Green Square Stormwater Drain Decision Report

Transcription

1 Green Square Stormwater Drain Decision Report July 2014 Sydney Water Green Square Stormwater Drain Decision report Page 1

2 Sydney Water Corporation (2014). Commercial in Confidence. All rights reserved. No part of this document may be reproduced without the express permission of Sydney Water. File Reference: SWIM://Deliver Projects/Manage Projects/Projects/ Green Square Trunk Drainage/ Green Square Stormwater Drain Decision Report Publication number SW3 07/14 Sydney Water Green Square Stormwater Drain Decision report Page 2

3 Table of contents 1. Introduction Purpose of the Decision report Planning approval framework Summary of the project from the REF Changes to the project Consultation Project development and REF preparation REF public exhibition Submissions Further consultation Submissions Formal submissions Consideration of issues Legislation and planning context Scope of work Flooding Topography, geology and soils Water and drainage Groundwater Flora and fauna Heritage Traffic and access Community and stakeholder consultation Construction Environmental Management Plan Summary of mitigation measures Conclusion Justification of the project Determination of the project Recommendation References Glossary and abbreviations Appendix 1 Community and stakeholder communications...38 Appendix 2 Submissions...41 List of Figures Figure 1: The Project as described in the REF... 6 List of Tables Table 1: Summary of issues raised in submission...10 Table 2: Summary of mitigation measures...26 Sydney Water Green Square Stormwater Drain Decision report Page 3

4 1. Introduction The Green Square Stormwater Drain (GSSD) is a new stormwater drainage system to be built in partnership by Sydney Water and the City of Sydney Council. Located about 3.5 km south of the city centre, Green Square is one of the City of Sydney s key urban renewal precincts earmarked for development, transforming an industrial area into a village hub and major centre. The broader Green Square Urban Renewal Area will accommodate about 40,000 new residents and 22,000 new workers by The Green Square Town Centre (GSTC) is located on a flood plain. The area currently experiences major flooding at both Joynton Avenue and Botany Road. City of Sydney has done a number of flood management investigation studies since 2008, culminating in the Green Square Trunk Drain Concept Design (May 2013), which has led to this project. The project provides for a stormwater drain to carry the flow from the entire catchment, upstream of Joynton Avenue, to discharge into Alexandra Canal. It considers amplifying and re-directing an existing stormwater drain from Link Road to Joynton Avenue and providing a new stormwater drain from Joynton Avenue to Alexandra Canal. We will create about 2.4 km of new stormwater drain. Buildings that are likely to be demolished to construct the GSSD include 140 Joynton Avenue, the City of Sydney portion of the Waverly Council Depot, 334 Botany Road and Botany Road. The project objectives are to: reduce the flood risk to the future community of GSTC from Joynton Avenue and Botany Road achieve zero or minimal ponding at Joynton Avenue in a 20 year average recurrence interval (ARI) flood event significantly reduce ponding at both Joynton Avenue and Botany Road in a 100 year ARI event manage the flood risk at the Epsom Park Precinct and the Mid-block Precinct by capturing and transferring a 20 year ARI pipe flow from these future developments. Sydney Water completed the Review of environmental factors (REF) for the project in April The REF concluded that the project is unlikely to have a significant impact on the environment. Sydney Water exhibited the REF from 28 April to 23 May We invited community members and other interested stakeholders to comment on the project. The closing date for submissions was 23 May We received nine submissions following the public exhibition of the REF. The main issues raised included flood mitigation in the wider catchment, potential groundwater impacts during construction and operation, and cumulative temporary traffic impacts. This Decision report responds to the submissions made. 1.1 Purpose of the Decision report This Decision report: considers the issues raised in the submissions identifies and assesses whether any changes to the project are required, based on the submissions identifies whether any new mitigation measures, or changes to existing mitigation measures, are required Sydney Water Green Square Stormwater Drain Decision report Page 4

5 recommends whether Sydney Water should proceed with the project. 1.2 Planning approval framework The Environmental Planning and Assessment Act 1979 (EP&A Act) provides the statutory context for the project s environmental assessment. We are assessing and determining the project under Part 5 of the EP&A Act, with Sydney Water the determining authority. The State Environmental Planning Policy (Infrastructure) 2007 allows Sydney Water to complete the project without development consent from City of Sydney. The REF assessed the potential environmental impacts associated with constructing and operating the GSSD. We considered potential impacts against the matters listed in clause 228 of the Environmental Planning and Assessment Regulation 2000 (EP&A Regulation). Our assessment concluded that it is unlikely that the project will have a significant impact on the environment. We have not changed this conclusion after considering the submissions, so an environmental impact statement is not required. 1.3 Summary of the project from the REF The project and proposed activities are unchanged from those described in section 4 of the REF, The proposed alignment for the 2.4 km stormwater drain is made up of six sections (A to G), with two alternative alignments between Maddox Street and O Riordan Street, as shown in Figure 1. The GSSD project involves: constructing a 2.4 km large stormwater drain from Link Road, Zetland to Alexandra Canal (up to 6.5 m wide and 1.8 m deep) by open trenching or trenchless technologies installing associated infrastructure including: o a stormwater quality improvement device o drainage pits and stubs for existing and future drainage connections o high capacity inlet pit structures at Joynton Avenue o energy dissipation structure at the outlet of the stormwater drain in Alexandra Canal demolishing City of Sydney buildings on the alignment. 1.4 Changes to the project Sydney Water has not changed the project since public exhibition of the REF. However, we have provided additional information in this Decision report, including: explaining the Flood Risk Management process (Chapter 4) responding to submissions adding several new mitigation measures to address issues raised in submissions (see Chapter 5, Table 2). Sydney Water Green Square Stormwater Drain Decision report Page 5

6 Figure 1: The project as described in the REF Sydney Water Green Square Stormwater Drain Decision Report Page 6

7 2. Consultation Sydney Water developed a communications strategy to ensure that the local community and key stakeholders are given clear, accurate and timely information during the project s various stages. We identified key stakeholders according to their interests or the project s potential impacts. As part of this communications strategy, we consulted with the local community and key stakeholders while preparing and exhibiting the REF. This Decision report documents our responses to issues raised in this consultation, focusing on submissions made during public exhibition of the REF. The following sections describe the consultation Sydney Water has already done and consultation we propose to do. 2.1 Project development and REF preparation While preparing the REF and developing the project, we: wrote to customers near the proposed route about the project and the environmental studies, site inspections, surveys and geotechnical investigations we were doing in the local area to support the REF put information about the project on Sydney Water s and City of Sydney s websites set up a community information line and project address. 2.2 REF public exhibition The REF was on public exhibition from 28 April to 23 May 2014 at the following locations: City of Sydney Customer Service Centre, Town Hall House, 456 Kent Street, Sydney Green Square Library, 100 Joynton Avenue, Zetland Sydney Water website sydneywater.com.au Sydney Water Talk sydneywatertalk.com.au We invited the community and stakeholders to provide comments or submissions on the project by 23 May During public exhibition of the REF, Sydney Water consulted with the community and stakeholders and invited comments and submissions by: advertising the REF public exhibition and information sessions in the local newspapers, the Southern Courier and in the Inner West Courier on Tuesday 29 April 2014 and in the Sydney Morning Herald on Monday 28 April delivering 4,000 newsletters to local residents through a letterbox drop. These informed the community about where to get information including the two drop in sessions and how to give feedback. attending the City of Sydney s two community drop in sessions at Green Square Markets on 10 May 2014 (10 am 1 pm) and at City of Sydney s Green Square Have Your Say Day on 17 May 2014 (10 am 2 pm). Sydney Water and City of Sydney representatives attended to talk about the project and answer questions. We had information available at these sessions, including printed copies of the REF, a fact sheet with photographs, images and maps of the project. Sydney Water Green Square Stormwater Drain Decision Report Page 7

