ADI Mulwala Contamination Management Project CONTAMINATION MANAGEMENT … · 2015-06-26 · and groundwater will be undertaken. MANAGEMENT OF THE OFF-SITE GROUNDWATER PLUME Based

HLA

ADI Mulwala Contamination Management ProjectCONTAMINATION MANAGEMENT PLAN17 December 2003

Prepared for Department of Defenceand ADI LimitedBayly Street,Mulwala, NSW 2647

Report By:HLA-Envirosciences Pty LtdABN: 34 060 207 70246 Clarendon StreetSouth Melbourne VIC 3205Ph: 61 3 8699 2199Fax: 61 3 8699 2122

HLA Ref: D006005_RPT236Rev03_17Dec03

ADI Mulwala Contamination Management Project CONTAMINATION MANAGEMENT PLAN 17 December 2003 Prepared for: Department of Defence and ADI Limited Bayly Street, Mulwala, NSW 2647 Report by: HLA-Envirosciences Pty Limited ABN: 34 060 204 702 46 Clarendon Street Melbourne VIC 3205 Australia Ph: +61 3 8699 2199 Fax: +61 3 8699 2122 HLA Ref: D006005_RPT236Rev03_17Dec03

ADI Mulwala Contamination Management ProjectCONTAMINATION MANAGEMENT PLAN

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DISTRIBUTION ADI Mulwala Contamination Management Project CONTAMINATION MANAGEMENT PLAN 17 December 2003 Copies Recipient Copies Recipient

2

Doug Wilson ADI Limited Bayly Street Mulwala, NSW 2647

1

Rob Monteith NSW Environment Protection Authority 553 Kiewa Street Albury, NSW 2640

1

Mark Imber Department of Defence B9-2-24 REO – CSI-ACT/SNSW Canberra, ACT 2600

1

Mark Bourne NSW Environment Protection Authority 59 – 61 Goulburn Street Sydney, NSW 2000

1

Peter Nadebaum GHD 380 Lonsdale Street Melbourne, Victoria 3000

1

Jack Chubb NSW Department of Infrastructure, Planning and Natural Resources 512 Dean Street Albury, NSW 2640

1

Bob Parr Corowa Shire Council Cnr Bow Street and Honour Avenue Corowa, NSW 2646

2

Project File HLA-Envirosciences Pty Limited 46 Clarendon Street Melbourne, VIC 3205

1

Corowa Shire Council Mulwala Library Melbourne Street Mulwala, NSW 2647

1

Defence Library HLA-Envirosciences Pty Limited 46 Clarendon Street Melbourne, VIC 3205

By HLA-Envirosciences Pty Limited ABN: 34 060 204 702 46 Clarendon Street Melbourne VIC 3205 Australia ____________________________________ Damien Wigley Senior Environmental Scientist

___________________________________ Damien Chappell Senior Environmental Scientist

Peer Review: Date: 17 December 2003

Patrick Clarke Principal Geological Engineer


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LIMITATIONS This document was prepared for the sole use of the Department of Defence, ADI Limited, the Auditor and the regulatory agencies that are directly involved in this project, the only intended beneficiaries of our work. No other party should rely on the information contained herein without the prior written consent of HLA-Envirosciences Pty Limited, the Department of Defence and ADI Limited. From a technical perspective, the subsurface environment presents very substantial uncertainty. It is a heterogeneous, complex environment, in which small subsurface features or changes in geologic conditions can have substantial impacts on water and chemical movement. Major uncertainties also plague source characterisation assessment of chemical fate and transport in the environment, assessment of exposure risks and health effects, and remedial action performance. These factors make uncertainty an inherent feature of potentially contaminated sites. Technical uncertainties are characteristically several orders of magnitude greater at contaminated sites than for other kinds of projects. HLA's professional opinions are based upon its professional judgement, experience, and training. These opinions are also based upon data derived from the limited testing and analysis described in this report. It is possible that additional testing and analysis might produce different results and/or different opinions. HLA has limited its investigation to the scope agreed upon with its client. HLA believes that its opinions are reasonably supported by the testing and analysis that have been done, and that those opinions have been developed according to the professional standard of care for the environmental consulting profession in this area at this time. That standard of care may change and new methods and practices of exploration, testing and analysis may develop in the future, which might produce different results.


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CONTENTS EXECUTIVE SUMMARY..............................................................................................................I 1 INTRODUCTION ..........................................................................................................1

1.1 General..........................................................................................................1 1.2 Objectives of Contamination Management Plan ............................................1 1.3 Development of the Scope of the Contamination Management Plan.............2 1.4 Stakeholder Consultation...............................................................................2 1.5 Structure of Contamination Management Plan ..............................................2

1.5.1 Report ............................................................................................2 1.5.2 Appendices.....................................................................................3

2 MANAGEMENT TARGETS AND OBJECTIVES .........................................................4 2.1 Regulatory Framework and the Role of the Environmental Auditor ...............4 2.2 Remedial Works ............................................................................................5 2.3 Current Groundwater Uses............................................................................5 2.4 Potential Beneficial Uses of Groundwater......................................................6 2.5 Cleanup Goals...............................................................................................8

3 PROOF-OF-CONCEPT AND DESIGN OF WORKS ....................................................9 3.1 Trial and Design Concepts ............................................................................9 3.2 Off-site Groundwater Plume Management.....................................................9

3.2.1 Management of Current Groundwater Uses ...................................9 3.2.2 Monitoring Natural Attenuation .....................................................10

3.3 Source Area Management...........................................................................10 3.3.1 Groundwater Carbon Source Addition ..........................................10 3.3.2 Soil Carbon Source Addition.........................................................11 3.3.3 Groundwater Pumping and Irrigation............................................12 3.3.4 Source Area Capping ...................................................................14

3.3.4.1 Phytocapping.................................................................14 3.3.4.2 Clay Capping.................................................................15

3.3.5 Excavation, Relocation and On-Site Containment of Contaminated Soil ........................................................................17

4 PLAN FOR CONTAMINATION MANAGEMENT .......................................................18 4.1 Off-site Groundwater Plume Management...................................................19

4.1.1 Management of Current Groundwater Uses .................................19 4.1.2 Monitoring Natural Attenuation .....................................................20

4.2 Source Management Areas .........................................................................20 4.2.1 Source Management Area A ........................................................21

4.2.1.1 Groundwater Carbon Source Addition...........................21 4.2.1.2 CSA Soil Remediation ...................................................22 4.2.1.3 Pumping and Irrigation ..................................................22 4.2.1.4 Source Area Capping ....................................................22

4.2.2 Source Management Area B ........................................................23 4.2.2.1 Inspection of the Effluent Drain......................................23


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4.2.2.2 Phytocapping.................................................................23 4.2.2.3 Clay Capping.................................................................24

4.3 Source Management Area C .......................................................................24 4.3.1.1 Excavation, Relocation and On-site

Containment of Contaminated Soil ................................24 4.3.1.2 Phytocapping.................................................................25 4.3.1.3 Clay Capping.................................................................25

4.4 Source Management Area D .......................................................................25 4.4.1.1 Excavation, Relocation and On-site

Containment of Contaminated Soil ................................25 4.4.1.2 Phytocapping.................................................................26 4.4.1.3 Clay Capping.................................................................26

4.5 Source Management Area E .......................................................................27 4.5.1.1 Phytocapping.................................................................27 4.5.1.2 Clay Capping.................................................................27

4.6 Long-Term Environmental Management .....................................................28 4.7 Remediation Environmental Management ...................................................28 4.8 Contingency Management...........................................................................28

5 SCHEDULE................................................................................................................29 6 REFERENCES...........................................................................................................30

TABLES Table 1: Maximum Concentrations in Groundwater compared against Drinking Water Quality

Guidelines. Table 2: Maximum Concentrations in Groundwater compared against Irrigation and Stock

Watering Guidelines. Table 3: Source Management Area Descriptions

FIGURES Figure 1: Site Location Figure 2: Source Management Areas

APPENDICES Appendix A: Background Information Appendix B: Previous Investigations Appendix C: Remediation Feasibility Assessment Appendix D: Management Plans

Appendix D1: Long-Term Management Plan Appendix D2: Remediation Environmental Management Plan Appendix D3: Contingency Management Plan

Appendix E: Gantt Chart


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EXECUTIVE SUMMARY HLA-Envirosciences Pty Limited (HLA) was commissioned by ADI Limited (ADI) to prepare a Contamination Management Plan (CMP), including development of remediation strategies for groundwater contamination associated with the ADI Explosives and Chemicals manufacturing facility, located in Mulwala, New South Wales (the site) in February 2002. Previous investigations have identified a number of on-site sources of contaminants that have contributed to the significant nitrate and sulphate groundwater plumes identified in shallow and deeper aquifers beneath the site and off-site to the south and southwest. This CMP forms part of a phased systematic approach to the preparation of a plan for the management of groundwater contamination identified at the site. A number of environmental site investigations, including numerical flow and solute transport model analysis was undertaken to establish nature and extent of impacts and sources of groundwater contamination. A remediation feasibility assessment was also undertaken to identify and evaluate potential remedial technologies that may be utilised to chemically, physically or biologically remove contaminants from groundwater and soil and restore impacted potential beneficial uses. The CMP was developed to manage the soil and groundwater contamination identified at the site in addition to the protection of the environment during the remedial activities proposed. It provides a description of the cleanup goals with respect to the protection of current groundwater uses, restoration of potential beneficial uses and the extent of remediation required to demonstrate to the stakeholders that a pro-active approach to remediation of contaminated soil and groundwater will be undertaken. MANAGEMENT OF THE OFF-SITE GROUNDWATER PLUME Based on the outcomes of the Remediation Feasibility Assessment report (HLA, 2003f), iIt has been determined that all but one of the available remediation technologies do not represent practicable options for remediation the off-site groundwater plume. Pump and irrigation has been retained for futher assessment during the proof-of-concept phase to determine whether this method could provide a useful reduction in time to restore beneficial uses. Trial pumping and groundwater modelling will be undertaken as part of the proof-of-concept phase proposed for Source Management Area A and used to further assess the practicability of pump and irrigation for off-site plume management. If pump and irrigation is not practicable, it is recommended that the groundwater plume be managed through continued partnership with the current groundwater users and Monitoring Natural Attenuation (MNA) of the off-site plume, in conjunction with the pro-active management measures to deal with the source areas as follows: • Regular communication of the contamination levels in groundwater within the area of

drinking water guideline exceedence for nitrate and sulphate, which is not recommended for use as a potable (drinking) water supply.

• Provision to groundwater users, via the CMP of summary guidelines for use of impacted groundwater for stock watering, such as diluting groundwater used to water poultry and new born stock etc.

• Arrangement for a replacement groundwater bore to be installed if any existing land owner’s

extraction bore is found to contain nitrate and sulphate levels exceeding the stock watering


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guidelines for a twelve month period or more, if the deeper or shallower formation is known to be of suitable quality and yield at that location.

• Monitoring natural attenuation by on-going groundwater monitoring twice a year. • Establishment and maintaining of a register of properties and landowners located within the

area of groundwater impact (exceed drinking water guidelines). • Preparation of an information brochure on the plume and annual mail outs to each property

within the plume to ensure new residents are informed of limitations on groundwater use. • On-going regular community consultative group meetings. • Provision of an annual groundwater monitoring report to all Stakeholders and to be made

available to the public, prepared in a manner that preserves land owner confidentiality to the extent possible.

MANAGEMENT OF SOURCE AREAS Priority source areas identified in the Remediation Feasibility Assessment Report (HLA, 2003f) were grouped together based on their locations and their potential to contribute to groundwater contamination. The location of each source management area is shown in Figure 2 and the management approach adopted for each source management area is discussed below Source Management Area A Source Management Area A was identified as the primary area contributing to the northern arm of the groundwater plume in the Shallow Aquifer and the plume in the Deep Aquifer. As such, it is the primary source area and will be given a greater focus in terms of development and implementation of the most appropriate management strategy. The recommended approach to management of soil and groundwater contamination in Source Management Area A is summarised in the following flow diagram:


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Source Management Area B was identified as the source of the southern arm of the groundwater plume in the Shallow Aquifer. As such, it is one of primary areas contributing to off-site contamination in the Shallow Aquifer. The recommended approach to management of contamination in each of the Source Management Areas B is summarised as follows:

Source Management Area B Management Strategy Effluent Drain.

Source 70

Undertake an inspection of the effluent pipe and (if necessary) undertake remedial actions to minimise or prevent effluent leakage into the unsaturated zone and underlying groundwater.

Backfill drain with soil and supplement with additional natural material, to provide a nominal level of capping to reduce ponding of surface water in the base of the drain.

Planting over the backfilled drain using an appropriate selection of deep and shallow rooting plant species to reduce infiltration of contaminants to groundwater. If monitoring indicates phytocapping does not prove effective in reducing leaching of contaminants from soil, construct a low permeability capping system (i.e. clay cap).

Is CSA Groundwater ManagementPracticable?

1

Is CSA Soil Remediation Practicable?

2

Is Capping of Source Areas Practicable?

Implement CSA Soil and Groundwater Remediation

Implement Capping

Yes

Undertake Proof-of-Concept

Trial

Implement Monitoring Natural

Attenuation

Note: CSA - Carbon Source Addition 1 - Management of dissolved nitrate and sulphate within aquifer(s) at the source 2 - Cleanup of nitrate and sulphate contamination in soil (base of dune sand and clay in upper Shepparton Formation)

Yes

No

Is Pump & Irrigation Practicable?

NoNo

YesYes

No


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Source Management Areas C and D are located in areas where they may be contributing to the northern arm of the groundwater plume in the Shallow Aquifer and are areas where waste material is present across the ground surface. As such, Source Management Areas C to D were identified as areas requiring management. The recommended approach to management of contamination in each of the Source Management Areas C and D are summarised as follows:

Source Management Area C Management Strategy Dump Areas-Current Boiler House and Coal Yard.

Source 106

Excavate waste materials (i.e. gypsum) and placement in either an off-site landfill, licensed to accept the waste, an engineered on-site landfill (i.e the area along the southern boundary of the site where the Shepparton Formation is absent) or under the proposed modernisation building footprints.

Replace waste and soil removed from source area with topsoil or a growing medium. Plant a phytocap of an appropriate selection of deep and shallow rooting plant species. If monitoring indicates phytocapping does not prove effective in reducing leaching of contaminants from soil, construct a low permeability capping system (i.e. clay cap).

Source Management Area D Management Strategy Dump Area-Iron Oxide and Sulphur Dumps.

Source 103

Dump Areas (NG) - Sulphur Dump.

Source 102

Excavate waste material and placement in either an off-site landfill, licensed to accept the waste, an engineered on-site landfill (i.e the area along the southern boundary of the site where the Shepparton Formation is absent) or under the proposed modernisation footprint.


Source Management Area E was identified as having some potential to be contributing to the northern arm of the groundwater plume in the Shallow Aquifer based on it’s location. As it could not be ruled out as a potentially significant source area, management measures were recommended for Source Management Area E. The recommended approach to management of contamination in each of the Source Management Areas E is summarised as follows:


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Source Management Area E Management Strategy Oleum Area - 314 Sulphur Store and Former Sulphur Store.

Sources 50 & 51

Acid Area - Acid Drains.

Source 35

Implementation of a cap over Source Management Area E using clay and topsoil and an appropriate selection of deep and shallow rooting plant species to aid in the removal of shallow nitrate and reduce rainfall infiltration. Existing and future buildings and pavements are assumed to act as effective capping.

Plant a phytocap of an appropriate selection of deep and shallow rooting plant species in areas not covered by buildings or pavements. If monitoring indicates phytocapping does not prove effective in reducing leaching of contaminants from soil, construct a low permeability capping system (i.e. clay cap).

Prior to the implementation of the recommended remediation and management approaches to the source management areas, the following two main preparation measures are required:

• Proof-of-Concept trial.

• Detailed Design of works. A proof-of-concept trial is required to avoid unnecessary time and expense on unsuccessful remediation measures and to confirm the practicability of the methods selected for remediation. It is also intended to assist with determining the detailed design of works. The scope of the proof-of-concept trials required to evaluate the technologies proposed in the Remediation Feasibility Assessment report (HLA, 2003f) are summarised as follows:

PROOF-OF-CONCEPT AND DESIGN The first phase of implementation of the CMP is a proof-of-concept phase which involves additional assessment of the practicability and development of detailed design parameters for potential management strategies in Source Management Area A and the off-site groundwater plume.

Groundwater Carbon Source Addition Proof-of-concept testing is to be completed out prior to undertaking the remediation program to adequately confirm details such as the final configuration of injection, monitoring and re-injection bores and monitoring frequency. It is intended that the testing also:

• prove the carbon source addition concept to enhance microbial denitrification, and avoid manganese and sulphate reduction in the aquifer;

• evaluate reaction rates; and

• evaluate the production of other intermediary chemicals and end products.

The testing form’s the basis of a detailed design that includes, but is not limited to, the following:


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• The number and configuration of injection and monitoring wells including consideration of diffusivity and the most cost-effective delivery system for carbon source addition.

• The cost and practicability of horizontal injection bores.

• The mass and rates of carbon source addition required.

• Cost benefit analysis of carbon source type (eg. ethanol, glucose, etc.) against the number of bores necessary.

• Logistics such as carbon source storage, deliver, labour and resource requirements, contingency planning materials and equipment.

• Consideration of any design requirements to address areas where the permeability of the clay separating the two aquifers is higher (i.e. the location of the principal pathway from Shallow to Deep Aquifers).

Soil Carbon Source Addition It is intended that the infiltration of a carbon source into soil will enable a bio-reactive zone to be created in the unsaturated zone to facilitate the biodegradation of nitrate and sulphate in clay layers of the upper Shepparton Formation which area acting as secondary sources of groundwater contamination in both the shallow and deeper aquifers. Testing will be undertaken to form the basis of a detailed design that includes, but is not limited to, the following:

• The most effective and cost-effective methods for diffusing the carbon source material throughout the soil profile.

• Locations and configuration of injection / diffusion points.


• Cost benefit analysis of carbon source type (eg. ethanol, glucose, etc.) against the number of injection / diffusion points necessary.

• Logistics such as carbon source storage, delivery, labour and resource requirements, contingency planning materials and equipment.

• Consideration of any design requirements to address areas where permeability of the soil profile varies (including the higher permeability aquitard area).

Source Area Phytocapping To assist with completion of the final design and meet the objective of evaluating the practicability of phytocapping of selected source areas, the proof-of-concept trial will include the following as a minimum:

• Undertake a study into the types of plants that can be used for preferential uptake of nitrate, but will withstand the presence of other contaminants in soil.


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• Establishment of baseline conditions beneath the trial area, with respect to the existing levels of soil and groundwater contamination, saturated and unsaturated soil profile conditions, using lysimeters, and utilising where possible the available existing information.

• Installation of phytocapping by placement of topsoil (existing stockpiled soil adjacent to the effluent drain may be suitable at that location) and selected shallow and deep rooting plant species.

• Installation of lysimeter monitoring infrastructure as part of the capping construction to monitor the unsaturated and saturated zone conditions through the soil profile, to prove the effectiveness of the phytocapping capping approach.

• Assessment of appropriate spacing for planting of deep and shallow rooting species.

• Quarterly groundwater monitoring for nitrate and sulphate to determine whether infiltration and impact to groundwater are reducing over time.

The results of the trials will also be used to prepare detailed designs for each of the capping areas that includes (but is not limited to) the following:

• Confirmation of which areas will be phytocapped and which will be managed with clay capping or a combination of the two.

• Management of stormwater run-on.

• Revegetation and erosion control.

• Overall design specifications sufficiently developed for use in tendering for construction.

• The precise area of capping required (which will involve further delineation including sampling and analysis of soils in source areas).

• Identification and removal of any underground services that may be sources of additional infiltration.

• Consideration of the nature and working life of capping medium utilised.

• Impact of capping on the extent of and concentration within the plume.

• An inspection and testing plan for cap integrity.

• Recognition that capping does not remove soil contaminants and therefore that on-going groundwater monitoring will be required.

• Recognition of existing paved and built-out areas as capping and designing around maintaining or enhancing those (including leaving concrete slabs in place in the event that any building demolition is carried out).

• The level of surficial soil contamination (i.e. sulfates) with respect to the ability of the soil to support revegetation.

• The potential need for imported clay and topsoil to support surface revegetation over contaminated soils in some locations.

• The effectiveness of planting in nitrate reduction – i.e. “Phytoremediation”.


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• The effectiveness of planting in reducing sulphate mobilisation by reducing infiltration rates sufficiently.

• On-going management – plant life, harvesting, grazing etc.

• The depth of penetration of nitrate reduction by plants.

Excavation, Relocation and On-site Containment of Contaminated Soil As part of the detailed designs for capping and landfilling of waste and contaminated soils, any area where contaminated soil is to be excavated (as is proposed for soil and surface contamination proposed for containment onsite) requires a detailed design which will include (but not be limited to) the following:

• Planning for compliance with all of the applicable precautions for erosion control, excavation and related activities.

• Any of the applicable considerations for capping (phytocapping or clay capping) of the landfill.

• Sourcing topsoil/growing medium.

• Determination of soil volumes in areas to be excavated, through further soil sampling and analysis, giving consideration to the remedial objectives and reduction in downgradient groundwater concentrations.

• Handling and disposal intentions for excavated source zone material (e.g. transport, placement, spreading, compaction, containment capping etc).

• Capping and re-instatement of source areas from where soil is excavated to avoid erosion and further infiltration.

• Determination of validation criteria and reinstatement objectives.

STAND ALONE ELEMENTS OF THE CMP Long-Term Environmental Management The Long-Term Management Plan provides a summary of the potential environmental issues anticipated to require management in the long-term, including the period prior to commencement of any contamination management / remediation measures outlined in the body of the CMP report. It also outlines the necessary management strategies, actions, monitoring and reporting measures to be undertaken to minimise the risk of any further impact to the environment and to meet the environment protection expectations of Government authorities and the community. Remediation Environmental Management The Remediation Environmental Management Plan describes the environmental management procedures including monitoring and reporting measures to be undertaken during remediation, to minimise the risk of impact to the environment and to meet the environment protection expectations of Government authorities and the community and minimise safety risks and inconvenience to operations at the facility and the community, including nearby residents relating to the proposed remediation activities.


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Contingency Environmental Management The Contingency Management Plan addresses the management target and objectives in the case that the remediation management plan is unsuccessful. TIMING The timeframe to manage the off-site groundwater plume and on-site source areas including undertaking proof-of-concept trials, and detailed design of the works prior to implementation of the remediation is presented for the implementation of the Contamination Management Plan has been developed based on the technologies selected for remediation.


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1 INTRODUCTION

1.1 General HLA-Envirosciences Pty Limited (HLA) was commissioned by ADI Limited (ADI) to prepare a Contamination Management Plan (CMP), including development of remediation strategies for groundwater contamination associated with the ADI Explosives and Chemicals manufacturing facility, located in Mulwala, New South Wales (the site) in February 2002. Previous investigations have identified a number of on-site sources of contaminants that have contributed to the significant nitrate and sulphate groundwater plumes identified in shallow and deeper aquifers beneath the site and off-site to the south and southwest. This CMP report outlines the implementation of the most practicable approach to the remediation or management of off-site groundwater and on-site sources of contamination.

1.2 Objectives of Contamination Management Plan The objectives of the CMP are to describe the development of the management target and objectives, including an outline of the regulatory framework and the approach to the remediation or management of soil and groundwater contamination in accordance with the NSWEPA Guidelines for Consultants Reporting on Contaminated Sites (NSW EPA, 1998). The CMP has been developed to deal with the soil and groundwater contamination identified at the site. It provides a description of the cleanup goals with respect to the protection of current groundwater uses, restoration of potential beneficial uses and the extent of remediation required to demonstrate to the stakeholders that a pro-active approach to remediation of contaminated soil and groundwater will be undertaken.

The CMP provides a long-term management plan to be incorporated prior to the commencement of the plan for contamination management and beyond the completion of any remediation works. The long-term management plan provides a summary of the potential environmental issues anticipated to require management in the long-term, including the period prior to commencement of any contamination management / remediation measures outlined in the body of the CMP report. It also outlines the necessary management strategies, actions, and monitoring and reporting measures to be undertaken to minimise the risk of any further impact to the environment to meet the environment protection expectations of Government authorities and minimise safety risks and inconvenience to operations at the facility and the community, including nearby residents relating to the proposed remediation activities. Any remediation will be undertaken in accordance with the Remediation Environmental Management Plan (Appendix D2). The Remediation Environmental Management Plan describes environmental management procedures including monitoring and reporting measures to be undertaken during remediation, to minimise the risk of impact to the environment and to meet the environment protection expectations of Government authorities and the community, and minimise safety risks and inconvenience to operations at the facility and the community, including nearby residents relating to the proposed remediation activities. Should it be found that trigger levels signalling unsatisfactory performance of the clean up/management technologies are reached then contingency planning measures outlined in Appendix D3 (Contingency Management Plan) for the protection of the environment will be


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implemented. The contingency management plan addresses the management targets and objectives in accordance with the NSWEPA Guidelines for Consultants Reporting on Contaminated Sites (NSW EPA, 1998).

1.3 Development of the Scope of the Contamination Management Plan

This CMP forms part of a phased systematic approach to the preparation of a plan for the management of groundwater contamination identified at the site. A number of environmental site investigations, including numerical flow and solute transport model analysis was undertaken to establish nature and extent of impacts and sources of groundwater contamination. A remediation feasibility assessment was also undertaken to identify and evaluate potential remedial technologies that may be utilised to chemically, physically or biologically remove contaminants from groundwater and soil and restore impacted potential beneficial uses. The CMP was developed as a management plan for the remediation of contaminated soil and groundwater identified at the site in addition to the protection of the environment and human health during the remedial activities proposed for the site and surrounds.

1.4 Stakeholder Consultation ADI and Defence have undertaken to maintain regular communications with relevant stakeholders including the Auditor (Dr Peter Nadebaum), New South Wales Environment Protection Authority (NSW EPA), NSW Department of Infrastructure, Planning and Natural Resources (DIPNR), Corowa Shire Council and the community consultative group during the project. Regular meetings have been held between the sate and local regulatory authorities, occurring at approximately 3 - 4 monthly intervals during the project. Presentations to the community consultative group have also been undertaken at a similar frequency and open meetings with the Yarrawonga/Mulwala community have been held every 6 months to inform the broader residential population of the issues and findings of the study. ADI and Defence’s partnership with the groundwater user residents and Council have enabled the effective communication of specific issues relating to the site and the impact of the off-site groundwater to all relevant stakeholders outlined above. The development of the CMP has been undertaken with input from each of the relevant stakeholders during each phase of the investigative works, and their respective role’s have been written into the CMP to enable continued effective management of the identified contamination issues.

1.5 Structure of Contamination Management Plan The CMP is not intended to provide a history of the previous investigations undertaken, extensive analysis of the geological and hydrogeological settings, or describe in detail the extent to which the remedial technologies have been evaluated to come up with the remediation strategy(s) for the site. The background and related information is presented within the previous six reports prepared by HLA (HLA 2003a, 2003b, 2003c, 2003d, 2003e and 2003f) and summarised in Appendices A to C, attached to the CMP report.

1.5.1 Report The structure of the report, presented herein, is summarised as follows:


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• Section 2 presents a summary of the remedial targets and objectives through an

interpretation of the regulatory framework and derivation of cleanup goals and extent of remediation required for the protection of current groundwater users and the restoration of potential beneficial uses.

• Section 3 presents a description of the proof-of-concept and design of works that will be

undertaken as the first stage of management of the off-site groundwater and on-site source areas.

• Section 4 presents the plan for management including the approach to manage soil and

groundwater contamination identified off-site and within five on-site source areas (Source Management Areas A to E).

• Section 5 presents the Schedule including a timeframe for implementation of the

Contamination Management Plan. • Section 6 lists references used to compile this report.

1.5.2 Appendices The content of each appendix is described below: • Appendix A summarises the background information, including historical and current on-

site and surrounding land uses, topography and drainage, regional geology, hydrogeology and water quality and the geological and hydrogeological setting of the investigation area (including geophysics and surface water body influences), obtained from a number of previous reports in addition to a number of studies undertaken by HLA.

• Appendix B details of the previous investigations undertaken at the site including

environmental site investigations, numerical flow and solute transport model analysis and remediation feasibility studies. A summariy of the condition of the site by describing the priority contaminants, the nature and extent of impacts and sources of groundwater contamination on and off the site is also included in Appendix B.

• Appendix C presents a summary of the Remediation Feasibility Assessment report (HLA,

2003f), which identified and evaluated all possible remedial technologies and recommended preferred management strategies to reduce the potential for groundwater contamination to restore impacted beneficial uses at the site.

• Appendix D discusses the details of the operational phase of the Contamination

Management prepared for the ADI site. This appendix consists of the following plans.

• Appendix D1, Long-Term Management Plan details the preferred outcome of the contamination management plan based on the previously defined goals and objectives for management of the contaminated soil and groundwater.

• Appendix D2, Remediation Environment Management Plan details the administrative functions required for implementation of the preferred strategy.

• Appendix D3, Contingency Management Plan details contingency plans for management of the contaminated soil and groundwater should the preferred strategy detailed in the long-term management plan not deliver the expected outcomes.


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2 MANAGEMENT TARGETS AND OBJECTIVES

2.1 Regulatory Framework and the Role of the Environmental Auditor

There is no legal requirement guideline under Commonwealth legislation for assessment and management of historical groundwater contamination issues to be addressed. The site is owned by the Commonwealth, and therefore, not under state jurisdiction. The NSW EPA has not formally declared the area a significant risk of harm. However, Defence has agreed to involve all relevant stakeholders (including the NSW EPA, DIPNR, Corowa Shire Council, and local residents) and to assess and manage groundwater in general accordance with relevant state legislation, consistent with an aim to promote best practice in environmental management. The NSW regulatory framework for the protection of groundwater quality throughout NSW is outlined in the NSW State Groundwater Policy Framework Document (1997). Protection of groundwater from contamination and the regulation of groundwater contamination and clean up is enforced by the NSW EPA through components of the Protection of the Environment Operations (POEO) Act (1997) and the Contaminated Land Management (CLM) Act (1997). The management of groundwater resources and the identification of groundwater beneficial uses is regulated by DIPNR on a site specific basis under the provisions of the Water Management Act (2000). Normal practice at sites under NSW jurisdiction with soil and groundwater contamination would include assessment of contamination and development and implementation of remedial strategies to be independently audited by an NSW EPA-appointed Environmental Auditor. ADI engaged Dr Peter Nadebaum, a NSW EPA-appointed Environmental Auditor, to audit the work performed by HLA and other consultants. Although it has not formally been adopted by the NSW EPA, an approach to the assessment of clean up requirements for groundwater contamination which is similar to the Environment Protection Authority Victoria’s (EPAV) guidelines has been adopted for the site. In essence, the EPAV approach leads to a remediation feasibility assessment to identify the most practicable approach to clean up of groundwater contamination. The approach generally involves the following steps:

1. Establish the potential beneficial uses of groundwater based on background salinity.

2. Establish water quality criteria relevant to the potential beneficial uses of groundwater.

3. Delineate the horizontal and vertical extent of contamination above water quality criteria.

4. Assess the long-term fate of groundwater contamination, typically using groundwater modelling techniques.

5. Screen potential remediation technologies and identify the most practicable approach for clean up with respect to:

(a) Technical feasibility (i.e. the ability to achieve clean up goals);


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(b) Logistical constraints;

(c) Timing; and

(d) Cost.

6. Implement the most practicable approach under a groundwater management plan. Details of Steps 1 to 4 at the site are presented in earlier reports prepared by HLA and are summarised in Appendices A (Background Information) and B (Previous Investigations). The Remediation Feasibility Assessment report (HLA, 2003f) documents Step 5 of the process and is summarised in Appendix C. This CMP addresses Step 6 of the process and the preparation of a plan for the management of groundwater contamination identified at the site. It follows the same process and uses the same assumptions inherent in the approach outlined above. Under the NSW State system, the Auditor will make decisions on appropriate management strategies with regard to the Contaminated Land Management (CLM) Act (1997) and consideration of what represents cleanup to the extent practical. In many cases cleanup to restore all protected beneficial uses of groundwater is not practical or environmentally sustainable and therefore maintaining natural attenuation may be the preferred management strategy.

2.2 Remedial Works Any remedial works will be subject to relevant Commonwealth legislation. The Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) is the Commonwealth Governments primary environmental protection legislation. The objectives of the EPBC Act are to promote ecologically sustainable development, the conservation of biodiversity, promote a co-operative approach to the protection and management of the environment involving governments, the community, and landholders, and to assist in the co-operative implementation of Australia's international environmental requirements. Under the assessment and approval provisions of the EPBC Act, actions that are likely to have a significant impact on a matter of national environmental significance are subject to a rigorous assessment and approval process. An action includes a project, development, undertaking, activity, or series of activities. Triggers for evoking the EPBC Act may occur in relation to any works or development; either on- or off-site, that impacts on the six matters of National significance listed under the Act. Any proposed actions for remediation will be referred to Environment Australia for consideration under the EPBC Act.

2.3 Current Groundwater Uses The Corowa Shire Council’s Development Control Plan (DCP) states that no dwellings can be constructed within the Mulwala Homestead Estate, without connection to the Shire’s mains water supply. All residential properties in a hydraulically down-gradient direction of the site, have been notified of elevated concentrations of nitrate and sulphate in groundwater. All properties have access to mains water and as a result, residents have been able to accommodate not using groundwater


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as a drinking water supply. It is our understanding that only one resident used groundwater as a drinking supply and that resident has since ceased that use of groundwater. Under Section 149 of the Environmental Planning and Assessment Act 1979 (EP&A Act), a local council is required, upon application, to issue a certificate providing information of planning controls or property affectations relating to any piece of land within the council area. Currently, all properties within the area identified by the nitrate and sulphate plumes have a Section 149 certificate which reads ‘ Information available to Council indicates that this property is in an area where the groundwater may contain higher levels of sulphate, nitrate and salinity than that recommended for human consumption by the Australian Drinking Water Guidelines, 1996. Persons should satisfy themselves by their own inquires as to the nature of any contamination that may affect any proposed land use.’ However, the council has no power to restrict the use of the groundwater for drinking purposes. Groundwater within the plume areas is currently used for irrigation and domestic purposes (i.e. washing). Groundwater users have found that the use of impacted groundwater was not suitable for irrigation of a number of plant species, particularly some indigenous plant species that are generally less tolerant to nitrate. Residents have modified their selection of plant species and the impacted groundwater has proved a viable irrigation water supply for nitrate tolerant species. Given the rural residential nature of the properties within the plume, it is likely that groundwater is used for stock watering (including a limited numbers of sheep, poultry, horses and domestic pets). In discussions with ADI and residents, it is our understanding that unacceptable impacts associated with use of groundwater for stock watering have not been identified to date.

2.4 Potential Beneficial Uses of Groundwater The average TDS of groundwater in both aquifers, outside the areal extent of impacts associated with the site, was generally found to be less than 1,000 mg/L. Based on the adopted regulatory framework the potential beneficial uses considered applicable for both the shallow and deep aquifers are as follows:

• Maintenance of ecosystems;

• Potable water supply;

• Potable mineral water supply;

• Agricultural water supply: irrigation;

• Agricultural water supply: stock watering;

• Industrial water use;

• Primary contact recreation; and

• Buildings and structures. Results of groundwater investigations have shown that surface water bodies have not been impacted by contaminated groundwater. Therefore, there has been no impact on Maintenance of Ecosystems by groundwater contamination associated with the site. Beneficial uses other than Maintenance of Ecosystems primarily relate to the extraction of groundwater. Of the uses associated with groundwater extraction, which have been impacted in the Shallow and Deep Aquifers, the most sensitive beneficial use is drinking water (human health guidelines).


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The ANZECC (2000) guidelines for Primary Contact Recreation (44.3 mg/L nitrate, 400 mg/L sulphate and 100 mg/L manganese), which are based on the Raw Water for Drinking Water Supply values documented in the ANZECC Water Quality Guidelines (1992) are conservative for non-volatile inorganic contaminants. According to the ANZECC 2000 guidelines, the acceptable guidelines for recreational primary contact water use can be up to 20 times higher than the proposed guideline value (based on ingestion considerations). Based on this, it would be reasonable to assume that acceptable concentrations for Primary Contact Recreational use for nitrate could be up to 880 mg/L, sulphate – up to 8,000 mg/L and manganese – up to 2,000 mg/L. Therefore, it can be seen that there are no exceedences of these chemicals in groundwater in the off-site plume. However, it should be noted that there are a number of exceedences for pH in groundwater in the off-site plume and therefore groundwater may not be suitable for Primary Contact Recreation, due to low pH values. The maximum encountered concentrations of nitrate, sulphate, pH and manganese compared with the water quality guidelines for drinking water are summarised in Table 1 below:

Table 1: Maximum Concentrations in Groundwater compared against Drinking Water Quality Guidelines

Beneficial Use Assessment Criteria 1

Chemical Maximum

Concentration (in Shallow Aquifer)

Maximum Concentration

(Calivil Aquifer) NHMRC 1996 2

Drinking Water (Human Health)

NHMRC 1996 2

Drinking Water (Aesthetic)

Nitrate (as Nitrate)

BH93A

1825 mg/L

BH93B

691 mg/L 50 mg/L -

Sulphate BH53A

1220 mg/L

BH93B

1220 mg/L 500 mg/L 250 mg/L

pH BH88

3.11 units

BH94B

5.15 units -

6.8 – 8.5

units

Manganese BH11

9.26 mg/L

BH55B

5.60 mg/L 0.5 mg/L 0.1 mg/L

Notes: 1 Additional applicable beneficial uses with less sensitive cleanup goals apply that have not been

included herein. Refer to HLA-Envirosciences (2003, b)

2 National Health and Medical Research Council, Agriculture and Resource Management Council of Australia and New Zealand (1996). Australian Drinking Water Guidelines.

Based on the estimated and calculated aquifer properties (refer to HLA, 2003b) and the calculated area of nitrate above the drinking water criteria value of 50 mg/L, the volume of the plume is estimated to be 3,630 ML. Of this plume volume, approximately 1790 ML is from the Shepparton Formation (of which 1005 ML is located outside the ADI site boundaries), while 1840 ML is for the Calivil Formation (of which 1665 ML is located beyond the ADI site). Further details of the derivation of plume volumes is provided in the Remediation Feasibility Assessment Report (HLA, 2003f).


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2.5 Cleanup Goals Based on an assessment of the relevance of beneficial uses of groundwater off-site, the drinking water guidelines for the protection of human health (nitrate 50 mg/L and sulphate 500 mg/L) will be adopted as cleanup goals. Although the drinking water guildelines were adopted as the groundwater quality abjectives, further refinement of these cleanup goals may be undertaken if additional information into the nature, physical or chemical behaviour, toxicity or risk associated with nitrate and sulphate in groundwater becomes available in the near future.


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3 PROOF-OF-CONCEPT AND DESIGN OF WORKS

3.1 Trial and Design Concepts Prior to the implementation of the recommended remediation and management approaches to the site, the following two main preparation measures are required:

• Proof-of-Concept trial.

