recommends that land clearing not extend beyond the parameters indicated in Table of Chapter 4 Design standards and technique selection; that being the minimum necessary to provide either of the following: 1. up to eight (8) weeks of site activity during those months when the expected rainfall erosivity is less than 100, six (6) if between 100 and 285, four (4) weeks if between 285 and 1500, and two (2) weeks if greater than up to eight (8) weeks of site activity during those months when the actual or average rainfall is less than 45 mm, six (6) if between 45 and 100 mm, four (4) weeks if between 100 and 225 mm, and two (2) weeks if greater than 22 mm. Condition ii generally only applies if directed by the relevant regulatory authority. Acceptable Solution A33(c) Clause A33(c) does not imply that land clearing should occur to the full extent of these limits, rather that all reasonable and practicable measures are taken to limit land clearing to no more than these limits. In all cases, land clearing must be limited to the minimum necessary to complete the approved works. Acceptable Solution A34(c) During such tree clearing, all reasonable and practicable measures must be taken to minimise unnecessary removal of, or disturbance to, any existing ground cover (organic or inorganic) until just prior to final grubbing and topsoil removal. In some cases it might be advantageous to perform bulk removal of trees and shrubs at the beginning of each stage of works, followed by the establishment of a temporary grass, mulch or other ground cover. Final grubbing of roots and topsoil removal should then be delayed until just prior to commencement of bulk earthworks. Acceptable Solution A35(a) This clause excludes that (minimal) land clearing required for the purpose of installing such ESC measures, in which case only that land clearing required to install such measures shall occur prior to their installation and operation. 8 Soil and stockpile management Acceptable Solution A36 Topsoil should be stripped only while in a moist condition. If the soil is too dry it will pulverise the soil, if too wet it may lead to clodding or hardsetting particularly if the soil has a high silt or clay content. The soil should be wet enough to form a clump when squeezed, but not wet enough to squeeze-out water. Further discussion on the management of soils is provided in Section 6.11 of Chapter 6 Site management. Performance Criterion A37 Applies to all areas of proposed soil disturbance, including footprint of proposed stockpiles prior to placement of soil within such areas. Does not include any material best described as subsoil. Acceptable Solution A37(b) Current (2008) best practice recommendations for the management of topsoil are presented in Table 6.2 in Chapter 6 Site management. Acceptable Solution A38(ii) The diversion of up-slope stormwater is recommended during those periods when rainfall is possible and the up-slope catchment area exceeds 1500 m. 209

224 Urban Stormwater Quality Planning Guidelines Current (2008) best practice recommendations for the protection of sand and soil stockpiles from the erosive effects of wind and rainfall are presented in Table in Chapter 4 Design standards and technique selection. Acceptable Solution A38(iv) Current (2008) best practice recommendations for the selection of an appropriate sediment control system is presented in Table in Chapter 4 Design standards and technique selection. Short-term stockpiles of erodible material located outside of an appropriate sediment control zone must be covered if it is raining, or if rain is imminent or possible. Acceptable Solution A39 Dispersive soils normally need to be stabilised (i.e. treated with gypsum or lime depending on desired ph adjustment) and/or buried under a layer of non-dispersive soil prior to placement of channel lining (whether rock, gabion, synthetic material, or concrete), or initiation of revegetation. Refer to Section 6.12 in Chapter 6 Site management, or Section C11 in Appendix C Soils and revegetation for further discussion on the management of dispersive soils. Acceptable Solution A40 Refer to Section 6.12 in Chapter 6 Site management, or Section C11 in Appendix C Soils and revegetation for further discussion on the management of acid sulfate soils. Within Queensland, guidelines on the management of acid sulfate soils is provided in State Planning Policy 2/02 Guideline: Planning and Managing Development involving Acid Sulfate Soils, and Dear, et al. 2002, Queensland Acid Sulfate Soil Technical Manual Soil Management Guidelines. Department of Natural Resources and Mines, Indooroopilly, Queensland. 9 Drainage control The intent of this section is to take all reasonable and practicable measures to prevent, or at least minimise, environmental harm and public nuisance resulting from the exposure of soil to the erosive forces of flowing water. It is not the intent to unfairly burden those performing landdisturbing activities with the cost and inconvenience of installing and maintaining drainage control measures if there is no risk of such environmental harm and public nuisance. Acceptable Solution A41(a) Current (2008) best practice construction phase drainage standards are presented in Table of Chapter 4 Design standards and technique selection. Drainage systems must be designed to have a minimum non-erosive hydraulic capacity (excluding 150 mm freeboard) in accordance with this table. Acceptable Solution A41(b) Construction Drainage Plans are normally prepared for sites with a soil disturbance exceeding 2500m. Further discussion on the requirements of Construction Drainage Plans is presented in Acceptable Solution A11(d). Acceptable Solution A41(d) This clause requires compliance with Performance Criteria P21 and P22. Acceptable Solution A42(b) Sandbag flow diversion banks, catch drains, and flow diversion banks are examples of appropriate drainage systems that can be used to divert stormwater around excavations and other soil disturbances. 210