8 placing the REF and other project information on the Sydney Water Talk website (sydneywatertalk.com.au) mailing a letter and newsletter to 17 directly impacted and nearby property owners ing known groups that use Perry Park, for example Redfern Red Sox and Ecuadorian walking group mailing copies of the REF to key stakeholders. We sent 11 hard copies and 10 electronic copies to the following stakeholders: o City of Sydney o Transport for NSW, including Rail Corp and Roads and Maritime Services o NSW Office of Water o Fisheries NSW o Environment Protection Authority o NSW Office of Environment and Heritage o Heritage Council (OEH) o Department of Planning and Environment o NSW Trade and Investment (Crown Lands). Following the exhibition of the REF, Sydney Water has prepared this Decision report to address the issues raised in submissions. We will distribute it to stakeholders who made a submission. 2.3 Enquiries and submissions Sydney Water received the following enquiries and submissions in response to the REF: 10 calls to the community information line seven s to the project address over 60 attendees at the two information sessions nine submissions from stakeholders. Overall, the community and stakeholder feedback received was positive. Most people we spoke to support the project. Many local residents told us they have experienced flooding in the local area and would support the project if it will alleviate the flooding. Some residents expressed concern about the cumulative construction impacts from to the amount of development occurring in the area. A particular concern is increased traffic. We also had a query from the Alexandria Residents Action Group about whether the project will increase flooding in their area, which is to the north and west. Representatives of Sydney Water and City of Sydney presented to this group on 11 June 2014, answering their questions in that forum. Chapters 3 and 4 address issues raised in these enquiries and submissions. Appendix 2 includes copies of the submissions received. Sydney Water Green Square Stormwater Drain Decision report Page 8

9 2.4 Further consultation Sydney Water and the City of Sydney are committed to informing and consulting the community and stakeholders, we will continue to consult throughout the project s design, construction and operation. This will ensure the community and stakeholders are kept informed and that we understand their issues and concerns. The Alliance will develop and implement a community and stakeholder engagement plan for the detailed design and delivery phases of the project, in line with Sydney Water s Communications strategy and stakeholder engagement policy. The Alliance must keep the community informed throughout construction and manage issues and complaints. After commissioning, Sydney Water s standard policies and procedures for customer and community relations will apply. Sydney Water Green Square Stormwater Drain Decision report Page 9

10 3. Submissions This chapter summarises the submissions we received, in response to public display of the REF. 3.1 Formal submissions We received nine formal written submissions from government agencies and stakeholders, raising issues and comments about the project. We have summarised and addressed all the issues raised in the submissions. We identified 47 issues or comments from the submissions. Table 1 outlines these issues and comments, categorised by topic and author. Our responses to these submissions are provided in Chapter 4. The more common issues relate to flood mitigation, groundwater and traffic. We have listed general comments and support for the project in Table 1, but these are not addressed in Chapter 4. Table 1 also notes requests for information. We will meet these requests as we develop the information, during the next stages of the project, as part of our commitment to stakeholder and community consultation. Copies of the submissions received are included in Appendix 2. We have omitted the names and addresses of private individuals and community members, as required by the Privacy Act s, phone calls and the drop in sessions did not raise any additional issues. Table 1: Summary of issues raised in submission No. Issue/comment Submission /agency Location where issue addressed in this report. General 1. EPA considers that the potential environmental impacts of the project have been adequately addressed in the REF. EPA Noted. 2. The Heritage Council notes the REF generally addresses the potential impacts that the works will have on heritage within the proposed route. The Heritage Council Noted. 3. Submission 7 supports the GSSD project and would like to collaborate with Sydney Water to investigate mutually beneficial outcomes in terms of design and timing. Submission 7 Noted. 4.1 and The City of Sydney supports this project and understands that the objective is to reduce the risk of flooding in the Green Square Town Centre, particularly at Joynton Avenue and Botany Road. The City of Sydney acknowledges that the project is critical to enable the future development of the Green Square Town Centre and the surrounding areas. City of Sydney Noted. Legislation and planning context 5. The REF states (page 15) that a S139 permit under the Heritage Act is required for an activity that is likely to result in an item of non-aboriginal cultural significance being discovered, exposed, moved, damaged or destroyed. This is not correct. Section 139 of the Heritage Act only speaks in terms of protecting relics. It does not protect all items of non-aboriginal cultural significance. Heritage Council 4.1 Sydney Water Green Square Stormwater Drain Decision report Page 10

11 6. Heritage Council recommends that Sydney Water seek approvals under Section 139 and Section 60 of the Heritage Act, as work may impact both historical archaeology and the Alexandra Canal. Depending on the impacts on of these works on this heritage, it may be that Sydney Water will not be able to determine the Section 60 using their Heritage Council delegation. Heritage Council The NSW Office of Water considers the project described, to be an aquifer interference activity according to the definition in the Water Management Act 2000 and recommends the project is conducted according to the NSW Aquifer Interference Policy. NSW Office of Water Before approving the project, Sydney Water must consult with the Office of Water in relation to groundwater and water licensing issues associated with this project. NSW Office of Water Sydney Water requires a licence for temporary construction dewatering activities under Part 5 of the Water Act The Office of Water requests a copy of the Geotechnical Assessment, as part of the documentation supporting the licence application. NSW Office of Water The EPA notes that Sydney Water will consult with the EPA to confirm whether, under the POEO Act 1997, Sydney Water will need an EPL to discharge contaminated groundwater from any localised areas of pollution that are identified during the construction phase of works. EPA Noted. Scope of work 11. Submission 7 appreciates the opportunity to discuss staging, with a view to integrating the developments and minimising duplicated costs to Sydney Water and the developer. The submission notes that construction of section A in 2016 would be the best solution to meet their proposed development program. They would like the opportunity to understand Sydney Water s program and work together to define a mutually acceptable program. Submission City of Sydney requests that the REF nominates the location of construction compounds, work sites and concrete batching plans. Sections and 4.5 of the REF provide general references as to where these are likely to be located. However, the City of Sydney recommends that Sydney Water nominates the locations and assesses them for environmental impacts. Sydney Water may do this in the Construction Environmental Management Plan, provided that the environmental impacts are known and mitigated measures are nominated, where required, within the REF. City of Sydney 4.2 Flood mitigation 13. OEH comments that the most appropriate method to assess the development of flood prone land is through the floodplain risk management process, detailed in the NSW Government s Floodplain Development Manual (2005). OEH OEH comments that the objectives in Section 4.1 of the REF, giving very substantial benefits to the development precincts, have not considered the hydrologic and hydraulic design aspects of the proposed drain. OEH Sydney Water must give further consideration, during the detailed design stage, to the potential downstream impacts (flood risks to neighbouring properties and mobilisation of contaminated sediments) in Alexandra Canal from increased flows to the canal. This should include liaison with the EPA and the Office of Environment and Heritage. EPA OEH recommends that Sydney Water identifies the downstream hydraulic impact of the works and minimises, and/or satisfactorily manages this, for both Alexandra Canal and other areas draining to the canal. OEH 4.3 Sydney Water Green Square Stormwater Drain Decision report Page 11

12 17. To understand the impact of the GSSD on overland flow, Submission 7 seeks Sydney Water input and support for its proposed development program to recalculate the flood study as part of their Stage 2 DA to be submitted in mid to late Submission 7 asks for Sydney Water input to their studies and a collaborative approach to expedite a solution for the local area and their site. Submission The proposed drain has been conceived to very significantly reduce flooding at Epsom Park and Green Square in the event of a 20 year or 100 year ARI flood event. The designers will be aware that larger floods than the 100 year event will occur. OEH 4.3 OEH recommends that detailed design should ensure the safety of people and property for the full range of possible flooding. 19. Public safety is a concern, particularly for special use developments (eg a childcare centre is proposed for Section C and/or D (S5.10.1)) and generally for public spaces situated underground with entrances or services below the level of the PMF. Designs should be failsafe and this could be achieved by structural means or through evacuation planning. OEH The design appears only to consider the needs of development that is currently proposed. OEH recommends Sydney Water consider the floodplain management needs of future development and of those of existing and future users of the floodplain. OEH 4.3 Topography, geology and soils Fisheries NSW asks Sydney Water to send detailed plans of any works to be conducted within Alexandra Canal itself to them before starting construction. Fisheries NSW It requests that the information provided by Sydney Water complies with s.199(1)(a) of the Fisheries Management Act concerning any proposed dredging or reclamation activities. Provided these activities are conducted with appropriate erosion and sedimentation controls and appropriate treatment and disposal of any spoil on land above the mean high water mark, Fisheries NSW has no objections to these works. Water and drainage 22. NSW Office of Water recommends that Sydney Water implement adequate environmental control measures for the operation of the project, to minimise impacts on flows and potential impacts downstream in the Cooks River. NSW Office of Water 4.5 Groundwater 23. The REF notes that where groundwater is likely to be encountered the volumes will be determined, but it is unclear when this detail is to be provided (page 16). NSW Office of Water Sydney Water must provide a clear prediction of the total volumes of groundwater likely to be dewatered, as well as detailed justification and methodologies to support that prediction. NSW Office of Water Depending on the length of time and volumes to be dewatered, it is likely that the Office of Water s preference would be to reinject the groundwater dewatered during construction, back into the Botany Sands Aquifer downgradient of the construction works. NSW Office of Water recommends that the detailed design of the project considers this option. NSW Office of Water The REF indicates the most practical disposal option for groundwater is to discharge to stormwater (p44), but it notes that the DMP will outline how the project will manage groundwater discharge during construction. NSW Office of Water The Office of Water asks Sydney Water to provide a copy of the Dewatering Management Plan for them to review and assess before the plan is finalised. NSW Office of Water The REF correctly notes that baseline groundwater monitoring (level and flows) NSW Office 4.6 Sydney Water Green Square Stormwater Drain Decision report Page 12