• Detailed Design of works. A proof-of-concept trial is required to avoid unnecessary time and expense on unsuccessful remediation measures and to confirm the practicability of the methods selected for remediation. It is also intended to assist with determining the detailed design of works. The scope of the proof-of-concept trial needs to include evaluation of all of the technologies proposed in Section 4, as recommended in the Remediation Feasibility Assessment report (HLA, 2003f). Specifically, the proof-of-concept trial is required to confirm the practicability and efficiency of the following:

• Groundwater remediation by Carbon Source Addition (CSA) direct injection.

• Groundwater remediation by recirculation comprising extraction, ex-situ CSA mixing and re-injection.

• Groundwater extraction and irrigation.

• Soil source remediation by direct CSA application to soil.

• Phytocapping.

• Relocation of contaminated soil to on-site containment structure In determining practicability the trial needs to take into account all of the considerations addressed in the Remediation Feasibility Assessment report (HLA, 2003f), including the estimated time to achieve clean-up goals and any adverse impacts to the existing use of the groundwater for irrigation, domestic use (i.e. washing) and as stock water. The specific items recommended for the proof-of-concept trial are discussed in Sections 3.2 and 3.3 as follows.

3.2 Off-site Groundwater Plume Management

3.2.1 Management of Current Groundwater Uses There are no specific proof-of-concept or technical design requirements for managing the current groundwater uses. However, it is necessary to confirm that the proposed management measures are acceptable to the community and other stakeholders. It is also necessary for the management programme to provide for continuous improvement and future modification, in consultation with the stakeholders, to allow for changes in the circumstances of the contamination. The long-term environmental management plan is detailed in Appendix D.1 and a summary of the management measures to be implemented is outlined in Section 4.1.1.


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3.2.2 Monitoring Natural Attenuation No specific proof-of-concept testing is required to complete the design and commencement of an on-going groundwater monitoring programme. On-going groundwater monitoring will be required in conjunction with other proposed remediation and management measures (see Appendix D1, Section D1.6.3.5). Monitoring is proposed twice a year. Regular review of the monitoring programme in consultation with the Auditor (Dr Peter Nadebaum), community consultative group and other stakeholders will be undertaken to establish any trends that develop in monitoring results and to ensure that all affected domestic extraction bores are included, along with an optimal selection of monitoring wells and appropriate analytes for testing. On-going groundwater monitoring will include all groundwater users in the affected area (as are currently monitored) and a selection of monitoring wells that optimises confirmation of the boundaries of exceedence for adopted (drinking and stock watering) guidelines in the Calivil and Shepparton formation aquifers. As with management of the current groundwater uses, monitoring and natural attenuation is a long-term requirement and the relevant measures are detailed in Appendix D.1 Long-Term Environmental Management Plan, attached. A summary of the measures intended for implementation is provided in Section 4.1.2.

3.3 Source Area Management

3.3.1 Groundwater Carbon Source Addition The proof-of-concept testing is to be undertaken to confirm details such as the final configuration of injection, monitoring and re-injection bores and monitoring frequency. It is intended that the testing also:

• prove the carbon source addition concept to enhance microbial denitrification, and avoid manganese and sulphate reduction in the aquifer;

• evaluate reaction rates; and

• evaluate the production of other intermediary chemicals and end products.

To assist with completion of the final design and meet the objective of evaluating the practicability of the CSA direct injection and CSA re-circulation approaches, the proof-of-concept trial will include the following as a minimum:

• Injection of carbon source material into at least two existing bores, followed by groundwater sampling from adjacent monitoring bores (at least two per injection bore, hydraulically down-gradient and cross-gradient) to determine diffusivity of the carbon source and the radius of influence for contaminant degradation.

• The analysis for the monitoring samples would need to include most, if not all of the parameters listed for Monitoring of Natural Attenuation in Appendix D.1, as well as ethanol or any other carbon source adopted for trial.

• Hydrogeological pumping tests and groundwater modelling to determine the radius of influence for extraction and re-injection, the amount of pumping required to achieve a reverse in vertical hydraulic gradient from the Calivil Formation into the Shepparton


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Formation and the bore configuration required to achieve a capture zone of the highest concentration groundwater contamination.

• Qualitative identification and evaluation of any risks posed by potential adverse by-products generated.

The testing will form the basis of a detailed design that includes, but is not limited to, the following:

• The number and configuration of injection and monitoring wells including consideration of diffusivity and the most cost-effective delivery system for carbon source addition.

• The cost and practicability of horizontal injection bores.


• Cost benefit analysis of carbon source type (eg. ethanol, glucose, etc.) against the number of bores necessary.

• Logistics such as carbon source storage, deliver, labour and resource requirements, contingency planning materials and equipment (see Appendix D.3).

• Consideration of any design requirements to address areas where the permeability of the clay separating the two aquifers is higher (i.e. the location of the principal pathway from Shallow to Deep Aquifers).

It is anticipated that the configurations for direct injection and re-circulation will approximate the conceptual cross-sections presented in the Remediation Feasibility Assessment report (HLA 2003f, Figures 6 and 7). However, it is considered likely that horizontal drilling will be more efficient at diffusion of the carbon source.

3.3.2 Soil Carbon Source Addition It is intended that the infiltration of a carbon source into soil will enable a bio-reactive zone to be created in the unsaturated zone to facilitate the biodegradation of nitrate (and potentially sulphate) in clay layers of the upper Shepparton Formation which area acting as secondary sources of groundwater contamination in both the shallow and deeper aquifers. To assist with completion of the final design and meet the objective of evaluating the practicability of the CSA soil remediation, the proof-of-concept trial will include the following as a minimum:

• Drilling to recover at least two intact cores from the unsaturated soil profile of the Upper Shepparton Formation clays and completion of laboratory scale carbon source application tests to determine permeability, diffusivity and depth of influence for contamination breakdown, etc. Chemical analysis as part of the soil profile testing will include, at a minimum, the parameters listed for Monitoring of Natural Attenuation in Appendix D.1, as well as ethanol or any other carbon source adopted for trial.

• Trial of effective diffusion and penetration for various methods of direct application of

carbon source (infiltration gallery, injection into shallow Dune Sand bores, etc). The testing will form the basis of a detailed design that includes, but is not limited to, the following:


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• The most effective and cost-effective methods for diffusing the carbon source material throughout the soil profile.

• Locations and configuration of injection / diffusion points.


• Cost benefit analysis of carbon source type (e.g. ethanol, glucose, etc.) against the number of injection / diffusion points necessary.

• Logistics such as carbon source storage, delivery, labour and resource requirements, contingency planning, materials and equipment.

• Consideration of any design requirements to address areas where permeability of the soil profile varies (including the higher permeability aquitard area).

Prior to commencing the CSA trials, DIPNR will be consulted with respect to the carbon source proposed and the method of application.

It is anticipated that the configuration for CSA to soil will approximate the conceptual cross-section presented in the Remediation Feasibility Assessment report (HLA 2003f, Figure 8). The means of applying the carbon source to the ground is expected to require on-site storage and manual application, although this will be confirmed by the proof-of-concept trial and built into the final design. It is considered unlikely that further soil investigations to define the extent of contamination laterally and to depth in the Source Management Areas would add significant value (particularly in Source Management Area A). Migration of contaminants to depth is likely to be associated with preferential pathways associated with naturally occurring features, such as shrinkage cracks, or the effects of acids on the clays in the upper Shepparton Formation. Given the nature of the nitrate and sulphate contamination (i.e. spills of concentrated acids) it is unlikely that the additional costs associated with collecting and analysing soil samples from a grid will result in the exact delineation of the contamination given that the contaminants have spread vertically through the soil profile and horizontally within preferential pathways with the Source Management Areas. The recommended approaches to managing soil contamination (CSA for Soil and Capping) and the estimated lateral extent of source areas are believed to be sufficiently robust to address the issue. However, if it can be justified using a cost benefit approach, then it may be applicable to undertake further sampling within the Source Management Area to significantly reduce the remediation costs.

3.3.3 Groundwater Pumping and Irrigation Further assessment is required regarding the practicability of using groundwater extraction and irrigation to remediate the broader plume. Pumping and irrigation of contaminated groundwater may have some targeted use in sources areas as a stand alone remedial option or in conjunction with other technologies such as re-circulation and CSA, which might benefit from strategic extraction to reduce further migration of groundwater contamination off-site. This approach will be undertaken if CSA groundwater management is not feasible, to provide an alternative water supply to the nearby golf-course as well as providing nutrients in the form of dissolved nitrate. This would also provide a benefit to the community and the surrounding environment by reducing the requirement for importing fertilisers.


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Proof-of-concept testing will be required, to assist with the completion of the final design and in particular evaluate the practicability of groundwater extraction from as a supplementary method. The trial will include the following as a minimum:

• Hydrogeological pumping tests and groundwater modelling to determine the radius of influence for pumping extraction, the amount of pumping required to achieve a reverse gradient from the Calivil Aquifer into the Shepparton Aquifer and the bore configuration required to achieve a capture zone of the highest concentration contaminated groundwater.

• The pumping tests and groundwater modelling will include sufficient testing and modelling to determine whether a pump and irrigate approach to remediation of groundwater can be facilitated without significant impact to the existing domestic irrigation resource for groundwater users hydraulically down-gradient.

• Mathematical estimation of the likely range of analyte concentrations (including all identified contaminants and potential by-products) that would be present in the groundwater delivered to the irrigation system and impact of contaminants on soils and plants at the golf course.

• Based on the specific characteristics of the water extracted, evaluation of potential irrigation strategies, sustainable irrigation rates, suitable crop types and likely costs will be undertaken.

• Confirmation of the on-site areas available and suitable for irrigation.

It should be noted that the DIPNR have an embargo on the area for irrigation purposes. An application for the extraction and irrigation of groundwater will need to be lodged with DIPNR prior to undertaking the trials. The results of groundwater modelling will be presented to DIPNR to assist in their assessment of groundwater extraction on the resource potential of the aquifers. The DIPNR have also expressed an interest in reviewing the application of extracted contaminated groundwater to soil in accordance with the Soil Conservation Act (1938) for the protection of soil health.

The testing will form the basis of a detailed design that includes (but is not limited to) the following:

• Bore configurations, yields and pumping rates required to reverse the hydraulic gradient so that the flow direction is vertically upward from the Calivil Aquifer into the Shepparton Aquifer.

• Bore configurations, yields and pumping rates required to create a capture zone within the Shepparton formation, thereby minimising on-going expansion of the broader plume down-gradient while minimising the impact to the existing groundwater use for domestic irrigation.

• Area required for sustainable irrigation based on the pumping rates determined above (note that guidelines for the appropriate application rates and areas required for groundwater irrigation are provided in the Remediation Feasibility Assessment Report).

• Configuration of water reticulation, storage, pumping and irrigation infrastructure.

• Logistics such as operational and maintenance labour and resource requirements.


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3.3.4 Source Area Capping The following have been selected as practicable technologies for capping contaminated source areas and soil containment / landfilling facilities constructed at the site:

• Clay capping – engineered design, placement and compaction of 150 – 300 mm of clay material over the top of the source, soil containment or landfilled area, including some revegetation and construction of sufficient surface grade to drain surface water run-off (i.e. 3%).

• Phytocapping – planting of a range of shallow and deep rooting plant species over source

areas to reduce rainwater infiltration and to achieve at least partial take-up of nitrate by the plants.

The areas designated for capping are presented in Section 4 below. As discussed in the Remediation Feasibility Assessment report (HLA, 2003f), if phytocapping can be shown to be effective in sufficiently reducing leaching of contaminants from contaminated soil acting as secondary sources, it would be preferred over clay capping as it may result in the partial removal of some of the contaminant mass (nitrate). Therefore, phytocapping may potentially be more effective and environmentally sustainable.

3.3.4.1 Phytocapping To assist with completion of the final design and meet the objective of evaluating the practicability of phytocapping of selected source areas, the proof-of-concept trail and detailed design will include (but not be limited to) the following:

• Undertake a study into the types of plants that can be used for preferential uptake of nitrate, but will withstand the presence of other contaminants in soil.

• Establishment of baseline conditions beneath the trial area, with respect to the existing levels of soil and groundwater contamination, saturated and unsaturated soil profile conditions, using lysimeters, and utilising where possible the available existing information.

• Installation of phytocapping by placement of topsoil and selected shallow and deep rooting plant species.

• Installation of lysimeter monitoring infrastructure as part of the capping construction to monitor the unsaturated and saturated zone conditions through the soil profile, to prove the effectiveness of the phytocapping capping approach.

• Assessment of appropriate spacing for planting of deep and shallow rooting species.

• Quarterly groundwater monitoring for nitrate and sulphate to determine whether infiltration and impact to groundwater are reducing over time.

• Confirmation of which areas will be phytocapped and which will be managed with clay capping or a combination of the two.

• Management of stormwater run-on.

• Revegetation and erosion control.



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• The precise area of capping required (which will involve further delineation including sampling and analysis of soils in source areas).

• Identification and removal of any underground services that may be sources of additional infiltration, potentially leading to the leaching of contaminants to groundwater.





• The level of surficial soil contamination (i.e. sulfates) with respect to the ability of the soil to support revegetation.


• The effectiveness of planting in nitrate reduction – i.e. “Phytoremediation”.

• The effectiveness of planting in reducing sulphate mobilisation by reducing infiltration rates sufficiently.

• On-going management – plant life, harvesting, grazing etc.

• The depth of penetration of nitrate reduction by plants.

It should be noted that the DIPNR have a preference for the use of locally native species and would like to review the list of plants prior to undertaking any proof-of-concept trails.

3.3.4.2 Clay Capping The Remediation Feasibility Assessment report (HLA, 2003f), details computer modelling that HLA conducted using US EPA’s Hydrologic Evaluation of Landfill Performance (HELP) model, to assess the performance of proposed clay capping. The modelling undertaken indicated that an appropriately designed and engineered clay cap with suitable topsoil and vegetation layer, overlying the existing lithological profile, would result in reduction of infiltration to the upper most aquifer beneath the nitrate source area. However, to ensure the efficiency and integrity of the cap, installation and maintenance of the cap system will be conducted in accordance with relevant standards and guidelines, and a prepared Construction Quality Assurance Plan (CQAP). The CQAP will outline construction requirements with reference to, but to limited to, Australian Standard 1289, Methods of Testing Soil for Engineering Purposes, and Australian Standard 3798, Guidelines on Earthworks for Commercial and Residential Developments. Specific construction requirements detailed in the CQAP may include required material permeability, maximum uncompacted lifts of capping material (eg. 200 mm), placement requirements, cap grades, geotechnical testing such as permeability tests at a range of compaction densities (eg. 95%, 97%, 99%), standard compaction tests (optimum moisture content (OMC) and maximum dry density (MDD)), and frequency of tests (eg. 1 per 500m3). In addition, field samples for


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particle size distribution may be required to ensure material used for the cap is suitable to achieve the required permeability. To assist with completion of the final design the following will be undertaken as a minimum: • Sources of appropriate clay capping material and topsoil/growing medium.

• The practicability of “keying” the clay capping layer into the Upper Shepparton Formation clays around the margins of the source area.

• Establishment of baseline conditions beneath the trial area, with respect to the existing levels of soil and groundwater contamination, saturated and unsaturated soil profile conditions where available .

• Identification and removal of any underground services that may be sources of additional infiltration.

• Installation of monitoring bores hydraulically down-gradient to monitor the effectiveness of the clay capping in reducing the leaching of contaminants into groundwater. Quarterly groundwater monitoring for nitrate and sulphate to determine whether infiltration and impact to groundwater are reducing over time.

• Modelling of a low permeable cap.

The results will also be used to prepare detailed designs for any of the areas to be clay capped that includes (but is not limited to) the following:


• The precise area of capping required (which will involve further delineation including sampling and analysis of soils in source areas)




• Recognition that capping does not remove soil contaminants and therefore that on-going groundwater monitoring will be required.



• Identification of possible sources and the cost of clay capping material.



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3.3.5 Excavation, Relocation and On-Site Containment of Contaminated Soil

At the commencement of the remediation and contamination management programme no specific proof-of-concept testing is considered necessary for the excavation, relocation and on-site containment (landfilling) of contaminated soils and waste material. However, further delineating the volumes of material to be excavated and establishment of the availability of an appropriate area in the southern portion of the site or an area within the section designated for the modernisation project will be undertaken prior to the detailed design phase. As part of the detailed designs for capping and landfilling above, any area where contaminated soil is to be excavated (i.e. soil and surface contamination proposed for containment onsite) requires a detailed design which will include (but not be limited to) the following:

• Planning for compliance with all of the applicable precautions for erosion control, excavation and related activities as outlined in the Remediation Environmental Management Plan attached as Appendix D.2.

• Any of the applicable considerations for capping (phytocapping or clay capping) of the landfill discussed in Section 3.3.3 above.

• Sourcing topsoil/growing medium.

• Determination of soil volumes in areas to be excavated, through further soil sampling and analysis, giving consideration to the remedial objectives and reduction in downgradient groundwater concentrations.

• Handling and disposal intentions for excavated source zone material (e.g. transport, placement, spreading, compaction, containment capping etc).

• Capping and re-instatement of source areas from where soil is excavated to avoid erosion and further infiltration (refer to section 3.3.3 for phytocapping and clay capping).

• Determination of validation criteria and reinstatement objectives.


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4 PLAN FOR CONTAMINATION MANAGEMENT This plan for contamination management was developed based on the results of the Remediation Feasibility Assessment report undertaken by HLA (HLA, 2003f) to manage the off-site groundwater plume and on-site source areas. The location of the source management areas are shown in Figure 2 and a description of each Source Management Area and the sources included in them is presented in Table 3 as follows:

Table 3: Source Management Area Descriptions

Source Management Area A Oleum Area - Acid Drains, Former Nitric Acid Plant, Ammonia Oxidation and Former Ammonia Storage (Bld. 301C).

Sources 46, 48, 49 and 57

Effluent Treatment Plant and Effluent Treatment Plant Acid Drains

Sources 71 & 72

Nitrocellulose Area - Former Acid and Effluent Drains and Former Labyrinths.

Sources 10 & 11

Former Gypsum Ponds.

Source 74

Source Management Area B Effluent Drain.

Source 70

Source Management Area C Dump Areas-Current Boiler House and Coal Yard.

Source 106

Source Management Area D Dump Area-Iron Oxide Dumps.

Source 103 Dump Areas (NG) - Sulphur Dump.

Source 102

Source Management Area E Oleum Area - 314 Sulphur Store and Former Sulphur Store.

Sources 50 & 51 Acid Area - Acid Drains.

Source 35

The approach to remediation of both the off-site plume and on-site Source Management Areas were determined based on technical, financial and logistical considerations to chemically, physically or biologically remove nitrate and sulphate and restore impacted potential beneficial uses of groundwater.


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The plan for Contamination Management is presented in the following sections.

4.1 Off-site Groundwater Plume Management Based on the outcomes of the Remediation Feasibility Assessment report (HLA, 2003f), it has been determined that all but one of the available remediation technologies do not represent practicable options for remediation the off-site groundwater plume. Pump and irrigation has been retained for futher assessment during the proof-of-concept phase to determine whether this method could provide a useful reduction in time to restore beneficial uses. Trial pumping and groundwater modelling will be undertaken as part of the proof-of-concept phase proposed for Source Management Area A and used to further assess the practicability of pump and irrigation for off-site plume management. If pump and irrigation is not practicable, it is recommended that the groundwater plume be managed through continued partnership with the current groundwater users and Monitoring Natural Attenuation (MNA) of the off-site plume, in conjunction with the pro-active management measures to deal with the source areas as follows:

4.1.1 Management of Current Groundwater Uses Current groundwater uses in the plume areas have been, and will continue, to be effectively managed by ADI and Defence in partnership with the community consultative group and Council. The specific management requirements concerned involve a range of measures to accommodate individual groundwater use as detailed in the Contamination Management Plan (Appendix D1). One of these is an undertaking from ADI to continue regular community liaison meetings and on-going consultation with resident groundwater users. Other communications measures outlined in Appendix D.1 (Long-Term Environmental Management Plan). It is important that these measures be implemented in conjunction with the more active management measures for source area contamination discussed in Section 6 of the Remediation Feasibility Assessment report (HLA, 2003f). The main management measures proposed for the CMP include: • Regular communication of the contamination levels in groundwater to groundwater users

within the area where concentrations of nitrate and sulphate exceed drinking water guidelines.

• Completion of further research to clarify long-term guidelines for maximum nitrate and sulphate concentrations and irrigation volumes for application to domestic gardens and crops in the affected area. These will be provided to groundwater users in the affected areas.

• Provision to groundwater users summary guidelines for use of impacted groundwater for

irrigation, such as the times for watering, types of species for planting, washing salt build-up from leaves etc.

• Groundwater within the area of stock watering guideline exceedence for nitrate and

sulphate should not be used for stock watering until specific assessments are completed of the sensitivity of the stock species to contaminants in groundwater.


D006005_RPT236Rev03_17Dec03 20

• Provision to groundwater users, via the Contamination Management Plan of summary guidelines for use of impacted groundwater for stock watering, such as diluting groundwater used to water poultry and new born stock etc.

• Provision of advice to residents to avoid prolonged exposure of concrete structures to

groundwater due to potential corrosion of concrete associated with sulphate. • On-going groundwater monitoring twice a year (see Appendix D1, Section D1.6.3.5). • Establishment and maintainence of a register of properties and landowners located within

the area of impacted groundwater exceeding drinking water guidelines. • Preparation of an information brochure on the off-site groundwater plume and annual mail

outs to each property within the effected area to ensure new residents are informed of limitations on groundwater use.

• On-going regular community consultative group meetings. • Provision of on-going groundwater monitoring results (reporting twice a year) to land owner

groundwater users, including recommendations for appropriate uses of their groundwater and any identified changes in groundwater quality over time.

• Provision of an annual groundwater monitoring report to all stakeholders to be made

available to the public, prepared in a manner that preserves land owner confidentiality to the extent possible.

4.1.2 Monitoring Natural Attenuation No specific proof-of-concept testing is required to complete the design and commencement of an on-going groundwater monitoring programme. As discussed in Section 3.2.2, on-going groundwater monitoring will be required in conjunction with other proposed remediation and management measures. Monitoring is proposed twice a year. Regular review of the monitoring programme in consultation with the Auditor (Dr Peter Nadebaum), community consultative group and other stakeholders will be undertaken to establish any trends that develop in monitoring results and to ensure that all affected domestic extraction bores are included, along with an optimal selection of monitoring bores and appropriate analytes for testing. The groundwater monitoring programme is discussed further in Appendix D1, Section D1.6.3.5

4.2 Source Management Areas Priority source areas identified in the Remediation Feasibility Assessment Report (HLA, 2003f) were grouped together based on their locations and their potential to contribute to groundwater contamination. The location of each source management area is shown in Figure 2 and the management approach adopted for each source management area is discussed below


D006005_RPT236Rev03_17Dec03 21

4.2.1 Source Management Area A Based on an assessment of the most practicable management strategies proposed in Section 4.3.2 and 4.3.3 of the Remediation Feasibility Assessment report (HLA, 2003f), the recommended plan for contamination management of Source Management Area A is as follows: The most practicable remedial approaches for Source Management Area A are summarised in the following sections (4.2.1.1 to 4.2.1.3).

4.2.1.1 Groundwater Carbon Source Addition Undertake a proof-of-concept trial as outlined in Section 3.3.1 to establish whether carbon source addition will remediate nitrate in groundwater and achieve the clean-up goals outlined in Section 2.5. Details such as the final configuration of injection and monitoring bores and monitoring frequency will be determined from the results of the proof-of-concept testing, which will include field testing and further modelling for the development of a design for the efficient delivery of a carbon source into the aquifer. The final design of the system may include horizontal bores or a


1


2



Implement Capping

Yes


Trial


Attenuation


Yes

No


NoNo

YesYes

No


D006005_RPT236Rev03_17Dec03 22

carbon source addition recirculation cell for the efficient mixing and delivery of a carbon source to groundwater to stimulate denitrification. Following the success of the proof-of-concept trial, undertake detailed design of the proposed system to enable tendering on the construction and implementation of the CSA system as detailed in Section 3.3.1 to be undertaken. Regular monitoring and review of the management system will be undertaken to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.

4.2.1.2 CSA Soil Remediation If CSA results in successful biodegradation of nitrate in the groundwater (either through direct injection or re-circulation) and a proof-of-concept trial indicates that CSA is practicable for soil, then direct carbon source addition to the soil be implemented to remediate nitrate in Source Management Area A, as outlined in Section 3.3.2. The final configuration of the system will detail an effective method for introducing a carbon source to the underlying soils in addition to mass and rates of carbon source addition to stimulate denitrification. The final design may include a hydraulic barrier (i.e. a bentonite slurry wall) to contain mounding in the Dune Sand within the source area. Following the success of the proof-of-concept trial, undertake a detailed design of the proposed system to enable tendering on the construction and implementation of the CSA system to be undertaken, as detailed in Section 3.3.2. Regular monitoring and review of the management system will be undertaken to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.

4.2.1.3 Pumping and Irrigation Pumping and irrigation of contaminated groundwater may have some targeted use in sources areas as a stand alone remedial option or in conjunction with other technologies such as re-circulation and CSA, which might benefit from strategic extraction to reduce further migration of groundwater contamination off-site. This approach will be undertaken if CSA groundwater management is not feasible to provide an alternative water supply to the nearby golf-course as well as providing nutrients in the form of dissolved nitrate. This would also provide a benefit to the community and the surrounding environment by reducing the requirement for importing fertilisers.

Proof-of-concept testing will be required, to assist with the completion of the final design. The requirements for a proof-of-concept trial, in addition to an outline of the requirements to fulfil a detailed design of a pump and irrigation system are outlined in Section 3.3.3..

4.2.1.4 Source Area Capping Should it be found that implementing CSA is not practicable, it is recommended that capping, as outlined in Section 3.3.4, be undertaken to reduce the dissolution of contaminants in soil found in Source Management Area A, migrating to groundwater. The final configuration of the system may include one or more of the following: • maintaining existing paved and built-out areas (including leaving concrete slabs in place in

the event that any building demolition is carried out) providing run-off is directed outside source areas;


D006005_RPT236Rev03_17Dec03 23

• Capping with a low permeable capping system (i.e. clay and topsoil); and

• Phytocapping with deep and shallow rooting plant species to partially remove nitrate from the underlying soils.

A detailed design of the proposed capping system will be undertaken to enable tendering on the construction and implementation of the capping layer, as detailed in Section 3.3.4. Regular monitoring and review of the capping system will be carried out to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.

4.2.2 Source Management Area B Based on an assessment of the most practicable management strategies proposed in Section 4.3.2 and 4.3.3 of the Remediation Feasibility Assessment report (HLA, 2003f), the recommended plan for contamination management of Source Management Area B (Effluent Drain) is as follows:


Source 70


Backfill drain with soil and supplement with additional natural material, to provide a nominal level of capping to reduce ponding of surface water in the base of the drain.

Planting over the backfilled drain using an appropriate selection of deep and shallow rooting plant species to reduce infiltration of contaminants to groundwater. If monitoring indicates phytocapping does not prove effective in reducing leaching of contaminants from soil, construct a low permeability capping system (i.e. clay cap).

4.2.2.1 Inspection of the Effluent Drain It is recommended that an inspection of the stormwater drain constructed in the former Effluent Drain easement be undertaken in light of the deterioration observed in the duel stormwater drains located in the floodplain, further to the south of the site. Leaks from the stormwater drain are likely to render capping ineffective in reducing the leaching of nitrate and sulphate from soil. Should it be found that sections of the main pipe are in poor condition, then they will be repaired, either through relining or replacement of the damaged sections (which could potentially be the entire length of the effluent drain) prior to the implementation of any proof-of-concept or design of works in Source Management Area B.

4.2.2.2 Phytocapping Phytocapping, as outlined in Section 3.3.4.1, will be undertaken following the inspection and repair (if required) of the effluent drain to achieve the clean-up goals outlined in Section 2.5. Details including the placement of lysimeters within the trial area in addition to a number of bores installed hydraulically up- and down-gradient of the drain to monitor performance will be established prior to undertaking a detailed design of the proposed system. This will enable


D006005_RPT236Rev03_17Dec03 24

tendering on the construction and implementation of the phytocapping system to be undertaken, as detailed in Section 3.3.4.1. Regular monitoring and review of the management system will be undertaken to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.

4.2.2.3 Clay Capping Should it be found that phytocapping is not practicable then capping with a low permeable capping system (i.e. clay and topsoil) as outlined in Section 3.3.4.2, will be undertaken to reduce leaching of contaminants in soil found in Source Management Area B to groundwater. A detailed design of the proposed capping system to enable tendering on the construction and implementation of a low permeability capping system to be undertaken, as detailed in Section 3.3.4.2. Regular monitoring and review of the capping system will be undertaken to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.

4.3 Source Management Area C Based on an assessment of the most practicable management strategies proposed in Section 4.3.3 of the Remediation Feasibility Assessment report (HLA, 2003f), the recommended plan for contamination management of Source Management Area C is as follows:


Source 106

Excavate waste materials (i.e. gypsum) and placement in either an off-site landfill, licensed to accept the waste, an engineered on-site landfill (i.e the area along the southern boundary of the site where the Shepparton Formation is absent) or under the proposed modernisation building footprints.


4.3.1.1 Excavation, Relocation and On-site Containment of Contaminated Soil No specific proof-of-concept testing is considered necessary for the excavation, relocation and on-site containment (landfilling) of contaminated soils and waste material, with the exception of further delineating the volumes of material to be excavated and establishment of the availability of an appropriate area in the southern portion of the site or within the section designated for the modernisation project for consolidation of the contaminated soil and waste materials. A detailed design for the capping of the landfill will be undertaken prior to inviting the submission of tenders for the construction and implementation of the capping layer, including the implementation of erosion control to be undertaken, as detailed in Section 3.3.4. Regular monitoring and review of the capping system and landfill will be undertaken to establish if the landfill is adequate to minimise contamination of the underlying groundwater.


D006005_RPT236Rev03_17Dec03 25

4.3.1.2 Phytocapping Phytocapping, as outlined in Section 3.3.1, will be undertaken following removal of the contaminated soils and waste materials to achieve the clean-up goals outlined in Section 2.5. Details including the placement of lysimeters within the trial area in addition to a number of bores installed hydraulically up- and down-gradient of the drain to monitor performance will be established prior to undertaking a detailed design of the proposed system. This will enable tendering on the construction and implementation of the phytocapping system to be undertaken, as detailed in Section 3.3.3.1. Regular monitoring and review of the management system will be undertaken to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.

4.3.1.3 Clay Capping Should it be found that phytocapping is not practicable then capping with a low permeable capping system (i.e. clay and topsoil) as outlined in Section 3.3.3.2, be undertaken to reduce leaching of contaminants in soil found in Source Management Area C to groundwater. A detailed design of the proposed capping system to enable tendering on the construction and implementation of a low permeability capping system to be undertaken, as detailed in Section 3.3.3.2. Regular monitoring and review of the capping system will be undertaken to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.

4.4 Source Management Area D Based on an assessment of the most practicable management strategies proposed in Section 4.3.2 and 4.3.3 of the Remediation Feasibility Assessment report (HLA, 2003f), the recommended plan for contamination management of Source Management Area D is presented below:


Source 103


Source 102



4.4.1.1 Excavation, Relocation and On-site Containment of Contaminated Soil No specific proof-of-concept testing is considered necessary for the excavation, relocation and on-site containment (landfilling) of contaminated soils and waste material, with the exception of further delineating the volumes of material to be excavated and establishing the availability of


D006005_RPT236Rev03_17Dec03 26

an on-site landfill or an area within the area designated for the modernisation for filling of the contaminated soil and waste materials. A detailed design for the capping of the landfill will be undertaken prior to inviting the submission of tenders for the construction and implementation of the capping layer, including the implementation of erosion control to be undertaken, as detailed in Section 3.3.4. Regular monitoring and review of the capping system and landfill will be undertaken to establish if the landfill is adequate to minimise contamination of the underlying groundwater.

4.4.1.2 Phytocapping Phytocapping, as outlined in Section 3.3.1, will be undertaken following removal of the contaminated soils and waste materials to achieve the clean-up goals outlined in Section 2.5. Details including the placement of lysimeters within the trial area in addition to a number of bores installed hydraulically up- and down-gradient of the drain to monitor performance will be established prior to undertaking a detailed design of the proposed system. This will enable tendering on the construction and implementation of the phytocapping system to be undertaken, as detailed in Section 3.3.3.1. Regular monitoring and review of the management system will be undertaken to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.

4.4.1.3 Clay Capping Should it be found that phytocapping is not practicable then capping with a low permeable capping system (i.e. clay and topsoil) as outlined in Section 3.3.3.2, be undertaken to reduce leaching of contaminants in soil found in Source Management Area D to groundwater. A detailed design of the proposed capping system to enable tendering on the construction and implementation of a low permeability capping system to be undertaken, as detailed in Section 3.3.3.2. Regular monitoring and review of the capping system will be undertaken to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.


D006005_RPT236Rev03_17Dec03 27

4.5 Source Management Area E Based on an assessment of the most practicable management strategies proposed in Section 4.3.2 and 4.3.3 of the Remediation Feasibility Assessment report (HLA, 2003f), the recommended plan for contamination management of Source Management Area E is presented below:


Sources 50 & 51


Source 35

Implementation of a cap over Source Management Area E using clay and topsoil and an appropriate selection of deep and shallow rooting plant species to aid in the removal of shallow nitrate and reduce rainfall infiltration. Existing and future buildings and pavements are assumed to act as effective capping.

Plant a phytocap of an appropriate selection of deep and shallow rooting plant species in areas not covered by buildings or pavements. If monitoring indicates phytocapping does not prove effective in reducing leaching of contaminants from soil, construct a low permeability capping system (i.e. clay cap).

4.5.1.1 Phytocapping Phytocapping, as outlined in Section 3.3.3.1, will be undertaken to reduce the impact of nitrate and sulfates on groundwater and achieve the clean-up goals outlined in Section 2.5. Details including the placement of lysimeters within the trial area in addition to a number of bores installed hydraulically up- and down-gradient of the drain to monitor performance will be established prior to undertaking a detailed design of the proposed system. This will enable tendering on the construction and implementation of the phytocapping system to be undertaken, as detailed in Section 3.3.3.1. Regular monitoring and review of the management system will be undertaken to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.

4.5.1.2 Clay Capping Should it be found that phytocapping is not practicable then a proof-of-concept trial for capping with a low permeable capping system (i.e. clay and topsoil) as outlined in Section 3.3.3.2, be undertaken to reduce leaching of contaminants in soil found in Source Management Area E to groundwater. A detailed design of the proposed capping system to enable tendering on the construction and implementation of a low permeability capping system to be undertaken, as detailed in Section 3.3.3.2. Regular monitoring and review of the capping system will be undertaken to establish whether the proposed remediation will achieve the clean-up goals in a practicable amount of time.


D006005_RPT236Rev03_17Dec03 28

4.6 Long-Term Environmental Management Management of the contaminated soil and groundwater will be undertaken in accordance with the Long-Term Environmental Management Plan (Appendix D1). The Long-term Management Plan is to be incorporated during prior to the commencement of the plan for contamination management and beyond the completion of any remediation works. The plan provides a summary of the potential environmental issues anticipated to require management in the long-term, including the period prior to commencement of any contamination management / remediation measures outlined in this CMP report. It also summarises the necessary management strategies, actions, monitoring and reporting measures required to be undertaken to minimise the risk of any further impact to the environment and to meet the environment protection expectations of Government authorities and the community.

4.7 Remediation Environmental Management Any remediation will be undertaken in accordance with the Remediation Environmental Management Plan (Appendix D2). The Remediation Environmental Management Plan describes environmental management procedures including monitoring and reporting measures to be undertaken during remediation, to minimise the risk of impact to the environment to meet the environment protection expectations of Government authorities and the community, and minimise safety risks and inconvenience to operations at the facility and the community, including nearby residents relating to the proposed remediation activities.

4.8 Contingency Management If it is found that the trigger levels signalling unsatisfactory performance of the clean up/management technologies are reached, then contingency planning measures outlined in Appendix D3 (Contingency Management Plan) for the protection of the environment will be implemented. The Contingency Management Plan re-addresses the management target and objectives in the case that the remediation management plan is unsuccessful in accordance with the NSWEPA Guidelines for Consultants Reporting on Contaminated Sites (NSW EPA, 1998).


D006005_RPT236Rev03_17Dec03 29

5 SCHEDULE An estimate of the timeframe to manage the off-site groundwater plume and on-site source areas including undertaking proof-of-concept trials, and detailed design of the works prior to implementation of the remediation is detailed in a Gantt Chart presented in Appendix E.


D006005_RPT236Rev03_17Dec03 30

6 REFERENCES ADI Industrial Decontamination Division (ADI, 1992a). Site Investigation Report of Mulwala

Facility, Weapons and Engineering Division - Volume 1 Executive Summary, March 1992. ADI Industrial Decontamination Division (ADI, 1992b). Site Investigation Report Of Mulwala

Facility, Weapons and Engineering Division - Volume 2 Procedures, March 1992. ADI Industrial Decontamination Division (ADI, 1992c). Site Investigation Report Of Mulwala

Facility, Weapons and Engineering Division - Volume 3 Results, March 1992. ADI Industrial Decontamination Division (ADI, 1992d). Site Investigation Report Of Mulwala

Facility, Weapons and Engineering Division - Volume 4 Discussions and Conclusions, March 1992.

ADI Industrial Decontamination Division (ADI, 1992e). Site Investigation Report Of Mulwala

Facility, Weapons and Engineering Division - Volume 5 Site Sample Point Maps, March 1992.

ADI Industrial Decontamination Division (ADI, 1992f). Site Investigation Report Of Mulwala

Facility, Weapons and Engineering Division - Volume 6 Groundwater Monitoring System Revision, Report prepared by Golder Associates for ADI IDD, March 1992.

ADI Mulwala Environmental Section (ADI, 2001), Remediation of the Offsites Drainage

Channel, Final Validation Report, ADI Mulwala, 2001. CH2MHill Australia Pty Ltd (CH2MHill, 1999a). Mulwala Facility Groundwater Contamination

Audit”, May 1999, Report No. 101651.01.Rev1, CH2MHill Australia Pty Ltd. CH2MHill Australia Pty Ltd (CH2MHill, 1999b). Mulwala Facility Preliminary Groundwater Risk

Review. Supplementary Assessment Risk Ranking, Report No. 110015.016-Rev1. June 1999.

CH2MHill Australia Pty Ltd (CH2MHill,1999c). Mulwala Facility Soil and Groundwater Baseline

Study for Potassium Nitrate Evaporation Ponds, Report No. 110014.001.Rev0. November 1999.

CH2MHill Australia Pty Ltd (CH2MHill, 2000). Mulwala Facility Soil and Groundwater Baseline

Study of Alcohol Evaporation Pond in Finishing Area, Report No. 110014.019.Rev2. March 2000.

Department of Water Resources, 1992 - Jerilderie Hyrdogeological Map (1:250,000 scale)

AGSO, Canberra, Australia. Deutsch, W.J., 1997. Groundwater Geochemistry – Fundamentals and Applications to

Contamination. CRC Press. P 10 –11. Gutteridge Haskins & Davey Pty Ltd (GHD, 1987). Relocation of Albion Explosives Factory to

Mulwala, Draft Environmental Impact Statement. Report No. CP-57281 U. September 1997.