225 Urban Stormwater Quality Planning Guidelines Acceptable Solution A42(c) Current (2008) best practice for the lateral spacing of drainage channels down open soil (non vegetated) slopes is presented in Table of Chapter 4 Design standards and technique selection. Acceptable Solution A42(d) The relevant design discharge is related to Acceptable Solution A41(a). The design flow or design discharge is the design hydraulic capacity of that component of the drainage system. All temporary and permanent drainage systems must be able to accept the design flow within 10 days of construction. This may require the application of an appropriate permanent or temporary channel liner, or the use of velocity control check dams. Acceptable Solution A43(a) Temporary drainage systems are only utilised during the construction phase, and only until the permanent drainage systems are constructed and made operational. The intent of installing the permanent drainage system as soon as practicable is to maximise the effective passage of clean water through the site without the risk of contamination by on-site sediment. Acceptable Solution A43(b) Clean water is defined as water that either enters the property from an external source and has not been further contaminated by sediment within the property; or water that has originated from the site and is of such quality that it either does not need to be treated in order to achieve the required water quality standard, or would not be further improved if it was to pass through the type of sediment trap specified for the site. Acceptable Solution A43(f) Does not refer to excavations and trenches that form or act as sediment traps. Performance Criterion P44 Active work areas includes site office and car park areas. Acceptable Solution A44(a) The intent is to minimise soil erosion and sediment runoff, and on-site safety issues, by reducing the generation of mud within active work areas. The roof water drainage system needs to be installed before the roof covering is laid. Appropriate roof water drainage systems may be formed from either temporary (i.e. temporary solid or flexible) downpipe, or the permanent drainage system. Acceptable Solution A44(c) Does not apply to contaminated (e.g. sediment-laden) roof water. 10 Erosion control The intent of this section is to take all reasonable and practicable measures to prevent, or at least minimise, environmental harm and public nuisance resulting from the exposure of soil, sand, silt, mud or cement to the erosive forces of wind, rain and flowing water. It is not the intent to unfairly burden those performing land-disturbing activities with the cost and inconvenience of installing and maintaining erosion control measures if there is no risk of such environmental harm and public nuisance. Acceptable Solution A46(a) Current (2008) best practice (construction phase) land clearing and site rehabilitation standards are presented in Table of Chapter 4 Design standards and technique selection. Unless 211