13 will be required before construction commences. The Office of Water would like to review and comment on the proposed baseline monitoring program. of Water 29. The Office of Water asks Sydney Water to provide them a copy of the results of the baseline monitoring. NSW Office of Water The REF notes that Sydney Water will manage operational impacts on groundwater by considering appropriate underlay materials to allow groundwater to drain beneath the stormwater drain where it is anticipated to act as a barrier to groundwater flow (page 47). The Office of Water asks for further details on this mitigation measure. NSW Office of Water The stormwater drain is anticipated to act as a barrier to groundwater flow with potential up-gradient flooding impacts, and for this reason Office of Water recommends that Sydney Water monitor groundwater both up gradient and down gradient of the stormwater drain to mitigate operational impacts and ensure that he groundwater is draining beneath the drain. NSW Office of Water 4.6 Groundwater levels may need to be monitored for a period during the operational phase of the project to confirm that the pipeline is not leading to unintended groundwater level impacts. 32. NSW Office of Water recommends that Sydney Water liaises with the EPA regarding groundwater quality issues associated with the project. NSW Office of Water Noted. Flora and fauna 33. Fisheries NSW (ph ) requests that Sydney Water immediately notify both them and OEH (ph ) of any fish kills near the works. In these cases, all works other than emergency response procedures are to cease until the issue is rectified and Fisheries NSW or OEH issues written approval to proceed. Fisheries NSW 4.7 Heritage 34. Heritage Council requests that Sydney Water contacts them to discuss any potential issues before lodging any approval applications that assess heritage impacts. Heritage Council Heritage Council recommends that Sydney Water update Table 16 (section 5.7.2) of the REF to include Alignment Section G and note that a Section 60 will be required to impact Alexandra Canal. Heritage Council 4.8 Traffic 36. Roads and Maritime Services (RMS) requests Sydney Water provide detailed methods for crossing the RMS controlled roads, Botany Road and O' Riordan Street, to RMS for review. RMS 4.9 Transport for NSW recommends that work should not restrict existing pedestrian and cycle desire lines and accessibility. Proposed detours should: Transport for NSW 4.9 facilitate connection and access for all users 37. incorporate Disability Discrimination Act (DDA) compliance providing sufficient width and a surface free of trip hazards, especially noting the use of wheel chairs provide a safe environment, considering Crime Prevention Through Environmental Design, (CPTED) guidelines. 38. Transport for NSW comments that temporary pedestrian paths should also consider safe passage for persons in wheel chairs. Transport for NSW 4.9 Sydney Water Green Square Stormwater Drain Decision report Page 13

14 39. Transport for NSW comments that the Bourke Street cycle facility is an identified Strategic Bicycle Corridor, and notes that the requirement for bike riders to dismount on Strategic Bicycle Corridors detracts from the objectives set out in the NSW Government s Sydney s Cycle Future. Transport for NSW 4.9 Transport for NSW recommends that if the Bourke Street cycle facility requires closure, Sydney Water should identify an alternative option that: Transport for NSW maintains desired lines, operation, safety, connection and accessibility (through detour to local streets or providing a time-managed control arrangement, should bike riders need to use the road system) is in operation at all times doesn t limit functionality. 41. Transport for NSW requests that when Sydney Water reinstates cycle way facilities, they ensure that all surfaces and transitions to existing conditions are smooth and free of obstructions. All cycle way signs, symbols, pavement colour treatments and line markings must be reinstated as per the relevant standards and guidelines. Transport for NSW Transport for NSW recommends that Sydney Water identifies potential construction impacts to regular bus services and bus facilities operating on roads near the work site. This should include details of service rerouting, road closures or changes, and impacts to pedestrian access to public transport infrastructure. Sydney Water should clearly explain the duration and implementation of any impacts and mitigation measures. Transport for NSW Transport for NSW recommends Sydney Water consults with bus operators, about any impact on buses operating near the site. Transport for NSW Agreed and noted Community and stakeholder consultation 44. Heritage Council requests they be included as a key external stakeholder (Section 1.3.1), as Sydney Water will require approval for any works that impact Alexandra Canal or and historical archaeology along the route of the stormwater drain. Heritage Council Submission 7 requests information to help them understand the impact of the proposed works and the staging on the existing business, if residential development has not commenced before the GSSD works. Submission 7 recognises that Sydney Water has notified land owners of the works, but would also like to understand the Sydney Water position (development program) as it affects ongoing commercial and industrial activities. Submission Submission 7 seeks an opportunity to discuss permanent access options for residential blocks to allow them to advance their Stage 2 Development Approval for their own development. Submission Construction Environmental Management Plan (CEMP) 47. Transport NSW recommends that Sydney Water completes a CEMP to address issues identified in their submission. Transport for NSW Agreed and noted Sydney Water Green Square Stormwater Drain Decision report Page 14

15 4. Consideration of issues This chapter outlines the issues raised in the submissions received in response to the REF exhibition period. Sydney Water reviewed each submission and identified and categorised specific concerns based on the chapters and issues in the REF. Sydney Water has structured its response to issues raised by presenting the issues raised by submissions in the boxes below and providing Sydney Water s response below each box. 4.1 Legislation and planning context 5. The REF states (page 15) that a S139 permit under the Heritage Act is required for an activity that is likely to result in an item of non-aboriginal cultural significance being discovered, exposed, moved, damaged or destroyed. This is not correct. Section 139 of the Heritage Act only speaks in terms of protecting relics. It does not protect all items of non-aboriginal cultural significance. Agreed the sentence on page 15 of the REF that refers to Section 139 of the Heritage Act should read: In addition, under Section 139, a permit is required for an activity that is likely to result in a relic being discovered, exposed, moved, damaged or destroyed. 6. Recommends that Sydney Water seek approvals under Section 139 and Section 60 of the Heritage Act, as work may impact both historical archaeology and the Alexandra Canal. Depending on the impacts on of these works on this heritage, it may be that Sydney Water will not be able to determine the Section 60 using their Heritage Council delegation. Sydney Water is committed to mitigating potential impacts to heritage during the project. The REF listed a number of mitigation measures to manage heritage impacts. One of the mitigation measures has been refined, as described below, and included in Chapter 5 of this Decision report: works within the curtilage of Alexandra Canal will require a heritage assessment and a permit under Section 57 of the Heritage Act 1977, this permit will be submitted for approval according to Subdivision 1 of Division 3 of the Act. Sydney Water has already committed to seeking an exemption under Section 140 of the Heritage Act, as work may impact relics of historical archaeology, as described in Section 139. As noted in response to item 34, we will consult with the Heritage Council to determine the appropriate approval authority under Section 60 before lodging any permit applications and supporting Statements of heritage impact. Sydney Water Green Square Stormwater Drain Decision report Page 15

16 7. The NSW Office of Water considers the project described, to be an aquifer interference activity according to the definition in the Water Management Act 2000 and recommends the project is conducted according to the NSW Aquifer Interference Policy. 8. Before approving the project, Sydney Water must consult with the Office of Water in relation to groundwater and water licensing issues associated with this project. 9. Sydney Water requires a licence for temporary construction dewatering activities is required under Part 5 of the Water Act The Office of Water requests a copy of the Geotechnical Assessment as part of the documentation supporting the licence application. As identified through geotechnical investigations and described in the REF (Section 2.2), the project will intercept groundwater during construction. Accessing groundwater is still regulated under Part 5 of the Water Act, however is also subject to the NSW Office of Water (NOW) Aquifer Interference Policy, and therefore the project will be conducted according to the Aquifer Inference Policy. During the detailed design phase for the project, and before construction, the Alliance will further investigate groundwater and water licensing issues. This will include determining total groundwater volumes required for construction dewatering. If required, Sydney Water will apply for a water access licence under Part 5 of the Water Act. Sydney Water and/or the Alliance will continue to consult with the Office of Water during detailed design and before submitting any licence applications. We will provide a geotechnical assessment with the licence application. 4.2 Scope of work 11. Submission 7 appreciates the opportunity to discuss staging with a view to integrating the developments and minimising duplicated costs to Sydney Water and the developer. Submission 7 notes that that construction of section A in 2016 would be the best solution to meet their proposed development program. They would like the opportunity to understand Sydney Water s program and work together to define a mutually acceptable program. The GSSD will be constructed in four key stages, to ultimately meet development timeframes: Section F (Perry Park) August 2015 Section C (within the Green Square Town Centre) December 2015 Sections B, D, E and G December 2016 Section A December The timeframe for Section A has been determined to align with redevelopment of the Epsom Park Precinct. It is our understanding that a number of sites around the Epsom Park Precinct are looking to be redeveloped around this time and we will coordinate the delivery of the works to minimise disruption to property owners. As noted in section 4.10, once the detailed design is prepared, we will be in a position to hold further discussions with property owners and developers to identify how the works and program may affect their current business or their proposed development. Sydney Water Green Square Stormwater Drain Decision report Page 16