D006005_RPT236Rev03_17Dec03 31

Grigg, A. M., Pate, J. S. and Unkovich, M.J. (2000). "Responses of native woody taxa in Banksia woodland to incursion of groundwater and nutrients from bordering agricultural land." Australian Journal of Botany 48: 777-792.

Hem., J.D, 1989, Study and Interpretation of the Chemical Characteristics of Natural Water, U.S

Geological Survey Water-Supply Paper 2254. HLA-Envirosciences Pty Limited (HLA, 2003a). Groundwater Investigation Report (Phase 2 and

3), ADI Mulwala. 25 March 2003. HLA-Envirosciences Pty Limited (HLA, 2003b). Source Investigation Report, ADI Mulwala. 25

March 2003. HLA-Envirosciences Pty Limited (HLA, 2003c). ADI Mulwala Contamination Management

Project, Draft Numerical Flow and Solute Transport Model Analysis. 10 June 2003. HLA-Envirosciences Pty Limited (HLA, 2003d). ADI Mulwala Contamination Management

Project, Baseline Numerical Flow and Solute Transport Model Analysis. 25 June 2003. HLA-Envirosciences Pty Limited (HLA, 2003e). ADI Mulwala Contamination Management

Project, Priority A Sources Investigation Report. 13 June 2003. HLA-Envirosciences Pty Limited (HLA, 2003f). ADI Mulwala Contamination Management

Project, Remediation Feasibility Assessment Report. 31 October 2003. Lawrence, C.R, 1975. Geology, hydrodynamics and hydrochemistry of the southern Murray

Basin. Geological Survey of Victoria Memoir 30 (2), Department of Mines. Tickell, S.J. 1977. Geology and hydrogeology of the eastern part of the Riverine Plain in

Victoria. Geological Survey of Victoria Report 1977/1978. Department of Industry, Technology and Resources.

Tickell, S.J. & Humphrys, W.G., 1987. Groundwater resources and associated salinity problems

of the Victorian part of the Riverine Plain. Geological Survey of Victoria Report. Department of Industry, Technology and Resources.

URS Australia Pty Ltd (URS, 2000), Letter Report – Assessment of Areas formerly used for

Discharge of Waste Waters to Ground and Bare Areas, Mulwala Facility. 2000. URS Australia Pty Ltd (URS, 2001a), Further Environmental Site Assessment of

Commonwealth Property Located Outside ADI Mulwala Facility Fence Line. November 2001.

URS Australia Pty Ltd (URS, 2001b), Final Report - Environmental Site Assessment ADI

Mulwala, November 2001.


D006005_RPT236Rev03_17Dec03

Figures

1

FIGURESITE LOCATION

ADI Mulwala Contamination Management Project

Contamination Management PlanHLA

PROJECT-FILE NAME DATE DRAWN APPROVEDD0060 OCT 2003 SR

N

A4

0 1000500

Approximate Scale (metres)

NSite Boundary

PROJECT FILE NAMEDATEDRAWNAPPROVED

D0060OCT 2003SR

War

atah

Rd

Bayley Street

Morris Rd407,500

407,500

408,000

408,000

408,500

408,500

409,000

409,000

6,016,000

6,016,000

6,016,500

6,016,500

6,017,000

6,017,000

Surface Water Body

Legend

Site Boundary

ADI Mulwala Contamination Management Project

SOURCE MANAGEMENT AREAS

Contamination Management Plan

FIGURE

2

Source Management Areas

Area A

Area B

Area C

Area D

Area E

I0 100 20050

MetersAMG Zone 55 (AGD66) 1: 6000


D006005_RPT236Rev03_17Dec03

Appendices


D006005_RPT236Rev03_17Dec03

Appendix A Background Information

ADI Mulwala Contamination Management Project CONTAMINATION MANAGEMENT PLAN Appendix A – Background Information 17 December 2003 Prepared for: Department of Defence and ADI Limited Bayley Street, Mulwala, NSW 2647 Report by: HLA-Envirosciences Pty Limited ABN: 34 060 204 702 46 Clarendon Street Melbourne VIC 3205 Australia Ph: +61 3 8699 2199 Fax: +61 3 8699 2122 HLA Ref: D006005_RPT236Rev03_17Dec03_AppendixA


Appendix A – Background Information

D006005_RPT236Rev03_17Dec03_AppendixA i

CONTENTS A APPENDIX A – BACKGROUND INFORMATION........................................................1

A.1 INTRODUCTION...........................................................................................1 A.2 SITE IDENTIFICATION.................................................................................1 A.3 HISTORICAL AND CURRENT ON-SITE LAND USES.................................1 A.4 CURRENT SURROUNDING LAND USE AND ENVIRONMENT ..................2 A.5 TOPOGRAPHY AND DRAINAGE ................................................................2 A.6 REGIONAL GEOLOGY, HYDROGEOLOGY AND WATER

QUALITY.......................................................................................................3 A.6.1 Regional Geology...........................................................................3 A.6.2 Regional Hydrogeology ..................................................................4 A.6.3 Background Groundwater Quality...................................................5 A.6.4 Regional Groundwater Use ............................................................6 A.6.5 Regional Surface Water Quality .....................................................6

A.7 INVESTIGATION AREA GEOLOGICAL AND HYDROGEOLOGICAL SETTING .................................................................7 A.7.1 Geology..........................................................................................7

A.7.1.1 Dune Sand Area..............................................................7 A.7.1.2 Floodplain Area ...............................................................8

A.7.2 Hydrogeology .................................................................................8 A.7.2.1 Dune Sand Aquifer ..........................................................9 A.7.2.2 Shallow Aquifer System...................................................9 A.7.2.3 Calivil Aquifer ................................................................10

A.7.3 Geophysics...................................................................................11 A.7.4 Surface Water Body Influence......................................................12

A.8 REFERENCES............................................................................................12

TABLES Table A1: Summary of Background Groundwater Quality Data Table A2: Summary of Background Regional Surface Water Quality Data LIMITATIONS This document was prepared for the sole use of the Department of Defence, ADI Limited, the Auditor and the regulatory agencies that are directly involved in this project, the only intended beneficiaries of our work. No other party should rely on the information contained herein without the prior written consent of HLA-Envirosciences Pty Limited, the Department of Defence and ADI Limited.



D006005_RPT236Rev03_17Dec03_AppendixA 1

A APPENDIX A – BACKGROUND INFORMATION

A.1 INTRODUCTION Appendix A presents the background information obtained from a number of sources of information, including previous investigations undertaken at the site and studies undertaken by HLA (HLA 2003a, 2003b, 2003c, 2003d and 2003e).

A.2 SITE IDENTIFICATION The site is located in southern NSW on land in the Local Government of Corowa, Parish of Mulwala, County of Denison. It occupies an area of approximately 1,013 ha on the western margin of the township of Mulwala. The site is bounded by Bayly St to the south; Lucan, Dunmore, Leigh and Edward Streets to the east; Mulwala Canal to the north and the Murray River Floodplain to the west. The Murray River and associated wetlands are located directly to the west (Mulwala State Forest), southwest and further removed to the south of the site. Semi-rural/residential land separates the site from the Murray River floodplain to the south. The Corowa Shire Council Sewerage Treatment Plant is located directly to the south of the site, on the eastern side of Wanani Rd, and Yarrawonga and Border Golf Course occupies the floodplain further south of the site. The site is leased by ADI from the Commonwealth.

A.3 HISTORICAL AND CURRENT ON-SITE LAND USES The site was commissioned in 1943 and was initially used to produce propellants for small arms and artillery ammunition for military purposes. Expansion of production capabilities commenced in 1987, associated with the relocation of the Department of Defence Albion Explosives Factory (REFA) to the Mulwala site. The south-eastern segment of the site housed the original processing areas for explosives. It comprised various structures, some of which are still in commission today, including: administration buildings, a boiler house, laboratory, nitric and sulphuric acid storage areas, ammonia oxidation and diethyl ether production plants, nitrocellulose production plants and the effluent treatment plant. Wastewater from ethanol production was disposed of into an effluent pond in the central eastern section of the site until 1998. The southern margin of the site adjacent to Bayly St was formerly used as an ash and iron oxide dump and storage area and for hard waste such as empty drums and car batteries. Remediation of gypsum storage ponds adjacent to the acid storage area occurred in 2000. A gypsum dump and sulphur dump are located to the west and north of old gypsum storage ponds site. A nitroglycerine production plant and finishing area occupy the central segment of the original Mulwala facility. Historically, a fertiliser manufacturing plant was also located in this area until it was decommissioned in 1960. Other features of note in this area include magazine stores, asbestos and nitrocellulose dumps, and a former potassium nitrate pond. Former potassium nitrate ponds, an alcohol evaporation pond and the former Shire of Corowa Landfill are located in the north-eastern section of the site.




A high explosives production area is located in the central western section of the site, outside the boundary of the original Mulwala facility. A former open effluent drain located to the south of the site was used to discharge wastewater to the Murray River.

A.4 CURRENT SURROUNDING LAND USE AND ENVIRONMENT

The site is generally surrounded by pastoral/agricultural land on all sides with the exception of the eastern boundary. Residential properties in the township of Mulwala lie directly to the east of the site and low-density rural residential development is present and increasing to the south and southwest (Mulwala Homestead Estate) of the site. Several sensitive environments exist within close proximity to site. Lake Mulwala is located less than 1 km to the east of the site, while a caravan/holiday park is currently located between the lake and railway line. The Murray River and Yarrawonga - Mulwala golf course are located to the south and southwest of the site, while an area of rural residential zoned properties are located further to the west.

A.5 TOPOGRAPHY AND DRAINAGE The highest elevation in the Mulwala area occurs at a bedrock outcrop where a water tower is located to the southeast of the site (approximately 148 mAHD – Australian Height Datum). This area is known locally as the “Water Tower Hill”. It is surrounded by predominantly flat alluvial plains to the north and east, the undulating surface of Yarrawonga and Border Golf Course to the south and a slightly lower wooded outcrop of bedrock to the west. Elevation of the alluvial plain between Lake Mulwala and the site is generally around 130–135 mAHD, but falls in a west/south-westerly direction from the site at an average grade of 7 m/km. Elevations reduce to approximately 120 - 130 mAHD around the swales and peaks of the hummocky aeolian dune systems that are scattered throughout the area between the site and the floodplain. The site is located in gently undulating terrain sloping towards the Murray River to the southwest. Surface elevation varies from 120 - 135 mAHD between the dunes and swales of surficial aeolian sands. The floodplain of the Murray River is located to the west, southwest and south of the site and generally has elevations ranging from 116-120 mAHD. A steep grade is evident where the early Quaternary sediments of the Upper Shepparton Formation have been incised by the more recent deposition of the floodplain sediments (Coonambidgal Formation). Outlying dune systems and ephemeral lagoonal depressions on the floodplain can have elevations ranging from 114-125 mAHD. Drainage patterns in the study area are irregular due to the undulating surface of the aeolian dune systems. There are two major drainage pathways from the site towards the floodplain. The effluent channel directly to the south of the site lies in a topographical low point bounded by dunes to the east and west. Surface runoff from the dunes and further north converges on this low point as it moves towards the floodplain. A topographical low point also extends from the vicinity of BH15 and the toluene storage tank, towards the floodplain. It runs in a south-westerly direction and crosses Bayly St and Pimpala Cres. Dunes to the southeast and northwest of the area cause runoff to accumulate at the above described low point and anecdotal evidence indicates flooding is often observed in this area during periods of above average rainfall.




A.6 REGIONAL GEOLOGY, HYDROGEOLOGY AND WATER QUALITY

A.6.1 Regional Geology The Mulwala/Yarrawonga region is located in the eastern extremities of the Riverine Plain within the Murray Basin. The regional geologic setting consists of a sequence of fluvial sediments ranging in age from Tertiary to Recent that unconformably overlie fractured Palaeozoic bedrock. The bedrock comprises slates, sandstones, siltstones and phyllites displaying varying degrees of weathering at outcrop and within the subsurface (Dept of Water Resources, 1992). Mechanical and chemical weathering between the Silurian/Ordivician and Tertiary time periods led to micro-valleys being incised into the bedrock surface. These valleys were then infilled by silts, sands and gravels of fluvial origin in the Tertiary and clays, clayey sands and discontinuous sands and gravels in the Quaternary to Recent periods. In this region, sheet deposits of the Tertiary aged Renmark Group are largely absent but literature and current drilling records indicate the relatively younger sands and gravels of the Calivil Formation are present in western parts of the region including the profile underlying the site. These deposits infilled the valleys incised into the bedrock and consist predominantly of unconsolidated gravel and coarse sand (Tickell, 1977), forming the basal unconsolidated aquifer system in the region. The depth of the unconsolidated alluvial sediments and consequently that of the Calivil Formation increases in a westerly/north-westerly direction from Mulwala/Yarrawonga. Structure contours for the top of the bedrock show increasing depth in a northwesterly direction and this is consistent with increasing thickness of the Calivil Formation in that direction. These sediments form a multiple aquifer channel approximately 5 km wide between bedrock highs adjacent to the site, at the water tower to the southeast and Mt Boomanoomana to the northwest. The Quaternary aged Shepparton Formation overlies the Calivil Formation in the geologic profile and its deposition is associated with current and palaeo-fluvial systems in the region. It consists predominantly of fluviatile clay with common occurrences of interbedded ‘shoestring’ sands and gravels. The clay of this formation is characteristically mottled, brown, reddish brown, grey, white, yellow and often sandy, silty and micaceous (Tickell, 1977). The sands and gravels commonly display spatial variation and in some cases, highly variable physical characteristics. In generalised terms, there are two reasonably consistent sand layers within the Shepparton Formation throughout the region. For the purposes of this investigation they will be referred to as Upper and Lower Shepparton Formation. The Coonambidgal Formation was incised into the Shepparton Formation along major drainage channels later in the Quaternary and formed two distinct low-level terraces adjacent to such drainage features. Both terraces have flat upper surfaces, and lie at elevations of between two and ten metres below the youngest Shepparton Formation terrace (O’Shea, 1977). The clays, clayey silts, silts and silty sands of the Coonambidgal Formation frequently occur in low-lying areas adjacent to the Murray River and lagoonal systems in the region. Overlying the Shepparton Formation, in elevated areas adjacent to the floodplain, are large systems of more recent aeolian dune sands. They can reach a thickness of up to thirteen metres at the dune peaks and can be substantially thinner in areas of swales. They consist of fine-grained red brown sand and silt and drilling records indicate that in some cases, clay hardpans have formed at the base of the dune systems overlying the Shepparton Formation.




A.6.2 Regional Hydrogeology Mulwala is located in an intermediate zone of the Murray Basin groundwater flow system. The regional hydrogeologic profile is made up of six aquifers in this area of the Riverine Plain. Aeolian dune sands, Upper and Lower Shepparton Formation, Calivil Formation, Renmark Group (where present), Connambidgal Formation and Palaeozoic bedrock form the major aquifer units influencing the hydrogeologic regime in the region. The aeolian dune sands have localised effects on infiltration of rainfall and perching of shallow groundwater. The eastern extremities of the Riverine Plain are a recharge zone for the unconfined to semi-confined Upper Shepparton Formation and confined Calivil Formation and Renmark Group (where present). Both are laterally extensive but the Upper Shepparton Formation was subject to inconsistent fluvial deposition and as a result displays variable groundwater flow direction and aquifer characteristics. The Calivil Formation formed in more consistent sheet-like deposits and generally has more consistent groundwater flow direction and aquifer characteristics than the overlying Upper Shepparton Formation. Borelogs suggested these units were the same basal aquifer overlying bedrock in the hyrdogeologic profile. The surficial Coonambidgal Formation is associated with recent and current surface water bodies and can be found extensively along the Murray River Floodplain and its tributaries closer to the eastern highlands. Groundwater flow within the Coonambidgal Formation is closely linked with adjacent surface water bodies and generally flows parallel to these as it moves along the regional flow path. Palaeozoic bedrock can be considered an aquitard or flow boundary for the purposes of this investigation. Groundwater moves through the bedrock via fractured rock permeability and preferential flow paths. Static water levels differ between the bedrock and the overlying Calivil Formation by tens of metres, which suggest there is no interaction between them. The Murray River is the principle surface water body in the region and displays seasonal variability when interacting with the underlying aquifers. Current data and previous investigations (Lawrence, 1975; Tickell and Humphrys, 1987), suggest the Murray River system is acting as recharge source for the Coonambidgal Formation in the region. The above Tertiary and Quaternary sediments are termed the Wunghnu Group (Lawrence, 1975). This group of unconsolidated, fluvial lithologies has been found to govern groundwater movement and contaminant transport within the study area. Temporal stage data for the Murray River suggests that there could be potential for a reversal of hydraulic gradient between the river and adjacent groundwater in abnormally wet years. A combination of above average recharge to the unconfined aquifer closer to the site and limited discharge from the Yarrawonga Weir may cause a reversal in hydraulic gradient to occur. Currently, surface water manipulation at Yarrawonga Weir is maintaining a constant head in the Murray River that is preventing groundwater discharge into the Murray River occurring. Regional groundwater flow direction is generally to the north/northwest with variability evident on a local scale in low-lying areas adjacent to the Murray River. In these areas, groundwater flow roughly follows the Murray River and floodplain.




A.6.3 Background Groundwater Quality Evaluation of the background groundwater quality is important in determining both the potential beneficial uses of groundwater at the site and the overall impact of any site operations on groundwater quality. The background groundwater quality has been evaluated via examination of field and analytical parameters observed beyond the nitrate and sulphate plumes, and a review of regional hydrogeological maps (1990). According to the 1:250,000 Jerilderie Hydrogeological Map (Dept of Water Resources, 1992) the salinity of the Shepparton Formation Aquifer ranges from <500 mg/L up to 1,000 mg/L (as TDS). The salinity of the Calivil Formation Aquifer ranges from 3,000 mg/L to 7,000 mg/L (as TDS). However, the Calivil Aquifer in the investigation area is believed to be recharged from Lake Mulwala and the Murray River which is likely to result in lower background salinity levels. URS (2001) summarised background groundwater quality in the Shepparton Formation Aquifer based on water quality data for the groundwater monitoring bores BH01, BH13 and BH24. HLA installed two background groundwater monitoring bores, BH59 and BH60 on the eastern portion of the site, between Dunmore and Lucan Streets to assess water quality in both the Shallow Aquifer System (BH60) and Calivil Formation (BH59). A summary of the background groundwater quality data is presented in Table A1.

Table A1: Summary of Background Groundwater Quality Data

Shallow Aquifer System

Chemical Background Concentrations

(URS, 2001) 1

Background Concentrations

(HLA, 2002)2

Calivil Aquifer Background

Concentrations (HLA, 2002)3

EC (µS/cm) 600 1174 1732

TDS - 678 10304

pH (units) 6.1 – 7.2 6.84 – 7.53 6.83 – 7.53

Nitrate as nitrate (mg/L) 10 0.4 – 3.81 2.53 – 4.25

Sulphate (mg/L) 25 52 - 55 78 - 82

Iron (mg/L) 1.5

Ferric Iron - <0.1

Ferrous Iron – 0.4 NA

Manganese (mg/L) 2 NA NA

Notes: 1. Based on BH01, BH13, BH24 (Note BH24 is screened in bedrock and should not be considered as a

background bore for the shallow aquifer system). 2. Based on BH60 (from October 2002 sampling event). 3. Based on BH59 (from October 2002 sampling event). 4. Lower TDS concentrations were measured in Calivil bores, other than BH59, outside the areal extent of impacts associated with the site. Based on the low results in other Calivil bores and the likelihood of aquifer recharge from Lake Mulwala and the Murray River, a background TDS of less than 1,000 mg/L was conservatively assumed for the Calivil Aquifer in the investigation area. NA – Not Analysed




A.6.4 Regional Groundwater Use Groundwater downgradient of the site is primarily used for pasture irrigation and garden maintenance. Limited stock watering occurs in this zone but this is predominantly from surface water bodies. and groundwater contributes a relatively small portion of this. Regional groundwater use is predominantly irrigation and stock watering to the north of the site. Private domestic supply groundwater bores have been noted in the township of Mulwala and further to the north east. Groundwater quality to the north-west of the site limits use to some irrigation and stock watering. An area north west and west of the site, known as Groundwater Management Area 016, is currently embargoed for any additional groundwater licenses due to a perceived insufficient groundwater supply to meet any requirements other than that those of current licensees. Yields can be up to 50L/s in parts of the Shepparton and Calivil Formations in the region but are mostly around 5 - 10L/s (Dept of Water Resources, 1992). The Murray River in the Mulwala area is a regional recharge feature (Dept of Water Resources, 1992), and groundwater quality adjacent to the river system is generally very good. Groundwater quality across the region becomes more saline deteriorates in a northerly and northwesterly direction from the Murray River in the region.

A.6.5 Regional Surface Water Quality The establishment of regional background surface water quality is important in determining any environmental impact of contaminant discharges on surface water systems . Weekly and monthly surface water quality data, collected from January 1995 to June 2001, provided by the Murray Darling Basin Commission (MBDC), downstream of the site from the Murray River, is summarised in Table A2.

Table A2: Summary of Background Regional Surface Water Quality Data

CHEMICAL RESULTS

MURRAY RIVER (DOWNSTREAM) SAMPLING INTERVAL

pH (units) 6.1* – 9 Weekly

EC (µS/cm) 1 – 105 Weekly

Nitrates (NOx as N, mg/L) 0.005 – 0.720 Weekly

Sulfate (mg/L) 1 – 8 Monthly

Soluble Organic Carbon 0.7-100 Monthly

Calcium (mg/L) 2 – 4 Monthly

Magnesium (mg/L) 1 – 3 Monthly

Sodium (mg/L) 1 – 10 Monthly

Potassium (mg/L) 1 – 4 Monthly

Bicarbonate (mg/L) 16 – 40 Monthly

Chloride (mg/L) 2 – 9 Monthly

*- A pH reading of 2.0 was recorded on February 23, 1999. This result has not been replicated and is considered anomalous.




Additional level data upstream of the Yarrawonga Weir and the Mulwala Canal has also been recorded by the MDBDC.

A.7 INVESTIGATION AREA GEOLOGICAL AND HYDROGEOLOGICAL SETTING

A.7.1 Geology The investigation area geology has been defined mainly from historical drilling and test pitting programs and recent investigations undertaken by HLA in relation to the site. Geophysical logging of monitoring and private irrigation bores is discussed in Section A.7.3. In addition, regional government bore hole data, local and regional topographic maps, geological maps and aerial photography have also been used for interpretation. The investigation area surface geology includes Recent age aeolian ‘dune’ sands (including the site and an area south of Bayly St) and floodplain alluvium proximal to the Murray River. The floodplain alluvium includes newer and older sequences of sediments collectively called the Coonambidgal Formation. The main investigation area has been split into two areas to assist reporting which are herein termed the Dune Sand and Floodplain areas. The geological sequences within these areas are discussed separately below.

A.7.1.1 Dune Sand Area The dune sands consist of a fine to medium grained red brown sand. The dunes sands are of variable thickness ranging from 13 m beneath dunes to less than one metre (and in some formations not present) beneath swales. The dune sands overlie a sequence of clayey sediments with sandy interbeds (the Quaternary age Shepparton Formation). The thickness of the Shepparton Formation varies from 10 to 20 m. There are two main sandy beds within the Shepparton Formation. The upper sandy bed commonly occurs within five to ten metres of the Shepparton Formation surface. The upper sandy bed consists of a medium grained pyritic and variably clayey sand which is typically 0.5 to 3.5 m thick and of limited lateral extent. The lower sandy bed commonly occurs within 15 to 20 m of the Shepparton Formation surface. The lower sandy bed consists of a coarse grained sand to sandy gravel, which is typically 3.0 to 6.0 m thick and present beneath the majority of the Dune Sand area. The clayey sediments above and between the sandy beds are mottled red, brown, grey low plasticity clays. Conformably underlying the Shepparton Formation (directly underlying the lower sandy bed) is the Tertiary aged Calivil Formation. The Calivil Formation consists of a fine to coarse sandy gravel. The surface of the Calivil Formation is typically between 20 m to 30 m of ground surface, five to twenty metres thick and is consistently present throughout this area. The Calivil Formation directly overlies Silurian/Ordovician age bedrock.




A.7.1.2 Floodplain Area The newer Coonambidgal Formation sediment sequence consists of medium to coarse grained sand and clays up to 12 m thick. The Older Coonambidgal Formation sediment sequence consists of medium sand to medium gravel and clays up to 4 m thick. Both the newer and older sediment sequences overlie the Shepparton Formation. The Shepparton Formation in this area consists of a mottled, red, brown, and grey low plasticity clay commonly between five and ten metres thick. No sandy interbeds are present in this area. The Shepparton Formation overlies the Calivil Formation. The Calivil Formation is as described for the Dune Sand Area, however here the formation is thinner (approximately three to six metres thick) and directly overlies Silurian/Ordovician age bedrock. In general, the thickness of the sedimentary sequence above bedrock is thinner is this area compared to the Dune Sand Area.

A.7.2 Hydrogeology Aquifer systems occur in all of the geological formations described in Section A.7.1. There are two main aquifer systems beneath the investigation area as shown in the simplistic conceptual cross sectional figure: The hydrogeological system beneath and hydraulically down-gradient of the site can be divided into the following

• Shallow Aquifer system – including aquifers in the upper sand bed of the Shepparton Formation, and the older and newer Floodplain sediments. These aquifers are all in hydraulic communication and form a separate shallow aquifer system beneath the investigation area.




• Calivil Aquifer system – including the Calivil Formation and the lower sand bed of the Shepparton Formation. These aquifers are in direct hydraulic communication and thus form one deeper aquifer.

In addition to the two main aquifer systems, there is also an ephemeral aquifer within the surficial dune sands (referred to as the Dune Sand Aquifer), which does not play a major role in the overall hydrogeological regime.

A.7.2.1 Dune Sand Aquifer An unconfined, ephemeral, perched aquifer system occurs in some locations at the Dune Sand-Shepparton Formation clay contact. The level of saturation is generally up to one metre. The Dune Sand aquifer is recharged by direct rainfall infiltration and is expected to discharge by direct evaporation/evapotranspiration, to the Shepparton Formation below, occasional seepage to ground surface in swale areas, and to Flood Plain sediments. This aquifer was intersected in some of the bores drilled in the Dune Sand Area. However, no bores have been constructed solely within this aquifer. Bore BH52 is screened across the Dune Sand and Older Floodplain aquifers. Bore BH72C is screened across the Dune Sand and Newer Floodplain aquifers and Bore BH79 is screened across the Dune Sand and Upper Shepparton Formation aquifers. There is expected to be hydraulic communication between all of these systems. The direction of groundwater flow in the Dune Sand aquifer is expected to follow the topography of the clay surface of the Shepparton Formation which generally slopes toward the Murray River.

A.7.2.2 Shallow Aquifer System

A.7.2.2.1 Older Floodplain Aquifer

An unconfined aquifer occurs in the older Coonambidgal Formation at approximately three to four metres below ground surface. Bores BH28R, BH74A, BH61, BH53A, BH92, BH52 (screened across the Older Floodplain and Dune Sand aquifers), BH71, BH73C, BH69C, and BH89 are screened in this aquifer. The aquifer is bounded, at its base by Shepparton Formation clays. Aquifer recharge is expected to occur by direct rainfall infiltration, periodic inundation, from the Dune Sands, the Shepparton aquifer and directly from the Murray River. Aquifer discharge is expected to occur to by direct evaporation/evapotranspiration and to the underlying Shepparton Formation sediments. An aquifer recovery test using the Theis Recovery method was conducted on Bore 74A. The estimated transmissivity for the Older Floodplain Aquifer near Bore 74A is approximately 30 m2/d. TDS concentrations in the Older Floodplain Aquifer system range from 936 mg/L to 2930 mg/L. The Older Floodplain Aquifer exhibits a trend of Calcium, Magnesium – Chloride, Sulphate dominant groundwater on-site and close to the contaminant source areas and becomes more bicarbonate dominant on approach to the floodplain.

A.7.2.2.2 Newer Floodplain Aquifer

An unconfined aquifer occurs in the newer Coonambidgal Formation at approximately three to six metres below ground surface. Bores BH77C, BH76C, BH66C, BH65C, BH56A, BH55A,




BH55C, BH67C, BH67B, BH64C, BH68C, BH70C, BH72C (screened across the Newer Floodplain and Dune Sand aquifers) have been screened in this aquifer. The aquifer is bounded at its base by Shepparton Formation clays. Aquifer recharge is expected to occur by direct rainfall infiltration, periodic inundation, from the Dune Sands aquifer, from the Shepparton aquifer and directly from the Murray River. Aquifer discharge is expected to occur by direct evaporation/evapotranspiration and to the underlying Shepparton Formation sediments. A constant rate aquifer test was conducted on Bore BH67B. A Theis recovery test was conducted on Bore 55A. The estimated transmissivity for the Newer Floodplain Aquifer near Bore BH67B and BH55A is approximately 140 m2/day and 0.5 m2/day respectively. TDS concentrations in the Newer Floodplain aquifer system range from 122 mg/L to 2530 mg/L. The Newer Floodplain aquifer has a Calcium, Sodium – Bicarbonate, Chloride dominant groundwater.

A.7.2.2.3 Shepparton Aquifer

An unconfined to semi-confined aquifer occurs in the Upper Shepparton Formation at approximately six to ten metres below ground surface. Bores BH08, BH09, BH11, BH12, BH15, BH20A, BH21A, BH22A, BH34, BH48A, BH49A, BH50A, BH54A, BH57, BH60, BH62, BH75, BH78, BH79, BH83, BH84, BH85, BH86, BH87 and BH88 are screened in this aquifer. The aquifer is bounded at its base by Shepparton Formation clays. Aquifer recharge is expected to occur by direct rainfall infiltration, periodic inundation and from the Dune Sands. Aquifer discharge is expected to occur via direct evaporation/evapotranspiration, vertical seepage to the underlying clays and sandy beds within the Shepparton Formation and discharge to the Older and Newer Floodplain Aquifers (Coonambidgal Formation). The dune sand sediments directly overly the Shepparton Aquifer in some areas (eg BH52, BH79) and are in direct hydraulic communication. Theis recovery tests were conducted on bores BH49A and BH54A. The estimated transmissivity for the Shepparton Aquifer near these bores is approximately and 10 m2/day and 30m2/day respectively. TDS concentrations in the Shepparton aquifer range from 72 mg/L to 5810 mg/L. The Shepparton Aquifer shows a Calcium, Magnesium – Chloride, Sulphate signature proximal to the site becoming more bicarbonate dominant with distance from the site. Once groundwater has reached the floodplain, bicarbonate has become the dominant anion.

A.7.2.3 Calivil Aquifer A confined aquifer occurs in the lower sandy bed of the Shepparton Formation and the Calivil Formation, approximately fifteen to twenty metres below the ground surface. Bores BH58, BH59, BH20B, BH22B, BH45, BH47B, BH48B, BH49B, BH50B, BH53B, BH54B, BH55B, BH56B, BH63, BH68B, BH69B, BH70B, BH73A, BH74B, BH90 and BH91B are screened in this aquifer. This aquifer is bounded at its base by bedrock and overlain by Shepparton Formation clays. Aquifer recharge is expected to occur from vertical leakage from the overlying Shepparton Formation and directly from the Murray River. Aquifer discharge occurs further down gradient from the investigation area and to the Murray River.




Theis recovery tests were conducted on Bores BH48B, BH53B and BH54B. The estimated transmissivity for the Calivil Aquifer for these bores is approximately 100 m2/day, 3 m2/day and 90 m2/day respectively. TDS concentrations in the Calivil aquifer system range from 74 mg/L to 2520 mg/L. The Calivil aquifer has a Calcium, Magnesium – Chloride, Sulphate signature proximal to the site becoming, more bicarbonate dominant with distance from the site. Groundwater in the Calivil Formation underlying the floodplain is predominantly of Calcium – Bicarbonate type.

A.7.3 Geophysics Gamma logs for the private irrigation bores of Smale, Hird, Jenkins and McKenzie indicate the varying nature of water bearing sand lenses within the shallow groundwater flow system. Bores Jenkins and McKenzie are constructed within the Upper Shepparton Formation and show a consistent clay layer at approximately four to eight metres bgl overlying the water bearing zone (approximately one to two metres thick) in these areas. Hird appears to be constructed in the Calivil Formation and intercepts eight metres of dune sands overlying a thin lense of Upper Shepparton Formation sand and approximately seven metres of Lower Shepparton Formation Sands. The Smale irrigation bore is constructed on the floodplain and shows a much more variable sequence of sands and clays in the sub-surface. It is screened in the more recent sediments of the Coonambidgal Formation, which forms part of the shallow groundwater flow system and is in hydraulic connection with the Upper Shepparton Formation. ADI groundwater monitoring bores logged also showed similar trends. The logs for BH09, BH31 and BH07 show a consistent clay layer between four and eight metres bgl overlying the water-bearing zone of the Upper Shepparton Formation (approximately two to four metres thick). Gamma logs for BH15 and BH04 in the western part of the site show a distinct difference in lithology between the bore locations. BH15 shows dune sands approximately five metres thick overlying a variable sequence of clays and clayey sands whereas BH04 shows a very consistent profile of surficial dune sands, 5 metres of clay and approximately ten metres of sand. Gamma logging undertaken in April 2002 refined HLA’s conceptual model. The logs for BH58 and BH59 showed two distinct water bearing zones between five and ten metres thick overlying the silty clays of weathered bedrock. These logs indicated that the Lower Shepparton Formation and the Calivil Formation were effectively the same basal aquifer underlying the site. Gamma logging for BH57 confirmed the presence of a thin lens of Upper Shepparton Formation sands 2 m thick overlying a bedrock high adjacent to the southern boundary of the site. The final phase of gamma logging showed an increase in depth of the geologic profile in a westerly direction towards the floodplain. BH74B and BH69B both showed a similar profile to a depth of twenty four metres. Below this BH69B showed a variable sequence of clays and sands until refusal on bedrock whereas BH74B showed a sandy gravel to a greater depth of approximately forty metres. BH56B shows the variable Coonambidgal Formation sediments that have incised the Upper Shepparton Formation and are overlying the Lower Shepparton Formation. BH78 is located in an area of dunes and shows similar trends to the previously logged bores, with a consistent clay layer down to eight metres bgl, overlying the sand of the Upper Shepparton Formation which is approximately one to two metres thick in this location.




A.7.4 Surface Water Body Influence The surface water bodies in the Murray River floodplain form integral parts of the conceptual hydrogeological model developed by HLA. Surface water elevations indicate that the Murray River is recharging both the Shallow and Calivil aquifer systems in the floodplain within the investigation area. The ephemeral lagoonal systems form a line along the floodplain sub-parallel to the Murray River, and appear likely to be aligned along a former meander of the Murray River. Groundwater flow in the floodplain moves toward a current backwater of the Murray River known as ‘The Black Hole’. Below average rainfall over the past two years has left all but two of the investigation area lagoons completely dry. Historical photographs indicate that the different lagoons can act as both recharge sources and groundwater discharge areas at different points in time, depending on rainfall and other conditions.

A.8 REFERENCES Department of Water Resources, 1992 - Jerilderie Hyrdogeological Map (1:250,000 scale)

AGSO, Canberra, Australia. HLA-Envirosciences Pty Limited (HLA, 2003a). Groundwater Investigation Report (Phase 2 and




Project, Baseline Numerical Flow and Solute Transport Model Analysis. 25 June 2003. HLA-Envirosciences Pty Limited (HLA, 2003e). ADI Mulwala Contamination Management

Project, Priority A Sources Investigation Report. 13 June 2003. Lawrence, C.R, 1975. Geology, hydrodynamics and hydrochemistry of the southern Murray

Basin. Geological Survey of Victoria Memoir 30 (2), Department of Mines. Tickell, S.J. 1977. Geology and hydrogeology of the eastern part of the Riverine Plain in

Victoria. Geological Survey of Victoria Report 1977/1978. Department of Industry, Technology and Resources.

Tickell, S.J. & Humphrys, W.G., 1987. Groundwater resources and associated salinity problems

of the Victorian part of the Riverine Plain. Geological Survey of Victoria Report. Department of Industry, Technology and Resources.

URS Australia Pty Ltd (URS, 2001a), Further Environmental Site Assessment of

Commonwealth Property Located Outside ADI Mulwala Facility Fence Line. November 2001.

URS Australia Pty Ltd (URS, 2001b), Final Report - Environmental Site Assessment ADI

Mulwala, November 2001.


D006005_RPT236Rev03_17Dec03

Appendix B Previous Investigations

ADI Mulwala Contamination Management Project CONTAMINATION MANAGEMENT PLAN Appendix B – Previous Investigations 17 December 2003 Prepared for: Department of Defence and ADI Limited Bayley Street, Mulwala, NSW 2647 Report by: HLA-Envirosciences Pty Limited ABN: 34 060 204 702 46 Clarendon Street Melbourne VIC 3205 Australia Ph: +61 3 8699 2199 Fax: +61 3 8699 2122 HLA Ref: D006005_RPT236Rev03_17Dec03_AppendixB


Appendix B – Previous Investigations

D006005_RPT236Rev03_17Dec03_AppendixB i

CONTENTS B APPENDIX B - PREVIOUS INVESTIGATIONS ...........................................................1

B.1 INTRODUCTION...........................................................................................1 B.2 SITE CONTAMINATION CHARACTERISATION .........................................1

B.2.1 Previous Environmental Site Investigations....................................1 B.2.1.1 Dames & Moore, 1987.....................................................1 B.2.1.2 GHD, 1987 ......................................................................1 B.2.1.3 ADI Industrial Decontamination Division, 1992................1 B.2.1.4 Woodward-Clyde, 1998 ...................................................2 B.2.1.5 CH2MHill, 1999 and 2000 ................................................2 B.2.1.6 URS, 2000.......................................................................3 B.2.1.7 URS, 2001.......................................................................3 B.2.1.8 ADI (Environmental Section), 2001 .................................3 B.2.1.9 HLA, April and May 2002.................................................3 B.2.1.10 HLA, July 2002 ................................................................4 B.2.1.11 HLA, September and October 2002 ................................4 B.2.1.12 HLA, November 2002......................................................4 B.2.1.13 HLA, March 2003 ............................................................5 B.2.1.14 HLA, May 2003................................................................5

B.2.2 Priority Contaminants .....................................................................6 B.2.3 Nature and Extent of Impacts .........................................................6 B.2.4 Sources of Groundwater Contamination.........................................7

B.3 NUMERICAL FLOW AND SOLUTE TRANSPORT MODEL ANALYSIS ....................................................................................................8 B.3.1 Shallow Aquifer ..............................................................................8

B.3.1.1 Nitrate..............................................................................8 B.3.1.2 Sulphate ..........................................................................8

B.3.2 Deeper Aquifer ...............................................................................9 B.3.2.1 Nitrate..............................................................................9 B.3.2.2 Sulphate ..........................................................................9

B.3.3 TDS................................................................................................9 B.3.3.1 Shallow Aquifer ...............................................................9 B.3.3.2 Deep Aquifer ...................................................................9

B.4 REMEDIATION FEASIBILITY ASSESSMENT ...........................................10 B.4.1 Cleanup Goals..............................................................................10 B.4.2 Evaluation of Remedial Technologies...........................................10 B.4.3 Practicability of Off-Site Groundwater Plume

Management ................................................................................10 B.4.4 Practicability of Source Area Management...................................11 B.4.5 Source Management Areas..........................................................12

B.4.5.1 Source Management Area A .........................................12 B.4.5.2 Source Management Areas B to E ................................13

B.5 REFERENCES............................................................................................14

FIGURES Figure B1: History of Environmental Groundwater Investigation Works



D006005_RPT236Rev03_17Dec03_AppendixB ii

LIMITATIONS This document was prepared for the sole use of the Department of Defence, ADI Limited, the Auditor and the regulatory agencies that are directly involved in this project, the only intended beneficiaries of our work. No other party should rely on the information contained herein without the prior written consent of HLA-Envirosciences Pty Limited, the Department of Defence and ADI Limited.