226 Urban Stormwater Quality Planning Guidelines otherwise stated by the relevant Regulatory authority, the potential erosion risk is based on the rating outlined in Table of Chapter 4 Design standards and technique selection. In addition, all temporary earth banks, flow diversion systems, and sediment basin embankments should be machine-compacted, seeded and mulched within ten (10) days of formation for the purpose of establishing a vegetative cover, unless otherwise stated within an approved Site Stabilisation Plan, Revegetation Plan, or Vegetation Management Plan. Acceptable Solution A46(b) Erosion control measures primarily focus on the control of fine sediments such as clay and siltsized particles. Thus, with respect to the value of erosion control measures, potential environmental harm is strongly related to the susceptibility of the receiving waters to environmental harm resulting from turbid runoff (i.e. suspended fine sediments). Erosion control measures need to be appropriate for the land slope and the expected wind, rain and hydraulic conditions. Application of effective drainage control measures should help to control hydraulic conditions such that damage to adopted erosion control measures during regular rainfall events is minimised. Acceptable Solution A46(c) This clause requires compliance with Performance Criteria P21 and P22. Acceptable Solution A47(a) Such a clause shall not reduce the responsibility to apply and maintain, at all times, all necessary sediment control measures. The minimisation of soil erosion requires the application of effective drainage and erosion control throughout each and all subcatchments. Acceptable Solution A48(b) Compliance with this clause requires: 1. soil disturbance within any subcatchment to be delayed as long as possible, and ideally, not until the principal on-site activities within that area are ready to commence 2. soil disturbance at any given time to be limited to the minimum necessary to perform the required works 3. the extent of unnecessary soil disturbance, including disturbances outside the designated work area, to be minimised. Disturbed soils associated with non-completed earthworks that are likely to be exposed to rainfall are protected from soil erosion: 1. if further soil disturbances are likely to be delayed for more than 30 days during those months when the expected rainfall erosivity is less than 100, or 20 days if between 100 and 285, or 10 days if between 285 and 1500, or 5 days if greater than 1500: or 2. where directed by the regulatory authority, further soil disturbances are likely to be delayed for more than 30 days during those months when the expected rainfall is less than 45 mm, or 20 days if between 45 and 100 mm, or 10 days if between 100 and 225 mm, or 5 days if greater than 225 mm. Acceptable Solution A48(c) Compliance with the requirements outlined within Table of Chapter 4 Design standards and technique selection does not diminish the need to apply all reasonable erosion control measures as soon as practicable. A sub-area is an area within a given subcatchment fully contained within a set of drainage control structures designed to minimise the risk of rill erosion within that area. Acceptable Solution A48(d) 212

227 Urban Stormwater Quality Planning Guidelines If the adopted erosion control measures incorporate temporary or permanent grassing, then the application of that grass cover must not be unnecessarily delayed simply because it is (inappropriately) viewed by the principal contractor as part of site revegetation that has been subcontracted to another contractor. In cases where it is not possible for the principal contractor to apply a temporary grass cover (for the purposes of erosion control), then alternative erosion control measures must be applied to protect the site during the intervening period. Acceptable Solution A49(a) Condition ii generally only applies if directed by the relevant regulatory authority. Acceptable Solution A49(b) Existing ground covers include mulch (organic or inorganic), grasses, and other low-growing plants. This clause required compliance with Performance Criterion P34. Acceptable Solution A49(c) Dispersive soils normally need to be stabilised (i.e. treated with gypsum or lime depending on desired ph adjustment) and/or buried under a layer of non-dispersive soil prior to placement of channel lining (whether rock, gabion, synthetic material, or concrete), or initiation of revegetation. Refer to Section 6.12 in Chapter 6 Site management, or Section C11 in Appendix C Soils and revegetation for further discussion on the management of dispersive soils. Acceptable Solution A50 All stormwater, sewer line and other service trenches not in streets are mulched and seeded, or otherwise appropriately stabilised, within 7 days after backfill, or otherwise rehabilitated in accordance with an approved Site Stabilisation Plan, Landscape Plan, Revegetation Plan, or Vegetation Management Plan. Acceptable Solution A51(b) This clause requires compliance with Performance Criterion P Sediment control The intent of this section is to take all reasonable and practicable measures to prevent, or at least minimise, environmental harm and public nuisance resulting from the exposure, placement, or displacement of sediment (including soil, sand, silt, mud and cement). It is not the intent to unfairly burden those performing land-disturbing activities with the cost and inconvenience of installing and maintaining sediment control measures if there is no risk of such environmental harm and public nuisance. Acceptable Solution A52(a) Current (2008) best practice (construction phase) sediment control standards are presented in Table of Chapter 4 Design standards and technique selection. Acceptable Solution A52(b) Relevant site conditions include the soil type, design flow rate, flow condition (i.e. sheet flow or concentrated flow), and erosion hazard. The erosion hazard may be related to the expected soil loss rate (as presented in Table of Chapter 4, and Appendix E Soil loss estimation), or other factors such as discussed in Appendix F Erosion hazard assessment. Unless otherwise noted within this document, or specified by the regulatory authority, the design storm for sediment traps (excluding de-watering and instream sediment control measures) must be taken as 0.5 times the 1 in 1 year ARI peak discharge. The potential environmental risk is discussed in Acceptable Solution A1(a), and is summarised in Table 5.1 of Chapter 5 Preparation of plans. 213