17 12. City of Sydney requests that the REF nominates the location of construction compounds, work sites and concrete batching plants. Sections and 4.5 of the REF provide general references as to where these are likely to be located. However, the City of Sydney recommends that Sydney Water nominates the locations and assesses them for environmental impacts. Sydney Water may do this in the Construction Environmental Management Plan, provided that the environmental impacts are known and mitigated measures are nominated, where required, within the REF. We will determine the location and number of construction compounds during the detailed design phase when the construction program and methodology are confirmed. The location of these compounds will also be subject to agreement with landowners on the alignment. Mitigation measures identified in the REF will apply to construction compounds, works sites and concrete batching plants, where applicable. We will prepare site-specific environmental management plans that consider environmental impacts for any construction compounds, work sites or concrete batching plants outside the construction corridor. These plans will show the environmental controls we will implement to minimise and mitigate potential environmental impacts. These plans will be approved by the environmental representative before construction. The following mitigation measure has been added in Chapter 5: We will prepare and implement site-specific environmental management plans for any work sites, construction compounds and concrete batching plants 4.3 Flooding 13 OEH comments that the most appropriate method to assess the development of flood prone land is through the floodplain risk management process, detailed in the NSW Government s Floodplain Development Manual (2005). The City Of Sydney prepared the Alexandra Canal Floodplain Risk Management Study and the Green Square - West Kensington Floodplain Risk Management Study according to the NSW Government s Floodplain Development Manual (2005). The Alexandra Canal Floodplain Risk Management Study provides a holistic assessment of existing, future and continuing flood risk and recommends a comprehensive suite of possible mitigation measures including flood modification, property modification and response modification. The Green Square - West Kensington catchment is a subset of the Alexandra Canal catchment and looks at Green Square in greater detail. The City of Sydney displayed the results of this study in The Green Square Stormwater Drain (GSSD) project is a direct recommendation of the above studies. More information is available in the City of Sydney s Green Square Catchment Floodplain Risk Management Plan. The studies and plan are available on the City of Sydney s website: cityofsydney.nsw.gov.au 14. OEH comments that the objectives in Section 4.1 of the REF, giving very substantial benefits to the development precincts, have not considered the hydrologic and hydraulic design aspects of the proposed drain. The hydrologic and hydraulic design of the proposed stormwater drain is currently the subject of an independent validation by specialist consultants engaged by Sydney Water and the City of Sydney. Sydney Water Green Square Stormwater Drain Decision report Page 17

18 The scope of the independent validation includes constructing, establishing and/or confirming catchment models suitable for assessing existing flood behaviour and any reduced flood risk arising from the GSSD. This validation will include detailed reporting on: model establishment, model assumptions, design flood modelling assessment of internal culvert hydraulics. We are also considering an option to develop a physical model of elements of the trunk drain. This information will help confirm the performance criteria applicable to the GSSD that will service the GSTC and surrounding areas, and support the detailed design of the GSSD. 15. Sydney Water must give further consideration, during the detailed design stage, to the potential downstream impacts (flood risks to neighbouring properties and mobilisation of contaminated sediments) in Alexandra Canal from increased flows to the canal. This should include liaison with the EPA and the Office of Environment and Heritage. 16. OEH recommends that Sydney Water identifies the downstream hydraulic impact of the works and minimises, and/or satisfactorily manages this, for both Alexandra Canal and other areas draining to the canal. City of Sydney considered the downstream impacts of the project in the floodplain risk management plan and concept design, (City of Sydney, 2013). The hydraulic modelling of the stormwater drain indicates that there will be minor impacts in the immediate vicinity of the outlet at Alexandra Canal and that these impacts diminish rapidly downstream of the outlet. Figures 9 and 10 from the Green Square Trunk Drain concept design are included in Attachment 3. These show the existing flood extent and proposed option flood extent. We will consider these impacts more during the detailed design phase of the project. As a result it we expect that potential downstream impacts will be managed. We will consult with the EPA and OEH during the detailed designs, regarding potential impacts of the project on Alexandra Canal. 17. To understand the impact of the GSSD on overland flow, Submission 7 seeks Sydney Water input and support for its proposed development program to recalculate the flood study as part of their Stage 2 DA to be submitted in mid to late Submission 7 asks for Sydney Water input to their studies and a collaborative approach to expedite a solution for the local area and their site. We are committed to consulting with the community and stakeholders throughout the project. After development of detailed design, we will further consult property owners and developers to identify how the work may affect any proposed developments. The City of Sydney will also work with developers taking into account the GSSD and can provide assistance with flood planning levels. Sydney Water Green Square Stormwater Drain Decision report Page 18

19 18. The proposed drain has been conceived to very significantly reduce flooding at Epsom Park and Green Square in the event of a 20 year or 100 year ARI flood event. The designers will be aware that larger floods than the 100 year event will occur. OEH recommends that detailed design should ensure the safety of people and property for the full range of possible flooding. The Alexandra Canal Floodplain Risk Management Study and the Green Square - West Kensington Floodplain Risk Management Study, considered the entire flood risk up to the Probable Maximum Flood (PMF) as recommended by the Floodplain Development Manual and the City of Sydney s adopted Interim Flood Management Policy. However, the manual acknowledges that it is not feasible to mitigate the PMF. The Floodplain Risk Management Plan considers the GSSD an acceptable solution to mitigate the predicted 20 year ARI and significantly reduce the risk of flooding for the 100 year ARI event. In addition, these plans include other measures to be implemented in parallel with the GSSD solution, such as property modification and behaviour modification measures to manage the continuing risk. 19. Public safety is a concern, particularly for special use developments (eg a childcare centre is proposed for Section C and/or D (S5.10.1)) and generally for public spaces situated underground with entrances or services below the level of the PMF. Designs should be failsafe and this could be achieved by structural means or through evacuation planning. 20. The design appears only to consider the needs of development that is currently proposed. OEH recommends Sydney Water consider the floodplain management needs of future development and of those of existing and future users of the floodplain. The Alexandra Canal Floodplain Risk Management Study recommends amendments to existing planning instruments to ensure existing controls are consistent and appropriate. The City of Sydney has also adopted an Interim Floodplain Management Policy to guide development until current planning instruments can be amended. This policy requires development to consider safety beyond the flood planning level used to determine finished floor levels and also requires basement entrances to be protected up to the PMF. Incorporating additional flood plain risk management strategies for future development designs is outside the scope of this project, and as noted above, current and future planning controls will be the mechanism to ensure public safety is considered and managed for new developments. The stormwater drain focuses on providing flood mitigation for current redevelopment precincts within the catchment. These precincts represent most of the future development within the catchment that is serviced by the stormwater drain. There will be secondary benefits for existing flood risk, as the existing drainage system will be relieved of some overland flows. We have considered and will continue to consider opportunities to address flood risk outside the development precincts, as part of the holistic water management of the Alexandra Canal stormwater catchment Sydney Water Green Square Stormwater Drain Decision report Page 19