D006005_RPT236Rev03_17Dec03_AppendixB 1

B APPENDIX B - PREVIOUS INVESTIGATIONS

B.1 INTRODUCTION Appendix B provides details of the previous investigations undertaken at the site including environmental site investigations, numerical flow and solute transport model analysis and the remediation feasibility studies and summarises the condition of the site by describing the priority contaminants, the nature and extent of impacts and sources of groundwater contamination.

B.2 SITE CONTAMINATION CHARACTERISATION

B.2.1 Previous Environmental Site Investigations A number of environmental site investigations have been undertaken at the site. Information relating to the historical and current site conditions including soil and groundwater analytical data was used as part of the development of this Contaminant Management Plan. Soil location areas investigated prior to 2001 has previously been presented in the URS Folio Series, March 2001 (URS, 2001). A list of the relevant reports and summary of the scope of works undertaken is presented herein.

B.2.1.1 Dames & Moore, 1987 Dames & Moore conducted a soil investigation for explosive organic compounds and metals at the site. Seven surface and eighteen test pit sample locations were investigated within the Finishing Area and analysed for a number of chemicals. The results of the investigation were presented in the Draft Report, Environmental Effects of Government Explosives Factories, Mulwala, April 1987.

B.2.1.2 GHD, 1987 GHD Pty Ltd prepared a preliminary assessment of groundwater contamination including the installation and sampling of twelve groundwater monitoring wells across the site numbered BH1 to BH14. Two of these wells were destroyed while the remainder are located north of the Finishing Area, in the HE area, off-site adjacent to Wanani and Waratah Rd, and along the southern boundary fence. Groundwater monitoring bore locations are presented on Figure B1. The results of the investigation were presented in the Environmental Impact Statement, Relocation of Albion Explosives Factory to Mulwala, September 1987.

B.2.1.3 ADI Industrial Decontamination Division, 1992 ADI Industrial Decontamination Division conducted a site investigation reported in six volumes. Ten groundwater monitoring bores were installed during this investigation. Groundwater monitoring bore locations are presented on Figure B1.




In addition to groundwater sampling, 1,439 soil samples from 634 locations were investigated within the site and analysed for a number of chemicals of concern. The combined analytical programme aimed to assess the potential for groundwater contamination across the site. The results of the investigation were presented in ADI Site Investigation Report of Mulwala Facility, Weapons and Engineering Division - ADI Industrial Decontamination Division, March 1992, Volumes 1 – 6, 1992.

B.2.1.4 Woodward-Clyde, 1998 Woodward-Clyde conducted Phase 1 and Phase 2 investigations of the Mulwala Facility during 1998. A review of existing environmental data available for the site was included in the Phase 1, and was consequently used for the preparation of the Phase II investigation scope of work. Ten groundwater monitoring bores were installed and analysed for a number of chemicals of concern. Bores were located north of the Finishing Area, the HE area and off-site. Groundwater monitoring bore locations are presented on Figure B2. In addition to groundwater monitoring bore installation and sampling, 395 soil samples from 322 locations were analysed for chemicals of concern. The results of the investigation were presented in Phase 1 and Phase 2 Environmental Site Assessment, ADI Mulwala, NSW. AGC Woodward-Clyde Pty Limited. 1998.

B.2.1.5 CH2MHill, 1999 and 2000 In 1999, CH2MHILL conducted a number of groundwater assessments which included the installation of an additional ten groundwater monitoring bores both on and off-site and sampling/analysis for chemicals of concern. Groundwater monitoring bore locations are presented on Figure B1. In addition to the broader groundwater investigation, the localised effect of the evaporation pond in the Finishing Area was also investigated. The results of the investigation were presented in Preliminary Groundwater Risk Review, CH2MHILL, June 1999. Subsequent Results and revisions were presented in:

• Soil and Groundwater Baseline Study of Alcohol Evaporation Pond in Finishing Area, CH2MHILL, March 2000;

• Groundwater Data Review and Conceptual Model Update, CH2MHILL, July 2000; and • Draft Groundwater Remediation Action Plan, CH2MHILL, September 2000.




B.2.1.6 URS, 2000 In 2000, URS undertook assessment of possibly contaminated areas associated with wastewater discharge on-site from certain site processes. The objective was to assess and characterise possible contamination and obtain data for areas, where information had previously not been available to assist URS with the completion of the ESA report. The results of the investigation were presented in a Letter Report, Assessment of Areas Formerly used for Discharge of Waste Waters to Ground and Bare Areas, Mulwala Facility, URS, 2000.

B.2.1.7 URS, 2001 In 2001, URS summarised all previous investigations and aimed to address any unresolved environmental issues associated with current and historical operation of the site. This was undertaken in order to assist ADI address its obligations under the Contaminated Land Management Act (CLM Act) (1997), with particular reference to site issues that may represent a Significant Risk of Harm (SRH) to human health or the environment as defined by the CLM Act. Furthermore, URS sought to identify site conditions which may warrant implementation of specific management procedures or remediation works in order to address identified SRH issues, or as part of a general improvement of environmental conditions at the facility. The results of the investigation were presented in Final Report, Environmental Site Assessment, ADI Mulwala, URS, November 2001 (Volumes 1 and 2).

B.2.1.8 ADI (Environmental Section), 2001 In 2001, the Environmental Section of ADI supervised the excavation and off-site disposal of contaminated soil from the Drainage Channel. The purpose of the remediation was primarily to remove lead and mercury contaminated sediments present at the base of the channel. Approximately 2400 tonne of contaminated soil was removed from the Channel and stockpiled on the helipad for characterisation, prior to disposing of the contaminated soil to the Corowa Landfill. Backfill material consisting of sandy soil, sourced from an area on-site which had no history of association with the processing plant, was used to reinstate the excavation. A selection of indigenous trees and grasses were planted in and along the banks of the channel. The scope of work, methodology and results are presented in Remediation of the Offsites Drainage Channel, Final Validation Report, ADI Mulwala (Environmental Section), 2001.

B.2.1.9 HLA, April and May 2002 An initial groundwater monitoring bore installation and sampling phase was undertaken during April and May 2002. Nineteen groundwater monitoring bores were installed to define plume extent and movement both on and off-site. The locations of the groundwater monitoring bores are shown on Figure B1. Static Water Levels (SWL’s) were measured in all bores, and in addition to the new HLA bores, twelve previously installed ADI bores were sampled and analysed for a wide range of chemicals of concern.




HLA installed three data loggers to assess the response of the Upper Shepparton Formation to draining of Lake Mulwala, which commenced in early May 2002. Data loggers measuring SWL and groundwater quality (pH, EC, Eh, Turbidity, Temp) were installed in three bores. Data collected over a three-month period was used to estimate the potential draw down on the Upper Shepparton Formation Aquifer system during dewatering of Lake Mulwala. Down hole geophysical logging was also undertaken in a total of 16 groundwater monitoring bores. The results of the investigation were presented in Groundwater Investigation Report (Phase 2 and 3), ADI Mulwala, HLA-Envirosciences, 25 March 2003.

B.2.1.10 HLA, July 2002 Nine test pits were excavated on the properties of Mrs N Boal, Mr J Richards, Mr M McGlynn, Yarrawonga & Border Golf Course and public land adjacent to the property of Mr A Smale in July 2002 to assess the underlying geology at the margins between the Shepparton Formation and floodplain to the south west of the site. The results of the investigation were presented in Groundwater Investigation Report (Phase 2 and 3), ADI Mulwala, HLA-Envirosciences, 25 March 2003.

B.2.1.11 HLA, September and October 2002 Twenty eight groundwater monitoring bores were installed in off-site locations during this phase of the groundwater investigation. The locations of the groundwater monitoring bores are shown on Figure B1. Sampling was repeated for both previously installed bores and the newly installed HLA groundwater monitoring bores. Six surface water samples were collected and analysed from a number of billabongs located in the floodplain area and the Murray River in September 2002. The locations of surface waters samples are shown on Figure B1 HLA conducted three transects of the Murray River using a depth sounder on a small outboard powered boat in October 2002. Transects were conducted perpendicular to river flow and depth measurements were taken for every metre travelled laterally along the river surface. The results of the investigation were presented in Groundwater Investigation Report (Phase 2 and 3), ADI Mulwala, HLA-Envirosciences, 25 March 2003.

B.2.1.12 HLA, November 2002 In November 2002, HLA installed six groundwater monitoring bores in the shallow Upper Shepparton Formation adjacent to known on-site source areas as part of source investigation works. An additional five groundwater monitoring bores were installed in Mulwala State Forest. The locations of the groundwater monitoring bores are shown on Figure B1. Following installation, these bores were sampled as part of the final phase of the groundwater investigation. Aquifer recovery tests to assess transmissivity were also conducted on two bores.




The results of the investigation were presented in Groundwater Investigation Report (Phase 2 and 3), ADI Mulwala, HLA-Envirosciences, 25 March 2003 and Source Investigation Report, ADI Mulwala, HLA-Envirosciences, 25 March 2003.

B.2.1.13 HLA, March 2003 A number of steps were taken to assess the potential impact of the identified nitrate and sulphate in groundwater on remnant native trees in the vicinity of the Mulwala site. A visual site survey was undertaken by ADI environmental staff (Mr D. Wilson, Ms J Hay, March 2003) to assess general tree health of large remnant river redgums in the area to the north east of the end of Bayley Street. An examination of aerial photographs taken of the site over a number of years, up until 2000, was also undertaken so assess any evidence of impact to the tree canopy. In addition, a search and survey of scientific literature was conducted by HLA to seek information on nitrate and sulphate impact to native vegetation. The results of the investigation were presented in Groundwater Investigation Report (Phase 2 and 3), ADI Mulwala, HLA-Envirosciences, 25 March 2003.

B.2.1.14 HLA, May 2003 In May 2003, HLA undertook a follow up investigation aimed at assessing the Priority A source areas identified in the Source Investigation Report. The potential existence of nitric and sulphuric acids at on-site source as dense non-aqueous phase liquids (DNAPLs) and residual secondary sources within the unsaturated zone were investigated in two phases:

B.2.1.14.1 Priority A Acid Source Areas

The following scope of work was undertaken with the aim of assessing the potential for migration of DNAPL behaving acids in Priority A source areas identified by HLA:

• Installation of 3 groundwater monitoring bores in the Shallow Aquifer. • Installation of 4 groundwater monitoring bores within each process areas to assist in

assessing the potential for DNAPL acids to be present at the base of the Shallow Aquifer.

• Installation of 4 groundwater monitoring bores in the Calivil Formation Aquifer. Four of

these bores were installed within process areas 2, 43, 48 and 49 to assess the potential for acid DNAPLs to be present at the base of the Calivil Formation Aquifer. Two bores were installed to the north-west and north-east of the main process areas within the facility, to further delineate the depth to bedrock and help to identify the direction of potential movement of acid DNAPLs should they be present.

B.2.1.14.2 Priority A Non-Acid Source Areas

The following scope of work was undertaken to investigate the relative contribution to groundwater contamination of the highest priority non-acid source areas:

• Sampling of soils using a continuous coring drill rig (i.e. Geoprobe®) at two locations within each of the following source areas 70, 106, 72, 35 and 10.




• Prior to undertaking continuous core drilling in the source area 106 (Dump Areas - Current Boiler House and Coal Yard), test pitting was undertaken using a backhoe at 11 locations. This was carried out to establish areas of significant contamination which would subsequently be targeted with soil bores. Representative samples were collected and analysed for soil pH and soil EC in the field, based on visual inspection of the fill material.

The results of the investigations were presented in ADI Mulwala Contamination Management Project, Priority A Sources Investigation Report, HLA-Envirosciences, 13 June 2003

B.2.2 Priority Contaminants Based on the results of the previous investigations, in addition to the work undertaken by HLA including extensive sampling for a wide range of potential contaminants, the primary contaminants of concern identified above levels acceptable for drinking water were nitrate and sulphate primarily derived from acids handling and spills on the site. Consequent with the release of these contaminants there has been an increased in the acidity of the groundwater (lower pH) and therefore an increase in the solubility of manganese, which is also present at concentrations above drinking water guidelines. The primary contaminants (nitrate and sulphate) occur naturally in groundwater, however, concentrations above naturally occurring background levels have been found beneath and “downstream” of the site.

B.2.3 Nature and Extent of Impacts The main chemicals of concern (nitrate and sulphate) are associated with the same sources and generally cover the same lateral extent in the Shallow Aquifer System and Calivil Aquifer, forming essentially two plumes that extend in a south westerly to westerly direction for over 1000m towards the river flood plain. Surface water ecosystems in the Murray River and surface water bodies in the flood plain were found to have not been impacted by groundwater contamination associated with the site (i.e. migration pathways were shown not to be complete). The general extent of the nitrate and sulphate plumes is shown in the following figures:

Approximate extent of Shallow Aquifer nitrate/sulphate concentrations impacting drinking water beneficial use.




Approximate extent of Calivil Aquifer nitrate / sulphate concentrations impacting drinking water beneficial use.

B.2.4 Sources of Groundwater Contamination Based on the previous investigations, the sources of soil and groundwater contamination can be summarised as follows:

• The primary sources (i.e. plant infrastructure) of nitrate and sulphate contamination have been removed or ceased operation. The sources remaining at the site, which may require management or remediation, are secondary sources consisting primarily of contaminants adsorbed to soil or waste materials.

• Source fluids (either dissolved phase or potentially DNAPLs) would have had to fully

penetrate the clay strata above the deeper aquifer at or near some of the on-site source areas.

• The primary mechanism for migration of contaminants down from the shallow to the

deep aquifer appears to be dissolved phase migration associated with a vertical downward hydraulic gradient and a more permeable material separating the aquifers in the vicinity of the Oleum and Effluent Plant Areas.

• No evidence was found to indicate the presence of DNAPLs beneath the acid source

areas.

• Nitrate and sulphate contamination adsorbed to material at the base of the Dune Sand and clay in the upper Shepparton formation (i.e. overlying the Shallow aquifer) appears to be the most significant secondary source of contamination beneath source areas.

• Assuming secondary source feed to groundwater ceases, nitrate in the shallow and

deeper aquifers will take over 50 years (potentially in the order of up to 100 to 150 years) before the concentrations within the current plume area are below the current drinking water quality guidelines (50 mg/L).




• Assuming secondary source feed to groundwater ceases, it will take les than 50 years (potentially in the order of 20 to 30 years) before concentrations of sulphate in the shallow and deeper aquifers are below the drinking water quality criteria for human health (500 mg/L).

B.3 NUMERICAL FLOW AND SOLUTE TRANSPORT MODEL ANALYSIS

A Numerical Flow and Solute Transport Model was developed for the site, with the primary objective of determining the behaviour over time of nitrate, sulphate and also total dissolved solids (salinity) present in groundwater on and off the site. After construction and calibration, the model was used to determine the total mass of contaminants that is currently present in both aquifers and then the mass that would enter the river flood plain over a 50 year period assuming that the contaminant sources are removed (i.e. remediated or capped to reduce infiltration) and that no further plume remediation was undertaken. In addition the model was used to determine the concentrations that would remain in the aquifers after this period. The modelling results were presented in ADI Contaminant Management Project, Baseline Numerical Flow and Solute Transport Model Analysis, ADI Mulwala, HLA-Envirosciences, 25 June 2003. A summary of the findings, with regard to the chemicals of concern, are presented below:

B.3.1 Shallow Aquifer

B.3.1.1 Nitrate It was estimated that the current total mass of nitrate in the aquifer was 456,000 kg and covered a total area of 139 ha. After 50 years, a broad plume extending from site will still have concentrations exceeding 50 mg/L, however the majority of plume area will contain concentrations less than approximately 155 mg/L nitrate. Approximate nitrate plume (50mg/L – Drinking Water Guideline) reduction over next 50 years: 45% by area. Based on this it may take up to 100 to 150 years for nitrate concentrations in the current plume to reduce to below the current drinking water quality guidelines for human health (50 mg/L).

B.3.1.2 Sulphate The total mass of sulfate in the shallow aquifer was estimated to be 1,080,000 kg and covered a total area of 83 ha. After 50 years, the majority of area will contain concentrations less than about 300 mg/L of sulphate to the south of the site. This equates to a 100% reduction in area of the 500mg/L (Drinking Water Guidelines - Health) sulphate plume and approximately a 49% reduction of 100 mg/L plume area after 50 years. Based on this it may take 20 to 30 years for sulphate concentrations in the current plume to reduce to below the current drinking water quality guidelines for human health (500 mg/L).




B.3.2 Deeper Aquifer

B.3.2.1 Nitrate It was estimated that the current total mass of nitrate in the aquifer was 416,000 kg and covered a total area of 84 ha. After 50 years, a remnant plume will remain near the flood plain boundary with concentrations exceeding 50 mg/L but majority of area with less than about 150 mg/L nitrate. It has been estimated that the nitrate plume (50 mg/L – Drinking Water Guideline) will reduce by 43%, by area, over next 50 years. Based on this it may take up to 100 to 150 years for nitrate concentrations in the current plume to reduce to below the current drinking water quality guidelines for human health (50 mg/L).

B.3.2.2 Sulphate The total mass of sulphate in the deep aquifer was estimated to be approximately 800,000 kg and covers a total area of 45 ha. After 50 years, the majority of plume area will be less than approximately 300 mg/L sulphate. It has been estimated that their will be a 100% reduction of the 500 mg/L (Drinking Water Guideline - Health) sulphate plume over next 50 years and an approximate 46% reduction of 100 mg/L plume area. Based on this it may take 20 to 30 years for sulphate concentrations in the current plume to reduce to below the current drinking water quality guidelines for human health (500 mg/L).

B.3.3 TDS

B.3.3.1 Shallow Aquifer The current total mass of TDS in the shallow aquifer was estimated to be 5,460,000 kg. After 50 years, a broad plume will remain to the south-west of site with concentrations in the range 300 to 1000 mg/L TDS but the majority of the plume will contain TDS concentrations in the range of 500 to 800 mg/L TDS. It should be noted that background TDS was determined to be 678 mg/L.

B.3.3.2 Deep Aquifer The current total mass of TDS in the shallow aquifer was estimated to be 5,800,000 kg. After 50 years, a remnant plume will remain near the flood plain boundary containing TDS concentrations in the range of 500 mg/L to over 900 mg/L TDS with some bedrock areas remaining above 1000 mg/L TDS. It should be noted that background TDS was determined to be less than 1000 mg/L, Lower TDS concentrations measured in Calivil bores outside the areal extent of impacts associated with the site are probably due to aquifer recharge from Lake Mulwala and the Murray River. Therefore a background TDS of less than 1,000 mg/L was conservatively assumed for the Calivil Aquifer in the investigation area.




B.4 REMEDIATION FEASIBILITY ASSESSMENT The objectives of the Remediation Feasibility Assessment were to identify and evaluate potential remedial technologies that may be utilised to chemically, physically or biologically remove nitrate and sulphate from groundwater and soil and restore impacted potential beneficial uses. Remedial technologies were also assessed with respect to managing elevated manganese concentrations and low pH, which appear to be associated with the nitrate and sulphate plumes in some areas. A detailed description of the Remediation Feasibility Assessment report is presented in Appendix C and summarised below:

B.4.1 Cleanup Goals The drinking water guidelines for the protection of human health (nitrate 50 mg/L and sulphate 500 mg/L) will be adopted as cleanup goals. Further refinement of these cleanup goals may be undertaken if additional information into the nature, physical or chemical behaviour, toxicity or risk associated with nitrate and sulphate in groundwater becomes available in the near future.

B.4.2 Evaluation of Remedial Technologies An extensive literature search was conducted to identify any potential remedial technologies that may be applicable to groundwater contamination associated with the site. Remedial technologies were screened with respect to feasibility (i.e. ability to achieve clean up goals), logistical constraints, time and cost. Some of the more promising technologies were further evaluated to assess their practicability for the off-site groundwater plume and management of source areas.

B.4.3 Practicability of Off-Site Groundwater Plume Management The assessment did not identify any practicable technologies to actively remediate the broader off-site groundwater plume. Based on screening of potential technologies, the most promising approaches to clean up of the off-site groundwater plume, were pumping and irrigation and carbons source addition (CSA). Pumping and irrigation was shown to be potentially limited by the area required to accept the loading of contaminants in groundwater (sulphur and nitrate). Therefore, pumping and irrigation has been retained for further consideration as part of the proof-of-concept phase. CSA was shown to be impractical for the off-site plume due to the number of bores required, lack of control over potential sulphide generation (sulphidogenesis) and the relatively limited reduction in time to achieve cleanup. Therefore, it is recommended that the off-site groundwater plume be managed as follows:

• Clean up or management of the main onsite source areas.

• Management of the current uses of groundwater off-site (irrigation, domestic use and stock watering) through continuation of the partnership between Defence, ADI, off-site residents and the Corowa Shire Council.




• Monitoring natural attenuation of the groundwater plume.

The specific management requirements concerned are detailed in the CMP and include measures such as restriction of groundwater uses according to contamination levels, on-going bi-annual groundwater monitoring, establishment of a register of affected properties and landowners located within the area of groundwater impact (exceed drinking water guidelines).

B.4.4 Practicability of Source Area Management The clean up and management strategies for onsite source areas considered to be practical, or at least potentially practical, are as follows:

• CSA to groundwater in the source areas using either horizontal bores or a Recirculation Cell.

• CSA to soil acting as a secondary source of groundwater contamination in source areas by shallow infiltration.

• Pumping and irrigation of contaminated groundwater leaching from source areas.

• Capping with a low permeability capping system.

• Capping with deep and shallow rooting plant species (phytocapping).

Capping is considered practicable for the source areas of greatest significance. If phytocapping is shown to be effective in sufficiently reducing leaching of contaminants from contaminated soil acting as secondary sources, it would be preferred over clay capping as it may result in the partial removal of some of the contaminant mass (nitrate) and is potentially more cost effective and environmentally sustainable. The principal disadvantage of either form of capping is that they are simply a means of managing leaching of contaminants from impacted soil and will need to be maintained indefinitely. CSA addition for groundwater and soil in Source Management Area A will be retained for further evaluation of practicability based on field trials and detailed modelling. CSA of groundwater and soil represents an opportunity to clean up soil acting as secondary sources rather than simply managing infiltration rates. Contaminated soil in Source Management Area A has been identified as the most significant area of contamination as it is the primary source of both the northern arm of the off-site plume in the Shallow Aquifer and of the off-site plume in the Deep Aquifer. CSA using a Recirculation Cell and Direct Injection via horizontal bores are considered potentially practicable approaches to managing migration of groundwater from source areas. However, the principal limitation of these approaches is that they will need to be operated for a significant period of time (potentially decades) unless CSA for soil proves an effective means of removing contaminants from source area soils. The effectiveness of CSA for groundwater would need to be demonstrated prior to implementation of CSA for soil. Effective management of groundwater contamination provides a means of controlling of some of the potential impacts on groundwater quality associated with CSA for soil. The primary potential impact of CSA for soil on groundwater quality relates to additional flushing of contaminants by increasing vertical hydraulic gradients through source zone soils.




Pumping and irrigation for containment of contaminated groundwater migration from source areas will be retained for further consideration as an alternative to CSA to Groundwater. Although it may not prove to represent a complete management solution, ADI and Defence may wish to consider an option to provide groundwater extracted from source areas to the golf course as means meet the golf clubs water use needs and assisting in maintaining capture zones around source areas.

B.4.5 Source Management Areas Based on characteristics of each source area and the type of remediation or management measures recommended to reduce the release of nitrate and sulphate to groundwater, the onsite source areas were grouped into five Source Management Areas. The recommended approach to remediation or management of each area is presented below:

B.4.5.1 Source Management Area A The recommended approach to management of soil and groundwater contamination in Source Management Area A is summarised in the following flow diagram:


1


2



Implement Capping

Yes


Trial


Attenuation


Yes

No


NoNo

YesYes

No




B.4.5.2 Source Management Areas B to E The recommended approach to management of contamination in each of the Source Management Areas B to E are summarised as follows:


Source 70


Backfill drain with soil in the adjacent mounds and supplement with additional natural material, to provide a nominal level of capping to reduce ponding of surface water in the base of the drain.

Planting over the backfilled drain using an appropriate selection of deep and shallow rooting plant species to reduce infiltration of contaminants to groundwater. If monitoring indicates phytocapping does not prove effective in reducing leaching of contaminants from soil, construct a low permeability capping system.


Source 106

Excavate waste materials (i.e. gypsum) and placement in either an off-site landfill, licensed to accept the waste, an engineered on-site landfill (i.e the area along the southern boundary of the site where the Shepparton Formation is absent) or under the proposed modernisation building footprints..

Replace waste and soil removed from source area with topsoil or a growing medium. Plant phytocap of appropriate selection of deep and shallow rooting plant species. If monitoring indicates phytocapping does not prove effective in reducing leaching of contaminants from soil, construct a low permeability capping system.


Source 103


Source 102







Sources 50 & 51


Source 35

Implementation of a cap over Source Management Area E using clay and topsoil and an appropriate selection of deep and shallow rooting plant species to aid in the removal of shallow nitrate and reduce rainfall infiltration.

Existing and future buildings and pavements are assumed to act as effective capping. Plant phytocap of appropriate selection of deep and shallow rooting plant species in areas not covered by buildings or pavements. If monitoring indicates phytocapping does not prove effective in reducing leaching of contaminants from soil, construct a low permeability capping system.

B.5 REFERENCES A summary of the previous assessment results have been presented in each of the investigation reports as follows:

ADI Industrial Decontamination Division (ADI, 1992a). Site Investigation Report of Mulwala Facility, Weapons and Engineering Division - Volume 1 Executive Summary, March 1992.

ADI Industrial Decontamination Division (ADI, 1992b). Site Investigation Report Of Mulwala Facility, Weapons and Engineering Division - Volume 2 Procedures, March 1992.

ADI Industrial Decontamination Division (ADI, 1992c). Site Investigation Report Of Mulwala Facility, Weapons and Engineering Division - Volume 3 Results, March 1992.

ADI Industrial Decontamination Division (ADI, 1992d). Site Investigation Report Of Mulwala Facility, Weapons and Engineering Division - Volume 4 Discussions and Conclusions, March 1992.

ADI Industrial Decontamination Division (ADI, 1992e). Site Investigation Report Of Mulwala Facility, Weapons and Engineering Division - Volume 5 Site Sample Point Maps, March 1992.

ADI Industrial Decontamination Division (ADI, 1992f). Site Investigation Report Of Mulwala Facility, Weapons and Engineering Division - Volume 6 Groundwater Monitoring System Revision, Report prepared by Golder Associates for ADI IDD, March 1992.

ADI Mulwala Environmental Section (ADI, 2001) Remediation of the Offsites Drainage Channel, Final Validation Report, ADI Mulwala, 2001.

CH2MHill Australia Pty Ltd (CH2MHill, 1999a). Mulwala Facility Groundwater Contamination Audit”, May 1999, Report No. 101651.01.Rev1, CH2MHill Australia Pty Ltd.

CH2MHill Australia Pty Ltd (CH2MHill, 1999b). Mulwala Facility Preliminary Groundwater Risk Review. Supplementary Assessment Risk Ranking, Report No. 110015.016-Rev1. June 1999.




CH2MHill Australia Pty Ltd (CH2MHill,1999c). Mulwala Facility Soil and Groundwater Baseline Study for Potassium Nitrate Evaporation Ponds, Report No. 110014.001.Rev0. November 1999.

CH2MHill Australia Pty Ltd (CH2MHill, 2000). Mulwala Facility Soil and Groundwater Baseline Study of Alcohol Evaporation Pond in Finishing Area, Report No. 110014.019.Rev2. March 2000.

Gutteridge Haskins & Davey Pty Ltd (GHD, 1987). Relocation of Albion Explosives Factory to Mulwala, Draft Environmental Impact Statement. Report No. CP-57281 U. September 1997.

HLA-Envirosciences Pty Limited (HLA, 2003a). Groundwater Investigation Report (Phase 2 and 3), ADI Mulwala. 25 March 2003.

HLA-Envirosciences Pty Limited (HLA, 2003b). Source Investigation Report, ADI Mulwala. 25 March 2003.

HLA-Envirosciences Pty Limited (HLA, 2003c). ADI Mulwala Contamination Management Project, Draft Numerical Flow and Solute Transport Model Analysis. 10 June 2003.

HLA-Envirosciences Pty Limited (HLA, 2003d). ADI Mulwala Contamination Management Project, Baseline Numerical Flow and Solute Transport Model Analysis. 25 June 2003.

HLA-Envirosciences Pty Limited (HLA, 2003e). ADI Mulwala Contamination Management Project, Priority A Sources Investigation Report. 13 June 2003.

URS Australia Pty Ltd (URS, 2000), Letter Report – Assessment of Areas formerly used for Discharge of Waste Waters to Ground and Bare Areas, Mulwala Facility. 2000.

URS Australia Pty Ltd (URS, 2001a), Further Environmental Site Assessment of Commonwealth Property Located Outside ADI Mulwala Facility Fence Line. November 2001.

URS Australia Pty Ltd (URS, 2001b), Final Report - Environmental Site Assessment ADI Mulwala, November 2001.



D006005_RPT236Rev03_17Dec03_AppendixB

Figures

ADI Limited

PROJECT FILE NAME D0060

DATE OCT 2003

DRAWN SR

APPROVED

HISTORY OF ENVIRONMENTAL GROUNDWATER INVESTIGATION WORKS

FIGURE

1Previous InvestigationsAMG Zone 55 (AGD66) Scale: 1:15000

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BH71

BH63

BH62

BH61

BH60

BH59

BH58

BH57

BH52

BH51

BH46

BH45

BH44

BH43BH42

BH41BH39

BH38

BH37

BH36

BH34

BH33

BH32

BH31BH30

BH29

BH28

BH27

BH26

BH25

BH24

BH23

BH19

BH17

BH16

BH15

BH14

BH13

BH12

BH11BH09

BH08

BH07

BH06 BH04

BH03

BH02

BH01

BH91C

BH91B

BH77C

BH76C

BH74B

BH74A

BH73C

BH73ABH72C

BH70C

BH70B

BH69C

BH69B

BH68C

BH68B

BH66C

BH65C

BH64C

BH56B

BH56A

BH55C

BH55B

BH54B

BH54A

BH53BBH53A

BH50BBH50A

BH49BBH49A

BH48BBH48A

BH47B

BH28R

BH22BBH22A

BH20B

BH20A

BH92

BH40

BH18

BH67C

BH67B

BH55A

BH21B

BH21A

TP05TP06TP07

TP08

TP09

TP02

TP03TP04

TP01

406,000

406,000

407,000

407,000

408,000

408,000

409,000

409,000

6,015,000

6,015,000

6,016,000

6,016,000

6,017,000

6,017,000

6,018,000

6,018,000

6,019,000

6,019,000

I0 250 500 750125

Meters

Legend

Shepparton Formation Aquifer Bore

Surface Water Body

HLA - Surface Water Samples October 2002

Bedrock Aquifer Bore

A

A Older Floodplain Aquifer Bore

A Calivil Formation Aquifer Bore

A Floodplain Aquifer Bore

A

BH01

Site Boundary

Surface Water Sample

Ö

HLA - November 2002 BH01

HLA - September/October - 2002 BH01

HLA - Test Pit July 2002TP01

Test Pit LocationD

Woodward-Clyde - 1998BH01

CH2MHILL - 2000BH01

HLA - April/May - 2002 BH01

Golders - 1992BH01

GDH - 1987BH01

HLA - May 2003BH01


D006005_RPT236Rev03_17Dec03

Appendix C Remediation Feasibility Assessment

ADI Mulwala Contamination Management Project CONTAMINATION MANAGEMENT PLAN Appendix C – Remediation Feasibility Assessment 17 December 2003 Prepared for: Department of Defence and ADI Limited Bayley Street, Mulwala, NSW 2647 Report by: HLA-Envirosciences Pty Limited ABN: 34 060 204 702 46 Clarendon Street Melbourne VIC 3205 Australia Ph: +61 3 8699 2199 Fax: +61 3 8699 2122 HLA Ref: D006005_RPT236Rev03_17Dec03_AppendixC


Appendix C – Remediation Feasibility Assessment

D006005_RPT236Rev03_17Dec03_AppendixC.doc i

CONTENTS C APPENDIX C – REMEDIATION FEASIBILTY ASSESSMENT....................................1

C.1 INTRODUCTION...........................................................................................1 C.2 EVALUATION OF REMEDIAL TECHNOLOGIES ........................................1

C.2.1 Methodology...................................................................................1 C.2.1.1 Technology Assessment .................................................1 C.2.1.2 Probabilistic Cost Modelling ............................................2

C.2.2 Screening of Remedial Technologies .............................................3 C.2.3 Development of Management Strategies......................................11

C.2.3.1 Off-Site Groundwater Plume Management....................11 C.2.3.2 Source Area Groundwater Management .......................17 C.2.3.3 Pumping and Irrigation ..................................................20 C.2.3.4 Source Area Soil Remediation ......................................20

C.2.4 Summary......................................................................................23 C.2.4.1 Off-Site Groundwater Plume .........................................23 C.2.4.2 Source Management .....................................................24

C.3 SOURCE AREA MANAGEMENT ...............................................................25 C.3.1 Source Management Areas..........................................................25 C.3.2 Source Management Area A ........................................................26

C.3.2.1 Background ...................................................................26 C.3.2.2 Overall Approach...........................................................27 C.3.2.3 Proof-of-Concept Trial ...................................................28 C.3.2.4 CSA Direct Injection ......................................................28 C.3.2.5 CSA Re-circulation Cell .................................................28 C.3.2.6 CSA Soil Remediation ...................................................29 C.3.2.7 Source Area Capping ....................................................29 C.3.2.8 Monitoring Natural Attenuation ......................................29

C.3.3 Source Management Area B ........................................................29 C.3.3.1 Background ...................................................................29 C.3.3.2 Recommended Management Strategy ..........................30

C.3.4 Source Management Area C ........................................................31 C.3.4.1 Background ...................................................................31 C.3.4.2 Recommended Management Strategy ..........................31

C.3.5 Source Management Area D ........................................................32 C.3.5.1 Background ...................................................................32 C.3.5.2 Recommended Management Strategy ..........................32

C.3.6 Source Management Area E ........................................................32 C.3.6.1 Background ...................................................................32 C.3.6.2 Recommended Management Strategy ..........................33

C.4 REFERENCES............................................................................................33




D006005_RPT236Rev03_17Dec03_AppendixC.doc 1

C APPENDIX C – REMEDIATION FEASIBILTY ASSESSMENT

C.1 INTRODUCTION The objectives of this Remediation Feasibility Assessment were to identify and evaluate potential remedial technologies that may be utilised to chemically, physically or biologically remove nitrate and sulphate from groundwater and soil and restore impacted potential beneficial uses. Remedial technologies were also assessed with respect to managing elevated manganese concentrations and low pH, which appear to be associated with the nitrate and sulphate plumes in some areas. The feasibility assessment process included the following:

• Identification of all known potential remedial options that may be applied at the Mulwala site. A large number of publications and resources have been reviewed, and referenced at the end of this report.

• Screening of the potential remedial technologies with respect to technical feasibility, financial considerations, logistical constraints, on-going management requirements and timing (to reach clean-up objectives) to assist in establishing the practicability of remediation.

• Identification of preferred management strategies, incorporating one or more remedial technologies, to address impacts on potential beneficial use of groundwater off-site.

C.2 EVALUATION OF REMEDIAL TECHNOLOGIES The evaluation and ranking of remedial technologies or combinations of technologies to manage the various sources and the existing plumes associated with the site are presented in this section.

C.2.1 Methodology A summary of the methodology employed to evaluate the practicability of the remedial technologies is presented below:

C.2.1.1 Technology Assessment Research into potential remedial technologies was undertaken by HLA using a variety of information sources (refer to Section C.4). From the broad range of options and variations reviewed, technologies that have been successfully applied elsewhere to reduce nitrate and sulphate concentrations in groundwater to below drinking water guideline values were selected for further consideration and evaluation with respect to the site specific issues and constraints. The management responses have been separated into Off-site Groundwater Plume Management, Source Area Groundwater Management and Source Area Soil Remediation. These broad categories present very different constraints on technical feasibility, logistics and cost.




Each of the respective source areas differ in terms of their nature and likely contribution to groundwater impacts. Therefore, in addition to being ranked in terms of risk (Table 1 in Section 2.4.3 - Remediation Feasibility Assessment Report, HLA 2003e), the source areas have been grouped according to different recommended management strategies. Technical, financial and logistical considerations were collated for comparison and screening of the technologies in the context of the soil and groundwater contamination present at the site. A definition of each consideration and its relevance to determining the practicability of a particular technology is presented below:

• Technical considerations include the physical ability to remove the contamination within a reasonable timeframe. The chemical and physical properties of the contaminant and the medium to be remediated obviously affect the approach used to remove the contaminant.

• Logistical considerations include the accessibility of the contaminant, availability of remedial equipment / infrastructure and the disposal of wastes.

• Financial considerations include the capital costs such as equipment and its installation / commissioning, coupled with ongoing costs such as for maintenance and waste treatment / disposal.

Based on the screening process outlined above, the more promising technologies were either further evaluated in terms of practicability (i.e. for management of the off-site plume) or incorporated into clean up strategies for specific issues (i.e. Source Management Areas).

C.2.1.2 Probabilistic Cost Modelling A financial risk model was developed to calculate the financial costs in relation to each remediation and management scenario proposed in this remediation feasibility study. Identification of significant cost items and estimation of probabilistic input parameters for each remediation technology was completed by HLA personnel based on available information relating to existing contamination at the site. Cost estimates were calculated using a probabilistic financial risk model using Crystal Ball, a commercially available software add-on to Microsoft Excel. Costs for each cost item were estimated by defining a log-normal probability distribution and the distribution of total costs for implementation of each technology was obtained from the model using a Monte Carlo simulation. The principal values HLA’s uses from the distribution of total costs were the 60th percentile value (Optimistic Cost), the 80th percentile (Planning Cost) and the 95th percentile (Pessimistic Cost). HLA has used the Planning Cost for comparison between different technologies. The difference between the Pessimistic and Optimistic Costs has been used to reflect uncertainty in the potential costs associated with each technology.




