AGL ENERGY LIMITED TOMAGO TO HEXHAM PIPELINE

Transcription

1 Lucas Engineering and Construction Pty Ltd AGL Energy Limited Tomago to Hexham Pipeline ACID SULPHATE SOIL MANAGEMENT PLAN AGL ENERGY LIMITED TOMAGO TO HEXHAM PIPELINE EV NGSF LUC HPW EN PLN /11/2013 ISSUED FOR CONSTRUCTION DEn JBS ENV PSh REV DATE DESCRIPTION PREPARED CHECKED APPROVED

2 TABLE OF CONTENTS 1.0 INTRODUCTION OWNER OF THIS DOCUMENT PROJECT DESCRIPTION PURPOSE SCOPE RELEVANT LEGISLATION GUIDELINES MINISTER S CONDITIONS OF APPROVAL AND STATEMENT OF COMMITMENTS APPLICABLE DOCUMENTS ABBREVIATIONS ROLES AND RESPONSIBILITIES IDENTIFICATION AND ASSESSMENT ASS AND PASS ASS OCCURRENCES CONSTRUCTION ACTIVITIES ENVIRONMENTAL IMPACTS CONSULTATION AND COMMUNICATION STAKEHOLDER CONSULTATION TRAINING AND AWARENESS IMPLEMENTATION OF CONTROLS ASS MITIGATION AND MANAGEMENT MEASURES IDENTIFICATION OF ACID SULPHATE SOILS ASS MITIGATION AND MANAGEMENT MONITORING AND REVIEW MONITORING, INSPECTION AND REPORTING INCIDENT MANAGEMENT APPENDIX A FIGURES EV _0.docx Page 2 of 19

3 1.0 INTRODUCTION 1.1 OWNER OF THIS DOCUMENT The owner of this (ASSMP) is the Project Manager for Lucas Engineering and Construction (LEC). 1.2 PROJECT DESCRIPTION AGL Energy Limited (AGL) is developing the Newcastle Gas Storage Facility Project (the Project) in Tomago and Hexham, near Newcastle in New South Wales. The Project is being constructed to assist AGL to meet its peak gas demand in winter and to provide additional security of gas supply during supply disruption events in New South Wales. The project involves the design and of a liquefied natural gas plant and storage tank in Tomago and an interconnecting pipeline between Tomago and Hexham. The interconnecting gas pipeline will be a DN400 high pressure gas pipeline connecting the Newcastle Gas Storage Facility (NGSF) to the Jemena Gas Network (JGN) in Hexham approximately 5 km in length. 1.3 PURPOSE This ASSMP has been prepared to provide details on the management of ASS during the of the proposed Tomago Hexham Pipeline route from the Hexham Receiving Station to the Proposed Gas Plant Location in Newcastle NSW. This document has been prepared with the aim to ensure that: The life, health and well being of human and other forms of life is protected; The local amenity is protected; The environmental management of ASS material from the development is in accordance with the principles of Ecologically Sustainable Development (ESD); Staff, contractors and consultants are informed of appropriate safeguards and control measures implemented to minimise the environmental impact caused by Actual and Potential ASS (AASS and PASS respectively) material; All statutory environmental requirements in relation to ASS material are complied with; Strategies implemented are aimed at minimising environmental harm during the stage potentially caused by ASS material; and An Environmental Management System of ASS material, generally based on the key elements of AS/NZS IS Environmental Management Systems Specification with Guidance for use is followed. All personnel working under this management plan must be fully aware of the requirements and restrictions and comply with them at all times. 1.4 SCOPE This ASS Management Plan covers the treatment of AASS & PASS for pipeline installation via Horizontal Directional Drilling and open trenching in the areas highlighted below; 300m West of the Hunter River, 360m East of the Hunter River, 250m near the Pacific Highway EV _0.docx Page 3 of 19