20 4.4 Topography, geology and soils 21. Fisheries NSW asks Sydney Water to send detailed plans of any works to be conducted within Alexandra Canal itself to them before starting construction. It requests that the information provided by Sydney Water complies with s.199(1)(a) of the Fisheries Management Act concerning any proposed dredging or reclamation activities. Provided these activities are conducted with appropriate erosion and sedimentation controls and appropriate treatment and disposal of any spoil on land above the mean high water mark, Fisheries NSW has no objections to these works. Sydney Water will provide copies of detailed plans for work to occur within the Alexandra Canal to Fisheries NSW, before construction. Mitigation measures in the REF, and summarised in Chapter 5 of this Decision report, will ensure any dredging and reclamation work required is completed with appropriate erosion and sediment controls and appropriate waste disposal. Sydney Water notes that Fisheries NSW has no objection to the work as long as we implement appropriate mitigation measures. According to section 199(1)(a) of the Fisheries Management Act, we will notify the Minister of any dredging or reclamation work required, before commencing work. 4.5 Water and drainage 22. NSW Office of Water recommends that Sydney Water implement adequate environmental control measures for the operation of the project, to minimise impacts on flows and potential impacts downstream in the Cooks River. Mitigation measures in the REF (Chapter 5), and listed in Chapter 5 of this Decision report, will ensure potential environmental impacts of flows to the Cooks River are minimised during operation. In addition, we will consider the potential downstream impacts to both Alexandra Canal and the Cooks River during detailed design and in response to any further hydraulic modelling. After the work is done, Sydney Water s standard operating procedures will apply to the new stormwater drain. 4.6 Groundwater 23. The REF notes that where groundwater is likely to be encountered the volumes will be determined, but it is unclear when this detail is to be provided (page 16). 24. Sydney Water must provide a clear prediction of the total volumes of groundwater likely to be dewatered, as well as detailed justification and methodologies to support that prediction. 25. Depending on the length of time and volumes to be dewatered, it is likely that the Office of Water s preference would be to reinject the groundwater dewatered during construction, back into the Botany Sands Aquifer down-gradient of the construction works. NSW Office of Water recommends that the detailed design of the project considers this option. 26. The REF indicates the most practical disposal option for groundwater is to discharge to stormwater (p44), but it notes that the DMP will outline how the project will manage groundwater discharge during construction. Sydney Water Green Square Stormwater Drain Decision report Page 20

21 27. The Office of Water asks Sydney Water to provide a copy of the Dewatering Management Plan for them to review and assess before the plan is finalised. We will investigate and calculate total groundwater volumes required for construction dewatering during the detailed design phase. We will consider options for managing groundwater and choose those to implement, based on predicted flows and water quality. Options will include reinjecting groundwater back into the Botany Sands Aquifer down-gradient of the construction work and discharging to stormwater. We will continue to consult with the Office of Water during detailed design and before work commences. The dewatering option(s) identified will be included in the Dewatering Management Plan, which we will provide to the Office of Water. 28. The REF correctly notes that baseline groundwater monitoring (level and flows) will be required before construction commences. The Office of Water would like to review and comment on the proposed baseline monitoring program. 29. The Office of Water asks Sydney Water to provide them a copy of the results of the baseline monitoring. We have noted this. We are committed to monitoring and minimising potential risks to groundwater and will provide a copy of the baseline monitoring report to the Office of Water, and will continue to consult with the Office of Water during the project. 30. The REF notes that Sydney Water will manage operational impacts on groundwater by considering appropriate underlay materials to allow groundwater to drain beneath the stormwater drain where it is anticipated to act as a barrier to groundwater flow (page 47). The Office of Water asks for further details on this mitigation measure. 31. The stormwater drain is anticipated to act as a barrier to groundwater flow with potential up-gradient flooding impacts, and for this reason Office of Water recommends that Sydney Water monitor groundwater both up gradient and down gradient of the stormwater drain to mitigate operational impacts and ensure that he groundwater is draining beneath the drain. Groundwater levels may need to be monitored for a period during the operational phase of the project to confirm that the pipeline is not leading to unintended groundwater level impacts. As noted in the REF, while the stormwater drain is generally shallow, it may act as a barrier to groundwater flow. Proposed developments as part of the GSTC and surrounding area will modify the ground and include deeper excavations for basements and car parks. These are likely to reduce impacts the stormwater drain may have on long-term groundwater flow. We will confirm construction materials and provide further details for groundwater management during the detailed design phase. This will include investigating potentially permeable construction materials that reduce the potential for groundwater mounding. We have committed to monitoring during construction and commissioning of the project to verify anticipated groundwater impacts. The extent of operational monitoring will be determined by these monitoring results. Sydney Water Green Square Stormwater Drain Decision report Page 21

22 4.7 Flora and fauna 33. Fisheries NSW (ph ) requests that Sydney Water immediately notify both them and OEH (ph ) of any fish kills near the works. In these cases, all works other than emergency response procedures are to cease until the issue is rectified and Fisheries NSW or OEH issues written approval to proceed. The REF (section 5.1.3) requires mitigation measures to prevent water pollution during construction, which in turn will minimise the potential for fish kills. We do not anticipate there will be impacts to aquatic environments and fish kills during construction of the project. According to our environmental management system procedures, we would notify Fisheries NSW and OEH of any fish kills in the vicinity of the work. 4.8 Heritage 34. Heritage Council requests that Sydney Water contacts them to discuss any potential issues before lodging any approval applications that assess heritage impacts. 35. Heritage Council recommends that Sydney Water update Table 16 (section 5.7.2) of the REF to include Alignment Section G and note that a Section 60 will be required to impact Alexandra Canal. We are committed to minimising potential impacts to heritage within the project area. Alexandra Canal is the only listed heritage item to be directly impacted by the project, as the outfall for the GSSD will connect and discharge to the canal. Table 16, which summarises potential impacts to heritage by alignment option, includes Section G Maddox Rd to Alexandra Canal. The recommendation for Section G is to complete a Statement of Heritage Impact and fulfil Sydney Water s internal requirement with regard to delegation of power from the NSW Heritage Council to determine impacts to items on the SHR listed Alexandra Canal. We have committed to preparing a heritage impact assessment and applying for a permit under section 57 of the Heritage Act. We will consult with the Heritage Council to determine the appropriate approval authority under section 60 before lodging any permit applications and supporting Statements of heritage impact. The Statement of Heritage Impact will confirm whether the works and associated activities comply with the conservation policies in the CMP and will identify any additional mitigation measures to protect or minimise impact to the SHR listed - Alexandra Canal, to support the permit application and for inclusion in the CEMP. 4.9 Traffic and access 36. Roads and Maritime Services (RMS) requests Sydney Water provide detailed methods for crossing the RMS controlled roads, Botany Road and O' Riordan Street, to RMS for review. We are committed to minimising potential traffic impacts during construction of the project. We will consult with RMS during detailed design as methods and designs are progressed, and will provide detailed construction methods and traffic management proposals for crossing RMS controlled roads for your review at that time. Sydney Water Green Square Stormwater Drain Decision report Page 22

23 37. Transport for NSW recommends that work should not restrict existing pedestrian and cycle desire lines and accessibility. Proposed detours should: facilitate connection and access for all users incorporate Disability Discrimination Act (DDA) compliance providing sufficient width and a surface free of trip hazards, especially noting the use of wheel chairs provide a safe environment, considering Crime Prevention Through Environmental Design, (CPTED) guidelines. 38. Transport for NSW comments that temporary pedestrian paths should also consider safe passage for persons in wheel chairs. During construction we anticipate be some disruption to existing pedestrian routes and cycle ways next to the GSSD. Where this occurs, pedestrians and cyclists will be temporarily diverted to an alternative path. Section of the REF specifies that temporary pedestrian paths will be wide enough to accommodate two-way movements. This includes safe passing of a pram, free of obstructions. We will also ensure pedestrian paths are wide enough to safely accommodate persons in wheel chairs. We are committed to minimising impacts on pedestrians and cyclists. The construction contractor will be required to incorporate Disability Discrimination Act (DDA) and RMS requirements regarding traffic control and providing pedestrian and cycle paths. 39. Transport for NSW comments that the Bourke Street cycle facility is an identified Strategic Bicycle Corridor, and notes that the requirement for bike riders to dismount on Strategic Bicycle Corridors detracts from the objectives set out in the NSW Government s Sydney s Cycle Future. 40 Transport for NSW recommends that if the Bourke Street cycle facility requires closure, Sydney Water should identify an alternative option that: maintains desired lines, operation, safety, connection and accessibility (through detour to local streets or providing a time-managed control arrangement, should bike riders need to use the road system) is in operation at all times doesn t limit functionality. 41. Transport for NSW requests that when Sydney Water reinstates cycle way facilities, they ensure that all surfaces and transitions to existing conditions are smooth and free of obstructions. All cycle way signs, symbols, pavement colour treatments and line markings must be reinstated as per the relevant standards and guidelines. Where possible, alternative cycle routes will maintain: desire lines, operation, safety, connection and accessibility. The Alliance will identify alternative cycle routes during the development of the detailed design and construction method, and considering other traffic and pedestrian flows. Disruption to the cycle ways will be temporary, during construction of the project. After construction, we will restore cycle ways and pedestrian access ways. Restoration will be carried out according to any council, RMS or other NSW Government requirements regarding traffic control, access and road/footway restoration issues. Sydney Water Green Square Stormwater Drain Decision report Page 23