C.2.2 Screening of Remedial Technologies The remedial approaches identified have been screened (as presented in Tables 1 to 4) based on their ability to treat the primary contaminants of concern (i.e. nitrate and sulphate). For the purposes of the evaluation, the technologies were categorised as to whether they apply to remediation of the groundwater plume ex-situ (Table 1), or remediation of the groundwater plume in-situ (Table 2) or remediation of the source area soil contamination (Table 3). A summary of Carbon Source Addition (CSA) delivery systems for source management (Table 4) has also been presented. Table 1 to 4 are further explained below: Table 1 – Summary of Remedial Option - Ex-situ Groundwater Plume Management Technologies This table presents groundwater remediation technologies that rely on the extraction of impacted groundwater from the aquifers followed by physical, chemical or biological treatment at the surface. These ‘Pump and Treat” technologies all require subsequent disposal or re-use of the treated groundwater by either re-injection into the aquifers or disposal irrigation, evaporation or off-site discharge. Table 2 – Summary of Remedial Option - In-situ Groundwater Plume Management Technologies This table presents groundwater remediation technologies that involve physical, chemical or biological treatment of the groundwater within the aquifers without extraction to the surface. Where feasible, these technologies are generally favorable due to the preservation of the groundwater resource, however conversely the potential is greater for adverse side-effects to impact the groundwater compared to ex-situ treatment. Table 3 – Summary of Remedial Option - Source Area Soils This table presents active and passive technologies available to either remove nitrate and sulphate adsorbed to the unsaturated and saturated soils, or mitigate further vertical migration or release of nitrate and sulphate to groundwater. Table 4 – Summary Carbon Source Addition Delivery Systems for Source Management This table presents technologies for introducing a carbon source into aquifers and mixing the carbon in contaminated groundwater. A more detailed description of the methodology and costs associated with each of the technologies is presented in Appendix A of the Remediation Feasibility Assessment. Based on the screening presented in Table 1 to 4, the more promising technologies were retained for development of integrated remedial strategies and more detailed evaluation (see Section C.2.3) as to practicability to achieve clean up.




Table 1 - Summary of Remedial Options – Ex-situ Groundwater Plume Management Technologies

Surface Irrigation Surface Bioreactor Constructed Wetlands Reverse Osmosis Ion Exchange Distillation / Concentration via Evaporation Supercritical Water Oxidation

Brief Description

Extracted waters and contaminants are irrigated on to surface plantation to be taken up via plant transpiration.

Waters are pumped into a bioreactor whereby surface treatment conditions can proceed in a controlled environment. The bioreactor may incorporate the addition of nutrient sources, such as carbon addition, supplementation organisms, temperature control, electrokinetics or alternative treatment technologies.

Abstracted waters and contaminants are irrigated on specially constructed surface wetlands to stimulate organic matter and anaerobic degradation of contaminants. Additional organic additives may be required.

Water under pressure is passed through a fine membrane where salts and other larger molecular contaminants remain.

Process based treatment whereby one anion is exchanged for another (such as chloride for nitrate). The replacement ion is discharged in the outflow waters while the target ion is held in place via an intermediary product.

Waters are pumped into holding ponds and allowed to evaporate leaving an increasing concentration of nitrate & sulphate Evaporated water can be collected and recovered if required (distillation).

Waters are fed through and heated to supercritical water temperature (>324C) and pressure (22.1Mpa) where water exists as a single phase fluid that has different properties to water, ice or steam. Contaminants are typically disassociated.

Technical Considerations

Long term pumping required.

Area, location and size of irrigated crop. Possible limitations of grass and plant species capable of withstanding nutrient, sulphate, pH and salt (TDS) loading.

Sustainable volume per hectare of irrigation so that the land is not impacted by sulphate, pH and TDS (see Section 4.3.1.1). Also volumes irrigated to restrict re-infiltration into subsurface.

Ability to monitor and control irrigated area to avoid groundwater impacts.

Plants will uptake nitrate but sulphate will concentrate in shallow soil.

Location of irrigation areas relative to plumes and sources

Potential crop value.

DIPNR may object to long term groundwater extraction due to the embargo that is currently in place unless groundwater can be reinjected.


Potentially not effective for treatment of sulphate, manganese or pH.

Size of bioreactor.

Retention time required within treatment vessels restricts flow through and treatment rate.

At this stage it is unknown what bioremedial additives are needed to enhance the degradation processes – revert to treatability studies (lab/bench scale trials).

Concern over disposal requirements for large amounts of treated water expected to still contain elevated levels of sulphate and possibly TDS.

Proven to be expensive based on other projects undertaken in Australia.

DIPNR may object to long term extraction.


Area, location and size of constructed wetland.

Plant species capable of withstanding nutrient, sulphate, manganese, pH and TDS loading.

Possible persistence of sulphate and TDS which could potentially result in elevated levels remaining in sediments, soils and downstream outlet water.

Possible incompatibility for indigenous species, which could potentially require introduced species.

Requirement for holding pond prior to wetland release.

Catchment area and impact of rainfall run-off to treatment volumes and efficiency.

DIPNR may object to long term extraction unless reinjected.


Only 30 – 40% of water typically able to pass through membrane – therefore waste water stream needs to be considered.

Typically 60-90% of initial nitrate concentration and 90-99% sulphate removed. Reverse Osmosis able to be supplied in many varying sizes depending upon application.

Will not treat pH.

Concern over disposal requirements for waste water stream with significantly higher concentrations of nitrate, sulphate and TDS than the groundwater. Ongoing maintenance and replacement of filter media required.



Will not deal with both nitrate and sulphate at the same time. Waste stream and supply of ongoing exchange media required. Energy intensive.

Does not deal with manganese of pH issues.

Concern over disposal requirements for waste water stream with significantly higher concentrations of nitrate, sulphate and TDS than the groundwater.

DIPNR may object to long term extraction.


Optimal area of holding tanks to achieve maximum evaporative effect.

Length of time to achieve expected evaporative effect.

Disposal / treatment of enriched waters.

Concern over disposal requirements for waste water stream with significantly higher concentrations of nitrate, sulphate, manganese and TDS than the groundwater.



Very energy intensive and inefficient, Potential for incomplete combustion and generation of toxic gases.

Pollution control, regulation and monitoring of exhaust emissions required.

Very new technology and unproven treatment for nitrate.

Salt precipitation causes problems / blockages in most systems.

No energy recovery possible due to lack of organics.

Unsure of technical appropriateness for contaminants present.

Financial2

Considerations Planning Cost1 $2.35M

Optimistic Cost1 $2.18M

Pessimistic Cost1 $2.62M Potentially off-set by commercial value of crops if grown.

Planning Cost1 $6.12M


Pessimistic Cost1 $7.03M




Planning Cost1 $15M

Optimistic Cost1 $10M

Pessimistic Cost1 $20M Point source treatment: eg household consumption – circa $100-$2000 / unit

Planning Cost1 $10M


Pessimistic Cost1 $15M

Point source treatment: eg household consumption – circa $1,500-$5,000 / unit

Planning Cost1 $18M



Planning Cost1 $18M



Logistical Considerations

Land area available for irrigation – eg nearby farmland and/or on-site.

Ability to connect to any existing systems (e.g. golf course) and system requirements. Availability of plant species. Location with respect to extraction points.

Nature and source of carbon source or bioremedial additives is unknown.

Location and housing of treatment system, requirements re power, security.

Waste stream or re-injection infrastructure.

Availability of plant species. Location with respect to extraction points and reticulation.

Grading of site, location of holding pond (if required).

Location and housing of treatment system, requirements re power, security, waste reticulation and disposal.

Long-term labour-intensive maintenance including membrane rotation.

Location and housing of treatment system, requirements re power, security waste reticulation and disposal.

Long-term labour-intensive maintenance

Location and housing of evaporation ponds – difficult to achieve on a practicable scale.

Large land area required and waste reticulation and disposal infrastructure.

Location and housing of treatment system, requirements re power, security.

Exhaust scrubbers need to be included to manage SOx and NOx emissions.

Ongoing Management

Management and monitoring to ensure that the pumping and irrigation rates required are appropriate to avoid flooding, over irrigation and impacting the existing domestic irrigation groundwater supply.

Operational and maintenance management required. Close monitoring of effectiveness of remedial media.

Management and monitoring of treated fluid waste water prior to disposal, return to aquifer or alternative.

Power, security etc with reference to treatment stations

Operational and maintenance management required. Close monitoring of plant species, wetlands health and sulphate, nitrate, TDS, manganese and pH levels at inlet and outlet. life.

Management and monitoring of treated fluid prior to disposal, (eg return to aquifer or alternative during high rainfall periods).

Significant operational and maintenance management required.

Management of waste stream required.







Security etc with reference to treatment location

Significant operational and maintenance management required as well as monitoring of exhaust emissions.


Power, security etc with reference to treatment station.




Table 1 - Summary of Remedial Options – Ex-situ Groundwater Plume Management Technologies (cont.)

Surface Irrigation Surface Bioreactor Constructed Wetlands Reverse Osmosis Ion Exchange Distillation / Concentration via Evaporation Supercritical Water Oxidation

Timing Installation: 2-4+ months pumping system.

Likely to take at least two and possibly three decades to reach clean up goals.

Remedial Operation: based on field trials.

Installation: 3-12+ months

Likely to take at least one or more decades to reach clean up goals and likely to be a significant limitation in time associated with retention time for water in the bioreactor.

Remedial Operation: based on lab treatability studies & field trials.


Likely to take at least one or more decades to reach clean up goals.

Remedial Operation: based on lab treatability studies & field trials.

Installation: 3-12 months


Remedial Operation: based on field trials








Remedial Operation: based on lab treatability studies

Overall Rating 3 & Practicability

**

Not considered to be practicable based on the large areas required for irrigation and the long time period required to achieve clean up goals.

Care is needed with respect to sulphate, manganese pH and TDS accumulation in irrigated soils.

The subsequent requirement for vast irrigation areas is therefore the main limitation to this approach.

Because of the large areas of land, the logistics of pumping, piping and irrigation networks to distant irrigation areas are difficult and potentially cost prohibitive.

Because of land availability and timing issues associated with the capacity of the land to receive sulphate and TDS, the overall timing of clean-up may not be significantly sooner than natural attenuation and therefore may not warrant the expense.

**

Not considered practicable because of the effluent that would remain and require waste disposal stream and the time limitations associated with retention in the reactor.

Overall timing of clean-up is unlikely to be significantly sooner than natural attenuation and therefore would not warrant the expense of this technology.

Possibly technically effective approach for treating nitrate, however may not effective treat pH and TDS.

Treatability studies would be required to determine most effective amendment media and treatment rates / retention times.

High cost and long operational period.

**

Not considered practicable based on the likely adverse effects of persistent sulphate, TDS and possibly manganese. Effects expected to include sulphate and salt impact to vegetation, sediments and soils and flow-through of these persistent contaminants downstream as waste water.

Large construction area and long retention time likely to be required to counter these adverse effects and reduced treatable volume during periods when wetlands capacity is taken up by rainfall and surface run-off.

Because of the retention time limitations, the overall timing of clean-up may not be significantly sooner than natural attenuation and therefore may not warrant the expense.

If introduced species are required, the impact to existing indigenous vegetation and the potential for weed infestation would make this approach less appropriate.

Renders a large area of land unusable for other purposes

*

Does not deal with a majority of contaminants.

Not considered practicable due to high concentration waste stream, technical issues associated with process-based treatment and capital and operational costs.

Because of the treatment time limitations, the overall timing of clean-up may not be significantly sooner than natural attenuation and is unlikely to warrant the expense.

*


Not considered practicable due to high concentration waste stream, technical issues associated with process-based treatment and capital and operational costs.


*


Not considered practicable due to high concentration waste stream and very high capital and operational costs.


*


Not considered practicable due to very high capital and operational costs and uncertainties over technical appropriateness.


1 Note that cost estimates do not allow for long-term operating, maintenance and groundwater monitoring costs, which could increase the estimates by up to 50% or more if operation is required to continue for more than (approximately) 15 years. 2 Refer to explanation of costs in Section 4.1.2 – Note that limited accuracy applies to all cost estimates.

3 * = Inappropriate remedial technology ** = Not desirable although may have some application potential if significant limitations can be overcome *** = Potential remedial technology with some application potential **** = Likely suitable remedial technology with suitable application potential




Table 2 - Summary of Remedial Options – In-situ Groundwater Plume Management Technologies

In-situ Bioremediation via Anaerobic Enhancement (Carbon Source Addition)

Monitored Natural Attenuation (MNA)

Hydrogeological Modification

In-situ Bioremediation via Anaerobic Enhancement (Hydrogen Source Addition - HRC)

Phytoremediation In-situ Bioremediation via Electrokinetics

Brief Description Addition of a carbon source provides energy for microbial degradation of nitrate and reduction of sulphate.

Natural attenuation or intrinsic remediation is a passive approach that depends upon natural processes to degrade and dissipate contaminants, including aerobic and anaerobic biodegradation, dispersion and adsorption.

Groundwater depression & mounding via pumping. Altering the hydrogeological regime may assist in utilising the mechanics of attenuation and degradation, or assist in protecting sensitive receptors down-gradient. Modification may also allow the most impacted areas of the plume to be more successfully targeted by any other selected remediation technologies.

Addition of hydrogen source provides energy for autotrophic microbial degradation.

Phytoremediation is the direct use of living green plants for contamination reduction for soil, sludges, sediments, and ground water, through contaminant removal, degradation, or containment. Growing and, in some cases, harvesting plants on a contaminated site as a remediation method is an aesthetically pleasing, solar-energy driven, passive technique that can be used to clean up sites with shallow, low to moderate levels of contamination. Plants also have a proven role as water pumps in a variety of remedial situations in both open and closed systems. Techniques can be used along with or, in some cases, in place of mechanical cleanup methods.

Addition of electrodes into the ground. These electrodes are then energized so that an anode and cathode is generated. The resulting current can alter the redox potential of the aquifer to encourage biological degradation, or transport contaminants via electroosmosis and electromigration.


Nature of carbon source - options include either liquid addition (eg ethanol, glucose, vegetable oil, molasses; or solid (eg sugar, molasses, activated carbon, woodchips, sawdust) etc. Treatability studies of carbon sources to determine most appropriate and effective amendment medium.

Is a proven approach for nitrate and to a lesser degree sulphate plumes on other sites, implications for manganese, TDS and pH require assessmentSite specific data suggests biological activity in the aquifers is carbon limited.

Site hydrogeology, emplacement depth, no of locations, changes relating to plume dimensions and projected timelines.

Potential for generation of hydrogen sulphide gas.

Implementation: Rapid or slow release. Injection into aquifer under pressure, passive emplacement etc. Diffusive / dispersive carbon sources require less injection points (i.e. bores).

Network of injection bores must be carefully located to achieve maximum effect.

Diffusion of carbon source throughout the contamination plume is expected to be difficult to achieve practically. Considered likely to be a limitation to successful application and time required to achieve clean-up goals.

Potential for adverse effects to water quality such as ethanol hydrocarbon, pH changes (and H2S gas as described above). This potential may preclude the technology from being applied off-site up-gradient hydraulically from existing groundwater users.

Contingency plans and ready measures are required to counter these adverse effects.

Prediction of the rate of attenuation has been made based on fate and transport modelling.

Long term monitoring requirements. Need to consider all contaminants present.

Thorough understanding of site hydrogeology required. Modelling to determine regional effects based on particular scenarios.

Nature and type of pumping / mounding activities, any waste waters generated as a result of pumping activities.

Changes relating to plume dimensions and hence projected timelines.

Significant potential to impact existing groundwater users.

Considered unlikely to significantly reduce the amount of time required to reach clean-up goals compared to MNA.

Nature of hydrogen source – eg HRC emplacement. Treatability studies of hydrogen sources to determine most appropriate and effective amendment medium.

Potential for generation of hydrogen sulphide gas.

Implementation: Injection into aquifer under pressure, passive emplacement etc.

Site hydrogeology, emplacement depth, no of locations, changes relating to plume dimensions and projected timelines, impact on pH, TDS and manganese concentrations.

Potential to impact existing groundwater users.

Network of injection bores must be carefully located to achieve maximum effect.

Diffusion of HRC into the groundwater may difficult to achieve effectively. Possibly a limitation to successful application and time required to achieve clean-up goals.

The root zone of suitable plant species will not penetrate and effectively treat the deeper Calivil formation.

Nature and selection of plant species capable of withstanding sulphate, manganese, pH, TDS and nutrient loading Area, location and size of plant cropping.

Aquifer conditions with respect to eco-toxicity.

Field studies into nutrient (i.e. contaminant) uptake and ability to reduce infiltration to determine effectiveness.

Treatability and field studies would be required to determine arrangement of cathode / anode placement.

Effect on non nitrate contaminants present at the site.


Financial 2 Considerations




Planning Cost $3.50M

Optimistic Cost $2.50M

Pessimistic Cost $5.0M










Planning Cost1 $20M




Carbon source storage, distribution and injection infrastructure.

Contingency infrastructure and materials such as oxygen release and pH adjustment compounds.

Time constraints associated with the need to stage pilot-scale testing together with an approach to evolve testing into full-scale remediation.

No logistical constraints except access to the land for monitoring must be retained until attenuation to acceptable levels has occurred.

Moderate limitations. May be incorporated into existing well network and allowance within future building structure made.

Long-term operating, maintenance, HRC procurement and storage costs etc.

Land availability, area of plume that can be planted over.

Infrastructure limitations associated with a network of electrodes, cables, power source, land use, access and ownership constraints and labour intensive long-term operational costs.

Incorporation of equipment and access into future building structure would be considered if this technology was adopted. May need significant area for surface equipment.




Table 2 - Summary of Remedial Options – In-situ Groundwater Plume Management Technologies (cont.)

In-situ Bioremediation via Anaerobic Enhancement (Carbon Source Addition)

Monitored Natural Attenuation (MNA)

Hydrogeological Modification

In-situ Bioremediation via Anaerobic Enhancement (Hydrogen Source Addition - HRC)

Phytoremediation In-situ Bioremediation via Electrokinetics

Ongoing Management

Groundwater monitoring to ensure amendment diffusion occurring effectively, redox conditions optimal for nitrate, manganese, and sulphate reduction and no other adverse impacts to existing groundwater beneficial uses.

Ongoing operation of the CSA programme required including maintenance of any carbon source storage and injection infrastructure.

Groundwater and potentially surface water (Murray River) monitoring required to confirm that attenuation of all contaminants occurs at rate predicted by the modelling.

Monitoring of to ensure product is being recovered. Monitoring of recovered volumes and rates to establish effectiveness. Associated initial quarterly / biannual groundwater monitoring of well network.

Groundwater monitoring to ensure amendment diffusion occurring effectively and redox conditions optimal for nitrate, manganese and sulphate reduction.

Plant life monitoring, harvesting, grazing etc. Requirement for monitoring of vacuum or pressured conditions, GAC reactive media (if utilised) and “bounce back” scenario if system switched off. Associated initial quarterly / biannual groundwater monitoring of well network.

Timing Installation: 3 – 6 months. Treatment time would be determined during laboratory and field treatability studies. Likely to take at least one or more decades to reach clean up goals.

50 years to reach clean-up goals based on groundwater modelling results.


Remedial Operation: As determined by groundwater modelling (estimate).

Potentially the timeframe may not be significantly shorter to reach clean-up goals than MNA.

Would be determined after laboratory and field treatability studies.

Timeframe may not be significantly shorter to reach clean-up goals than MNA.

Installation: 3 – 6 months

Remedial Operation: effective period at least one decade or more. Timeframe may not be significantly shorter to reach clean-up goals than MNA.

Installation: 3 – 6 months

Remedial Operation: several years (estimate).

Overall Rating 3 & Preliminary Opinion

*****

Is considered likely to be practicable for on-site treatment in close proximity to the source areas and associated high groundwater concentration areas. Previous research, literature and on-site groundwater investigation indicate potential for success and practical implementation.

However not considered practicable to use this technology off-site, up-gradient or in the vicinity of existing groundwater users, due to the associated groundwater impact risks and the logistical difficulties associated with diffusion and broad-scale plume treatment.

The main time limitations are expected to be associated with diffusion of the material into the aquifer and the need to conduct a staged pilot scale project to evolve into full-scale clean-up.

Variation options for the implementation methodology of CSA are presented Table 4.

****

Is practicable and required in conjunction with source remediation.

However because of the timing is not preferable to implement MNA in isolation of any other technology as shown by modelling results.

**

Is not considered practicable for the broader plume area because of the potential to impact existing groundwater users and treatment time limitations. The overall timing of clean-up may not be significantly sooner than natural attenuation and is unlikely to warrant the expense.

Further, application potential requires modelling and if any water pumped and discharged ex-situ treatment technology required.

**

Is not considered practicable for the broader plume area because of the potential to impact existing groundwater users and the significant cost implications. The overall timing of clean-up may not be significantly sooner than natural attenuation and is unlikely to warrant the expense.

Is not considered as effective as CSA with respect to treatment success, cost and time.

**

Not considered practicable on the broader off-site plume due to constraints on land use and land availability and because the overall timing of clean-up may not be significantly sooner than natural attenuation and is unlikely to warrant the expense.

Is considered a useful approach to source area capping / phytoremediation, as discussed in Table 3.

Has only limited potential to deal with shallow contaminants and cannot deal with Calivil Formation groundwaters.

*

Does not deal with a majority of contaminants present.

Not considered practicable approach due to high capital and operational costs associated with technical issues, low aquifer yield and difficulty of maintenance, additional presence of non-volatile type hydrocarbons.

1 Note that cost estimates do not allow for long-term operating, maintenance and groundwater monitoring costs, which could increase the estimates by up to 50% or more if operation is required to continue for more than (approximately) 15 years. 2 Refer to explanation of costs in Section 4.1.2 Note that limited accuracy applies to all cost estimates. 3 * = Inappropriate remedial technology ** = Not desirable although may have some application potential if significant limitations can be overcome *** = Potential remedial technology with some application potential **** = Likely suitable remedial technology with suitable application potential




Table 3 - Summary of Remedial Options – Source Area Soils

Phytocapping Clay Capping Excavation & On-site Disposal In situ Bioremediation Excavation & Ex-situ

Bioremediation Excavation & Off-site Disposal Soil Washing Excavation & Thermal

Treatment Brief Description

Phytocapping is the direct use of living green plants for contamination reduction for soil through contaminant removal, degradation, or reducing infiltration. Growing and, in some cases, harvesting plants on a contaminated site as a remediation method is an aesthetically pleasing, solar-energy driven, passive technique that can be used to clean up sites with shallow, low to moderate levels of contamination

In-situ capping is an active remediation option where a layer of clean isolating material (clay) is placed to contain and stabilize the contaminated soil in place.

Prevents vertical infiltration of water into contaminated soils that would create contaminated leachate.

Excavation of impacted soils and disposal to a landfill constructed on-site.

Addition to the soil of a carbon source or alternative remedial amendments to provide energy for microbial degradation of nitrate and sulphate.

Excavation of soils into stockpiles. Soils are then stockpiled into biopiles and mixed with carbon source material and kept under cover in anaerobic conditions to enhance microbial degradation (also known as composting).

Excavation of impacted soils off-site disposal to approved landfill.

Flushing of soils with water or solvent to displace contaminants followed by drying and reinstatement or re-use of soils.

Excavation of soils into stockpiles. Soils are then stockpiled into heaps and passed into a desorption unit in order to thermally destroy contaminants and remove via wet scrubbing.


Nature and selection of plant species capable of withstanding nutrient loading.

Area, location and size of plant cropping.

Field studies into nutrient (i.e. contaminant) uptake to determine effectiveness.

Not effective on deeper contaminated soils.

Also reduces rainwater infiltration due to plant transpiration.

Nitrate can be removed but effect on sulphate is only to reduce infiltration rates (i.e. cap secondary sources).

Well used and known technology to reduce leaching from contaminated soils.

Can be undertaken in staged approach as areas become accessible.

Sourcing of capping material from on- or off-site and revegetation required.

Does not prevent horizontal flow of groundwater through the soil.

Difficult to monitor performance.

Little technical knowledge required. Not preferred within waste management hierarchy

Depth of affected soils.

Availability of on-site areas (including an engineered landfll or the modernisation) may potentially be used as repositories.

Difficult to control and understand pathways during in-situ bioremediation of surface soils within the unsaturated zone.

Difficult to predict remedial timeframes and rates of degradation.

Need to determine nature of amendment required.

Treatability studies and field trials necessary.

Difficult to introduce and diffuse amendment in fine grained soils.

May have the benefit of creating a bio-reactive zone in the underlying saturated zone thereby assisting with groundwater contamination.

Difficult to maintain anaerobic conditions in excavated soils.

Difficult to predict remedial timeframes and rates of degradation.

Need to determine nature of carbon source amendment – requires treatability studies and field trials.

Excavated area needs to be fenced or backfilled with fill whilst remediation being undertaken.


Little technical knowledge required. Not preferred within waste management hierarchy.


Requires large volumes of water and produces wastewater to treat or manage

Generally undertaken ex-situ after excavation of soils

Likely to be effective on nitrate and sulphate contaminants.


Potential for incomplete combustion and generation of toxic gases. Very energy inefficient.

Unproved technology for treatment of nitrate & sulphate. Salt precipitation causes problems / blockages in most systems.

No energy recovery possible due to lack of organics in source zone, likewise difficult to produce desired reaction by-products.

Generation of waste stream that requires further treatment - unsure of technical appropriateness for works (requires treatability study).

Financial 2

Considerations Planning Cost1 $6.00M

























In-situ remediation of soil materials whilst site remains operational – not entirely practical

Capping of some source areas whilst site remains operational may not be practical. Off-site source of capping material may need to be identified.

Excavation of soil materials whilst site remains operational – not entirely practical

Sourcing of imported fill material to replace removed soils.

Ongoing monitoring.

In-situ remediation of soil materials whilst site remains operational – not entirely practical



Determination of landfill or repository willing to accept excavated soils.

Sourcing of imported fill material to replace removed soils.


Location and housing of treatment system, requirements re power, security etc. Treatment of wastewater stream required


Location and housing of treatment system, requirements re power, security etc

Ongoing Management

Plant life monitoring, harvesting, grazing etc.

Periodic inspection and testing of cap integrity. Ongoing groundwater monitoring since secondary source remain in-situ.

Periodic inspection and testing of containment. Ongoing groundwater monitoring since secondary source remains in-situ.

Monitoring of favourable conditions may require ongoing irrigation and nutrient / amendment addition.

Management of biopiles required until remediation complete.

Negligible Negligible Management of waste stream required.


Timing Installation: 3-12+ months


Installation: 2-4+ months Installation: 3-6+ months. Timing depends on treatability studies and is difficult to quantify. Potentially several years or a decade or more.


Remedial Operation: based on lab treatability studies & field trials. Likely to be long term, slow process. Potentially several years to a decade or more depending on the level of investment and effort

Installation: 3-12+ months Establishment and remedial operation: 3 – 12+ months


Remedial Operation: based on lab treatability studies




Table 3 - Summary of Remedial Options – Source Area Soils (cont.)

Phytocapping Clay Capping Excavation & On-site Disposal In situ Bioremediation Excavation & Ex-situ

Bioremediation Excavation & Off-site Disposal Soil Washing Excavation & Thermal

Treatment Overall Rating3 & Preliminary Opinion

****

Is considered a practical approach and has good application potential in source areas. However will not remove nitrate from deeper soils and will only act as a capping layer (not a remediation measure) for sulphate in soil. Unlikely to remove sulphate. Good cost benefit.

****

This is considered an appropriate and practicable approach for on-site source areas, since primary concern (further migration of nitrate, sulphate, TDS and low pH acids to groundwater) will be mitigated.

Will not remove contaminants. Long-term monitoring required.

***

This is considered a practicable and reasonable approach to specific needs for some of the source areas on-site.

High costs associated with soil excavation and transport by comparison to capping.

***

May have some practical application in Source Area A but is only recommended in that area if proof-of-concept testing confirms its potential to assist with groundwater remediation.

Would not be considered practicable in other source areas as a means of soil remediation due to difficulty in delivering the amendment media to the impacted soil.

**

Not considered reasonable approach due to logistical constraints whilst site is operational, large-scale areas required for treatment, high treatment costs, unknown timeframe for bioremediation and tenuous appropriateness for the nature of contaminants encountered (expected to be several years or potentially a decade or more depending on the level of investment and effort).

**

Not considered practicable approach due to logistical constraints whilst site is operational, high costs associated with soil excavation and transport, failure to mitigate liability from contaminant removal.

*

Not considered practicable approach due to logistical constraints and low cost effectiveness. May have some application in shallow source areas but other approaches are considered more appropriate.

*

Not considered practicable approach due to logistical constraints whilst site is operational, logistical constraints of treatment facility location, extremely high costs associated with soil excavation, treatment and waste stream management.





Table 4 - Summary Carbon Source Addition Delivery Systems for Source Management

Direct Injection via Groundwater Bores Recirculation Cell Direct Injection via Horizontal (Directional Drilling) Bores

Funnel & Gate - Permeable Reactive Barrier (PRB) Slurry Trench

Brief Description

Introduction undertaken by pumping of selected remedial amendment in liquid form into the aquifer via groundwater bores using downhole technologies. Pumping may be via gravity feed or under pressure. Amendment medium mixes with groundwater via attenuation processes.

An injection wall may also be implemented where a number of bores are installed perpendicular to aquifer flow, so as to have the same effect across the plume width (such as a PRB).

Pumping of selected remedial amendment into aquifer by using downhole technologies, however pumping via injection and extraction points to encourage flow circulation between points. May create artificial hydraulic gradients and assist in improved amendment mixing in certain environments.

Recirculation cells may be developed between more than one groundwater bore or within any particular groundwater bore unit.

Horizontal directional drilling is commonly undertaken to install services or pipelines. A pilot bore is first drilled to the desired depth (ideally within the aquifer material and re-emerges at the desired downstream point. The pipeline is then attached at the downstream end and then reamed backwards for installation. The amendment media is then applied under pressure or gravity fed at one or both ends.

Permeable Reactive Barriers (PRBs) may either funnel groundwaters (via a subsurface vertical wall) through a “gate” system(s) made of emplaced treatment media, or may be a continuous medium emplaced within the aquifer, perpendicular to groundwater flow. PRBs effectively allow the natural flow of groundwater to continue but via a reactive zone of chosen amendment media.

The reactive medium of a PRB is limited only by the imagination of the designer, and includes all other I-situ technologies described herein.

Excavation with a long arm excavator and consequent permeability control facilitated by a slurry wall could facilitate addition of remedial fluids through a horizontal piping system installed at the same time as the slurry wall.

Similar to installation of a funnel and gate system, a slurry trench may include a horizontal, slotted piping system installed to facilitate emplacement of remedial fluids added from the surface.


Nature of amendment medium - treatability studies to determine most appropriate and effective for all contaminants encountered.

Implementation: Rapid or slow release. Injection into aquifer under pressure, passive emplacement etc.

Diffusivity of the amendment


Nature of amendment medium - treatability studies to determine most appropriate and effective for all contaminants encountered.

Implementation: Rapid or slow release. Injection into aquifer under pressure, passive emplacement etc.

Site hydrogeology, emplacement depth, no of locations, changes relating to plume dimensions and projected timelines. Control over localised groundwater movements

Length location / emplacement of installed pipeline. Amendment media and application across whole plume length - or if hydraulic properties result in treatment only occurring near injection ends.

Treatability studies of reactive media (amendment fluids) required.

Lateral and vertical dimensions of PRB need to be determined following hydrogeological evaluation.

Transmissivity of active media emplaced in barrier with respect to aquifer needs to be determined.

Bench / Pilot scale studies necessary, including treatability studies of reactive media and with respect to subsurface design.

Reactive media needs to be keyed in to base of aquifer in order to ensure entire plume can be treated. In order to do this, significant excavations across the plume are generally required.

Lateral and vertical dimensions of slurry trench need to be determined following hydrogeological evaluation.

Transmissivity of active media emplaced in barrier with respect to aquifer needs to be determined.

Bench / Pilot scale studies necessary, including treatability studies of reactive media and with respect to subsurface design.

Financial 2 Considerations

















Ready availability of remedial amendment media within Mulwala area.

Ability to locate injection points in desired locations (eg source areas).

Power, security etc with reference to amendment media stations.


Ability to locate injection and extraction points in desired locations (eg source areas)

Power, security etc with reference to amendment media stations


Depth to Calivil formation will generate significant logistical constraints (base of aquifer unit below 15m).

Availability of HDD equipment capable of desired depth and length.



Depth to Calivil formation will generate significant logistical constraints (base of aquifer unit below 15m). PRB should be keyed into base of aquifer, hence very deep excavation and emplacement required.

Ideal location of PRB may entail surface emplacement difficulties.

Availability of long reach excavator (if such a method is chosen)


Depth to Calivil formation will generate significant logistical constraints (base of aquifer unit below 15m).

Availability of long reach excavator (if such a method is chosen)


Ongoing Management

Requirement for monitoring application media emplacement (as part of overall plume monitoring).

Monitoring emplacement methodology (including structural and management systems) to ensure consistency in approach and delivery.


Monitoring emplacement methodology (including structural and management systems) to ensure consistency in approach and delivery.


Monitoring emplacement methodology (including physical delivery capabilities and biosliming over time), as well as management systems to ensure consistency in approach and delivery.


Monitoring of PRB media quality and degradation (if solid media utilised).


Monitoring emplacement methodology (including physical delivery capabilities and biosliming over time), as well as and management systems to ensure consistency in approach and delivery.

Timing Installation: 3-9 months

Remedial Operation: based on lab treatability studies & field trials



Installation: Installation: 3-9 months






Overall Rating 3 & Preliminary Opinion

****

Effective practicable approach for on-site source areas. Field studies required to determine rate / location etc of injection bores. Areal coverage may be limited.

****

Effective practicable approach however no technical requirement identified at present to require development of circulation cell as opposed to direct injection. As per flow diagram Section 6.2 is only recommended in the event that direct injection is found not to be practicable.

****

Potentially practicable effective approach for shallow plume, however difficult for deeper Calivil plume due to logistical constraints. The necessity of this approach should be considered in more detail as part of the recommended proof-of-concept testing.

**

Potentially effective, practicable approach for shallow plume, however high cost for installation into deeper Calivil plume. The necessity of this approach should be considered in more detail as part of the recommended proof-of-concept testing.

**

Potentially effective practicable approach for shallow plume, however difficult for deeper Calivil plume due to logistical constraints. The necessity of this approach should be considered in more detail as part of the recommended proof-of-concept testing.





C.2.3 Development of Management Strategies The following section presents detailed evaluation of the most promising technologies identified from the screening process (presented in Section C.2.2), and the rationale for the development of management strategies applicable to remediation of the off-site groundwater plume (Section C.2.3.1) and the onsite source areas. Evaluation of technologies for onsite sources areas were separated into strategies for managing groundwater contamination (Section C.2.3.2 - Source Area Groundwater Management) and strategies for remediation of contaminated soil acting as sources of groundwater contamination (Section C.2.3.3 - Source Area Soil Remediation).

C.2.3.1 Off-Site Groundwater Plume Management Based on screening of technologies, two technologies for cleanup of the off-site plume were retained for further consideration. The two clean up technologies are pumping and irrigation of contaminated groundwater and carbons source addition (CSA). Further assessment of pump and irrigation and CSA was used to assess the most practicable approach in comparison to management of the current groundwater uses and monitoring natural attenuation. The rationale behind each technology in addition to recommendations for implementation is presented in this section.

C.2.3.1.1 Pump and Irrigation

The practicability of managing the off-site plume using pump and irrigation was further assessed based on the following opportunities and constraints associated with the groundwater plume and areas available for irrigation of the contaminated groundwater:

• Areas available for irrigation of groundwater on the site and Golf Course; • The volume of the plume required to be remediated to achieve cleanup goals; • Yields from extraction bores installed in the plume; and • Radii of influence in both the Shepparton and Calivil Aquifers during extraction.

Other aspects relating to pump and irrigation for remediation of the groundwater plume that were considered in more detail included the composition of groundwater in the off-site plumes, monthly climatic and water balance data, irrigation requirement for proposed species and soil EC and nutrient loading. In order to determine whether irrigation using contaminated groundwater from the off-site plume is feasible, John Sykes Rural Consulting (John Sykes) was engaged to investigate and report on the application rate of abstracted groundwater over nearby land at the ADI facility and Yarrawonga & Border Golf Course. During irrigation of water on the ADI site, the contaminant that becomes limiting first is sulphate, which reaches 100% of utilization at a rate of application of groundwater of 0.40 ML/ha/yr. At this rate, 150 ha of land available on the facility will sustainably utilise approximately 60 ML/yr of water. On the Golf Course, the soil electrical conductivity limits the application of irrigated waters, with an initial maximum application of 1.3 ML/ha/yr increasing to 1.8 ML/ha/yr, if the soils are confirmed as alluvial soils.




Based on the conclusions drawn from the report, rates for the irrigation of groundwater on both the ADI and Golf Course sites were estimated as follows:

• An initial rate of 0.6 ML/ha/yr could be applied to the site. In the long term the rate would drop to 0.4 ML/ha/yr as the soil nutrient and salt level increase on the site.

• An initial rate of 1.3 ML/ha/yr can be applied to the Golf Course. In the long term the

rates could be adjusted up to 1.8 ML/ha/yr (alluvial soils) and 2.0 ML/ha/yr on areas of with chromosol soil types.

In the long-term, the rate of application of groundwater on the Golf Course should be as follows:

• 0.6 -1.3 ML/ha/yr on the sand soil • 1.8 ML/ha/yr on the alluvial soil • 2.0 ML/ha/yr on the chromosol soil

Based on a total plume volume of 3630 ML above the drinking water guideline of 50 mg/L for nitrate as nitrate (refer to 2.4.2), the following timeframes, based on two scenarios involving short and long-term irrigation, will be required to completely remove the plume by pumping and irrigating the groundwater over an area approximately 150 ha in size on site and 100 ha located in the Golf Course. Table 5: Irrigation Application Rates and Time to Remove Off-Site Plumes

Initial Long term ADI facility Golf Course ADI facility Golf Course Application Rate (ML/ha/y) 0.6 1.3 0.4 1.8

Irrigation Area (ha) 150 100 150 100

Irrigation Rate (ML/y) 90 130 60 180

Total Irrigation Rate (ML/y) 220 240

Plume Volume (ML) 3630

Time Required to Remove One Plume Volume (y) 16.5 15.1

Estimate of Equivalent Plume Volumes Removed to Achieve Clean Up

2 – 4* 2 – 4*

Total Estimated Time to Pump and Irrigate Plume (y) 33 - 66 30 - 60

* Note It is possible that (for example) after 20 years, the equivalent plume volume estimate could reach 5 times the actual volume or even beyond.

The reasonable application of groundwater pumping to remove the total volume of the plume will largely be controlled by the amount of excess uncontaminated groundwater water drawn from the aquifer as a result of the pumping activities. As shown in Table 5, the value is estimated to range from 2 to 4. This will be highly dependant on the location and siting of pumping bores, contaminant mobility within the aquifer and changes to the plume dimensions over time (particularly with pumping). The length of time required to remove the plume will proceed in a non-linear form, in which the more of the plume has been removed, the longer the




residual contaminants will take to be pumped from the aquifer system. The range of 2-4 is an estimate across the pumping lifetime that will require further evaluation during the proof-of-concept phase by trial pumping and groundwater modelling. An assessment of the number of groundwater bores required to meet the application rates was also considered. Using a pumping rate of 2.8 L/s (88 ML/y) from the Calivil Aquifer and an expected pumping rate of 1 L/s (35 ML/year) from the Shepparton Aquifer (and the optimal application rates as defined in Table 5 above), approximately 2 to 3 Calivil pumping bores or 7 to 8 Shepparton bores will be sufficient to meet the maximum irrigation application rate over the ADI site and Golf course. Whether or not this number of extraction bores is appropriate in terms of capturing the plume needs to consider the expected radius of influence from pumping. Further evaluation into the expected radius of influence of bore pumping activities (and therefore the optimal number of pumping bores required to meet the irrigation application rates) was undertaken using Theis (1935) Drawdown Predictions for Confined Aquifers, and is summarised in Table 6.