228 Urban Stormwater Quality Planning Guidelines Acceptable Solution A52(c) A supplementary sediment trap is a minor sediment trap, such as grass filter strips and most kerb inlet sediment traps, that is not effective enough to be classified as Type 3 sediment trap. Refer to Table of Chapter 4 Design standards and technique selection. Acceptable Solution A52(d) Such plans must appropriately verify the basin s dimensions, surface level elevation, and surface area (Type C basins) and/or volumes (Type F and Type D basins) comply with the approved design drawings. Acceptable Solution A53(a) Compliance with this clause means that no sediment control system is utilised if another more appropriate system (of equivalent treatment standard, i.e. Type 1, 2 or 3) is available. This means that straw bale sediment traps (appropriately wrapped in filter cloth) must not be used unless site conditions prevent the use of any other more appropriate sediment control systems. Acceptable Solution A53(b) This means that the catchment area of a sediment basin is not grubbed of vegetation, or stripped of topsoil, until the basin is fully constructed and operational. Acceptable Solution A53(d) This means that sediment control within a development site does not rely on the operation of an off-site sediment trap such as a downstream, council-operated, gross pollutant trap, or other stormwater treatment system. Acceptable Solution A53(e) This means that independent of the required sediment control standard within a given subcatchment, the following actions are taken: all reasonable and practicable measures are taken to utilise additional sediment traps of an equivalent or lower efficiency (including supplementary sediment traps) throughout the subcatchment every reasonable and practicable opportunity is taken to trap sediment as close to its source as possible. Acceptable Solution A53(f) This does not mean that sediment traps should be placed in inappropriate locations; an inappropriate location being one where existence of the sediment trap would likely result in the hydraulic failure of the sediment trap, or unacceptable soil erosion during moderate to heavy rainfall. Acceptable Solution A53(h) This clause means that sediment traps are not designed to simply divert sediment and sedimentladen waters away from stormwater inlets. Compliance with this clause includes the following actions: i. Wherever practical, sediment fences are located along the contour to maintain sheet flow conditions down-slope of each fence. Where this is not practical, regular returns are utilised to allow water to pond at regular intervals along the length of the fence ii. Acceptable Solution A55(a) Adopted roadside kerb inlet sediment traps are appropriate for the type of inlet (i.e. sag or on-grade), for further discussion refer to Principle 8.14 in Chapter 2 Principles of erosion and sediment control. 214

229 Urban Stormwater Quality Planning Guidelines The intent of this clause is to minimise the quantity of water that needs to be de-watered from excavations and trenches. Thus, if water does not need to be de-watered from such areas, then the clause does not apply. Acceptable Solution A55(b) Current (2008) best practice sediment control standards for de-watering activities are outlined in Table of Chapter 4 Design standards and technique selection. Alternatively, Table of Chapter 4 presents a water quality standard for de-watering operations based on Nephelometric Turbidity Units (NTU). Appropriate sediment controls placed down-slope of material stockpiles during the de-watering of such stockpiles are summarised in Table of Chapter 4 Design standards and technique selection. Acceptable Solution A55(c) The potential environmental risk is discussed in Acceptable Solution A1(a), and is summarised in Table 5.1 of Chapter 5 Preparation of plans. 12 Site stabilisation and rehabilitation Acceptable Solution A57(a) Current (2008) best-practice site rehabilitation standards are presented in Table of Chapter 4 Design standards and technique selection. Unless otherwise stated by the relevant Regulatory authority, the potential erosion risk shall be based on the rating outlined in Table of Chapter 4. Acceptable Solution A58 Data collection necessary to assist the design of site revegetation is outlined in Sections C3 and C9 of Appendix C Soils and revegetation. Acceptable Solution A59(a) Temporary revegetation conducted for the purpose of erosion control must be conducted in accordance with a Site Stabilisation Plan, Landscape Plan, Revegetation Plan, or Vegetation Management Plan, where such a plan specifically refers to such activities. Acceptable Solution A59(b) The type of permanent vegetation applied to completed earthworks must be compatible with the anticipated long-term land use, current and ongoing erosion risk, environmental requirements (including weed control), and associated components of the site rehabilitation. Acceptable Solution A59(c) A manageable drainage area refers to an area of open soil that can be managed (at any given time) within the limits of the specified ESC treatment standard without the need for the placement of erosion control measures (e.g. mulching) on any part of the soil. On a well-managed site, it is typical for a manageable drainage area to consist of a series of sub-areas interconnected by temporary or permanent drainage channels. A sub-area is an area within a given subcatchment fully contained within a set of drainage control structures designed to minimise the risk of rill erosion within that area. Acceptable Solution A60(a) Compliance with this clause required compliance with Performance Criterion P37. Unless otherwise directed by an approved Site Stabilisation Plan, Landscape Plan, Revegetation Plan, or Vegetation Management Plan, topsoil should be placed at a minimum depth of 75 mm on slopes 4:1 (H:V) or flatter, and 50 mm on slopes steeper than 4:1. 215