4 This document should be read in conjunction with other relevant project plans and procedures that pertain to work areas not covered in this document. 1.5 RELEVANT LEGISLATION Legislation relevant to the management of acid sulphate soils are presented in Table 1 1. Table 1 1 Key Policies, Legislation and Regulations Legislation / Policy Relevance NSW Environmental Planning and Assessment Act 1979 (EP&A Act) Protection of the Environment Operations Act 1997 (POEO Act) Port Stephens Local Environmental Plan (2000) and Port Stephens Council ASS Policy (2004) Newcastle Local Environmental Plan (2013) The EP&A Act and Regulation include provisions to ensure that proposals which have the potential to impact the environment are subject to detailed assessment, and provide opportunity for public involvement. The EP&A Act requires compliance with the conditions of the project approval granted for the Project under Part 3A of the EP&A Act. The purpose of the POEO Act is to control pollution and set up a licensing regime for certain activities. The POEO ACT also regulates waste, including excavated soils. The Port Stephens LEP and ASS Policy state that works to be undertaken on lands potentially at risk of ASS occurrence are not to proceed without an ASS investigation and implementation of an ASSMP (if required). The Newcastle LEP states that development consent must not be granted for the carrying out of works unless an ASSMP has been prepared for the proposed works in accordance with the Acid Sulphate Soils Manual Guidelines Guidelines and Standards relevant to ASS management include: Acid Sulphate Soil Manual, NSW Acid Sulphate Soil Management Advisory Committee, 1998; Soil Management Guidelines in Queensland Acid Sulfate Soil Technical Manual, Version 3.8 Dear, Moore, Dobos, Waitling and Ahern, Department of Natural Resources and Mines, Indooroopilly, Qld, Australia; Laboratory Method Guidelines in Queensland Acid Sulphate Soil Technical Manual Dear, Moore, Dobos, Waitling and Ahern, Department of Natural Resources and Mines, Indooroopilly, Qld, Australia; Australian and New Zealand Guidelines for Assessment and Management of Contaminated Sites, ANZECC/NHMRC, 1992; and Assessment Classification and Management of Liquid and Non Liquid Waste (EPA), EV _0.docx Page 4 of 19

5 1.6 MINISTER S CONDITIONS OF APPROVAL AND STATEMENT OF COMMITMENTS The conditions of approval relevant to this Sub Plan are listed in Table 1 2 below. Table 1 2 Conditions of Approval CoA Conditions Sub Plan Reference B57(g) B57 (g) As part of the Construction Environmental Management Plan required under condition B56 of this approval, the Proponent shall prepare and implement the following: a detailed prepared in consultation with DPI (Aquatic Habitat Protection Unit), and NOW prior to any activity in areas mapped as Potential Acid Sulphate Soils or Actual Acid Sulphate Soils. The plan shall include reference to the water quality monitoring programme contained in the Groundwater and Surface Water Management Plans. The plan shall be prepared in accordance with the Acid Sulphate Soils Manual (ASSMC, 1998). As part of the plan, a Contingency Plan to deal with the unexpected discovery of actual or potential acid sulphate soils shall be prepared in consultation with NOW. The Statement of Commitments relevant to this plan are presented in Table 1 3. This plan Table 1 3 Statement of Commitments SoC Commitments Sub Plan Reference 16 Conduct a detailed ASS assessment at the Hexham receiving station site Table 5 1 prior to at this site to determine the natural buffering capacity of the soil and ascertain that site works meet the requirements of clause 25 of Newcastle Local Environment Plan 2003 (Newcastle LEP 2003) (now superseded by Clause 6.1 of the Newcastle LEP 2012). 17 Minimise disturbance and exposure of ASS. Table Store excavated ASS in conditions that simulate its natural state, or treat and store away from water bodies and drainage lines. 19 Treat excavated ASS using agricultural lime with machinery sufficient to perform adequate mixing, where practicable. 20 Bund areas where ASS are exposed, including HDD entry and exit points for the pipeline beneath the Hunter River, to prevent leachate entering the wider environment. 21 Undertake any potential ASS remediation works in accordance with clause 25 of the Newcastle LEP 2003, and the Acid Sulfate Soils Manual (ASSMAC, 1998) 22 Undertake any potential ASS remediation works in accordance with the Port Stephens Council LEP (Port Stephens Council, 2000), the Port Stephens Council ASS Policy, 2004 and the Acid Sulfate Soils Manual (ASSMAC, 1998). 26 Monitoring soil quality around Project works prior to and during to ascertain the presence of contaminated soil or ASS. Table 5 1 Table 5 1 Table 5 1 Table 5 1 Table 5 1 Table 5 1 and Soil Management Sub Plan 29 Store PASS capable of producing leachate within lined bunds. Table Ensure that the banks of watercourses are not disturbed during. Table EV _0.docx Page 5 of 19