Table 6: Predicted Radius of Influence for Shepparton & Calivil Aquifers

Shepparton Formation Calivil Formation

Hydraulic Conductivity (K)* 1 5

Aquifer thickness (m)* 3.56 6.12

Storage Coefficient (S)* 0.0145 - 0.12 0.0145

Pumping Rate (l/min) 60 168

Predicted Pumping Radius of Influence (m) 35 - 100 290

* Note - Storage data provided by NSW DIPNR and applied based on the site specific encountered semi-confined properties of the Shepparton Formation. Other data obtained from HLA (2003a and 2003b). Based on the predicted radius of influence, the application of 2-3 Calivil bores or 7-8 Shepparton bores for pumping and irrigation may be appropriate in terms of plume capture to meet optimal irrigation rates for each Aquifer Unit. However, based on the data currently available, it is unlikely that the plumes in both Aquifers could be remediated using this approach. Trial pumping and groundwater modelling of aquifer drawdown, radius of influence (capture zone), and the time required to achieve clean up goals will be undertaken to confirm or otherwise the relevance of this factor and the influence on the time required to undertake remediation of the plume. Interference from multiple bores and more accurate estimates provided by numerical modelling may indicate that the radius of capture zones around pumped bores may be larger. The assumptions presented above are also dependant on the golf course accepting the volumes of irrigation water indicated and irrigation onsite not resulting in unacceptable impacts to operational activities. There may also be significant limitation on those application rates based on seasonal fluctuations in rainfall. Seasonal fluctuations in irrigation rates are also likely to create a need for significant storage facilities to allow continuous pumping over the periods estimated. If groundwater pumping cannot be conducted continuously, the time required to clean up the plumes will be longer than those estimated. Detailed trials and extensive




consultation with greens keepers would be required to prove the pumping and irrigation rates that would be possible over the golf course. An additional concern with pumping to clean up the plume is that it may significantly impact groundwater yields from existing bores and the current amenity of the off-site groundwater users. Further groundwater modelling would be required to assess the impacts of pump and irrigate on the current groundwater users. The estimated costs of pumping and irrigation for the off-site plume are as follows: Planning Estimate $2,352,000 Optimistic Estimate $2,180,000 Pessimistic Estimate $2,621,000 In summary, the length of time required to pump the plume and irrigate to both the ADI facility and the Golf Course is estimated to be in the range of approximately 30 to 66 years. This value may however be lengthened due to:

• The amount of water (and hence time) required to be pumped in order to remove the entire plume.

• An altered radius of influence based on further modelling or a change in understanding of aquifer properties.

• A reduction in irrigation rates due to climatic factors or a reduced area of land available for irrigation.

Significant uncertainty also remains regarding impacts on current groundwater users and irrigation rates over the golf course area. Most critically, the number of bores required to capture groundwater from a significant portion of the plume area in both aquifers may generate volumes of water which would far exceed the application rates for available irrigation areas. As groundwater has low pH and elevated levels of nitrate, the soil is likely to become acidic, particularly if the water is allowed to leach under the root depth. Therefore, the soil should be monitored to ensure that acidity does not increase. If the soil becomes acidic, then lime will be applied to neutralise the affects of acid and increase pH. Despite the uncertainties outlined above, pump and irrigation cannot be ruled out at this time as a potentially practicable means of significantly reducing the time required to restore the protected beneficial uses of groundwater in one or both aquifers. Trial pumping and groundwater modelling will be undertaken as part of the proof-of-concept phase in order to estimate timing and cost parameters. Modelling will need to consider the areas available for irrigation, the optimum application rates, bore locations, expected pumping radius of influence and time to achieve the clean up goals (i.e. restore drinking water quality). Pumping and irrigation of contaminated groundwater may also have some targeted use in the source areas (see Section C2.3.2.2).

C.2.3.1.2 Carbon Source Addition

The most obvious limitation to the CSA approach for remediation of the groundwater plume is one of delivery of the required volumes of carbon source over large areas, with relatively few existing points that could possibly be used as CSA injection points. In the absence of field data on the diffusivity of carbon sources such as ethanol into the Shallow and Deep aquifer systems




some doubts remain on the probability of delivering sufficient, but not excessive, carbon source throughout the plumes. As shown in Figures 4 to 7 of the Remediation Feasibility Assessment Report (HLA, 2003e), the groundwater plumes have moved a considerable distance off-site, in both the Deep and Shallow aquifers, beneath multiple private and public properties (including roads and road easements). A multiple injection strategy for CSA requiring frequent access to delivery and monitoring stations across the entire area of the plume would present property access issues. A minimal point injection strategy would require large doses of carbon source to be added and long travel times, possibly similar to the current travel times for the nitrate and sulphate, in order to deliver the carbon source to all required areas. The large initial doses of carbon source would increase the risk of onset of sulphidogenesis, as discussed in Appendix B of the Remediation Feasibility Assessment. The number of groundwater bores required for CSA injections can not be quantified precisely in the absence of diffusivity rates measured under field conditions, but in a recent successful CSA groundwater denitrification project in North America injection wells were installed at intervals of 2 to 3 metres to intercept a nitrate plume. On that basis, hundreds, or potentially thousands of injection wells would be required for the diffuse Deep and Shallow groundwater plumes emanating from the Mulwala facility. The diffusion rates for candidate carbon sources under field conditions are currently unknown. These would need to be determined if the CSA strategy was to be considered for the groundwater plumes. Low molecular weight solvents such as ethanol are known from chemistry literature to have high diffusivity coefficients into water, and ethanol is infinitely miscible with water. The difficulty in assessing the technical practicality of CSA to remediate the diffuse groundwater plumes is predicting the diffusion of the carbon source/groundwater mixture through the aquifer following injection. As discussed above, the mixture may not move through the aquifers at rates higher than the current migration rates for the nitrate and sulphate. If the migration rates are not significantly higher than those of the nitrate and sulphate it will not be possible to use a CSA injection strategy near source areas on site to “chase” and “catch” the nitrate and sulphate contamination which has already left the site. The precise amount of carbon source required will depend upon the carbon source selected, and upon the total mass of nitrate to be treated; in this case the mass of nitrate already in the diffuse plumes in the Shallow and Deep aquifers, plus any additional nitrate loading from source areas into the aquifer systems. A general rule of thumb is that 3kg of nitrate can be reduced to nitrogen for each 1kg of carbon source consumed by the denitrifying micro-organisms. Given the plume size it would be difficult to implement engineering controls if it is found that the carbon source has an adverse effect on the aquifer: A number of corrective actions are theoretically possible to ameliorate any localised adverse effects of CSA on the aquifer systems. The most likely adverse effect would result from an excess addition of carbon source such that all locally available nitrate becomes completed, low RedOx conditions develop, and sulphate reduction is initiated leading to sulphide formation. Typical corrective measures would involve addition of oxygen (air) or extra nitrate to be used as electron acceptors, instead of sulphate, until the carbon loading is lowered appropriately. In practice, corrective aeration is not practical over potentially large distances from the source areas or at multiple locations in the plume. Supplementary nitrate additions would be politically unfortunate against the primary aim of reducing offsite nitrate concentrations. In practice, control of CSA additions and provision of corrective measures is not viable over the large area of the diffuse Shallow and Deep aquifer plumes at Mulwala.




Indicative costs for carbon source addition to address both the off-site Shallow and Deep groundwater plumes are summarised as follows:

Planning Cost $6,118,000 Optimistic Cost $5,360,000 Pessimistic Cost $7,346,000

It should be noted that these costs was estimated based on the installation of a further 80 (50 % confidence limit or mean) to 200 groundwater bores (95 % confidence limit). The number of bores may increase based on the diffusivity of the carbon source chosen for the remediation. As it can be seen from the cost estimates presented above, a multiple well, multiple injection strategy throughout the diffuse plume would incur considerable time and cost penalties through travel to each individual injection point, set-up of injection equipment, carbon source injection and post-injection water flushing, dismantling of equipment, then transfer of the personnel and equipment to the next injection station. A similar series of activities for monitoring purposes at each location would further add to overall project costs. At this time it is not practicable to consider remote dosing and/or monitoring equipment at each potential injection station throughout the diffuse plume, bearing in mind that the properties are privately held and not under direct control by ADI and Defence. As most of the bores throughout the diffuse plume areas in the Shallow and Deep aquifers are situated on privately-owned land, necessitating on-going co-operation of the landowners throughout the entire period covered by the Contaminant Management Plan, and such co-operation is likely to wane if the frequency of required access to each well becomes too high because of a multiple injection/multiple monitoring campaign associated with a CSA strategy. A detailed description of the biochemical processes and attenuation mechanisms is presented in Appendix B of the Remediation Feasibility Assessment. However, in view of the potential problems outlined above, CSA is not considered to be a practicable option for the off-site, diffuse contamination throughout the Deep and Shallow aquifers at this time.

C.2.3.1.3 Management of Current Groundwater Uses

As reported in Section 3.3, current groundwater use within the plume area consists of the following:

• irrigation;

• domestic use (i.e. washing); and

• stock watering. The Corowa Shire Council’s Development Control Plan (DCP) states that no dwellings can be constructed within the Mulwala Homestead Estate, without connection to the Shires mains water supply. All residents of properties within the plumes have been notified of nitrate and sulphate in groundwater and all have access to mains water. As a result, residents have been able to accommodate not using groundwater as a drinking water supply and therefore, are effectively managing the groundwater plume themselves. Management of the current groundwater uses will be required until it has been determined that the groundwater has been cleaned up to the extent practicable.




C.2.3.1.4 Monitoring Natural Attenuation

Monitoring natural attenuation would involve an on-going groundwater sampling programme to monitor the assumed reduction in concentrations and extent of the off-site groundwater plumes over time. The monitoring programme is likely to involve biannual monitoring of selected bores within and around the current plume areas for key contaminants. The frequency of groundwater monitoring may reduce as temporal data begins to demonstrate that the natural attenuative processes are occurring. As the groundwater modelling undertaken for the site has shown that if the on-going sources of groundwater contamination are ceased, it will take over 50 years (potentially in the order of up to 100 to 150 years), for the existing nitrate plume to dissipate. Source area management would be required to achieve attenuation of the off-site plumes within an acceptable time frame. If source area management is not undertaken or is ineffective, the time required for the off-site plumes to naturally attenuate would be considerably longer. Given the costs associated with implementing carbon source addition and pump and irrigation, it is recommended that monitoring natural attenuation, in addition to management of the groundwater users and onsite source areas be implemented as the most practicable solution for managing the off-site groundwater plume.

C.2.3.2 Source Area Groundwater Management Unless contributions of nitrate and sulphate from the source areas are sufficiently reduced, natural attenuation of the dissolved phase plume within a period of 100 to 150 year (for nitrate) time frame would be ineffective. Therefore, management of the significant source areas would be a prerequisite to remediation of the existing groundwater plumes to restore potential beneficial uses. An assessment of the practicability of implementing carbon source addition (either through direct injection or introduction through a recirculation cell), pump and irrigation and monitoring natural attenuation to manage the source area groundwater contamination was undertaken to establish whether treatment of the source areas is practicable. The rationale behind each technology in addition to recommendations for implementation is presented in this section.

C.2.3.2.1 Carbon Source Addition

Based on the Remediation Feasibility Assessment and the previous investigations undertaken by HLA, the most promising remedial strategy for the Shallow and Deep aquifer plumes at the source locations and between the source areas and the site boundary is carbon source addition. It has been demonstrated that the biological decay of nitrate, and to a lesser degree, sulphate is naturally occurring in the Shallow Aquifer System and Calivil Aquifers. The presence of organic carbon compounds (measured as total organic carbon -TOC) and degradable (via oxidation) organic content (chemical - COD and biochemical - BOD) is believed to be supporting nitrate and sulphate degradation in groundwater down-gradient from the site. In bores where high values of TOC, COD and/or BOD were detected, and heterotrophic plate counts (a broad group of bacteria that are defined by their requirement to grow in the presence of a complex organic (carbon) source for nutrition) were elevated (HPCs >40,000 counts) concentrations of both sulphate and nitrate were reduced within the surrounding groundwater. These trends were observed at the down-gradient margins of the plumes and, notably, in the “gaps” within the plume in the Shallow Aquifer System centred on the Bedrock high onsite and between the western and southern arms of the plume southwest of the site. The presence of




elevated levels of TOC, COD and BOD are most likely associated with residential septic systems located in this area of the site. Figure 4 in the Remediation Feasibility Assessment Report (HLA, 2003e), shows the relationships between TOC concentrations and biological activity (HPC counts) across the groundwater plume area in the Shepparton Aquifer. As demonstrated above, if carbon can be introduced to the aquifers over a sufficiently large area onsite, dissolved nitrate will be removed from the groundwater through the biological processes stimulated by the addition of carbon. Descriptions of the general approach and factors affecting carbon source addition processes are presented in Appendices A and B respectively. The main limitations of this approach to remediation of the source area and on-site plumes are type and number of locations by which carbon may be introduced to the aquifers. An evaluation of the practicability and feasibility of methods of introduction of the carbon to the aquifers was undertaken and summarised in Table 4. Based on our assessment of the remediation technologies, injection of the carbon source into the aquifers onsite using one of the following methods is the preferred implementation method:

• Direct injection via vertical bores.

• Direct injection via horizontal bores.

• Recirculation cell. The number of bores required any of theses approaches has yet to be determined and is dependent on aquifer parameters and the nature of the carbon source. However, it is assumed that a more diffusive and dispersive carbon source, such as ethanol, will assist in reducing the number of injection points required for any of these approaches.

C.2.3.2.2 Direct Injection

A conceptual cross section showing the general configuration of CSA by direct injection via vertical bores is shown in Figure 6 in the Remediation Feasibility Assessment Report. Direct inject via horizontal bores would involve replacement of the vertical bores shown in Figure 6 with horizontal bores installed within the aquifers. The most quoted concern about direct carbon source injection into aquifers is the perceived difficulty of stimulating the required nitrate reduction reactions without concomitant stimulation of sulphate reduction to sulphide. As outlined in Appendix B (HLA, 2003e), numerous levels of monitoring and control strategies are available from literature and field studies to alleviate such concerns. Accordingly, the preferred implementation of a CSA strategy in groundwater beneath the source areas, and in on-site plumes at the Mulwala site, is a direct injection approach, with injection locations, carbon dose levels, and injection frequency to be determined in on-site pilot field trials. Major parameters to be determined in the field include the dispersivity of the added carbon source into the aquifer systems under field conditions, and the extent of localised biofouling, if any. The intention with carbon source addition is to promote denitrification and not the generation of excessive new biomass in the aquifer. It is expected that the use of an essential growth requirement as a limiting factor will prevent the overgrowth of bacteria within the aquifer (i.e. biofouling) when the carbon source loading is relatively high, on a localised basis, immediately after each injection.




The macronutrient status of the Deep and Shallow groundwater both pre- and post-injection will need to be determined under field conditions in order to optimise the macronutrient control strategy. Another major limitation on CSA by direct injection is the degree to which effective mixing can be achieved within the aquifer given the relatively slow travel times and small radius of influence around pumped bores. It is likely that this limitation would render direct inject via vertical bores impracticable. However, direct injection via horizontal bores within the aquifer across the full plume width immediately hydraulically up-gradient of the source areas is worth further consideration. Horizontal bores would ensure more thorough mixing of carbon and contaminants within the aquifer and installation of the bores hydraulically up-gradient of the source areas would significantly reduce the potential for bio-fouling around infiltration structures. The capital cost of direct injection via horizontal bores is likely to be significantly more that via vertical bores and comparable to a Recirculation Cell. However, the operations and maintenance costs for direct injection via horizontal bores will be less that other CSA options. The estimated costs for the three CSA options are presented in Table 4. If field trials indicate that direction injection via horizontal bores is feasible, it is likely that a final system would require horizontal bores hydraulically down-gradient of the source areas to further amend the aquifer to manage sulphidogenesis. Further amendment may involve increasing dissolved oxygen levels to stimulate the oxidations of Mn 2+ to Mn 4+ In summary, it is recommended that direct injection via horizontal bores be retained for further evaluation of practicability through modelling and field trials.

C.2.3.2.3 Recirculation Cell

A conceptual cross section showing the general relationship of the aquifers in Source Management Area A (see Figure 5, HLA 2003e), and configuration of CSA using a Recirculation Cell approach is shown in Figure 7 of the Remediation Feasibility Assessment Report. Should direct aquifer injection prove to be impractical on the basis of outcomes of the proposed field trials, an alternative approach to CSA will be to use hydraulic extraction and re-injection wells to establish a re-circulation cell in the aquifers beneath the source area. Contaminated groundwater extracted would be dosed above ground with a carbon source and reinjected via bores around the margins of the source area. The Recirculation Cell would effectively create a capture zone around the source area. There is also potential to capture contaminated groundwater from both the Shepparton and Calivil Aquifers by pumping from the shallow aquifer only if vertical hydraulic gradient can be reversed. The recirculation approach offers greater opportunity for monitoring and process control purposes, but will add considerably to operating costs. As discussed in Appendix B (HLA, 2003e), such levels of control to prevent sulphidogenesis and manganese reduction are almost certainly not necessary at full-scale providing that appropriate pilot trials are undertaken in the field before implementation of a full-scale CSA strategy. If the recirculation approach is required, the location of extraction and re-injection wells, together with acceptable flow rates, will be determined from the pumping tests and groundwater modelling. CSA using a Recirculation Cell approach has the potential to be a practicable solution to management of migration of groundwater contamination from source zones and should be retained for further consideration based on field testing and groundwater modelling.




C.2.3.3 Pumping and Irrigation The feasibility of pumping source area groundwater from the Mulwala site will be subject to the same constraints as pumping the larger groundwater plume, namely irrigation rates and areas available for irrigation. The significant change is a reduced plume area and volume that must be captured. As discussed in Section C.2.3.1.1, the effective radius or capture zone around bores in the Shepparton and Calivil Aquifers is likely to be limited, approximately 35 - 100 m and 290 m respectively. On this basis, a limited number of bores would be required to effectively contain migration of contaminated groundwater from source areas. For example, approximately 3 and 1 groundwater bores would be a reasonable estimate of the number of bores required in the Shepparton and Calivil Aquifers respectively to contain contaminated groundwater from Source Management Area A (see Figure 5). Assuming and average yield per bore of 1 L/second (35 ML/year) from the Shepparton Aquifer and 2.8 L/second (88 ML/year) from the Calivil Aquifer, the total annual volume of groundwater requiring irrigation would be approximately 193 ML/year. Based on estimates provided by John Sykes (see Table 5), where it was assumed that approximately 240 ML/year (long term) could be applied to 250 ha to irrigate 193 ML/year, approximately 201 ha would be required for irrigation. The area assumed for irrigation in Table 5 (250 ha) is the maximum area that is likely to be available. Although pumping tests and numerical groundwater modelling may indicate that less bores and lower yields may achieve an effective capture zone around source areas, careful consideration and confirmation of the areas available for irrigation will need to be established during the proof-of-concept phase of the project.

C.2.3.4 Source Area Soil Remediation An assessment of the practicability of implementing carbon source addition directly to the source area soils to remediate nitrate and capping of the source areas to reduce the mobilisation of nitrate and sulphate to groundwater was undertaken to establish whether treatment of the source areas is practicable. The rationale behind each technology in addition to recommendations for implementation is presented in the following sections.

C.2.3.4.1 CSA Soil Remediation

A conceptual cross section showing the general relationship of the aquifers in Source Management Area A (see Figure 5 in the Remediation Feasibility Assessment Report) and configuration of CSA directly to the source area soils to remediate nitrate and capping of the source areas to reduce the mobilisation of nitrate and sulphate to groundwater is shown in Figure 8 of the Remediation Feasibility Assessment Report. The soil in the source areas at Mulwala has historically allowed passage of the chemical contaminants from the near-surface soils into the Shallow aquifer, and ultimately the Deep aquifer, but the extent of on-going flux from soil to groundwater is currently unknown. It can be assumed that any carbon sources added into the unsaturated zone soils will eventually percolate through the soils to the saturated zone, by analogy with previous migration of the nitric and sulphuric acids. In a worst case-scenario for a CSA strategy for unsaturated zone soils, carbon sources added at a few locations only near the ground surface might percolate quickly into the Shallow aquifer through preferred flow pathways such that little, if any, denitrification is achieved within the near-surface soils. Such a scenario would require the installation of infiltration galleries to achieve a broad distribution of carbon source across the areal extent of the source zones, followed by a slow percolation through the general soil matrix except where preferred pathways were present.




Consideration would need to be given to the requirement for impermeable barriers around infiltration areas (see Figure 8 in the Remediation Feasibility Assessment Report) to contain the potential spread of a carbon source over the upper surface of the Shepparton Formation clay. Impermeable barriers would also provide an opportunity to create greater head of water infiltrating through the Shepparton clay and hence increase the rate of flushing and biological degradation of the source zone soils. Impermeable barriers are most likely to consist of bentonite slurry walls excavated through the Dune Sands and keyed into the underlying Shepparton Formation clays. An irrigation strategy for carbon source addition to surface soils in source areas would require determinations of acceptable moisture loadings, wettability indices, percolation rates, etc, but would otherwise be undertaken with a similar philosophy to the groundwater denitrification strategy where carbon source dosing is linked to known stoichiometric relationships between carbon consumption and nitrate utilization in denitrifying microorganisms. Sulphidogenesis is not of any realistic concern in moist, unsaturated zone soils open to the surface because the diffusion of oxygen, even slow diffusion, is typically sufficient to result in an overall Redox environment inappropriate for sulphate-reducing bacteria, as outlined in Appendix B (HLA, 2003e). Sulphidogenic conditions can be induced in near-surface soils but only if they are excessively moist (standing water saturation) and presented with excess carbon loading, both of which can be readily avoided. It is recommended that CSA Soil Remediation would only be undertaken in conjunction with CSA to address groundwater contamination in the source areas (see Section C.2.3.2.1). Once CSA for groundwater was established any additional flushing of contaminants or sulphidogenic conditions created in the Shallow Aquifer by CSA soil remediation could be addressed prior to leaving the site.

C.2.3.4.2 Clay Capping

A conceptual cross section showing the general relationship of the aquifers in Source Management Area A (see Figure 6 in the Remediation Feasibility Assessment Report) and configuration of clay and phytocapping to reduce the mobilisation of nitrate and sulphate to groundwater is shown in Figure 9 in the Remediation Feasibility Assessment Report. To assess the performance of the proposed capping system in reducing surface water percolation and infiltration into underlying geology and aquifer systems within nitrate source areas (HLA, 2003b), the US EPA’s Hydrologic Evaluation of Landfill Performance (HELP) Model V. 3.1 (Visual HELP), model was used. The HELP model is a widely used and accepted tool in landfill applications for conservatively assessing landfill hydrologic performance to determine leachate generation rates, and capping and liner performance. For the purposes of this assessment two models were established. Detailed model inputs are presented in Appendix C of the Remediation Feasibility Assessment. Model 1 was established to simulate existing (in-situ) geology conditions based on borelogs data, bulk permeability data from onsite investigations and averaged unit thicknesses. Based on this data, Model 1 comprised of a layer of topsoil (150mm), overlying the upper dunal sands layer (2.71m, K = 0.01m/day), overlying an upper clay layer (5.28m, K = 0.01m/day). As no permeability data was available for the topsoil layer 0.03m/day was used and a surface slope of 2% was nominally used. A bare ground condition was used as a conservative assumption regarding existing site conditions. Results from this model were compared to the recharge estimates of the upper aquifer system (below the above units) of 1.5 x 10-5 m/day (or 1% to




1.4% rainfall) from the Baseline Numerical Flow and Solute Transport Model (using MODFLOW), prepared by HLA (HLA, 2003c) to assess model accuracy. Model 2 was established to simulate the existing lithological profile (minus the topsoil layer) with an overlying engineered cap of 300mm, K = 1.0 x 10-9 m/sec (as per Landfill BPEMs) and overlying 150mm topsoil, k = 0.1m/day. A good stand of grass was modeled to simulate the vegetation layer which would be established to promote evapotranspiration from the cap system and reduce net infiltration. In addition, a surface grade of 3% was used as a nominal minimum grade to promote surface water shed. Each model was run for a 10 year period using HELP model generated synthetic rainfall, evaporation and solar radiation data, referenced to the Wagga meteorological station. Modelled areas were restricted to 4 Ha to simulate Source Management Area A. A summary of the output files are presented in Appendix D of the Remediation Feasibility Assessment Report (HLA, 2003e). Results from Model 1 indicate annual average percolation rates through the lower layer (in-situ clays) of around 43 mm/annum or 1.2 x 10-3 m/day (8% rainfall). This is greater than the solute transport model results (i.e. up to 1.4% rainfall) which may reflect differences in model calculations or algorithms. However, Model 1 was used as a basis for developing Model 2, using conservative estimates of percolation. Results for Model 2 (Model 1 with cay cap, topsoil and vegetated) indicate average annual percolation rates through the designed cap of around 3.3 x 10-4 m/day or 2% of rainfall. No percolation / recharge was calculated from the lower clay layer to the uppermost aquifer (Model calculated at 8% rainfall). Compared to Model 1, Model 2 also shows higher evapotranspiration rates, which is attributable to the designed vegetation and topsoil layer. In summary, the conservative HELP models suggest the installation of a properly engineered clay cap with suitable topsoil and vegetation layer, overlying the existing lithological profile, would result in no surface water infiltration to the upper most aquifer beneath the nitrate source areas (i.e. no aquifer recharge). However, to ensure the efficiency and integrity of the cap is maintained, installation and maintenance of the cap system should be conducted in accordance with relevant standards and guidelines, and necessary QA procedures implemented. Detailed monitoring of unsaturated zone (Lystimeters) and saturated zone conditions would be required to prove the effectiveness of the clay capping approach. Based on the modelling undertaken it has been assessed that a clay cap would be suitable to reduce the infiltration of rainwater through the Dune sands and Shepparton clays and therefore reduce the potential for mobilisation of nitrate and sulphate from soil to groundwater in these areas of the site. The main disadvantage of clay capping is that it will not remove contaminants in soil acting as a secondary source. Therefore, although maintenance costs are likely to be minimal, the clay cap will need to be maintained indefinitely. Based on the assessment presented above, clay capping is considered a potentially practicable approach for source areas.




C.2.3.4.3 Phytocapping

Phytocapping involves the planting of a range of shallow and deep rooting plant species over source areas to reduce rainwater infiltration and to achieve at least partial up-take of nitrate by the plants. A conceptual representation of phytocapping is shown in Figure 9 in the Remediation Feasibility Assessment Report. As demonstrated using the HELP model, phytocapping could also be implemented at the site, provided it sufficiently reduced the amount of rainfall infiltration through the source area soils and hence the amount of contaminants leaching to groundwater. Accurate modelling of the performance of plant capping is more difficult than modeling low permeability capping due to lack of accurate data on evapotranspiration rates for specific plant species and soil types. However, in principal phytocapping may reduce infiltration rates through the Shepparton Formation clays sufficiently to reduce concentrations of nitrate and sulphate leaching to the Shallow Aquifer. Field trials would be required to confirm the performance of phytocapping. The potential advantages of phytocapping over clay capping areas follows:

• Deep rooting plants may remove nitrate from the Dune Sands and upper layers of the Shepparton clay. Effectively removing some of the mass of contaminants in soils acting as a secondary source.

• If indigenous species can be selected or some cropping can be developed, phytocapping will be potentially more environmentally sustainable.

Based on the assessment presented above, phytocapping is considered a practicable approach for managing the source areas if it can be proven that the implementation of a phytoremediation cap is as effective as a clay cap in reducing infiltrating rainfall.

C.2.4 Summary

C.2.4.1 Off-Site Groundwater Plume Based on the evaluation presented in Section C.2, the most promising approaches to clean up of the off-site groundwater plume, pumping and irrigation and CSA, are not practicable. Pumping and irrigation was shown to be limited by the area required to accept the loading of contaminants in groundwater (sulphur and nitrate) and the number of bores and infrastructure required to effectively capture the off-site plume. CSA was shown to be impractical for the off-site plume due to the number of bores required, lack of control over potential sulphide generation (sulphidogenesis) and the relatively limited reduction in time to achieve cleanup. The recommended approach to management of the off-site groundwater plume are as follows:

• Clean up or management of the main source areas is undertaken.

• The current uses of groundwater off-site (irrigation, domestic use and stock watering) are managed.

• Natural attenuation of the groundwater plume is monitored.

Management measures for the off-site groundwater plume are outlined more fully in Section 5 of the Remediation Feasibility Assessment Report and detailed in the CMP.




C.2.4.2 Source Management The clean up and management strategies for source areas considered to be practical, or at least potentially practical, are as follows:

• Capping with a low permeability capping system.

• Phytocapping with deep and shallow rooting plant species.

• CSA to groundwater in the source areas using either horizontal bores or a Recirculation Cell.

• CSA to soil acting as a secondary source of groundwater contamination in source areas by shallow infiltration.

Pumping and irrigation for containment of contaminated groundwater leaching from source areas is not considered practicable for the same reasons as the off-site plume. Primarily, there is insufficient available irrigation area to receive the volume of groundwater likely to be required to contain groundwater migrating from source areas. Although it does not represent a complete management solution, ADI and Defence may wish to consider an option to provide groundwater extracted from source areas to the golf course as means to meet the golf clubs water use needs and assisting in maintaining capture zones around source areas (see Section C.2.3.2.2). Capping is considered practicable for the source areas of greatest significance. Further assessment is required to prove whether phytocapping can achieve the required clean up goals. If phytocapping is shown to be effective in sufficiently reducing leaching of contaminants from contaminated soil acting as secondary sources, it would be preferred over clay capping as it may result in the partial removal of some of the contaminant mass (nitrate) and is potentially more cost effective and environmentally sustainable. The principal disadvantage of either form of capping is that they are simply a means of managing leaching of contaminants from impacted soil and will need to be maintained indefinitely. CSA addition for groundwater and soil in Source Management Area A will be retained for further evaluation of practicability based on field trials and detailed modelling. CSA of groundwater and soil represents an opportunity to clean up soil acting as secondary sources rather than simply managing infiltration rates. Contaminated soil in Source Management Area A has been identified as the most significant area of contamination as it is the primary source of both the northern arm of the off-site plume in the Shallow Aquifer and of the off-site plume in the Deep Aquifer. CSA using a Recirculation Cell and Direct Injection via horizontal bores are considered potentially practicable approaches to managing migration of groundwater from source areas. However, the principal limitation of these approaches is that they will need to be operated for a significant period of time (potentially decades) unless CSA for soil proves an effective means of removing contaminants from source area soils. The effectiveness of CSA for groundwater would need to be demonstrated prior to implementation of CSA for soil. Effective management of groundwater contamination provides a means of controlling of some of the potential impacts on groundwater quality associated with CSA for soil. The primary potential impact of CSA for soil on groundwater quality relates to additional flushing of contaminants by increasing vertical hydraulic gradients through source zone soils.




Management measures for onsite Source Management Areas are outlined more fully in Section 6 and detailed in the CMP

C.3 SOURCE AREA MANAGEMENT

C.3.1 Source Management Areas Based on characteristics of each source area and the type of remediation or management measures recommended to reduce the release of nitrate and sulphate to groundwater, the source areas identified in Section 2.4.3 in the Remediation Feasibility Assessment Report were grouped into a Source Management Areas. The location of the Source Management Areas is shown in Figure 5 of the Remediation Feasibility Assessment Report and a description of each Source Management Area and the sources areas included in them is presented in Table 6.

Table 6: Source Management Area Descriptions

Source Management Area A Oleum Area - Acid Drains, Former Nitric Acid Plant, Ammonia Oxidation and Former Ammonia Storage (Bld. 301C).

Sources 46, 48, 49 and 57

Effluent Treatment Plant and Effluent Treatment Plant Acid Drains

Sources 71 & 72

Nitrocellulose Area - Former Acid and Effluent Drains and Former Labyrinths.

Sources 10 & 11

Former Gypsum Ponds.

Source 74

Source Management Area B Effluent Drain.

Source 70

Source Management Area C Dump Areas-Current Boiler House and Coal Yard.

Source 106

Source Management Area D Dump Area-Iron Oxide Dumps.

Source 103 Dump Areas (NG) - Sulphur Dump.

Source 102

Source Management Area E Oleum Area - 314 Sulphur Store and Former Sulphur Store.

Sources 50 & 51 Acid Area - Acid Drains.

Source 35




Based on technical feasibility, logistical constraints and cost, the most practicable remedial approaches for each Source Management Area have be summarised and presented in the following Sections (C.3.2 to C.3.3, inclusive). These areas were previously ranked with a risk value of 1, 2 and 3, where their potential to act as on-going sources of groundwater contamination were ranked very high, high and moderate, respectively. Area’s that were previously determined to have a low potential to act as an on-going source to groundwater contamination, ranked with a risk value of 4, are not considered to be significant and therefore no management or remediation strategies have been proposed for these areas. The locations of the source management areas A to E are shown on Figure 5 in the Remediation Feasibility Assessment Report.

C.3.2 Source Management Area A

C.3.2.1 Background Source Management Area A comprises approximately 4ha in area and is the largest on site source area that has been found during the investigation works undertaken by HLA. Concentrations above background levels of nitrate in soil have been found to depth (i.e. to around 6 m below ground level), indicating that the dissolution of nitrate is occurring to groundwater. Concentrations of nitrate and sulphate in the aquitard separating the aquifers are also above background levels and appear to extend to the Calivil Aquifer, which shows elevated concentrations of nitrate and sulphate in groundwater at this location. The aquitard separating the shallow aquifer and the Calivil Formation Aquifer at this location comprises sandy clay to clayey sand, indicating relatively higher hydraulic connection between the Shepparton and Calivil Aquifers and a pathway for nitrate and sulphate contamination to enter the deeper aquifer. Elevated concentrations of nitrate and sulphate were also found to be present in soil samples collected from the former acid and effluent drains within the nitrocellulose area and the effluent treatment plant acid drains, throughout the soil profile to depths of up to 6 m below ground level. As observed in the acid area and effluent treatment plan acid drains, concentrations of nitrate and sulphate in soil tended to decrease at and below the water table (i.e. at a depth of 6 to 7 m), indicating that that dissolution of these compounds is occurring in groundwater.




C.3.2.2 Overall Approach Based on the background information for Source Management Area A and an assessment of the most practicable management strategies proposed in Section C.2.3.2, the recommended approach to remediation of Source Management Area A is summarised in the following flow diagram: As discussed in Section C.2.3.2.1, it is likely that CSA will be less effective at biodegradation of sulphate, compared to nitrate, in both the groundwater and soil. The proof-of-concept trial is intended to confirm whether this is the case. Therefore, the descriptions of CSA remediation to follow refer to nitrate reduction only.


1


2



Implement Capping

Yes


Trial


Attenuation


Yes

No


NoNo

YesYes

No




C.3.2.3 Proof-of-Concept Trial A proof-of-concept trial is necessary to avoid unnecessary time and expense on unsuccessful remediation measures and to confirm the practicability of the methods of remediation selected for Source Management Area A.

The scope of the Proof-of-Concept trial needs to include evaluation of all of the technologies proposed in this Section C.2.3.2. The minimum requirements of the trial will be discussed in the CMP.

Should the proof-of-concept trial confirm that CSA direct injection is a practicable approach for the remediation of groundwater in the Source Management Area A, a program of remediation should be implemented using that technology.

C.3.2.4 CSA Direct Injection Figure 6 shows a conceptual cross section of the proposed CSA remediation technology by direct injection using vertical bores, to remediate nitrate in groundwater. However, as previously discussed in Section C.2.3.2.1.1, direct injection via horizontal bores within the aquifer hydraulically up-gradient of the full plume width would provide more thorough mixing of carbon and contaminants in the aquifer and reduce the potential for bio-fouling. Details such as the final configuration of injection and monitoring bores and monitoring frequency should be determined from the results of the proof-of-concept testing, which will include field testing and further modelling for the development of a design for the efficient delivery of a carbon source into the aquifer. A phased approach to the remediation would firstly consider the installation of a horizontal bore into the Shepparton formations installed hydraulically up-gradient from the main source areas. Depending on the whether the injection of carbon into the Shepparton formation is able to treat the nitrate in the Calivil formation, through infiltration through the less permeable aquitard separating the formations, there may be a requirement to install a horizontal bore into the deeper aquifer. Furthermore, secondary injection of an amendment media into a horizontal bore installed hydraulically down-gradient may be required to increase dissolved oxygen levels, should sulphidogenesis be found to be occurring (see Figure 6 in the Remediation Feasibility Assessment Report).

C.3.2.5 CSA Re-circulation Cell Should it be determined either during the proof-of-concept trial or during subsequent CSA remediation activities, that direct injection CSA is not feasible, the trial or implementation of a CSA and re-circulation methodology is recommended as a means of improving diffusion of the carbon source into the aquifer. This should comprise groundwater extraction from the source area, ex-situ carbon source mixing and re-injection at points up around the margins of a capture zone centred on the source to facilitate circulation of the groundwater and reduction of the nitrate in groundwater by in-situ biodegradation. Extraction and re-injection would initially be from the Shepparton Aquifer only if it can be proven through modelling that the hydraulic gradient can be reversed to flow from the Calivil Aquifer back into the Shepparton Aquifer. Excess groundwater generation could be treated by irrigation onto the ADI site or the golf course. Application rates would be limited to those outlined in the study undertaken by John Sykes.




Figure 7 in the Remediation Feasibility Assessment Report shows a conceptual cross section of this proposed remediation technology.

C.3.2.6 CSA Soil Remediation If CSA results in successful biodegradation of nitrate in the groundwater (either through direct injection or re-circulation), it is recommended (pending the results of the proof-of-concept trial) that direct carbon source addition to the soil be implemented to remediate nitrate in the soil in Source Management Area A. It is intended that the infiltration of a carbon source into soil will enable a bio-reactive zone to be created in the saturated zone facilitating the biodegradation of nitrate in both the shallow and (eventually) deeper aquifers. A conceptual cross-section of this proposed remediation technology is shown on Figure 9 in the Remediation Feasibility Assessment Report.

C.3.2.7 Source Area Capping Should it be found that implementing a technology based management approach is not practicable, it is recommended that Source Management Area A be capped to manage the leaching of contaminants from impacted soil to groundwater. In Source Management Area A, the recommended method of capping will be a combination of the following:

• Recognising and maintaining existing paved and built-out areas (including leaving concrete slabs in place in the event that any building demolition is carried out);

• Capping with a low permeable capping system (i.e. clay and topsoil); and

• Phytocapping with deep and shallow rooting plant species to partially remove nitrate from the underlying soils.

Capping methodologies are discussed in more detail in Section C.2.3.3 and the CMP.