24 42. Transport for NSW recommends that Sydney Water identifies potential construction impacts to regular bus services and bus facilities operating on roads near the work site. This should include details of service rerouting, road closures or changes, and impacts to pedestrian access to public transport infrastructure. Sydney Water should clearly explain the duration and implementation of any impacts and mitigation measures. 43. Transport for NSW recommends Sydney Water consultants with bus operators, about any impact on buses operating near the site. The existing road network and bus routes are described in Section and Figure 5-8 of the REF. Some road closures and changes will be required during construction. The Alliance will assess impacts and mitigation measures during the detailed design phase of the project, as we develop the construction program. As described in section of the REF we have identified bus operators and Transport for NSW as key stakeholders for the project. The Community and Stakeholder Engagement Plan for the project will detail all consultation requirements and methods for key stakeholders. Bus operators and Transport for NSW will be consulted regarding bus service rerouting and public access impacts before we commence work Community and stakeholder consultation 44. Heritage Council requests they be included as a key external stakeholder (Section 1.3.1), as Sydney Water will require approval for any works that impact Alexandra Canal or and historical archaeology along the route of the stormwater drain. We are committed to community and stakeholder consultation throughout the project, and acknowledge the Heritage Council as a key stakeholder. Section of the REF specifies that we will develop a Community and Stakeholder Engagement Plan (CSEP) for the detailed design and construction of the project. This plan will list key stakeholders and include the Heritage Council. The plan will also detail notification methods to key stakeholders and the wider community. 45. Submission 7 requests information to help them understand the impact of the proposed works and the staging on the existing business, if residential development has not commenced before the GSSD works. Submission 7 recognises that Sydney Water has notified land owners of the works, but would also like to understand the Sydney Water position (development program) as it affects ongoing commercial and industrial activities. 46. Submission 7 seeks an opportunity to discuss permanent access options for residential blocks to allow them to advance their Stage 2 Development Approval for their own development. We are committed to keeping existing businesses informed throughout the project. Project staging for construction is described in Section of the REF and Section 4.3 of this Decision report. We expect to complete detailed design of the GSSD in early to mid Once detailed design is prepared, we will be in a position to discuss with property owners how the works may affect their current business and/or proposed development. Where redevelopment of the property is not proposed to be done before 2017, arrangements will be discussed and negotiated with the relevant party. A number of alternatives may be considered Sydney Water Green Square Stormwater Drain Decision report Page 24

25 which includes staging the construction of Epsom Park, or delaying the delivery of some sections of the culvert indefinitely. These options would need to be tested to ensure that they do not affect flooding levels in the immediate vicinity Construction Environmental Management Plan 47. Transport NSW recommends that Sydney Water completes a CEMP to address issues identified in their submission. As noted in section 6.1 of the REF, we will prepare a CEMP and have it approved before construction starts. This CEMP will include, but not be limited to, the mitigation measures outlined in the REF, and additional mitigation measures identified in this Decision report. Table 2, in the following section includes a full list of mitigation measures. Sydney Water Green Square Stormwater Drain Decision report Page 25

26 5. Summary of mitigation measures We have revised the mitigation measures for the project in response to submissions. Table 2 lists the revised (final) mitigation measures we will implement, with changes highlighted in yellow. Table 2: Summary of mitigation measures Aspect Mitigation measures Stage Topography, geology and soils Install sediment and erosion control devices around work sites to minimise transport of sediment to the stormwater system consistent with the NSW Government s Blue Book (4 th Edition) (Landcom, 2004). Establish sediment and erosion control devices before work begins and maintain them in effective working order throughout the work, until the site is stabilised. Manage stockpiles of soils or fill appropriately to prevent dust, erosion and sediment run-off. Take measures to prevent tracking of soils/sediments from work sites to roadways and footpaths. Sweep up sediment/soil transferred to nearby roadways/footpaths at least daily before rainfall, and re-use them on-site, where appropriate. Place equipment, plant and materials in designated lay-down areas with bunding, where they are least likely to cause erosion or damage vegetation. Stabilise disturbed areas as soon as possible as work is completed. Restore the natural landform of the site(s) as close as possible to the pre-works condition. Monitor adopted site stabilisation and restoration measures for effectiveness and modify them, as required. Compact post construction backfill level across the alignment (including Perry Park) to prevent settlement and uneven surfaces. Prepare and implement site specific environmental management plans for any work sites, construction compounds and concrete batching plants. Prepare an Acid Sulfate Soil Management Plan (ASSMP) to evaluate the existing and potential future environmental impacts relating to ASS material and to detail mitigation, including lime dosing rates, measures to minimise the potential impacts on the environment near the proposed GSSD excavation works. A suitably qualified ASS specialist will prepare the ASS Management Plan. Manage ASS according to the Acid Sulfate Soils Assessment Guidelines (ASSMAC, 1998) Materials specifications will include a requirement that materials are capable of resisting corrosion in ASS or aggressive conditions. Based on the findings of the contamination assessment done for this REF, we will test soils to classify material for disposal according to the DECCW Waste Classification Guidelines. We will induct all site workers to ensure they are aware that asbestos may be present on-site and that if they find any or suspect they have found any asbestos, they must stop work and report it immediately to the site manager and/or manager. The site manager will ensure that a licensed contractor removes all Construction Sydney Water Green Square Stormwater Drain Decision report Page 26

27 Aspect Mitigation measures Stage Water and drainage asbestos contaminated materials. We will conduct validation sampling of the asbestos contaminated material excavation areas and analyse samples for asbestos. Should the soils beneath the asbestos contaminated material be impacted by asbestos fibres, we will excavate those soils and dispose of them appropriately off-site. We will consult with property owners about proposed remediation and validation works, where the project will disturb known contaminated fill or soil. If Sydney Water staff and contractors become aware of pollution incidents that have caused or threaten material harm to the environment, they must notify the Sydney Water project manager who will determine the appropriate course of action to comply with the NSW Protection of the Environment Operations Act We will assess the feasibility of stockpiling excavated materials at appropriate locations, during the GSSD construction, to determine whether we need to test materials on-site before construction begins. If suitable stockpiling areas are available, we could temporarily stockpile the materials and do ex situ validation testing to confirm either suitability for re-use onsite or for off-site waste classification. Constructing the GSSD will avoid disturbing the bed sediments of Alexandra Canal and all works will be completed according to the Alexandra Canal remediation order. Sydney Water will consult EPA during detailed design to ensure we comply with the remediation order. According to s.199 (1) (a) of the FM Act, we will notify the Minister of any dredging or reclamation work required, before commencing this work. Designing and installing energy dissipaters at the head of Alexandra Canal to dissipate outflows from the project. Considering limiting mobilisation through controlled removal of sediments near the head of the canal. Consulting with EPA to ensure continued compliance with the Alexandra Canal Remediation Order. Applying water sensitive urban design planning controls to new developments. We will manage erosion and sedimentation risks according to the Blue Book Managing Urban Stormwater Soils and Construction (Landcom 2004). We will divert all surface run-off away from areas of soil disturbance and stockpiles of erodible material. We will establish erosion and sediment control measures before work begins and maintain them in effective working order during works, until the site has been stabilised to prevent on-site erosion and off-site transport of eroded sediments. We will establish appropriate sediment controls at the entry points to any stormwater drains and channels to minimise sediment entering the stormwater system. We will keep functioning spill kits on-site at all times to clean-up any accidental chemical/fuel spills. We will store all chemicals and fuels within designated bunded areas and identify these storage areas with appropriate signage. We will record all chemicals stored on-site on a register and keep the relevant safety data sheets on-site. We will wash down equipment, machinery and vehicles within a designated bunded area before leaving the site. Operation Construction Sydney Water Green Square Stormwater Drain Decision report Page 27