6 1.7 APPLICABLE DOCUMENTS The following documents are referenced in this management plan: Client Documents HP EN PLN 0001 Construction Environmental Management Plan EV EN EN Lucas Documents Construction Environmental Management Plan Pipeline Project Execution Plan HDD Project Execution Plan 1.8 ABBREVIATIONS AASS AS ASS ACHCR AHIMS AQMP CEMP CHMP CLIENT CSMP DECCW EA ERP FFMP GMP HAZID HDD HSE ITP JGN Actual Acid Sulphate Soils Australian Standards Acid Sulphate Soil Aboriginal Cultural Heritage Consultation Requirements Aboriginal Heritage Information Management System Air Quality Management Plan Construction Environmental Management Plan Cultural Heritage Management Plan AGL Energy Limited Construction Safety Management Plan Department of Environment, Climate Change and Water Environmental Assessment Emergency Response Plan Flora and Fauna Management Plan Groundwater Management Plan Hazard Identification Horizontal Directional Drill Health, Safety and Environment Inspection and Test Plan Jemena Gas Network EV _0.docx Page 6 of 19

7 JHA LEC MS NDT NGSF NVMP OHS PASS PEP Job Hazard Analysis Lucas Engineering and Construction Method Statement Non Destructive Testing Newcastle Gas Storage Facility Noise and Vibration Management Plan Occupational Safety and Health Potential Acid Sulphate Soils Project Execution Plan POEO Protection of the Environment Operations Act 1997 PPE PPR Project ROW SMP SWMP SWMS VRMP WMP CLIENT EA GMP HAZID HDD ITP JGN JHA LEC NGSF OHS Personnel Protective Equipment Preferred Project and Response to Submissions Report Tomago to Hexham Pipeline Right of Way Soil Management Plan Surface Water Management Plan Safety Work Method Statement Vegetation and Rehabilitation Management Plan Waste Management Plan AGL Energy Limited Environmental Assessment Groundwater Management Plan Hazard Identification Horizontal Directional Drill Inspection and Test Plan Jemena Gas Network Job Hazard Analysis Lucas Engineering and Construction Newcastle Gas Storage Facility Occupational Safety and Health EV _0.docx Page 7 of 19

8 PEP PPR Project Execution Plan Preferred Project and Response to Submissions Report 2.0 ROLES AND RESPONSIBILITIES Roles and responsibilities are defined in section 5.0 and 6.0 of this document. 3.0 IDENTIFICATION AND ASSESSMENT ASS and PASS Acid sulphate soils are the common name given to naturally occurring sediments and soils containing iron sulphides (principally iron sulphide or iron disulphide or their precursors). The exposure of the sulphide in these soils to oxygen by drainage or excavation leads to the generation of sulphuric acid. acid sulphate soils include actual acid sulphate soils or potential acid sulphate soils. Actual and potential acid sulphate soils are often found in the same soil profile, with actual acid sulphate soils generally overlying potential acid sulphate soil horizons. actual acid sulphate soils are soils containing highly acidic soil horizons or layers resulting from the aeration of soil materials that are rich in iron sulphides. This oxidation produces hydrogen ions in excess of the sediment s capacity to neutralise the acidity resulting in soils of ph of 4 or less when measured in dry season conditions. These soils can usually be identified by the presence of pale yellow mottles and coatings of jarosite. potential acid sulphate soils are soils which contain iron sulphides or sulphidic material which have not been exposed to air and oxidised. The field ph of these soils in their undisturbed state is ph 4 or more and may be neutral or slightly alkaline. However, they pose a considerable environmental risk when disturbed, as they will become severely acidic when exposed to air and oxidised ASS Occurrences The NSW DECC (2008) ASS Risk Map for the Lower Hunter River Catchment indicates the following ASS conditions across the Project area: Low potential for the presence of PASS to depth 4 metres (bgl) along the northern boundary of the main NGSF site and the northern section of the high pressure gas pipeline route. High risk between 0 and 1.0 metres bgl along the northern bank of the Hunter River. High risk between 2.0 and 4.0 metres bgl in a section further inland between Pacific Highway, Tomago Road and Old Punt Road. High risk between 1.0 and 2.0 metres bgl at the HRS. 3.2 CONSTRUCTION ACTIVITIES Construction activities which have the potential to cause ASS related impacts include: Shallow excavations; Deep excavations; EV _0.docx Page 8 of 19