C.3.2.8 Monitoring Natural Attenuation If capping of Source Management Area A is not successful in reducing the dissolution of nitrate and sulphate from the underlying contaminated soils to groundwater then a Monitoring Natural Attenuation approach will be adopted as follows: • Bi-annual sampling and analyses of groundwater samples for the chemical and

biogeochemical parameters and analytes detailed in Section 5.2.2 of the Remediation Feasibility Assessment Report; and

• The number of bores and analytes will be reviewed in consultation with NSW EPA and the community liaison committee.

Monitoring Natural Attenuation is discussed in more detail in the CMP.

C.3.3 Source Management Area B

C.3.3.1 Background The soil in the base of the effluent drain was remediated by excavation to a depth of approximately 0.6 m by ADI in 2001 (Remediation of Offsite Drainage Channel, Final Validation Report, ADI 2001). The final remediation validation report of the effluent drain produced by ADI found that the soluble nitrate and sulphate from the original effluent had leached much deeper




into the soil (than the 0.6 m excavated) and possibly into the groundwater, over 10 metres deep. Concentrations of nitrate and sulphate returned in a number of samples collected by HLA confirmed that significant residual concentrations of nitrate and sulphate are present in the effluent drain at depths of up to 8 metres below ground level (bgl). Groundwater monitoring bores installed adjacent to the effluent drain have historically shown relatively high concentrations of nitrate and sulphate (Groundwater Investigation Report, HLA, 2003a), indicating that nitrate and sulphate within the soil profile of the effluent has leached into the groundwater. The dual 525 mm concrete effluent drains located in the Floodplain Aquifer are currently leaking treated effluent and storm water derived from the site at an undetermined rate. An inspection of the effluent pipelines, undertaken by Rostem Pty Ltd (Rostem) in August 2003, has shown that the pipes and associated inspection pits are badly deteriorated in a number of locations (Manhole 1 and 4), in the northern portions of the drains located in close proximity to the former effluent channel. In some case a large mass of root infiltration, silting and pooled water was visible in the pipes. In summary, Rostem concluded that there was damage throughout every section of the drain that was inspected.

C.3.3.2 Recommended Management Strategy Based on the background information for Source Management Area B and an assessment of the most practicable management strategies proposed in Section C.2.3.2, the recommended approach to remediation of Source Management Area B is described below. It is recommended that an inspection of the main drain be undertaken in light of the deterioration observed in the duel drains located in the floodplain, further to the south of the site. Should it be found that sections of the main effluent pipe are in poor condition, then they will be repaired, either through relining or replacement of the damaged sections (which could potentially be the entire length of the effluent drain) prior to the implementation of any remedial action in Source Management Area B. The proposed management and remediation strategy for Source Management Area B is summarised as follows:


Source 70


Backfill drain with soil in the adjacent mounds and supplement with additional natural material, to provide a nominal level of capping to reduce ponding of surface water in the base of the drain.

Planting over the backfilled drain using an appropriate selection of deep and shallow rooting plant species in a trial area. Combined with backfilling, this method will significantly reduce infiltration of contaminants to groundwater. If phytocapping does not prove effective in reducing leaching of contaminants from soil, construct a low permeability capping system.




C.3.4 Source Management Area C

C.3.4.1 Background Soil sample results and visual observations made from test pitting within the dump areas indicate that there are elevated concentrations of sulphate (and to a lesser extent nitrate) in the subsurface soils (HLA, 2003d). Nitrate concentrations were found to be slightly elevated above background levels whereas sulphate concentrations were found to be the highest of all soil sampling locations in this area (a sulphate concentration of 16,000 mg/kg was returned in one near-surface sample collected from the area – HLA, 2003d). Layers of raw gypsum were noted at the surface and near surface, therefore relatively high concentrations of sulphate were not unexpected at this location. Concentrations of nitrate and sulphate in soil were present throughout the unsaturated soil profile. These concentrations tended to decrease at and below the water table, indicating that that dissolution of these compounds is potentially occurring in groundwater.

C.3.4.2 Recommended Management Strategy Based on the background information for Source Management Area C summarised above and an assessment of the most practicable management strategies proposed in Section C.2.3.2, the recommended approach to remediation of Source Management Area C is summarised as follows:


Source 106

Excavate waste materials (i.e. gypsum) and place it in a constructed onsite landfill in the HDPE-lined former effluent ponds. Cap the landfilled waste material with clay and nominal topsoil and revegetation to prevent erosion and reduce infiltration.





C.3.5 Source Management Area D

C.3.5.1 Background Iron oxide and elemental sulphur observed to be present in the surface soils located in the iron oxide and sulphur dumps (Source 103) and NG Sulphur Dump are considered to be significant, with the potential to contribute to ongoing sulphate groundwater contamination.

C.3.5.2 Recommended Management Strategy Based on the background information for Source Management Area D summarised above and an assessment of the most practicable management strategies proposed in Section C.2.3.2, the recommended approach to remediation of Source Management Area D is summarised as follows:


Source 103


Source 102

Excavate waste material and place it in an onsite landfill in former HDPE-lined effluent ponds. Cap the landfilled waste material with clay and nominal topsoil and revegetation to prevent erosion and reduce infiltration.


C.3.6 Source Management Area E

C.3.6.1 Background The Oleum Area sulphur store and former sulphur store do not appear to be significant sources for ongoing nitrate contamination of groundwater, however they may be significant sources for ongoing sulphate groundwater contamination, based on historical surface soil results showing elevated concentrations of sulphate. Elevated concentrations of nitrate and sulphate were found to be present in unsaturated zone soils in and around the acid area acid drains (Source 35), but not within the aquitard separating the Shepparton Aquifer and Calivil Aquifer, with the exception of one anomalously high concentration found at a depth of 13 m – HLA, 2003d).




C.3.6.2 Recommended Management Strategy Based on the background information for Source Management Area E summarised above and an assessment of the most practicable management strategies proposed in Section C.2.3.2, the recommended approach to remediation of Source Management Area E is summarised as follows:


Sources 50 & 51


Source 35

Implementation of a cap over Source Management Area E using clay and topsoil and an appropriate selection of deep and shallow rooting plant species to aid in the removal of shallow nitrate and reduce rainfall infiltration.

Existing and future buildings and pavements are assumed to act as effective capping. Plant phytocap of appropriate selection of deep and shallow rooting plant species in areas not covered by buildings or pavements. If monitoring indicates phytocapping does not prove effective in reducing leaching of contaminants from soil, construct a low permeability capping system.

C.4 REFERENCES Previous Works HLA-Envirosciences Pty Limited (HLA, 2003 a). Groundwater Investigation Report (Phase 2 and




Project, Priority A Sources Investigation Report. 13 June 2003. HLA-Envirosciences Pty Limited (HLA, 2003e). ADI Mulwala Contamination Management

Project, Remediation Feasibility Assessment Report. 21 November 2003. John Sykes Rural Consulting (John Sykes, 2003). Plan for the Agricultural use of Bore Water

from ADI Mulwala. 28 September 2003. General Alleman, B.C. and Leeson, A. (1999) Bioremediation of Nitoraromatic and Haloaromatic

compounds Proceedings Fifth International In-situ & On-site Bioremediation Symposium, San Diego, 1999.

Aylward, G.H. & T.J.V. Findlay, 1967. Chemical Data Book, 2nd. Edition, John Wiley & Sons,

Australasia.




Brock, T.D. Biology of Microorganisms, 9th Edition, 2000. Prentice Hall, N.J., USA Cooper, K (2002) Nitrates in Drinking Water & Their Removal, University of Guelph Halden, R. Burge, S., Pico, T., Lima, M. Optimization study of Nitrate and Perchlorate Removal

by Ion Exchange. Environmental Restoration Division, Lawrence Livermore National Laboratory

Haugen, K.S., Semmens, M.J., Novak, P.J., (2002) A novel in situ technology for the treatment

of nitrate contaminated groundwater, Water Research 36, 3497-3506 Hem, J.D, 1989, Study and Interpretation of the Chemical Characteristics of Natural Water, U.S

Geological Survey Water-Supply Paper 2254 Kaufman, A. K. Krueger, C.C., Zalatel, F.D. Biodetoxification of Nitrate-Impacted Groundwater Du Preez, L.A. & Maree, J.P. Pilot Scale biological sulphate and nitrate removal utilising

producer gas as an energy source Water Science & technology Nuttall, H.E. A technology for the Insitu Denitirfication of Groundwater, Proceedings 42nd

Annual New Mexico Water Conference. Zehnder, A.J.B. & W. Stumm, 1988. Geochemistry and Biochemistry of Anaerobic Habitats,

A.J.B. Zehnder (Ed.) John Wiley & Sons, Inc., USA. Zhang, Y., Chen, Y, Lui, H, (2002) Denitrification of Nitrate in Groundwater Mediated by

Chemical Catalytic Action. Carbon Source Addition Corseuil, H.X., C.S. Hunt, R.C.F.D. Santos & P.J.J. Alvarez, 1998. The influence of the

gasoline oxygenate ethanol on aerobic and anaerobic BTEX biodegradation. Water Research, 32, 2065-2072.

Faris, B., Nuttall, E., Spalding, R., Erhman, D., Roberts, K., Williams Callison, A., Hill, S., (2000)

Emerging Technologies for Enhanced In Situ Biodentrification (EISBD) of Nitrate- Contaminated Ground Water, Interstate Technology and Regulatory Cooperation Work Group.

Gomez, M.A., Gonzalez-Lopez, J., Hontoria-Garcia, E.,(2000) Influence of carbon source on

nitrate removal of contaminated groundwater in a denitrifying submerged filter, Journal of Hazardous Materials B80, 69-80.

Gomez, M.A., Hontoria, E., Gonzalez-Lopez, J., (2002) Effect of dissolved oxygen concentration

on nitrate removal from groundwater using a denitrifying submerged filter, Journal of Hazardous Materials B90, 267-278.

Gomez, M.A., Galvez, J.M., Hontoria, E., Gonzalez-Lopez, J., (2003) Influence of Ethanol

Concentration on Biofilm Bacterial Composition from a Denitrifying Submerged Filter used for Contaminated Groundwater, Journal of Bioscience and Bioengineering, vol 95 No. 3, 245-251.




Haugen, K.S., Semmens, M.J., Novak, P.J., (2002) A novel in situ technology for the treatment of nitrate contaminated groundwater, Water Research 36, 3497-3506.

Khan, I.A., Spalding, R.F., (2003) Development of a Procedure for Sustainable In Situ Aquifer

Denitrification. Lathrop, S.B., Tharpe, W.T., Nuttall, H.E., Turner, B.G., Pilot-Scale field test results of enhanced

in situ denitrification. Mailloux, M., Tartakovsky, B., Milette, D., Guiot, S.R., Peisajovich, A., Olivier, L., Belanger, C.,

Lorrain, M.J., (2002) Evaluation of a Carbon-Source stimulated Bioremediation technology for the remediation of a nitrate-contaminated aquifer at an airport site, Groundwater and Water: Theory to Practice, 919-925.

Powers, S.E., Hunt, C.S., Heermann, S.E., Corseuil, H.X., Rice, D., Alvarez, P.J.J., The

Transport and Fate of Ethanol and BTEX in Groundwater Contaminated by Gashol. Ulrich, G., (1999) The Fate and Transport of Ethanol-Blended Gasoline in the in Environment,

Governors’ Ethanol Coalition. Constructed Wetlands Cooper, P. F., and B.C. Findlater (eds.). (1990) Constructed Wetlands in Water Pollution

Control. Proceedings of the International Conference on the Use of Constructed Wetlands in Water Pollution Control, Cambridge, UK, 24-28 September. WRc, Swindon, Wiltshire, UK. 605 pp.

Department of Land and Water Conservation New South Wales (1998) The Constructed

Wetlands Manual Moshiri, G. A. (ed.). (1993) Constructed Wetlands for Water Quality Improvement. CRC Press,

Boca Raton, FL. 632 pp. O’Sullivan, A.D. (2001) Constructed Wetlands for Passive Biological treatment of Mine Tailings

Water at Tara Mines, Ireland USDA Natural Resources Conservation Service and USEPA (district III), A handbook of

constructed wetlands PS5384RSEZ Electrokinetics Ibanez, J.G., Singh, M.M., Pike, R.M., Szafran, Z.: Laboratory Experiments on Electrochemical

Remediation of the Environment Vol 75 No 5 May 1998, Journal of Chemical Education Trombley, J (1994) Environmental Science & Technology 28, 289-291, 1994 Van Cauwenbergher, L (1997) Electrokinetics Technology Overview Report TO97-03

Groundwater Remediation Technology Analysis Centre, 1997




Permeable Reactive Barriers Strietelmeier, B.A., Espinosa, Adams, J.D, Leonard, P.A., and Hodge, E.M. (2001) Use of a

unique biobarrier to remediate nitrate and perchlorate in Groundwater Taylor, T.P., Strietelmeier, B.A., Ware, S.D., Espinosa, M.L., Sauer, N.N. and Conca, J., L.

(2001) Use of Novel Reactive Barrier Materials for treatment of Strontium, Uranium, Nitrate and Perchlorate in Groundwater Groundwater 2001 Conference, Sheffield, England

USEPA Office of Solid Waste and Emergency Response technology Innovation Office (2000),

Permeable Reactive Barriers for Inorganics Phytoremediation Brady, J. (1990). The design of a subsurface irrigation system utilizing poplar trees for nitrate

removal from agricultural drainage water. Iowa City, University of Iowa. Brix, H., B. K. Sorrell, et al. (1996). Gas fluxes achieved by in situ convective flow in Phragmites

australis. Aquatic Botany 54: 151-163. Burken Joel, G. and N. Marmiroli (1999). The INTERCOL workshop on phytoremediation.

INTERCOL 1998. CH2MHill (1999). Guidance for Successful Remediation, Centre for Waste Reduction

Technologies, American Institute of Chemical Engineers. EPA (1999). Phytoremediation Resource Guide. Washington, DC, U.S. Environmental

Protection Agency Office of Solid Waste and Emergency Response Technology Innovation Office.

Grigg, A. M., J. S. Pate and M.J. Unkovich (2000). Responses of native woody taxa in Banksia

woodland to incursion of groundwater and nutrients from bordering agricultural land. Australian Journal of Botany 48: 777-792.

Haycock, N.E., and G. Pinnay. (1993) Groundwater nitrate dynamics in grass and poplar

vegetated riparian buffer strips during the winter. J. Environ. Qual. 22:273-278. Hibbs, B. J. (2001). Sources of Nitrate Removal by a Surface Flow Wetland in a Southern

Californian Coastal Watershed. Proceedings of the 2001 Wetlands Engineering & River Restoration Conference, August 27-31, 2001,, Reno, Nevada, American Society Civil Engineers.

Jin, G., T. Kelley, et al. (2002). Removal of N, P, BOD5, and Coliform in Pilot-Scale Constructed

Wetland Systems. International Journal of Phytoremediation 4 (2). Kang, S., H. Kang, et al. (2002). Nitrogen removal from a riverine wetland: a field survey and

simulation study of Phragmites japonica. Ecological Engineering 18(4): 467-475. Krauter, P. W. (2002). Using a Wetland Bioreactor to Remediate Ground Water Contaminated

with Nitrate (mg/L) and Perchlorate (ug/L). International Journal of Phytoremediation 3(4).




Kruger, E. L., T. A. Anderson, et al. (1997). Phytoremediation of soil and water contaminants. Washington, DC, American Chemical Society.

Lamb, J.F.S., D.K. Barnes, M.P. Russelle, and C.P. Vance. (1995) Poster Abstract: Plant

breeding strategies in alfalfa (Medicago sativa L.) to address soil nitrate remediation. p. 123. In Proceedings/Abstracts of the Fourteenth Annual Symposium, Current Topics in Plant Biochemistry, Physiology, and Molecular Biology -Will Plants Have a Role in Bioremediation? ,Interdisciplinary Plant Group, University of Missouri

Mactec Environmental Restoration Services (1998), Monument Valley Groundwater

Remediation Work Plan; Native Plant farming and Phytoremediation Study, US Department of Energy Doc No. UOO29501

Mant, C. M. (2001). Studies on the use of Salix viminalis for the phytoremediation of

wastewaters. Matheson, F. E., A. B. Nguyen, et al. (2002). Fate of 15N-nitrate in unplanted, planted and

harvested riparian wetland soil microcosms. Ecological Engineering 19: 249-264. McKeon, C., E. P. Glenn, et al. (2000). Phytoremediation of Nitrate-Contaminated Groundwater

by Desert Phreatophytes, Environment Research Laboratory, University of Arizona. Myers, B. J., W. J. Bond, et al. (1999). Sustainable Effluent-Irrigated Plantations: An Australian

Guideline, CSIRO Forestry and Forest Products Division. Williams, J. B. (2002). Phytoremediation in Wetland Ecosystems: Progress, Problems, and

Potential. Critical Reviews in Plant Sciences 21(6): 607-635. Web resources www.clu-in.org http://www.dsa.unipr.it/phytonet/ http://www.prb-net.org http://www.rtdf.org/public/permbarr http://www.qeokinetics.com http://www.enpar-tech.com/ http://www.engg.ksu.edu/HSRC/97Proceed/Remediation1/nitrate.html


D006005_RPT236Rev03_17Dec03

Appendix D Management Plans


D006005_RPT236Rev03_17Dec03

Appendix D1 Long-Term Management Plan

ADI Mulwala Contamination Management Project CONTAMINATION MANAGEMENT PLAN Appendix D1 – Long-Term Environmental Management Plan 21 November 2003 Prepared for: Department of Defence and ADI Limited Bayley Street, Mulwala, NSW 2647 Report by: HLA-Envirosciences Pty Limited ABN: 34 060 204 702 46 Clarendon Street Melbourne VIC 3205 Australia Ph: +61 3 8699 2199 Fax: +61 3 8699 2122 HLA Ref: D006005_RPT236Rev03_17Dec03_AppendixD1


Appendix D1 – Long-Term Environmental Management Plan

D006005_RPT236Rev03_17Dec03_AppendixD1 I

CONTENTS D1 APPENDIX D1 – LONG-TERM ENVIRONMENTAL MANAGEMENT PLAN...............1

D1.1 INTRODUCTION...........................................................................................1 D1.1.1 Scope .............................................................................................1 D1.1.2 Long-Term Environmental Management Planning

Objectives.......................................................................................1 D1.1.3 Summary of Issues Requiring Long-Term Environmental

Management ..................................................................................2 D1.1.4 Sources for Background Information ..............................................2 D1.1.5 Remedial Works .............................................................................2

D1.2 ENVIRONMENTAL MANAGEMENT RESPONSIBILITIES...........................3 D1.2.1 Issues.............................................................................................3 D1.2.2 Objectives.......................................................................................3 D1.2.3 Management Strategy / Actions......................................................3 D1.2.4 Monitoring.......................................................................................3 D1.2.5 Reporting........................................................................................3

D1.3 COMMUNICATIONS PLANNING AND COMPLAINTS MANAGEMENT ............................................................................................4 D1.3.1 Issues.............................................................................................4 D1.3.2 Objectives.......................................................................................4 D1.3.3 Management Strategy / Actions......................................................4 D1.3.4 Monitoring.......................................................................................6 D1.3.5 Reporting........................................................................................6

D1.4 STORMWATER MANAGEMENT AND EROSION CONTROL .....................7 D1.4.1 Issues.............................................................................................7 D1.4.2 Objectives.......................................................................................7 D1.4.3 Management Strategy / Actions......................................................7 D1.4.4 Monitoring.......................................................................................9 D1.4.5 Reporting........................................................................................9

D1.5 CONTAMINATED SOIL MANAGEMENT ...................................................10 D1.5.1 Issues...........................................................................................10 D1.5.2 Objectives.....................................................................................10 D1.5.3 Management Strategy / Actions....................................................10 D1.5.4 Monitoring.....................................................................................11 D1.5.5 Reporting......................................................................................11

D1.6 CONTAMINATED GROUNDWATER MANAGEMENT...............................12 D1.6.1 Issues...........................................................................................12 D1.6.2 Objectives.....................................................................................12 D1.6.3 Management Strategy / Actions....................................................12



D006005_RPT236Rev03_17Dec03_AppendixD1 II

D1.6.3.1 Register of Affected Properties......................................12 D1.6.3.2 Current Appropriate Uses for Contaminated

Groundwater .................................................................13 D1.6.3.3 Guidelines for Irrigating with Impacted

Groundwater .................................................................15 D1.6.3.4 Guidelines for Stock Watering with Impacted

Groundwater .................................................................16 D1.6.3.5 Ongoing Groundwater Monitoring..................................17

D1.6.4 Monitoring.....................................................................................17 D1.6.5 Reporting......................................................................................18

FIGURES Figure 1 – ADI Mulwala CMP, Long-Term Environmental Management Plan, Groundwater Use Restriction Areas




D006005_RPT236Rev03_17Dec03_AppendixD1 1

D1 APPENDIX D1 – LONG-TERM ENVIRONMENTAL MANAGEMENT PLAN

D1.1 INTRODUCTION

D1.1.1 Scope This Appendix D1 Long-Term Environmental Management Plan (LTEMP) is concerned with the long-term management of known nitrate and sulphate contamination of groundwater extending south and south west of the ADI Mulwala Explosives and Propellants facility, Bayly Street Mulwala and known nitrate and sulphate impact to soil on-site beneath the facility. The extent of the area that this LTEMP refers to (noting that the LTEMP is concerned only with impact sourced from the ADI facility) is depicted on Figure 1 attached. It includes the ADI site and extends from the site south to the Murray River and west from the site to the Murray River billabong system. In addressing the long-term management, the scope of this document is intended to include the “interim” period until commencement of the measures outlined in the body of the Contamination Management Plan (CMP) report and beyond the completion of any remediation works. It is intended that this document also overlap and be referenced in conjunction with the following:

• The body text of the CMP;

• Appendix D2 – Remediation Environmental Management Plan (REMP);

• Appendix D3 – Contingency Management Plan (Contingency MP);

• ADI’s Environmental Management System (EMS)1 for operation of the Explosives and Propellants facility; and

• Environment Protection Licence Number 4848, for the ADI Explosives and Propellants facility, NSW EPA, 10 June 2003.

In particular, during any remediation works, the measures outlined in this LTEMP will still apply, as will additional environment protection measures outlined in the REMP.

D1.1.2 Long-Term Environmental Management Planning Objectives The objectives of this LTEMP are summarised as follows: • Provide a summary of the potential environmental issues anticipated to require

management in the long-term, including the period prior to commencement of any contamination management / remediation measures outlined in the body of the CMP report.

• Outline the necessary management strategies, actions, monitoring and reporting measures

to be undertaken to minimise the risk of any further impact to the environment and to meet the environment protection expectations of Government authorities and the community.

• Minimise safety risk and inconvenience to operations at the facility and the community,

including nearby residents. 1 ADI Mulwala Environmental Management System Manual - 2000




• Address the reporting guidelines for Long-Term and Interim Site Management Plans, as outlined in the NSWEPA Guidelines for Consultants Reporting on Contaminated Sites (NSW EPA, 1998).

More specific objectives, such as provision for ongoing groundwater monitoring and continuing open communications with the community etc are provided for each of the issues identified and addressed in Section D1.3 to follow.

D1.1.3 Summary of Issues Requiring Long-Term Environmental Management

The following issues require environmental management measures and are addressed in Sections D1.2 to D1.6 inclusive to follow:

• Environmental Management Responsibilities.

• Complaints Management.

• Stormwater Management and Erosion Control.

• Contaminated Soil Management.

• Contaminated Groundwater Management. Within the scope of the CMP, contaminated groundwater is the main issue requiring management. Section D1.6 outlines several aspects of managing contaminated groundwater applying to this LTEMP.

D1.1.4 Sources for Background Information Since the late 1980s several investigations have been conducted to date on the groundwater contamination and impacted soil on-site beneath the facility, culminating in the CMP that is the main body of this report. Pertinent background information on the site and the contamination, such as the regulatory framework, extent of contamination and planned measures to manage the contamination is provided either within the body of the CMP report and in the documents listed in Appendix B of the CMP.

D1.1.5 Remedial Works Remedial Works completed may alter the environmental conditions of the Site, and hence the long term environmental management required (and described herein). All remedial works undertaken should be in accordance with the CMP and REMP.




D1.2 ENVIRONMENTAL MANAGEMENT RESPONSIBILITIES

D1.2.1 Issues It is necessary to document a structure for environmental management responsibilities, to ensure that all aspects of environmental management planning are allocated to specific positions and roles. This helps to ensure that the management measures outlined are put into place.

D1.2.2 Objectives The objective of this component of the LTEMP is:

• To outline the main roles and responsibilities relating to environmental management measures.

D1.2.3 Management Strategy / Actions This LTEMP is intended for implementation in the long term, including the interim period until CMP measures are implemented and beyond the completion of any such remediation measures. Most of the responsibility for management and environmental management of the impact will rest with ADI Limited (ADI), unless otherwise outlined in this LTEMP. ADI will take responsibility for the following:

• Environmental management and monitoring of the known impact, in accordance with this IEMP, including each of the tasks detailed in Sections D1.2 to D1.6 inclusive unless the responsibilities are outlined to rest with other organisations.

• Ensuring that a clear hierarchy of authority and responsibility for environmental management remains in place within the organisation.

• Maintaining open communications with the community, NSW EPA and other authorities as required.

• Maintaining environmental management of the operating ADI explosives facility in accordance with the existing licence (EP Licence No. 4848) and applicable regulatory framework and in a manner to minimise the risk of further impact to the soil and groundwater beneath the site.

• Reviewing and if necessary updating this LTEMP every five years and/or after the implementation of any remediation measures outlined in the CMP and/or in the event that circumstances relating to the known impact change for any reason.

D1.2.4 Monitoring None required for the purposes of allocating Environmental Management Responsibilities.

D1.2.5 Reporting None required for the purposes of allocating Environmental Management Responsibilities.




D1.3 COMMUNICATIONS PLANNING AND COMPLAINTS MANAGEMENT

D1.3.1 Issues It is necessary for ADI to maintain communications with the community and other stakeholders. As part of this it is also necessary to maintain a register of any complaints from nearby residents, other community members or stakeholders, to ensure that any such complaints are appropriately addressed.

D1.3.2 Objectives To provide open communications to the community and stakeholder authorities and provide an appropriate response to any complaints received.

D1.3.3 Management Strategy / Actions • ADI undertakes to arrange meetings with the community consultative group every 3 to 4

months, with the frequency of meetings to be reviewed in consultation with the group at the end of 2004.

• ADI undertakes to facilitate a presentation open to the community at least every 6 months, with the frequency of presentations to be reviewed in consultation with the group.

• Where appropriate, ADI will include appropriate contact names and phone numbers on any correspondence or reports issued to the public and stakeholder authorities, for the purposes of communications. At the time of completing this LTEMP the appropriate contact for communications for environmental issues is:

ADI Limited Environmental Manager Mr Doug Wilson Phone (03) 57422479

• In accordance with EP Licence No. 4848 and the EMS, ADI will continue to maintain a

telephone complaints line and a register to record and manage any complaints received, including documentation of the response to each complaint on the Environmental Complaint Form below, to the point of closure for each instance.

• ADI will notify the public as appropriate of its’ complaints line so that the community knows how to make a complaint.

• ADI will allocate an appropriate “Investigating Officer” to complete the response to any complaints and report the findings in “Investigating Officer’s Comments” section of the Environmental Complaint Form.

• After completing the Environmental Complaint Form the Investigating Officer will report the findings to ADI management for endorsement prior to reporting to the complainant.

• ADI undertakes to provide this response to the complainant within a period of 14 days. • The Environmental Complaints Form shall then be filed in the Complaints Register. • In accordance with EP Licence No. 4848, ADI will keep any complaint records for a period

of at least four (4) years after the complaint was made.




The following Environmental Complaints Form will be used: ENVIRONMENTAL COMPLAINT FORM Complainants Name:......................................................................................... Address: ........................................................................................................... Telephone Number:

(H) ................................

(w).................................

Date:......./......./.......

Complaint Number:

Description of complaint: .................................................................................. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... Is the problem occurring now? Y / N Has a complaint been lodged with ADI previously? Y / N Taken by: ...................................

Time: .................. am/pm

Investigated by: ..........................

Time: .................. am/pm

Investigating Officer’s Comments: .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... Signature:...................................................... Date: ....../......../........ Action Taken: .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... Signature:....................................................... Date: ......./......./.......




D1.3.4 Monitoring Requirement Method Frequency

Monitoring for appropriateness of complaints response and closure.

Internal evaluation by ADI Quality Manager.

Quarterly (every 3 months).

D1.3.5 Reporting • Environmental Complaints Forms and register, see above.




D1.4 STORMWATER MANAGEMENT AND EROSION CONTROL

D1.4.1 Issues Some of the areas where soil is impacted by nitrate and sulphate contamination are relatively bare of grass cover and vegetation. During rainfall events there is potential for sediment, nitrate and sulphate to wash into stormwater and potentially off-site and into the Murray River catchment drainage network. Infiltration of rainfall is also a mechanism for nitrate and sulphate from impacted soil to continue entering the groundwater beneath the site. Capping and revegetation measures are outlined in the body of the CMP report, designed to reduce infiltration of contamination to groundwater and reduce mobilisation of nitrate and sulphate into surface water drainage. During the interim (prior to implementing the capping and revegetation outlined in the body of the CMP), any disturbance of impacted soil, for earthworks or construction projects must be managed to minimise erosion and the potential to mobilise impacted sediments into the stormwater. Measures to manage stormwater and erosion will remain necessary in the long-term, beyond the completion of any works outlined in the CMP.

D1.4.2 Objectives

• Minimise the sediment, nitrate and sulphate load to stormwater prior to implementation of the proposed capping and revegetation measures outlined in the CMP .

• Prevent and / or minimise soil loss potential impact to surface waters during and after any earthworks or construction disturbance carried out.

D1.4.3 Management Strategy / Actions The main adopted management strategy for the existing soil impact is to implement the capping and revegetation measures outlined in the CMP within a reasonable time frame, that allows for the synergies of carrying out most of the works in conjunction with the decommissioning of the plant, anticipated within the next 2 – 3 years. Based on the assessment and modelling results to date, this approach and time frame is considered unlikely to result in significant worsening of the groundwater impact. Any earthworks, construction or demolition works proposed at the site shall be managed in accordance with the following guidelines as a minimum:

• Protection of the Environment Operations Act (NSW EPA, 1997).

• "The Blue Book" – NSW Department of Housing, Production Division, "Managing Urban Stormwater: Soils and Construction", 1998.

• EPA Victoria Publication 480, Environmental Guidelines for Major Construction Sites, December 1995.




• EPA Victoria Publication 275, Construction Techniques for Sediment Pollution Control, May 1991.

• Victorian Department of Conservation Forests & Lands, Control of Erosion on Construction Sites, December 1987.

The DIPNR is responsible for reviewing matters pertaining to stormwater management and erosion control under the Soil Conservation Act (1938) and therefore would like to be involved in reviewing any specific management plans proposed for the site. In the event of any such works, the management of stormwater should aim to prevent and / or minimise runoff from the site and measures should include the following:

• Diverting water around the sites and working areas. Where practical sediment and erosion control structures will be installed including diversion berms and silt / sediment fences, prior to commencing disturbance earthworks.

• Where appropriate construct diversion berms at a low angle to the contour of the slope and drain away (down stream) from the site and into stable vegetation or erect a silt fence at the outlet point.

• Covering any stockpiles and containing runoff from potentially contaminated areas.

• In areas that do not present contamination issues filtration and removal of suspended silt from runoff waters by appropriate sediment control measures that may include silt fences, diversion bunds or settling ponds etc.

• The period that soil is left exposed to erosion shall be minimised where possible.

• Placement of geofabric, crushed rock and temporary tiling cover is required in unpaved areas where frequent vehicle, machinery and personnel will occur.

• Where practical the area of disturbance shall be restricted, and clearly demarcated, including working areas, access tracks and soil stockpile sites.

• Strip topsoil and stockpile separately from subsoil prior to commencing construction / remedial activities or in areas of high traffic movement.

• Soil / clay / rock / gravel transported onto site should be sourced locally where practicable and certified to be weed free.

• If stockpiles are to remain exposed for a long period of time these should be revegetated or covered to prevent erosion.

Planning and designing the working area for any earthworks, construction or demolition projects should include:

• Siting of soil stockpiles away from drainage lines.

• Ensuring adequate separation between stockpiles of topsoils, subsoils and construction clays to avoid mixing.

• If practicable siting of stockpiles upslope of excavations so that these may act as sediment sumps for runoff.

• Locating sediment / silt fences on the downslope side of soil stockpiles.

• Siting of water diversion structures (diversion bunds) upslope of the worksite and locally diverting water around the working area so that runoff from the site is minimised to catchment rainfall only.

• Placing appropriate diversion berms at the toe of the construction site or planning for a suitable configuration of sediment / silt fences.




• Where practicable using geofabric and crushed rock to prevent erosion in drains, to surface important access ways and to remove soil from the wheels of vehicle exiting the working sites.


Stormwater diversion features where appropriate

Surveillance Weekly during any earthworks or construction

Silt fences, bunds & settlement ponds as required


Soil stockpiles covered Surveillance Weekly during any earthworks or construction

Excavation sites Surveillance for erosion and adequacy of mitigation

Weekly during any earthworks or construction

Maintenance of disturbed areas

Surveillance for adequacy of mitigation


Rehabilitation of excavation sites and disturbed ground

Surveillance for adequacy Following works and weekly for 3 months after completion

D1.4.5 Reporting Incident reporting if any sediment / contamination is released off-site or to the Murray River catchment via stormwater discharge.




D1.5 CONTAMINATED SOIL MANAGEMENT

D1.5.1 Issues Based on the nature of the contaminants, the nitrate and sulphate impacted soil is unlikely to represent a significant exposure risk to workers at the site. However in the event that any excavation of soil is carried out in areas known or suspected to contain contamination, it is important to re-evaluate and ensure that the extent of investigation in the area concerned is sufficient to characterise the soil:

• for exposure risk to workers (more so due to potential low pH and metals etc, than nitrate and sulphate); and

• to determine how to manage the excavated soil (for example to determine whether it is suitable for re-use on-site or whether it requires remediation or disposal to an appropriately licensed facility off-site).

The other main issues associated with soil contamination relate to infiltration to groundwater and mobilisation to surface water, both addressed in Section D1.4 above.

D1.5.2 Objectives To ensure that any risks to human health and the environment due to contaminated soil at the site remain negligible at all times.

D1.5.3 Management Strategy / Actions • If any excavation is proposed in areas of known or suspected contamination, re-evaluation

of previous investigations will first be carried out to ensure that the soil is adequately characterised for exposure risk to workers and to determine how to manage the soil after it is excavated.

• Workers excavating soil will wear appropriate personal protective equipment (PPE) for the

level of contamination determined, which will include as a minimum no skin contact and appropriate dust suppression.

• Any soil excavation will be managed in accordance with the measures outlined in Section

D1.4 above. The following management measures shall be implemented to manage soil that is identified to be contaminated in excess of the adopted guidelines for industrial land use (NEPM F). Most of these measures are not considered necessary for the management of soil that is impacted only with nitrate and sulphate: • There may be circumstances under which contaminated soil can be re-used (but buried to

avoid exposure risk) and/or remediated on-site. Any proposed remediation of contaminated soil on-site shall be carried out in accordance with NSW EPA Guidelines for Consultants Reporting on Contaminated Sites (NSW EPA, 1998).

• Any proposal to dispose of contaminated soil off-site shall be carried out in accordance with

NSW EPA Guidelines for Consultants Reporting on Contaminated Sites (NSW EPA, 1998), and the NSW EPA (1999), Guidelines on the Assessment, Classification and Management of Liquid and Non-Liquid Wastes, including adequate validation of the environmental quality of the soil to determine how and where it should be disposed.




• Any excavated contaminated soils will be kept separate from stockpiles of other materials and be appropriately labelled (i.e. contaminated, imported clay, topsoil etc, date of placement). Material tracking forms will be used to track the movement of the soil until it reaches its destination.

• To prevent cross contamination of underlying soils, hardstand areas should be used to

stockpile contaminated soil. If hardstand areas are unavailable a low permeability liner should be placed underneath stockpiles. Appropriate diversion berms or bunding should be constructed around any contaminated soil stockpiles and they should be covered to prevent contamination of surface waters and runoff.

• All vehicles in contact with contaminated materials must be washed prior to leaving the site

and any wastewater generated from the cleaning of these vehicles should either be used to control dust or discharged to sewer under an appropriate licensing agreement. Since this washdown water may contain contaminants, the preference should be to use it to wet-down contaminated material, or otherwise consult a land contamination expert prior to using it for dust control on non-contaminated areas.

• All soil / fill materials requiring offsite disposal will be transported and disposed of at an

appropriate location or waste facility in accordance with statutory regulations and EPA guidelines. These include, but are not limited to: − NSW EPA Guidelines for Consultants Reporting on Contaminated Sites (NSW EPA,

1998) − Any other pertinent legislation, guidelines or practices.

• All soil materials(crushed rock sub-base, foundation and landscaping soil) imported to the

site to be used as clean fill will be required to be sampled and classified according to NSW EPA (May 1999), Guidelines on the Assessment, Classification and Management of Liquid and Non-Liquid Wastes,.


Adequate characterisation of any areas proposed for excavation where known or suspected contamination may be present.

Re-evaluate existing investigation results and supplement those if necessary with additional soil sampling.

As required

Classification and appropriate management of soil materials requiring offsite disposal

Sampling and analysis As required

D1.5.5 Reporting • Documentation will be kept to record adequate characterisation of any area proposed for

excavation.

• A comprehensive and professional health and safety plan will be prepared in the event that excavation of any soil found to be contaminated (in excess of NEPM F levels) is proposed.

• Documentation will be retained relating to contaminated soil transport off-site (such as waste transport certificates and disposal receipts etc).

• Validation reporting in the event that excavation is proposed as a remediation measure and soil sampling is carried out to confirm that the works have successfully remediated the target area.




D1.6 CONTAMINATED GROUNDWATER MANAGEMENT

D1.6.1 Issues Within the scope of this CMP, contaminated groundwater is the main issue requiring management. In determining the management requirements for this issue, the following aspects (sub-issues) are addressed:

• Register of Affected Land.

• Current Appropriate Uses for Contaminated Groundwater.

• Guidelines for Irrigation with Contaminated Groundwater.

• Guidelines for Stock Watering with Contaminated Groundwater

• Ongoing Groundwater Monitoring

D1.6.2 Objectives • To ensure that the risk to human health due to identified groundwater contamination is

minimised. • To minimise the risk of further impact or worsening of groundwater contamination,

especially in the interim period prior to any CMP measures being implemented, but also beyond that in the long-term.

• Minimise any inconvenience to groundwater users and property owners in the area of

groundwater impact. • Optimise the beneficial uses of the impacted groundwater without unacceptable risk to

livestock or domestic garden horticulture.

D1.6.3 Management Strategy / Actions

D1.6.3.1 Register of Affected Properties ADI undertakes to maintain a register of properties and landowners whose properties are located within the area of groundwater impact (defined as the area below which groundwater concentrations exceed drinking water guidelines – 50 mg/L for nitrate and/or 500 mg/L for sulphate). Landowners with monitoring bores within this area will be regularly informed of ongoing groundwater monitoring results, will be invited to the regular community consultative group meetings (see Section D1.3) and will be kept informed by appropriate correspondence. Along with the results, ADI will provide recommendations regarding appropriate uses for the groundwater. Based on the results of ongoing groundwater monitoring, the register of affected properties will be updated once a year, and on completion of any major remedial works phases, to ensure that any properties no longer falling within the impacted groundwater area are removed and any properties that become affected are added to the register.