28 Aspect Mitigation measures Stage Flora and fauna All vehicles carrying waste materials capable of discharging free liquid will be watertight to prevent leaks and we will check them to confirm the absence of leaks before they leave the site. We will regularly inspect installed sediment control devices to determine if they need repairs or cleanout. We will comply with specific water quality criteria, set out by the ANZECC (2000) Marine Ecosystem Guidelines (80% level of protection). Where water pumped out from excavations does not meet the ANZECC (2000) Marine Ecosystem Guidelines (80% level of protection) water quality criteria, we will treat it before it is discharged through appropriate sedimentation controls, in a manner that avoids flooding and erosion. We will treat contaminated water pumped out from excavations off-site at an appropriately licensed waste facility. During the dewatering program, we will maintain records to satisfy licence conditions. The following records are likely to be required: o daily discharge volume o o periodic quality of discharge water including ph, electrical conductivity and details of water quality treatment evidence of discharge monitoring or risk assessment. We will prepare a Dewatering Management Plan (DMP) before construction. The DMP will support any licence application and will: o o o establish background hydrogeological conditions outline measures to minimise the impact of dewatering and potential settlement on neighbouring properties and bores during construction outline how we will manage groundwater discharge during construction. We will test the quality of groundwater from dewatering and treat it appropriately if required, before discharging it to stormwater. We will obtain appropriate discharge licences and permits before construction commences. We will incorporate energy dissipators at the head of Alexandra Canal into the design to dissipate outflows from the project. We will install a gross pollutant trap in the GSSD upstream of Alexandra Canal. We will apply water sensitive urban design planning controls on new development. We will continue to comply with the Alexandra Canal remediation order, including considering sediment dynamics within the canal. We will not place materials, plant, equipment and stockpiles within the drip-lines of any trees not marked for removal. We will only cut roots when absolutely necessary and this will be done by a qualified arborist. Any weed removal/control will be done by suitably qualified and/or experienced licenced sub-contractors. We will manage declared noxious weeds according to the requirements of the Noxious Weeds Act We will identify a site rehabilitation plan for Perry Park or restoration measures in consultation with City of Sydney which will include cover regeneration and re-planting of local native species appropriate to the site, and considering the future redevelopment. We will delineate the location and full extent of any lopping, trimming, clearing or other vegetation disturbance required for the works. Operation Construction Sydney Water Green Square Stormwater Drain Decision report Page 28

29 Aspect Mitigation measures Stage To minimise the risk of injury to threatened bats we will incorporate the following mitigation measures : o o Before construction at the culvert near Link Road, an ecologist will observe the entrance to culverts on two consecutive nights from dusk to three hours after dusk to determine whether bats are roosting in the culvert. The ecologist will have an anabat (or similar) recorder to help determine whether bats are using the culvert. The observations will be done in weather conditions that bats would typically leave a roosting site. The survey should not be done on a rainy night when bats are unlikely to be leaving the site. If no bats are using the culvert no further mitigation measures relating to this culvert will be required. If bats are using the culvert, we will seek specific advice from the ecologist about how to prevent bats being injured during construction, such as placing a temporary barrier over the culvert on the evening before construction (after bats have left the culvert) to prevent the bats returning to roost. The barrier, such as orange paraweb fencing will be replaced at the end of each day s construction on this section of culvert to ensure bats do not re-enter the site. Air and energy Noise and vibration We will manage stockpiles to minimise dust generation, either by keeping them moist, or covering them, if they are to be there for longer than 28 days. We will always cover loads of excavated material, soil, fill and other erodible matter during transportation. We will rehabilitate disturbed areas progressively, as soon as practical after construction at each work site. A street sweeper will clean streets and access roads at the end of each day. We will maintain all work vehicles and machinery, so that exhaust emissions are not continuously visible for more than 10 seconds. We will implement measures to minimise energy use and greenhouse gas emissions during construction, including appropriately maintaining equipment and machinery, and not leaving work vehicles or machinery running when not in use. We will complete work according to the Interim Construction Noise Guidelines (ICNG). We will provide surrounding residences and businesses with reasonable notice of the proposed work (including proposed starting date, work methods and duration) according to Sydney Water s community liaison and notification policies. We will schedule respite periods in consultation with the community for construction activities expected to generate noise levels at or in excess of 75 db(a) at any receiver. We will consider respite options for residents affected by night construction work that is likely to incur significant noise levels (greater than 25 db above the NML) and where work is planned to occur for more than two consecutive nights. We will limit noise intensive works to the least sensitive times of the day, wherever possible. Work side construction training will alert construction workers to noise concerns and include education on noise sensitive issues and reducing noise where possible. We will install construction hoarding where required, to provide acoustic shielding to potentially noise affected residential receivers. Construction Construction Sydney Water Green Square Stormwater Drain Decision report Page 29

30 Aspect Mitigation measures Stage Waste management We will fit all trucks with mufflers and maintain them in good working order. We will select smaller equipment options or rubber-tracked equipment where equipment is fit-for-purpose and it is economically feasible. We will maintain and operate all equipment efficiently, according to manufacturer s specifications, to reduce adverse noise impacts. We will consider alternative work practices, which generate less noise in high impact locations, for example using electric equipment instead of diesel or petrol powered equipment. We will turn off plant and equipment when it is not being used. We will fit equipment with silencers, acoustical enclosures and/or other noise attenuation measures, where feasible. Where vibration from construction activities may affect residential receivers (human comfort), we will manage them according to the British Standard BS and Australian Standard AS Where vibration from construction activities may affect nearby structures, we will manage them according to British Standard BS 7385: Part Evaluation and Measurement of Vibration on Buildings. For historic buildings, which have a higher sensitivity to vibration, we will manage impacts according to German Standard DIN 4150: Part 3. We will consult with landowners and business owners to determine any specific vibration requirements. We will propose appropriate construction methods and schedules that comply with the agreed vibration requirements and Standards BS and AS We will avoid generating surplus materials by planning construction appropriately, including managing construction material quantities. We will minimise waste according to the hierarchy of avoid, re-use, recycle and finally disposal. We will re-use suitable excavated spoil on site for backfilling, landscaping and other uses, wherever possible. If we cannot re-use suitable spoil on-site, we will investigate opportunities for off-site re-use. If we cannot identify re-use opportunities or the spoil is unsuitable due to its geotechnical or contamination characteristics, we will classify spoil according to the Waste Classification Guidelines (DECCW, 2009) and dispose of it at an appropriately licensed facility. We will identify suitable spoil storage areas along the project alignment, during the detailed design stage. We will classify and store spoil separately, to avoid contamination. We will maintain a waste log on-site. We will handle all storage, transport and handling of dangerous goods according to the relevant Australian Standards and guidelines. We will investigate the feasibility of treating ASS in situ before considering disposal at an appropriately licensed off-site facility. We will do this according to the ASSMP for the project. We will survey hazardous material at all sites set for demolition, to determine the extent of any asbestos or other hazardous construction materials and waste. We will remove asbestos containing material according to the regulations and requirements of the NSW Work Health and Safety Regulation 2011 and the How to Safely Remove Asbestos Code of Practice issued by Safe Work Australia in 2011 We will inspect visual clearance before re-opening asbestos removal areas for demolition We will manage other hazardous materials according to the relevant Construction Sydney Water Green Square Stormwater Drain Decision report Page 30

31 Aspect Mitigation measures Stage ANZECC, federal or state legislative guidelines. Heritage Aboriginal and non- Aboriginal Traffic and access We will maintain and operate the project in line with our existing maintenance procedures. We will inspect any stormwater quality improvement devices (such as a gross pollutant trap) installed to capture litter and grass clippings and the relevant authority (Sydney Water or City of Sydney) will remove the waste. If we discover any item (or suspected item) of Aboriginal heritage significance during construction, we will cease all work in the immediate vicinity and the delivery contractor will inform the project manager immediately. The project manager will inform Sydney Water s heritage staff. Works may not recommence without the written approval from Sydney Water s heritage staff. The design will minimise impacts to the wall of Alexandra Canal where it connects, and consider impacts to the embankments further downstream. Works within the curtilage of Alexandra Canal will require a heritage assessment and a permit under Section 57 of the Heritage Act This permit will be submitted for approval according to Subdivision 1 of Division 3 of the Act. We will prepare and submit an Archaeological Research Design and Methodology to the NSW Heritage Council to obtain an exemption under Section 140 of the Heritage Act. If there are unexpected or unidentified historic finds (of unknown origin or significance) during construction, we will cease work and seek the advice of a qualified archaeologist. The following procedure will guide the management of unexpected and previously unidentified finds during construction: o o o o o o o o All work in the area is to cease immediately. Alert the project manager. If necessary, protect the area with fencing. Engage a suitably qualified archaeologist to assess the find/s. Assess the find using the guidelines for Assessing Significance for Historical Archaeological Sites and Relics (NSW Heritage Branch, 2009) If the archaeologist advises us to, we will prepare an Impact Assessment and Research design and methodology to submit to the Heritage Council for a Section 140 excavation permit or exception. We will complete archaeological mitigation according to the prepared documents and the permit/exception issued by the Heritage Council Once the site is mitigated to the satisfaction of the archaeologist and the Heritage Council, construction may resume. We will install flow dissipaters at the head of Alexandra Canal to dissipate outflows. We may also implement upstream water sensitive urban design to minimise the impacts of increased flow volumes on Alexandra Canal. We will erect appropriate signs to inform public road users of the proposed works and any temporary road closures. The static signposting will cover information, regulatory, warning and guide signs as defined in national and RMS standards. The contractor will comply with any council or RMS requirements Operation Construction Operation Construction Sydney Water Green Square Stormwater Drain Decision report Page 31