230 Urban Stormwater Quality Planning Guidelines Further discussion on soil preparation and treatment prior to planting is provided in Appendix C Soils and revegetation. Performance Criterion P61 Local environment includes local wildlife. 13 Site inspection and monitoring Acceptable Solution A62 Personnel preparing and/or supervising the preparation of the Monitoring and Maintenance Program must, collectively, have all of the following capabilities: i. an understanding of the local environmental values that could potentially be affected by the proposed works ii. a good working knowledge of the site s ESC issues, and potential environmental impacts, that is commensurate with the complexity of the site and the degree of environmental risk iii. a good working knowledge of current best practice ESC measures appropriate for the given site conditions and type of works iv. a good working knowledge of the correct installation, operational and maintenance procedures for the full range of ESC measures used on the site. Refer to A1(a) for discussion on potential environmental risk. Acceptable Solution A63(a) Discussion on scheduling and conducting site inspections by internal and external parties is provided in Chapter 7 Site inspection. In those instances where specific site monitoring stations are identified within the monitoring and maintenance program, then: during periods of water discharge from the site, water quality samples are collected at each monitoring station at least once on each calendar day until such discharge stops a minimum of three (3) water samples are taken and analysed, and the average result used to determine quality. Sediment basin water quality samples are taken at a depth no greater than 200 mm above the top surface of the settled sediment within the basin. Current (2008) best-practice procedures for high-risk sites, requires regular ESC audits to be: v. undertaken by a person suitably qualified and experienced in erosion and sediment control that can be verified by an independent third-party (this person must not be an employee or agent of the principal contractor) vi. conducted on the next business day following a rainfall event in which greater than 10 mm of rainfall has been recorded by the Bureau of Meteorology rain gauge nearest to the site vii. conducted at intervals of not more than one (1) calendar month commencing from the day of site disturbance until all disturbed areas have been adequately stabilised against erosion to the acceptance of the relevant Regulatory authority viii. conducted using an appropriate Site Inspection Checklist. High-risk sites are work sites that do either of the following: satisfy the requirements of a high-risk site as defined by either the State or local government 216

231 Urban Stormwater Quality Planning Guidelines satisfy the requirements of those risk categories greater than high-risk (such as extremerisk) where such categories have been defined (i.e. score a hazard rating equal to or greater than the critical hazard value ). Discussion on the assessment of erosion hazard and site risk assessment is presented in Chapter 3 Site planning, and Appendix F Erosion hazard assessment. ESC audits must include, as a minimum, all of the following: copies of all original site inspection checklists non-conformance and corrective action reports sediment basin water quality and site discharge water quality monitoring results a plan showing the areas of completed soil stabilisation rainfall records including date and rainfall depth. Acceptable Solution A64 Discussion on scheduling and conducting of site inspections is provided in Chapter 7 Site inspection. 14 Site maintenance Performance Criterion P65 Proper working order includes maintaining the required hydraulic capacity and operational effectiveness. Acceptable Solution A65(b) Current (2008) best practice requirements for the maintenance of sediment control devices requires these devices to be maintained and made fully operational as soon as reasonable and practicable in accordance with Table 6.1 of Chapter 6 Site management. The top of a sediment basin s sediment storage volume must be clearly identified by the horizontal member of a marker post (cross). 217