9 Horizontal directional drilling; and Dewatering. 3.3 ENVIRONMENTAL IMPACTS Potential ASS / PASS impacts from activities include: Uncontrolled surface runoff in areas of exposed actual ASS, causing a release of acid into the environment; Changes to surface run off patterns, promoting the release of acid into the environment; Leaching of acid into the environment at treatment sites; Exposing ASS at / near new drains or realigned creeks, thus causing the release of acid into the environment in the short and long term; and Exposure of PASS to the air, in new drains or realigned creeks, thus causing increased oxidisation and increased release of acid into the environment. 4.0 CONSULTATION AND COMMUNICATION 4.1 STAKEHOLDER CONSULTATION The Client is undertaking community and stakeholder relations on the project. LEC will conduct operations in line with AGL s Community Engagement Plan. 4.2 TRAINING AND AWARENESS All Project personnel will undergo a general project induction prior to commencing work with the Contractor. This will include an ASS component to reinforce the importance of management and the measures that will be implemented to address ASS and PASS issues. Ongoing toolbox talks will highlight specific environmental requirements associated with activities underway at the time. 5.0 IMPLEMENTATION OF CONTROLS 5.1 ASS MITIGATION AND MANAGEMENT MEASURES Project mitigation and management measures and responsibilities for ASS are outlined in this section. These mitigation and management measures have been developed from the SoC and mitigation measures described in the EA and to ensure compliance with relevant CoA, Revised SoC, legislation and best practice Identification of Acid Sulphate Soils The preliminary visual checking of potential ASS will be based on material type, colour and consistency. Dark grey and black, very soft to soft, occasionally firm clays and sandy and dark grey to grey clayey sands and sands will be classified as suspected acid sulphate soils. It should be noted that sands, with only minor amounts of silt and clay, can contain pyrite and therefore acidify upon exposure. A field screening test using hydrogen peroxide (H2O2) should be performed regularly on excavated soils in areas where ASS or PASS is anticipated, or on suspect soils. The peroxide screening test should be undertaken based on Appendix I of the Acid Sulphate Soils Assessment Guidelines (Ahern EV _0.docx Page 9 of 19

10 et al, 1998a). Soils that record a ph of below 4, following oxidation with H2O2, should be managed as acid sulphate soils. Based on the results of ph monitoring, visual assessment and field screening, selected soils samples (at a minimum rate of 10% of screened samples) will be sent for laboratory analysis using the chromium reducible suite (SCr) method to confirm the peroxide screening test results to confirm the required liming rate. 5.2 ASS MITIGATION AND MANAGEMENT A range of ASS management measures have been developed to be undertaken as part of the Project. Table 5 1 describes the management and mitigation measures which will be initiated during various activities across the Project. Table 5 1 ASS Management and Mitigation Measures ID Management Measure Timing Responsibility HRS SITE ASSESSMENT 1 Conduct detailed ASS assessment of the HRS site prior to at this site to determine the natural buffering capacity of the soil and ascertain that site works meet the requirements of clause 25 of the Newcastle LEP 2003 (superseded by Clause 6.1 of the Newcastle LEP 2012). SITE PREPARATION 1 Ensure appropriate areas are set aside for the treatment of ASS. These areas should be adequately barricaded and marked with appropriate signage. Sediment controls (such as silt fences or hay bales) should be established around the perimeter of these areas. EXCAVATION AND STOCKPILING OF ASS 1 Previous investigations indicate that estuarine clays (typically dark grey in colour) at depths of greater than approximately 2m are susceptible of being ASS. These soils should be excavated and stockpiled separately from other materials. Avoid unnecessary disturbance of the banks of watercourses during works. These stockpiles should be placed in the designated areas (as above). Stockpiles should be placed on an impermeable barrier and surrounded with appropriate sediment controls. Temporary stockpiling of untreated ASS should not exceed 5 days (for fine textured soils). Medium term stockpiles should not exceed 28 days (for fine textured soils) with provision for collection of leachate and run off water. Stockpiling timeframes are based on Table 4 and Table 5, page 50 of Queensland ASS Technical Manual, presented in Figures 4 and 5. TREATMENT OF ASS 1 ASS and/or PASS can be placed directly back within the trench, with no treatment, within four days of excavation provided there is no evidence of oxidation. To assess if oxidation has occurred the stockpile should be visually assessed for jarosite staining, and field ph testing carried out. If there is evidence of oxidation (i.e. jarosite staining or ph less than 4), or the material has been excavated for longer than 4 days, than the following treatment will be required: Supervisor Supervisor Supervisor EV _0.docx Page 10 of 19