32 Aspect Mitigation measures Stage Social and visual Cumulative impact regarding traffic control, access and road/footway restoration issues. We will use qualified traffic controllers to direct traffic around the work site. The contractor will liaise with the traffic authority in regard to works that occur within or bordering a road. We will notify emergency service providers of upcoming works at least two weeks before work starts and/or implement any traffic control plan for traffic movements. We will fence and secure worksites to avoid pedestrians inadvertently entering the work sites, during both work hours and outside work hours. We will position construction vehicles and equipment within the boundaries of the work site where possible or (where no on-site parking is available) in the nearest available roadway parking space so that it minimises disruption to other road users, businesses and the public. Measures to limit the impact to neighbouring industrial properties, such as those along Maddox Street and Bourke Road could include retaining an open access lane for 24 hour property access. Alternatively traffic controllers would manage property access using controlled access lanes 24 hours a day or as otherwise required to meet the needs of the neighbouring properties. The contractor will explore alternative parking arrangements with City of Sydney Council to compensate for any loss of parking due to construction before construction commences We will minimise the spread of stockpiles, waste, and construction staff vehicle parking. We will re-use or remove all waste generated during the course of the works from the work areas, as soon as practical and dispose of it according to waste disposal procedures. We will restore disturbed areas as close as possible to their original conditions. We will retain existing vegetation (street trees) wherever possible to help minimise the visual impact to nearby businesses. We will notify residents in advance of traffic, noise and service disruptions, for example, through advice in the local press and letters. Notification will follow Sydney Water's customer notification policies. We will repair any damage to tracks, steps or other recreational/management structures in consultation with relevant agencies/stakeholders. We will induct all project staff and contractors on the environmental sensitivities of the work site(s) and relevant mitigation measures before starting work. We will repair any accidental damage to property from the work. All staff will maintain a tidy appearance and exercise courtesy in dealings with the public. Where entry to private properties is required, we will provide a notice of entry letter at least 24 hours in advance. We will carefully plan and stage construction works to avoid, where possible, doing work that could disrupt traffic concurrently with disruptive works for other Green Square developments. We will complete a Traffic Management Plan in consultation with RMS and City of Sydney. We will engage with developers close to the project to determine measures to minimise cumulative noise impacts. Where practical, we will stage construction of separate GSSD sections Construction Construction Sydney Water Green Square Stormwater Drain Decision report Page 32

33 Aspect Mitigation measures Stage to avoid high noise generating works being done concurrently with adjacent noise generating activities of other developments. If night time work is required, we will schedule works concurrently, where we can, to minimise the number of nights during which the sleep disturbance criteria might be exceeded. Sydney Water Green Square Stormwater Drain Decision report Page 33

34 6. Conclusion 6.1 Justification of the project The GSTC is one of the City of Sydney s proposed key urban renewal precincts. Once fully developed, the GSTC will provide for future housing, retailing, public domain and community facilities. The proposed drain is a key element of Sydney Water s commitment to urban renewal and our Liveable Cities Strategy. It enables the development of Green Square, Epsom Park Precinct and Mid-block Precinct. Flooding is projected to increase in the future. The projected future housing in the GSTC is expected to reach more than 33,000 by 2021 (City of Sydney, 2014). In addition, we anticipate climate change may exacerbate the flooding hazard as extreme storm events are projected to increase in frequency and intensity in the region (IPCC, 2007). This means that resolution of the flooding hazard in the precinct is critical before the GSTC can be developed. The project objectives are to: reduce the flood risk to the future community of GSTC from Joynton Avenue and at Botany Road achieve zero or minimal ponding at Joynton Avenue in a 20 year average recurrence interval (ARI) flood event significantly reduce ponding at both Joynton Avenue and Botany Road in a 100 year ARI event manage the flood risk at the Epsom Park Precinct and the Mid-block Precinct by capturing and transferring a 20 year ARI pipe flow from these future developments. The Green Square Stormwater Drain is a direct recommendation of the City of Sydney s Alexandra Canal Flood Risk Management Study, to manage and mitigate flood risk. This justification remains unchanged as a result of this Decision report. 6.2 Determination of the project Sydney Water has assessed the potential impacts of the project, as required by Part 5 of the EP&A Act. The public consultation process completed for the project is outlined in Chapter 2 of this report. We received nine submissions following public exhibition of the Green Square Stormwater Drain REF in May The main issues raised in the submissions related to flood mitigation in the wider catchment, potential groundwater impacts during construction and operation, and cumulative temporary traffic impacts. Sydney Water has thoroughly considered and responded to the issues raised in the submissions in Chapter 4. In considering the issues raised, Sydney Water has adopted some additional mitigation measures, as listed in Table 2. Sydney Water considers that the proposed mitigation measures are appropriate to manage the project s potential impacts and no changes to the project are required. The project is not likely to result in a significant impact to the environment. Sydney Water Green Square Stormwater Drain Decision Report Page 34

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36 8. References Cardno (2008). Flood Mitigation Options Report Green Square Town Centre, July Cardno (2009). Floodplain Risk Management Plan for the Green Square Town Centre. Cardno (2012). Mid-term Drainage Concept for GSTC. Cardno (2013). Alexandra Canal Catchment Flood Study. Prepared for City of Sydney. September 2013, Draft Report. City of Sydney Council (2013). Green Square Trunk Drain Concept Design Report. Issue 2, May NSW Government (2005). Floodplain Development Manual WMA Water (2011). West Kensington - Green Square Flood Study Update, October WMA Water (2013). Green Square Catchment Floodplain Risk Management Plan Final Draft May Sydney Water Green Square Stormwater Drain Decision report Page 36

37 9. Glossary and abbreviations Alliance ARI CEMP The Alliance to deliver the project (yet to be established) Average recurrence interval Construction Environmental Management Plan CLM Act Contaminated Land Management Act 1997 EIS Environmental Impact Statement EP&A Act Environmental Planning and Assessment Act 1979 EPL m NSW PMF Environmental Protection Licence metres New South Wales probable maximum flood POEO Act Protection of the Environment Operations Act 1997 REF Stakeholder Review of Environmental Factors A stakeholder is any individual or group, which can affect or is affected by an organisation s activities. Sydney Water Green Square Stormwater Drain Decision report Page 37

38 Appendix 1 Community and stakeholder communications Stakeholder letter sample Sydney Water Green Square Stormwater Drain Decision report Page 38

39 Newsletter Sydney Water Green Square Stormwater Drain Decision report Page 39

40 Sydney Water Green Square Stormwater Drain Decision report Page 40

41 Appendix 2 Submissions Submissions received Submission number Name Date received 1 Fisheries NSW 23 April Roads and Maritime Services 30 April NSW Office of Water 9 May Environmental Protection Authority 13 May Heritage Council 13 May Office of Environment and Heritage 19 May Submission 7 23 May Transport for NSW 29 May City of Sydney 11 June 2014 Sydney Water Green Square Stormwater Drain Decision report Page 41

42 Submission 1 Sydney Water Green Square Stormwater Drain Decision report Page 42

43 Submission 2 Sydney Water Green Square Stormwater Drain Decision report Page 43

44 Sydney Water Green Square Stormwater Drain Decision report Page 44

45 Submission 3 Sydney Water Green Square Stormwater Drain Decision report Page 45

46 Sydney Water Green Square Stormwater Drain Decision report Page 46

47 Sydney Water Green Square Stormwater Drain Decision report Page 47

48 Submission 4 Sydney Water Green Square Stormwater Drain Decision report Page 48

49 Submission 5 Sydney Water Green Square Stormwater Drain Decision report Page 49

50 Sydney Water Green Square Stormwater Drain Decision report Page 50

51 Submission 6 Sydney Water Green Square Stormwater Drain Decision report Page 51

52 Sydney Water Green Square Stormwater Drain Decision report Page 52

53 Submission 7 Content has been omitted, to maintain privacy of names and addresses of private individuals and community members, as required by the Privacy Act This section of the submission does not relate to the REF. Sydney Water Green Square Stormwater Drain Decision report Page 53

54 Sydney Water Green Square Stormwater Drain Decision report Page 54

55 Sydney Water Green Square Stormwater Drain Decision report Page 55

56 Submission 8 Sydney Water Green Square Stormwater Drain Decision report Page 56

57 Sydney Water Green Square Stormwater Drain Decision report Page 57

58 Submission 9 Sydney Water Green Square Stormwater Drain Decision report Page 58

59 Appendix 3 Downstream flood extents Existing and proposed option flood extents from the Green Square Trunk Drain Concept Design (City of Sydney, 2013) Sydney Water Green Square Stormwater Drain Decision report Page 59

60 Sydney Water Green Square Stormwater Drain Decision report Page 60