232 Urban Stormwater Quality Planning Guidelines Appendix 2 Model erosion and sediment control plans 1 Introduction This appendix provides model erosion and sediment control plans (ESCPs). These model ESCPs are presented to demonstrate how ESC measures can be organised on various types of construction sites to control soil erosion and sediment run-off. The ESCPs primarily illustrate the drainage and sediment control measures. Landscaping and erosion control measures would normally be detailed within technical notes of associated contact documents. The following ESCPs demonstrate just one method of controlling soil erosion and sediment runoff within each site. It should not be implied that the ESCPs present the only acceptable method of managing each site. Due to the restrictions caused by presenting these example plans on A4-sized paper, the attached plans are not representative of actual ESCPs. An acceptable ESCP for each of these sites would need to be presented on an appropriately sized plan that allows adequate presentation and interpretation of all necessary information. This appendix is based on Appendix D Example plans, IECA 2008, Best practice Erosion and Sediment Control, International Erosion Control Association (Australasia), Picton NSW. 2 Example 1: Construction of university accommodation units Site description The site is covered with both native and non-native vegetation. The site receives flow from an 18 hectare catchment to the north-east. At present there exists minimal erosion on the site, however, the drainage gully has experienced some erosion as a result of recent developments within the catchment. Downstream of the site the overland flow path develops into a creek with defined bed and banks. Base flow exists in this creek for a number of days following rain. The creek discharges into a tidal river that eventually discharges into a bay. There are no wetlands downstream of the creek. Both the creek and the river have recognised environmental values, and both have a high potential for rehabilitation. The site is surrounded by medium density, private residential areas (north and east), university accommodation developments to the south, and the main university campus to the west. A timber perimeter fence has already been constructed around the site. The accommodation units will be constructed on a raised slab that will require little or no cut and fill earthworks. 218

233 Urban Stormwater Quality Planning Guidelines Soils information Geotechnical investigations of the site reveal that the topsoil consists of a low fertility, nondispersive, dark sandy loam with depths varying from 100 mm to 200 mm. Subsoils comprise a reddish clay loam (20 per cent finer than 0.02 mm) with low permeability and medium to high erodibility (assume K-factor = 0.03).and are non-dispersible. Some rock outcrops do exist, however no groundwater problems are anticipated. Explanatory notes 1. The attached plans are representative of the type of information that could be supplied in the supporting documentation to describe the construction sequence and the options considered for the development of the site s major sediment trap. Small A4-plans like these that complement the main A1-ESCP can be an effective way of communicating with construction personnel. 2. One of the principle aims on this site is to minimise the loss of existing vegetation, thereby allowing the accommodation units to integrate into the existing environment. Consequently, considerable effort has been placed on minimising site disturbance. 3. Figure A2.3 (Drawing No. A-001) demonstrates the importance of the early installation of the main pipeline to divert external catchment through the site prior to major land clearing and earthworks. 4. The entry exit point, stockpile area and the temporary access road are located in a position to minimise overall site disturbance. 5. The site office is located close to the site entry point and up-slope of the stockpile area thus reducing the potential for sediment-laden water to flow past the site office and car park. 6. The temporary watercourse crossing (TCC-1) will consist of a length of steel pipe installed under the access roadway to allow drainage of the upper catchment to pass under the roadway. 7. All sediment fences that are not installed along a line of constant elevation will contain returns at a spacing not exceeding 20 metres. 8. Figure A2.4 (Drawing A-002) demonstrates option 1 for the installation of a sediment basin. This option would result in major land clearing down-slope of the permanent site entry road. Due to space limitations, the sediment basin s embankment would need to be formed from gabions. A gabion outlet would be expensive to build and would reduce the basin s ability to control turbidity levels (that is,the basin would only represent a type-2 sediment trap). This option may also not provide the required basin surface area. In this option, a temporary sediment fence (SF-1) would have initially been installed instead of the proposed sediment weir (SW-1). 9. Figure A2.5 (Drawing A-003) demonstrates an alternative sediment basin (option 2). This option uses the construction of the raised internal road to form the main embankment. Drainage pit 3/1 would act as the riser pipe outlet structure if a type-c (dry) sediment basin is required, otherwise the pit will be sealed to allow the operation of a type-f (wet) basin (subject to discharge objectives for example, if clay content is significant, high turbidity levels are likely from a type-c basin.) The sediment weir (SW-1) would collect and treat any run-off from the lower end of the site that cannot be directed into the sediment basin. The efficiency of this sediment trap (SW-1) would be significantly reduced by the inflow of water from the external catchment discharging from the main pipeline. A sediment weir has been chosen because of its ability to withstand concentrated flow discharged from the pipeline. For the purpose of this example, this option 2 was chosen (subject to basin design criteria and spillway requirements). 10. Figure A2.6 (Drawing A-004) demonstrates a multiple sediment basin option (option 3). Sediment basin SB-2 would be sized (subject to size design criteria) in accordance with 219