11 A treatment pad is required in general accordance with Figure 4, page 24 of Queensland ASS Technical Manual (shown in Figure 6). A guard layer should also be provided. The treatment pad should be located at least 40m from a permanent waterway or creek and if possible placed in a topographically high area to avoid inundation following heavy rain. Stockpiled soil should be spread in thin (<200mm) layers on impervious pads within the boundary of the site works. Lime should be added by hand or light weight truck followed by mixing, using light weight rotators orsimilar tools. The following liming rates are to be applied, based on existing laboratory results: 3.7kg lime/tonne for aeolian soils near the NGSF site. The preliminary lime rates given above include a factor of safety of 1.5 to account for incomplete mixing and a neutralising value (NV) of 100. Appropriate records should be maintained regarding the treatment of ASS. IMPORTATION OF LIME FOR ASS TREATMENT 1 In order to neutralise ASS, lime should be imported onto the site. Lime imported should be accompanied with an appropriate Material Safety Data Sheet (MSDS). This MSDS procedure should be observed by personnel who be expected to handle the lime. Ensure that the lime is imported for direct use on ASS stockpiles, or is placed in a suitable designated area for later use. Ensure an appropriate lime register is maintained, listing the source of lime, quantity imported and where it is used on site. ON SITE RE USE OR OFFSITE DISPOSAL 1 Ensure that ASS stockpiles are not re used on site or disposed offsite until suitably treated. Successfully limed material is suitable for re use on site above the water table. Treated ASS stockpiles are required to be disposed to licensed landfill if offsite disposal is required. Further waste classification may be required prior to offsite disposal. DEWATERING 1 Ensure that an appropriate dewatering system is established to minimise the risk of impacted runoff water on the remainder of the site. Stormwater that collects in pits should be tested for ph and total dissolved solids. If the ph is above 6, and total dissolved solids are below 1500mg/L, than the water is suitable for use as dust suppression or to be irrigated over vegetated areas. If ph is less than 6, lime should be added to the water until the ph is above 6. If water is proposed to be discharged to nearby surface water bodies, then the surface water body should also be tested, and the results compared. If the results are similar, than the water may be suitable for discharge. Permission from the relevant regulatory authority (i.e. NSW Supervisor Supervisor EV _0.docx Page 11 of 19

12 Office of Water) must be obtained before disposal. Stormwater could also be disposed at a licensed liquid waste facility. CONTINGENCY 1 Materials encountered during works that is suspected of being ASS (material that is dark grey in colour and has a high organic odour) should be stockpiled separately and advice from a suitably qualified environmental consultant should be sought. REPORTING 1 ASS monitoring records; Excavation records; Stockpile tracking records; Register of lime used for ASS treatment; and Records of offsite disposal of treated stockpiles (i.e. landfill waste disposal dockets). Supervisor 6.0 MONITORING AND REVIEW 6.1 MONITORING, INSPECTION AND REPORTING ASS monitoring and reporting of levels of impact will occur for the duration of the Project. Daily visual inspections of the site will be undertaken to identify actual or potential ASS concerns. Documented weekly environmental inspections of the site will also be undertaken using a weekly environmental inspection checklist. The weekly checklist includes a section on ASS. The ASS monitoring, inspection and reporting program is shown in Table 6 1 below. Table 6 1 ASS Monitoring and Reporting Program Activity Area Resources Responsibility Frequency Reported to Monitoring of disturbed soil for ASS Monitoring of treated ASS Daily Environmental Inspection Weekly Environmental Inspection Field ph, 30% peroxide, chromium suite if required. ph, chromium suite ASS Chance Find Procedure Treatment of ASS Procedure ROUTINE INSPECTIONS As required, as soil is disturbed Weekly ph monitoring, chromium suite monthly to confirm neutralisation Supervisor Project Manager All Site Diary Daily Project Manager All Weekly Environmental Inspection Checklist Internal Audits All CEMP / Sub Plans / HSE Manager Weekly or following a heavy rain event Quarterly Project Manager Senior Management EV _0.docx Page 12 of 19

13 External Audits All External Audit Checklist Client Audits All Client Audit Checklist Monthly Environmental Reports Six Monthly Compliance Tracking Report All All Weekly Environmental Checklist Six Monthly Compliance Tracking Report External Representative Client REPORTING HSE Manager (Where required) HSE Manager (where required) Annually or as otherwise determined by the auditor Six Monthly or as determined by the auditor Monthly Six Monthly DoPI, Director General Project Manager / HSE Manager / AGL Senior Management Client Environmental Representative Table 5 2 below summarises specific inspection and monitoring requirements associated with ASS management controls. Management Practice Monitoring Timing Responsibility Carry out visual checks and field testing for potential ASS Field testing for ph in surface and groundwater Keep working face and areas of open excavation to a minimum Daily inspections during work Groundwater and Surface Water monitoring undertaken as described in Groundwater Mgt Plan and Surface Water Mgt Plan includes ph (monthly in first 12months of and at least quarterly thereafter during ). Daily inspections during work AGL Environmental Manager Stabilise disturbed areas as soon as possible Weekly inspections Minimise stockpiling by coordinating excavation, spreading, regarding, and compaction activities Cover/vegetate stockpiles where material is to remain exposed for a long period of time Weekly inspections Daily inspections of stockpiles EV _0.docx Page 13 of 19

14 Prevent the movement of sediment away from stockpiles and areas by installing erosion and sediment control structures Daily inspections of sediment controls Restrict traffic to defined roads Daily inspections Minimise on site vehicle activity on disturbed surfaces during and after rain events Monitoring of ASS stockpiles after treatment Management of treated ASS by appropriate and timely on site re use or offsite disposal Daily inspections during and for a period after rain events ph monitoring after initial treatment event. If ph values are <4, additional treatments will be required. The results of ASS monitoring events should be reported to the nominated AGL and LEC representatives in a timely manner so work stoppages are kept to a minimum. daily works 7.0 INCIDENT MANAGEMENT All environmental and safety incidents occurring on the Project will be managed by LEC as detailed in the Incident Management Plan [10371 HS ]. This includes notification, recording, reporting and response processes EV _0.docx Page 14 of 19

15 APPENDIX A FIGURES EV _0.docx Page 15 of 19

16 Figure 1 Acid Sulphate Risk Map EV _0.docx Page 16 of 19

17 AGL Tomago to Hexham Pipeline Acid Sulphate Soil Management Plan Contract No Lucas Engineering & Construction ABN Project No Figure 2 Acid Sulphate Soil Occurrence EV _0.docx Page 17 of 19

18 AGL Tomago to Hexham Pipeline Acid Sulphate Soil Management Plan Contract No Lucas Engineering & Construction ABN Project No Figure 3 Acid Sulphate Soil Occurrence EV _0.docx Page 18 of 19

19 Figure 4 Extract from Queensland ASS Technical Manual (Table 4) Figure 5 Extract from Queensland ASS Technical Manual (Table 5) Figure 6 Extract from Queensland ASS Technical Manual (Figure 4) EV _0.docx Page 19 of 19