234 Urban Stormwater Quality Planning Guidelines option 2 above. Sediment basin SB-3 would be sized to treat run-off only from the lower end of the site. The main pipeline would be temporarily extended through SB-3. The cost of constructing option 3 would be significant; however, it would provide the greatest opportunity to reduce turbidity levels within the site run-off. In this option, a sediment fence (SF-1) would have initially been installed instead of the proposed sediment weir (SW-1). 11. Sediment fence SF-3 would be optional depending on the risk of failure of catch drain CD It is assumed in this example that sediment fences SF-4 and SF-5 will be installed up against the existing property boundary fence and that this fence is strong enough to take the extra loading. If no property fence existed, then the sediment fences should be relocated along the lower edge of the proposed land clearing. If high sediment run-off rates were expected from the building of the accommodation units, then locating the sediment fences closer to the building works (rather than along the property boundary) would be preferable to reduce sediment deposition within the retained bushland. 13. All stormwater gully inlets will be sealed to prevent inflow until the site is stabilised. 14. During construction of the internal roads, the flow diversion bank (DB-1) would be formed as a temporary bank at the end of each day s work and prior to storm events to direct runoff from the roadway into the sediment basin. After completion of the road works, the flow diversion bank would be constructed as a temporary speed control device to continue to deflect run-off into the basin. Thus the flow diversion bank would be formed in a layer of heavy-duty filter cloth to assist in its eventual removal from the roadway. 15. Sediment fences SF-6 and SF-7 are installed prior to construction of units F and G to both minimise sediment run-off into the retained bushland between the units and the downslope sediment weir, and to trap sediment as close to its source as practical. In this case, trapping sediment as close to its source as practical is important given the limited ability of the sediment weir to control turbidity levels. Of course each site is different and thus the need for these two sediment fences would depend on actual site conditions. To do this, there is a need to look at the development in its entirety for example, what happens after civil works are complete and building commences? Will the sediment basin become a biofiltration basin? This may influence its siting. 220

235 Urban Stormwater Quality Planning Guidelines Installation sequence 16. The following installation sequence is based on sediment basin option 2 as shown in Figure A2.5 (Drawing A-003). Item Drawing Installed Removed Mark out initial limits of disturbance A-001 Prior to site disturbance Exit-1 A-001 Day one When permanent internal roads are sealed Clear access track to SF-1 A-001 After installing Exit-1 SW-1 A-001 After access track establishment. After installing SB-1 TCC-1 A-001 After SW-1 When constructing the permanent driveway Clear site office, pipeline and stockpile area A-001 After SW-1 SF-2 A-001 After clearing area After site stabilisation or as necessary to build Units A1-A4 Install site office A-001 After clearing area Install pipeline No. 1 A-001 After SW-1 SB-2 A-003 After installing the main pipeline After stabilising the site following completion of all Units SF-3 A-003 After SB-2 After site stabilisation SF-4 A-003 After SB-2 After site stabilisation SF-5 A-003 After SB-2 After site stabilisation CD-1 A-003 After SF-3 Roads and drainage A-003 After CD-1 DB-1 A-003 At end of each day and prior to storms After site stabilisation Bank stabilisation A-003 Upon completion of earthworks SF-6 A-005 Before constructing Unit G After site stabilisation SF-7 A-005 Before constructing Unit F After site stabilisation 221

236 Urban Stormwater Quality Planning Guidelines Figure A2.1 Development proposal Figure A2.2 Site drainage prior to development 222

237 Urban Stormwater Quality Planning Guidelines Figure A2.3 Site establishment and drainage works Figure A2.4 Option 1 for establishment of a sediment basin 223

238 Urban Stormwater Quality Planning Guidelines Figure A2.5 Option 2 for establishment of a sediment basin Figure A2.6 Option 3 for establishment of a sediment basin 224