Once a year Corowa Shire Council (Council) will be provided with a copy of the Register of Affected properties, potentially for use (at the discretion of Council) in identifying properties that may require Certificate of Title notification of the restrictions applying to the use of groundwater beneath the property concerned. The frequency of updating the register and providing information to landholders and Council will be reviewed by ADI in consultation with NSW EPA, Council and the community consultative group.

D1.6.3.2 Current Appropriate Uses for Contaminated Groundwater Groundwater Exceeding Stock Watering and Irrigation Guidelines: The area in which groundwater concentrations for nitrate and sulphate exceed the adopted guidelines for stock watering (400 mg/L for nitrate and 1000 mg/L for sulphate) is depicted on Figure 1.

Within this area, use of the groundwater for any purpose is not recommended. It is noted however that:

• there is only one known domestic extraction bore that contains nitrate or sulphate levels in excess of these guidelines; and

• it is possible that the groundwater in this area is suitable for irrigation of some plants, given that several domestic extraction bores continue to be used for irrigation without noticeable effects, despite containing nitrate in exceedence of the range recommended in the adopted Australian Water Quality Guidelines (AWQGs), 22 – 554 mg/L (as nitrate) (see Section D1.6.3.3 below).

As discussed in Section D1.6.3.1 above, ADI undertakes to keep bore owners informed of monitoring results, together with recommendations regarding appropriate uses of groundwater beneath their property. Furthermore, as discussed in Section D1.6.3.3 below, ADI undertakes to conduct further research to determine guidelines for maximum nitrate and sulphate concentrations and irrigation volumes for application to domestic gardens in the affected area. Groundwater Exceeding Drinking Water Guidelines: The area in which groundwater concentrations for nitrate and sulphate exceed the adopted guidelines for drinking water (50 mg/L for nitrate and 500 mg/L for sulphate) is depicted on Figure 1.

Within this area, (but outside of the area exceeding stock watering guidelines), groundwater is suitable for stock watering, subject to the guidelines in Section D1.6.3.4. Although groundwater within some of this area exceeds the adopted AWQG nitrate range for irrigation of 22 – 554 mg/L (as nitrate) (note that there is no clear sulphate guideline for irrigation use), it is considered likely that the groundwater in this area is suitable for irrigation of some plants, given that several domestic extraction bores continue to be used for irrigation without noticeable effects (see Section D1.6.3.3 below).




Groundwater within the area of drinking water guideline exceedence for nitrate and sulphate is not suitable for potable (drinking) water supply.

With respect to the maintenance of aquatic ecosystems, the impact identified as being sourced from the ADI facility does not and is not expected in the future to reach the aquatic ecosystems of the Murray River and its adjacent billabong system. The residential properties in the impacted area and those generally located to the south and south west of the site are connected to mains water and/or rainfall is collected and stored in water tanks. Therefore there is no reliance of the residents on groundwater as a drinking water supply or for primary contact water (swimming pools etc). It is also understood that none of the landholders concerned use the groundwater as a drinking water or swimming pool water supply. Industrial water use criteria have not been adopted for the investigation on the basis that the AWQG lists very specific industrial processes, which may or may not be applicable to the future use of the site. If a resident of property within the plume area intends to use groundwater for an industrial use, further assessment of the impact of groundwater quality on the industrial process should therefore be completed. However, it is worth noting that industrial activities are not consistent with the zoning of the land within the plume area under the Corowa Planning Scheme. Potential adverse impact on buildings and structures is assessed on a site specific basis and generally not relevant for this investigation. As the depth to contaminated groundwater is greater than 5m, it is unlikely that structural footings will be exposed to elevated sulphate and highly saline groundwater. Given the predominantly rural setting, there may be a potential for high sulphate (and potentially moderately low pH or corrosive waters), which may affect concrete structures if applied during irrigation etc. The most likely scenarios for impact to concrete structures are long-term storage of groundwater with high levels of sulphate and low pH within concrete tanks or troughs, and possibly repeated long-term washing of concrete slabs. The following precautions are recommended for groundwater use under either of these scenarios: • Non-concrete construction materials are preferred for any proposed tank or trough

structures for groundwater storage, such as polyethylene tanks. Otherwise the concrete structures should be polymer coated or appropriately painted. Products such as some proprietary concrete pipes and interceptor traps etc are known to be available with such coating, otherwise appropriate paints and coatings are available.

• Concrete structures in regular or constant contact with groundwater should be inspected at

least once every two years for indications of corrosion and degradation. If any such indications are observed and there is any uncertainty, advice from the supplier should be sought as to whether the structure requires repair or replacement.




Remainder of the Study Area: The results of the studies completed to date indicate that groundwater in the remainder of the study area (outside of the impacted area depicted on Figure 1), is suitable for the following uses:

• Potable (drinking) water supply.

• Potable mineral water supply.

• Irrigation of agriculture, parks and gardens (subject to the guidelines in Section D1.6.3.3).

• Stock watering (subject to the guidelines in Section D1.6.3.4).

• Industrial Water Use.

• Primary Contact Recreation.

• Buildings & Structures. Groundwater within some of the remaining study area may not be suitable for the maintenance of ecosystems, however as discussed above, impact from the ADI facility is not expected to reach the Murray River or its billabongs.

D1.6.3.3 Guidelines for Irrigating with Impacted Groundwater There remains some uncertainty regarding irrigation guidelines for both sulphate concentrations (for which no clear guidelines are provided in AWQG) and nitrate concentrations (for which the AWQG guidelines 22 – 554 mg/L (as nitrate) may be overly conservative for domestic garden applications). ADI therefore undertakes to conduct further research to clarify long-term guidelines for maximum nitrate and sulphate concentrations and irrigation volumes for application to domestic gardens in the affected area. When available the recommendations from this research will be provided to groundwater users in the affected area. In the mean time, it is understood that the groundwater abstraction users within the impacted area and the study area overall understand the limitations associated with using the groundwater to irrigate gardens and lawns. For some time landowners have successfully irrigated using the groundwater, even though it often exceeds the lower (22 mg/L) guideline and is sometimes high in the guideline range (up to 487 mg/L compared with the upper guideline of 554 mg/L nitrate (as nitrate)) for irrigation. Observations by landowners indicate that many plant species seem to benefit from the nutrient rich water. A number of residents have planted out their property with exotic/non native plant species, which have more of a tolerance to elevated nitrate than native Australian plant species. There are also likely to be available local indigenous species that have little or no requirement for irrigation and there may be other native Australian plant species available (such as certain types of eucalypt and banksia species) with a relatively higher tolerance to nitrate. As the potential for leaf burn from elevated TDS and sulphate in water has been realised, residents who use the groundwater to irrigate their gardens tend to water after the most intense heat during the day or after daylight hours.




In summary, the following measures should be adopted when using the impacted groundwater for irrigation: • In the interests of preserving natural biodiversity and conserving water resources, consider

the selection of local indigenous species that have little or no requirement for irrigation.

• Otherwise consider the selection of exotic and/or native plant species that are expected to have a relatively higher tolerance to nitrate.

• Water after the most intense heat during the day or after daylight hours.

• If a visible salt build-up occurs on the leaves of plants, use tap or tank water to gently wash the leaves.

• If vegetation shows signs of distress suspected to be due to watering with impacted groundwater, temporarily use tap or tank water for irrigation and gradually return to groundwater to observe whether the plant/s are able to develop a tolerance.

• Apply fertiliser in accordance with local nursery / horticulture advice, to balance out the nitrate derived from the groundwater.

• If necessary consider the use of tap or tank water on more sensitive plants, while using groundwater on more tolerant species on the property concerned.

D1.6.3.4 Guidelines for Stock Watering with Impacted Groundwater The investigation results to date indicate that in accordance with the AWQG guidelines, groundwater outside of the exceedence area depicted on Figure 1 may be used for watering stock. Discussion on the derivation of AWQG guidelines for stock watering refers to observations on the effects of nitrate and sulphate on cattle and pigs, however the guideline document does not clearly indicate how the trigger levels (400 mg/L for nitrate and 1,000 mg/L for sulphate) were determined. Literature and studies in this field often indicate that poultry may be more sensitive to many types of contamination. The following precautions are recommended when using impacted groundwater for stock watering: • Groundwater from within the exceedence area depicted on Figure 1 should not be used for

stock watering (at the time of writing only one land owner extraction is known to have exceeded stock watering guidelines in the past and concentrations since 1998 have reduced to fall within the guidelines).

• Care should be taken if use of groundwater from within the drinking water exceedence area

depicted on Figure 1 is proposed for watering poultry or new born stock. The water should preferably be mixed with 50% tap water prior to watering animals in these categories.

• Use of high nitrate level stock feeds such as pea straw and pasture irrigated with treated

effluent should be avoided while stock are being watered with impacted groundwater.




D1.6.3.5 Ongoing Groundwater Monitoring ADI undertakes to continue monitoring the groundwater beneath the site and the study area twice a year. Regular review of the monitoring programme in consultation with the Auditor (Dr Peter Nadebaum), community consultative group and other stakeholders will be undertaken to establish any trends that develop in monitoring results and to ensure that all affected domestic extraction bores are included, along with an optimal selection of monitoring wells and appropriate analytes for testing. The monitoring will be conducted as two separate programmes comprising the following:

• All known domestic groundwater abstraction bores in the study area, monitored to inform land owners of recommended uses for their bore water.

• A selection of the monitoring well network, to monitor attenuation of the broader plume. The results of the groundwater monitoring will be used to prepare an annual review of the groundwater impact, including discussion on any observations that might indicate natural attenuation or migration of the contamination. As discussed in Section D1.6.3.1 above, the monitoring results will also be used to confidentially inform bore owners of the quality of their groundwater and recommended allowable uses of the groundwater, twice a year.


Groundwater monitoring Sampling and analysis of abstraction bores and selected bores from the monitoring network

Twice a year (once every six months)

The bores that will be monitored as part of the on-going groundwater program to monitor natural attenuation will be as follows: Onsite Groundwater Monitoring Bores

Shepparton Formation BH09, BH11, BH12, BH20A, BH28R, BH83, BH84, BH85, BH86, BH87, BH88, BH93A, BH94A, BH95A, BH97B

Calivil Formation BH20B, BH58, BH93B, BH94B, BH95B, BH96B

Offsite Groundwater Monitoring Bores

Shepparton Formation




BH22A, BH48A, BH49A, BH62, BH75, BH78, BH79

Calivil Formation BH22B, BH47B, BH48B, BH49B, BH53B, BH54B, BH55B, BH56B, BH74B

Floodplain Aquifer BH52, BH53A, BH54A, BH55A, BH56A, BH74A, BH77C, BH92

The bores were selected based on historical elevated results and there position within the in the plumes. Other bores were selected from the Floodplain Aquifers to put a bound on the plume to the south and south west of the site. The frequency of sampling will be reviewed by ADI in consultation with NSW EPA and the community consultative group. Groundwater samples will be analysed for the following chemical and biogeochemical parameters and analytes: • Electrical Conductivity (EC); • pH; • Dissolved Oxygen (DO); • Reduction/Oxidation (Redox) Potential - Eh; • Temperature; • Total Dissolved Solids (TDS) • Sulphate and sulphide; • Nitrate, nitrite and ammonium; • Manganese; • Phosphorus; • Total Organic Carbon (TOC); and • Speciated ferrous iron (Fe2+) The chemicals were selected to monitor for natural attenuation and determine whether there are increasing or decreasing trends, potentially indicating that the plume is changing in size. The number of chemicals for analysis will be reviewed by ADI in consultation with NSW EPA and the community consultative group.

D1.6.5 Reporting • Confidential report to bore owners on groundwater quality and recommended allowable

uses of the groundwater, twice a year.

• Annual monitoring review report as discussed above, to be made available to NSW EPA and the public.



D006005_RPT236Rev03_17Dec03_AppendixD1

Figures

ADI Limited

FIGURE

1PROJECT FILE NAME

D0060DATE

OCT 2003DRAWN

SRAPPROVED

Mulwala

GROUNDWATER USE RESTRICTION AREAS LONG-TERM ENVIRONMENTAL MANAGEMENT PLANCONTAMINATION MANAGEMENT PLAN

War

atah

Roa

d

Bayley Street

Luca

n Stre

et

Dunmore Street

Leigh

Stre

et

Edward Street

Morris Road

Chickasaw Drive

MURRAYRIVER

The Black Hole

Albi

on R

oad

Albion RoadArdeer Road

Longlea Road

406,000

406,000

407,000

407,000

408,000

408,000

409,000

409,000

410,000

410,000

6,015,000

6,015,000

6,016,000

6,016,000

6,017,000

6,017,000

6,018,000

6,018,000

6,019,000

6,019,000

Surface Water Body

Legend

Site Boundary

Groundwater not suitable for drinking or stock watering

Groundwater not suitable for drinking

Boundary of long term EMP Area

I0 200 400 600100

Meters


D006005_RPT236Rev03_17Dec03

Appendix D2 Remediation Environmental Management Plan

ADI Mulwala Contamination Management Project CONTAMINATION MANAGEMENT PLAN Appendix D2 – Remediation Environmental Management Plan 17 December 2003 Prepared for: Department of Defence and ADI Limited Bayley Street, Mulwala, NSW 2647 Report by: HLA-Envirosciences Pty Limited ABN: 34 060 204 702 46 Clarendon Street Melbourne VIC 3205 Australia Ph: +61 3 8699 2199 Fax: +61 3 8699 2122 HLA Ref: D006005_RPT236Rev03_17Dec03_AppendixD2


Appendix D2 – Remediation Environmental Management Plan

D006005_RPT236Rev03_17Dec03_AppendixD2 i

CONTENTS D2 APPENDIX D2 - REMEDIATION ENVIRONMENTAL MANAGEMENT

PLAN............................................................................................................................1 D2.1 INTRODUCTION...........................................................................................1

D2.1.1 Scope .............................................................................................1 D2.1.2 Objectives.......................................................................................1 D2.1.3 Summary of Remediation Environmental Management

Issues.............................................................................................2 D2.1.4 Sources for Background Information ..............................................2

D2.2 SITE CONTACT DETAILS............................................................................3 D2.2.1 Issues.............................................................................................3 D2.2.2 Objectives.......................................................................................3 D2.2.3 Management Strategy / Actions......................................................3 D2.2.4 Monitoring.......................................................................................3 D2.2.5 Reporting........................................................................................3

D2.3 EMERGENCY CONTACT DETAILS.............................................................4 D2.3.1 Issues.............................................................................................4 D2.3.2 Objectives.......................................................................................4 D2.3.3 Management Strategy / Actions......................................................4 D2.3.4 Monitoring.......................................................................................4 D2.3.5 Reporting........................................................................................4

D2.4 ENVIRONMENTAL MANAGEMENT RESPONSIBILITIES...........................5 D2.4.1 Issues.............................................................................................5 D2.4.2 Objectives.......................................................................................5 D2.4.3 Management Strategy / Actions......................................................5 D2.4.4 Monitoring.......................................................................................6 D2.4.5 Reporting........................................................................................6

D2.5 COMMUNICATIONS PLANNING AND COMPLAINTS MANAGEMENT ............................................................................................7 D2.5.1 Issues.............................................................................................7 D2.5.2 Objectives.......................................................................................7 D2.5.3 Management Strategy / Actions......................................................7 D2.5.4 Monitoring.....................................................................................10 D2.5.5 Reporting......................................................................................10

D2.6 TRAINING AND AWARENESS ..................................................................11 D2.6.1 Issues...........................................................................................11 D2.6.2 Objectives.....................................................................................11 D2.6.3 Management Strategy / Actions....................................................11 D2.6.4 Monitoring.....................................................................................11 D2.6.5 Reporting......................................................................................11



D006005_RPT236Rev03_17Dec03_AppendixD2 ii

D2.7 HOURS OF OPERATION ...........................................................................12 D2.7.1 Issues...........................................................................................12 D2.7.2 Objectives.....................................................................................12 D2.7.3 Management Strategy / Actions....................................................12 D2.7.4 Monitoring.....................................................................................12 D2.7.5 Reporting......................................................................................12

D2.8 EMERGENCY AND INCIDENT RESPONSE PLANNING...........................13 D2.8.1 Issues...........................................................................................13 D2.8.2 Objectives.....................................................................................13 D2.8.3 Management Strategy / Actions....................................................13 D2.8.4 Monitoring.....................................................................................13 D2.8.5 Reporting......................................................................................14

D2.9 STORMWATER MANAGEMENT AND EROSION CONTROL ...................15 D2.9.1 Issues...........................................................................................15 D2.9.2 Objectives.....................................................................................15 D2.9.3 Management Strategy / Actions....................................................15 D2.9.4 Monitoring.....................................................................................16 D2.9.5 Reporting......................................................................................16

D2.10 SOIL MANAGEMENT .................................................................................17 D2.10.1 Issues 17 D2.10.2 Objectives.....................................................................................17 D2.10.3 Management Strategy / Actions....................................................17 D2.10.4 Monitoring.....................................................................................18 D2.10.5 Reporting......................................................................................18

D2.11 CONTAMINATED GROUNDWATER MANAGEMENT...............................19 D2.11.1 Issues 19 D2.11.2 Objectives.....................................................................................19 D2.11.3 Management Strategy / Actions....................................................19 D2.11.4 Monitoring.....................................................................................19 D2.11.5 Reporting......................................................................................19

D2.12 NOISE CONTROL PLANNING ...................................................................20 D2.12.1 Issues 20 D2.12.2 Objectives.....................................................................................20 D2.12.3 Management Strategy / Actions....................................................20 D2.12.4 Monitoring.....................................................................................21 D2.12.5 Reporting......................................................................................21

D2.13 DUST CONTROL PLANNING ....................................................................22 D2.13.1 Issues 22 D2.13.2 Objectives.....................................................................................22 D2.13.3 Management Strategy / Actions....................................................22



D006005_RPT236Rev03_17Dec03_AppendixD2 iii


D2.14 ODOUR CONTROL PLANNING.................................................................23 D2.14.1 Issues 23 D2.14.2 Objectives.....................................................................................23 D2.14.3 Management Strategy / Actions....................................................23 D2.14.4 Monitoring.....................................................................................23 D2.14.5 Reporting......................................................................................23

D2.15 OCCUPATIONAL HEALTH AND SAFETY PLANNING .............................24 D2.15.1 Issues 24 D2.15.2 Objectives.....................................................................................24 D2.15.3 Management Strategy / Actions....................................................24 D2.15.4 Monitoring.....................................................................................25 D2.15.5 Reporting......................................................................................25

D2.16 DATA AND INFORMATION MANAGEMENT.............................................26 D2.16.1 Issues 26 D2.16.2 Objectives.....................................................................................26 D2.16.3 Management Strategy / Actions....................................................26

D2.16.3.1 Document Control .....................................................26 D2.16.3.2 Data Collection and Storage .....................................26 D2.16.3.3 Data Verification and Data Validation........................26


D2.17 GENERAL REPORTING REQUIREMENTS ...............................................28 D2.17.1 Issues 28 D2.17.2 Objectives.....................................................................................28 D2.17.3 Management Strategy / Actions....................................................28

D2.17.3.1 Progress Reporting...................................................28 D2.17.3.2 Project Reporting ......................................................29






D2 APPENDIX D2 - REMEDIATION ENVIRONMENTAL MANAGEMENT PLAN

D2.1 INTRODUCTION

D2.1.1 Scope This Remediation Environmental Plan (REMP) is concerned with the management of the remediation activities proposed in the body of the CMP report, in order to minimise the potential for environmental impact during the remediation activities proposed for known nitrate and sulphate contamination of groundwater. This impact extends south and south west of the ADI Explosives and Propellants facility, Bayly Street, Mulwala and includes known nitrate and sulphate impact to soils on-site beneath the facility. It is intended that this document also overlap and be referenced in conjunction with the following:

• Appendix D1 – Long Term Environmental Management Plan (LTEMP);

• Appendix D3 – Contingency Management Plan (Contingency MP);




During any remediation works, the measures outlined in the LTEMP and Contingency MP will still apply, in addition to those outlined in this REMP.

D2.1.2 Objectives The objectives of this REMP are summarised as follows: • To provide a summary of the potential environmental issues anticipated to require

management during the contamination management / remediation measures outlined in the body of the CMP report.

• Outline the necessary management strategies, actions, monitoring and reporting measures

to be undertaken during the proposed remediation activities. • To minimise the risk of those activities contributing any further impact to the environment

and to meet the environment protection expectations of Government authorities and the community.

• To minimise safety risks and inconvenience to operations at the facility and the community,

including nearby residents relating to the proposed remediation activities.

1 ADI Mulwala Environmental Management System Manual - 2000




• To meet standard industry practice in reporting guidelines for Remediation Site Management Plans, such as outlined in the NSW EPA Guidelines for Consultants Reporting on contaminated sites (NSW EPA, 1998).

More specific objectives, such as minimisation of sediment, nitrate and sulphate load to stormwater during remediation works etc are provided for each of the issues identified and addressed in Section 2.9 to follow.

D2.1.3 Summary of Remediation Environmental Management Issues The following issues are anticipated to require environmental management during the contamination management and remediation activities proposed in the body of the CMP report and are addressed in Sections D2.4 to D2.17 inclusive to follow:

• Environmental Management Responsibilities

• Community Relations and Complaints Management

• Site Contact Details

• Emergency Contact Details

• Training and Awareness

• Hours of Operation

• Emergency and Incident Response Planning

• Stormwater Management and Erosion Control

• Contaminated Groundwater Management

• Soil Management Planning

• Noise Control Planning

• Dust Control Planning

• Odour Control Planning

• Occupational Health and Safety Planning

• Data and Information Management

• Reporting

D2.1.4 Sources for Background Information Since the late 1980s several investigations have been conducted to date on the groundwater contamination and impacted soil on-site beneath the facility, culminating in the CMP that is the main body of this report. Pertinent background information on the site and the contamination, such as the regulatory framework, extent of contamination and planned measures to manage the contamination is provided either within the body of the CMP report or in the documents listed in the CMP document.




D2.2 SITE CONTACT DETAILS

D2.2.1 Issues Site contact details are required to enable all stakeholders to contact ADI for any communications purposes.

D2.2.2 Objectives To provide site contact details to external stakeholders

D2.2.3 Management Strategy / Actions Site contact details are as follows:

Table 1: Site Contact Details

Site Address ADI Limited Bayly Street

Mulwala NSW 2647

Contact Name Mr Doug Wilson Environmental Manager - Propellants, Explosives and Chemicals

Contact Phone No. B.H. (03) 5742 2479

A.H. (03) 5742 2301

D2.2.4 Monitoring Not Applicable

D2.2.5 Reporting Not Applicable




D2.3 EMERGENCY CONTACT DETAILS

D2.3.1 Issues Contact details for emergencies should be prominent and easily available.

D2.3.2 Objectives To provide easily accessible contact details for any emergency that might arise.

D2.3.3 Management Strategy / Actions Emergency contact details are as follows:

Table 2: Emergency Contact Details

Ambulance 000

Police 000

Fire Brigade 000

EPA NSW (02) 6022 0606 Poisons Information Centre 131126

ADI Gatehouse B.H. (03) 5742 2301

ADI Emergency A.H.. (03) 5742 2301

D2.3.4 Monitoring Incident reporting required in the event of any accident, incident, emergency or near miss, as discussed in Section D2.15 (Occupational Health and Safety Planning).

D2.3.5 Reporting None required.




D2.4 ENVIRONMENTAL MANAGEMENT RESPONSIBILITIES

D2.4.1 Issues It is necessary to document a structure for environmental management responsibilities, to ensure that all aspects of remediation environmental management planning are allocated to specific positions and roles. This helps to ensure that the management measures outlined are put into place.

D2.4.2 Objectives The objective of this component of the REMP is:

• To outline the main roles and responsibilities relating to environmental management measures as they will apply during any contamination management and remediation activities.

D2.4.3 Management Strategy / Actions The following summarises the main roles applicable to the proposed contamination management and remediation activities:

Project Manager ADI Limited

Contractors / Consultants To be determined

Environmental Auditor Dr Peter Nadebaum, GHD Pty Limited

ADI Mulwala Community Liaison Committee

Corowa Shire Council

NSW Environmental Protection Authority

Stakeholders

NSW Department of Infrastructure, Planning and Natural Resources

It is assumed that during the implementation of contamination management and remediation measures, that various Contractors will be involved with the project. Responsibility for all management (including OH&S and environmental management) activities that a Contractor carries out rests with that Contractor. ADI Limited (ADI) shall be responsible for the following: • Ensuring that the Contractor is contractually bound to take responsibility for the

environmental management of the work area in accordance with this REMP as a minimum and in accordance with the Contractor’s own REMP and OHS plans.

• Periodic monitoring to ensure that the Contractor is carrying out its environmental

management responsibilities during the course of the project. • Reviewing and if necessary updating this REMP every five years and/or in the event that

circumstances relating to the expected program of contamination management measures changes significantly.

• Any other responsibilities allocated to ADI in this REMP.




The Contractor shall appoint a Site Manager, who will be responsible for the following: • Complying with all aspects of this REMP including reporting to ADI and other authorities as

required and including the issuing of its own REMP and OHS plan taking into account the specific design parameters, construction methodology, legal framework and responsibility structures determined during the commissioning process.

• Ensuring that a clear hierarchy of authority and responsibility for environmental

management is documented and communicated throughout its workforce. • Ensuring that all personnel are appropriately inducted prior to commencing work on the site.

The induction shall include appropriate environmental awareness training (commensurate with the roles and responsibilities of personnel) and training in the issues and implementation of this REMP.

• Ensuring that regular and open communications and all environmental reporting

requirements to ADI and other authorities as required are complied with. • Ensuring that any Emergency Response and OHS requirements are implemented as

outlined in Section D2.15 to follow. Copies of this REMP should be kept on-site at the Facility and by the Contractor in the work area and be available for inspection by any employee, or agent working at the premises on behalf of ADI. A copy of the REMP should be placed in the library to allow the community of Mulwala to be aware of the mitigation measures planned for any contamination management and remediation activities.

D2.4.4 Monitoring None required for the purposes of allocating Environmental Management Responsibilities.

D2.4.5 Reporting None required for the purposes of allocating Environmental Management Responsibilities.




D2.5 COMMUNICATIONS PLANNING AND COMPLAINTS MANAGEMENT

D2.5.1 Issues It is necessary for ADI to maintain communications with the community and other stakeholders. As part of this it is also necessary to maintain a register of any complaints from nearby residents, other community members or stakeholders, to ensure that any such complaints are appropriately addressed.

D2.5.2 Objectives To provide open communications to the community and stakeholder authorities and provide an appropriate response to any complaints received.

D2.5.3 Management Strategy / Actions • ADI undertakes to arrange meetings with the community liaison group / landowners

committee at least twice a year, with the frequency of meetings to be reviewed in consultation with the group at the end of 2004. Upon request by ADI, Contractors shall attend and present to the liaison committee on the progress of contamination management and remediation projects.

• ADI undertakes to facilitate a presentation open to the community at least once a year, with the frequency of presentations to be reviewed in consultation with the community consultative group. Upon request by ADI, Contractors shall attend and present to the community on the progress of contamination management and remediation projects.

• Where appropriate, ADI will include appropriate contact names and phone numbers on any correspondence or reports issued to the public and stakeholder authorities, for the purposes of communications. The appropriate contact for communications for environmental issues is listed in Section 2.2.3 above.

• In accordance with EP Licence No. 4848 and the EMS, ADI will continue to maintain a telephone complaints line and a register to record and manage any complaints received, including documentation of the response to each complaint on the Environmental Complaint Form below, to the point of closure for each instance. Complaints made to ADI or any employee or agent working at the premises on behalf of ADI shall be documented.

• ADI will notify the public as appropriate of its’ complaints line so that the community knows

how to make a complaint.

• As stated in Section M4 of the Environment Protection Licence (Licence No. 4848, File No.

240136) the record must include details of the following:

− The date and time of the complaint;

− The method by which the complaint was made;

− Any personal details of the complainant which were provided by the complainant or, if no such details were provided, a note to that effect;

− The nature of the complaint;




− The action taken by the licensee in relation to the complaint, including any follow-up contact with the complainant; and

− If no action was taken by the licensee, the reasons why no action was taken. • The form to follow shall be used to ensure that all of the above information is appropriately

recorded. • ADI will allocate an appropriate “Investigating Officer” to complete the response to any

complaints and report the findings in “Investigating Officer’s Comments” section of the Environmental Complaint Form.

• After completing the Environmental Complaint Form the Investigating Officer will report the findings to ADI management for endorsement prior to reporting to the complainant.

• ADI undertakes to provide this response to the complainant within a period of 14 days. • The Environmental Complaints Form shall then be filed in the Complaints Register and the

record of complaint must be kept for at least 4 years after the complaint was made. • The number and nature of complaints will be discussed as a recurring agenda item at

community liaison meetings.




The following Environmental Complaints Form will be used: ENVIRONMENTAL COMPLAINT FORM Complainants Name:......................................................................................... Address: ........................................................................................................... Telephone Number:

(H) ................................

(w).................................

Date:......./......./.......

Complaint Number:

Description of complaint: .................................................................................. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... Is the problem occurring now? Y / N Has a complaint been lodged with ADI previously? Y / N Taken by: ...................................

Time: .................. am/pm

Investigated by: ..........................

Time: .................. am/pm

Investigating Officer’s Comments: .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... Signature:...................................................... Date: ....../......../........ Action Taken: .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... Signature:....................................................... Date: ......./......./.......





Monitoring for appropriateness of complaints response and closure.

Internal evaluation by ADI Quality Manager.


D2.5.5 Reporting • Environmental Complaints Forms and register, see above.




D2.6 TRAINING AND AWARENESS

D2.6.1 Issues It is important for all personnel and Contractors associated with contamination management and remediation activities to understand any environmental risks that their work might involve and to know their obligations for environment protection.

D2.6.2 Objectives To provide a plan for ensuring that personnel and Contractor employees are adequately aware of environmental issues commensurate with their role in any contamination management and remediation activities.

D2.6.3 Management Strategy / Actions All personnel working on contamination management and remediation projects will be required to complete the following inductions and training:

• The existing site induction for the ADI facility, including Personal Protective Equipment (PPE), emergency procedures and assembly points and restrictions for operating on site;

• A job hazard analysis and training for Contractors working on site; and

• An environmental induction to outline environmental requirements and appropriate practices.


Check of personnel induction records.

Internal check by ADI including Contractor personnel working off-site.


D2.6.5 Reporting Induction register to be kept listing personnel who have completed the ADI site induction (responsibility of ADI) and separate inductions for specific remediation projects (responsibility of Contractors).




D2.7 HOURS OF OPERATION

D2.7.1 Issues Restriction of hours of operation for contamination management and remediation activities will assist to avoid noise and activity related inconvenience for neighbours and will assist compliance with any noise limitations of ADI’s licence for the facility.

D2.7.2 Objectives To minimise inconvenience to neighbours, complaints and non-compliance associated with hours of operation for contamination management and remediation activities.

D2.7.3 Management Strategy / Actions Any contamination management and remediation activities shall operate between the following hours:

• Monday to Friday – 7 am to 6 pm; and

• Saturday – 7 am to 1 pm

No works shall be conducted outside of these hours without written authorisation from ADI Limited.


Periodic check to ensure that no Contractor activity continues after hours.

Internal check by ADI. Quarterly (every 3 months) while projects are in progress.

D2.7.5 Reporting None required




D2.8 EMERGENCY AND INCIDENT RESPONSE PLANNING

D2.8.1 Issues An emergency response plan is required to deal with potential incidents that may occur on-site or outside of the facility and may cause harm to the environment.

D2.8.2 Objectives To minimise the risk of impact to the environment in the event of an incident associated with the contamination management or remediation activities, such as a spill incident or fire.

D2.8.3 Management Strategy / Actions An emergency response plan shall be prepared by Contractors for all activities associated with contamination management and remediation activities, to deal with potential incidents that may occur on-site or outside of the facility that might cause harm to the environment. The document must include procedures for dealing with anticipated potential incidents associated with the specific activity proposed, such as:

• Spills;

• Explosions; or

• Fire.

Any incidents that cause impact to or threaten the environment are to be reported to the EPA in accordance with the EPA Licence for the ADI facility. In the event of any accident, incident, emergency or near miss, an incident report form must be completed (see Example in Section D2.8.5). Completion of the form is the responsibility of the Employer involved with the incident, be it the Contractor or ADI. ADI shall allocate an investigation officer to ensure that the incident is adequately reported and that every opportunity is taken to learn from the incident and implement corrective action to avoid a recurrence. The Contractor shall take responsibility for closure of any incident report that it is involved with and co-operation with ADI in all aspects of safety and incident reporting. ADI shall maintain a register of incident reports.

D2.8.4 Monitoring None required




D2.8.5 Reporting Emergency response plan required from each Contractor for each contamination management / remediation activity proposed. In the event of any accident, incident, emergency or near miss, an incident report form must be completed and filed by those involved with the incident (responsibility of the employer associated with the incident). The following example Emergency Incident Report Form will be used, in addition to any incident report formats and requirements that ADI may have associated with site operations: Report No. ...........

Fire [ ] Spill [ ] Injury / Accident [ ]

Start of Incident

Date:..................

Time:..................

End of Incident

Date:..................

Time:..................

Incident reported to Site Supervisor

Date:..................

Time:..................

Incident Description (include cause of incident, any external authorities notified, details of any injuries, any contaminants released and quantity): .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... Actions Taken: .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ........................................................................................................................... Reported by: .................................................. (print name) Signature:....................................................... Date: ......./......./.......




D2.9 STORMWATER MANAGEMENT AND EROSION CONTROL

D2.9.1 Issues During any contamination management and remediation activities, preventative measures are required to minimise the risk of erosion, sediment mobilisation and nitrate / sulphate discharge to surface water drainage.

D2.9.2 Objectives • Minimise the sediment, nitrate and sulphate load to stormwater during earthworks and any

other contamination management and remediation activities.

D2.9.3 Management Strategy / Actions Any earthworks, construction or demolition works proposed at the site shall be managed in accordance with the following guidelines as a minimum:

• Protection of the Environment Operations Act (1997).

• "The Blue Book" – NSW Department of Housing, Production Division, "Managing Urban Stormwater: Soils and Construction", 1998.

• EPA Victoria Publication 480, Environmental Guidelines for Major Construction Sites, December 1995.

• EPA Victoria Publication 275, Construction Techniques for Sediment Pollution Control, May 1991.

• Victorian Department of Conservation Forests & Lands, Control of Erosion on Construction Sites, December 1987.

The DIPNR is responsible for reviewing matters pertaining to stormwater management and erosion control under the Soil Conservation Act (1938) and therefore would like to be involved in reviewing any specific management plans proposed for the site.

In the event of any such works, the management of stormwater should aim to prevent and / or minimise runoff from the site and measures should include the following:

• Diverting water around the sites and working areas. Where practical sediment and erosion control structures will be installed including diversion berms and silt / sediment fences, prior to commencing disturbance earthworks.

• Where appropriate construct diversion berms at a low angle to the contour of the slope and drain away (down stream) from the site and into stable vegetation or erect a silt fence at the outlet point.

• Covering any stockpiles and containing runoff from potentially contaminated areas.

• In areas that do not present contamination issues filtration and removal of suspended silt from runoff waters by appropriate sediment control measures that may include silt fences, diversion bunds or settling ponds etc.

• The period that soil is left exposed to erosion shall be minimised where possible.




• Placement of geofabric, crushed rock and temporary tiling cover is required in unpaved areas where frequent vehicle, machinery and personnel will occur.

• Where practical the area of disturbance shall be restricted, and clearly demarcated, including working areas, access tracks and soil stockpile sites.

• Strip topsoil and stockpile separately from subsoil prior to commencing construction / remedial activities or in areas of high traffic movement.

• Soil / clay / rock / gravel transported onto site should be sourced locally where practicable and certified to be weed free.

• If stockpiles are to remain exposed for a long period of time these should be revegetated or covered to prevent erosion.

Planning and designing the working area for any earthworks, construction or demolition projects should include:

• Siting of soil stockpiles away from drainage lines.

• Ensuring adequate separation between stockpiles of topsoils, subsoils and construction clays to avoid mixing.

• If practicable siting of stockpiles upslope of excavations so that these may act as sediment sumps for runoff.

• Locating sediment / silt fences on the downslope side of soil stockpiles.

• Siting of water diversion structures (diversion bunds) upslope of the worksite and locally diverting water around the working area so that runoff from the site is minimised to catchment rainfall only.

• Placing appropriate diversion berms at the toe of the construction site or planning for a suitable configuration of sediment / silt fences.

• Where practicable using geofabric and crushed rock to prevent erosion in drains, to surface important access ways and to remove soil from the wheels of vehicle exiting the working sites.


Stormwater diversion features where appropriate


Silt fences, bunds & settlement ponds as required


Soil stockpiles covered Surveillance Weekly during any earthworks or construction

Excavation sites Surveillance for erosion and adequacy of mitigation


Maintenance of disturbed areas

Surveillance for adequacy of mitigation


Rehabilitation of excavation sites and disturbed ground

Surveillance for adequacy Following works and weekly for 3 months after completion

D2.9.5 Reporting Incident reporting if any sediment / contamination is released off-site or to the Murray River catchment via stormwater discharge.




D2.10 SOIL MANAGEMENT

D2.10.1 Issues Based on the nature of the contaminants, the nitrate and sulphate impacted soil is unlikely to represent a significant exposure risk to workers at the site. However in the event that any excavation of soil is carried out in areas known or suspected to contain contamination, it is important to re-evaluate and ensure that the extent of investigation in the area concerned is sufficient to characterise the soil:

• For exposure risk to workers (more so due to potential low pH and metals etc, than nitrate and sulphate); and

• To determine how to manage the excavated soil (for example to determine whether it is suitable for re-use on-site or whether it requires remediation or disposal to an appropriately licensed facility off-site).

The other main issues associated with soil contamination relate to infiltration to groundwater and mobilisation to surface water, both addressed in Sections D2.9, above.

D2.10.2 Objectives • To ensure that any risks to human health and the environment due to contaminated soil at

the site remain negligible at all times.

• To minimise the potential for soil contamination to be spread into areas that are currently free of contamination.

D2.10.3 Management Strategy / Actions • If any excavation is proposed in areas of known or suspected contamination, re-evaluation

of previous investigations will first be carried out to ensure that the soil is adequately characterised for exposure risk to workers and to determine how to manage the soil after it is excavated.

• Workers excavating soil will wear appropriate personal protective equipment (PPE) for the level of contamination determined, which will include as a minimum no skin contact and appropriate dust suppression.

• Any soil excavation will be managed in accordance with the measures outlined above. The following management measures shall be implemented to manage soil that is identified to be contaminated in excess of the adopted guidelines for industrial land use (NEPM F). Most of these measures are not considered necessary for the management of soil that is impacted only with nitrate and sulphate: • There may be circumstances under which contaminated soil can be re-used (but buried to

avoid exposure risk) and/or remediated on-site. Any proposed remediation of contaminated soil on-site shall be carried out in accordance with the NSW EPA Control of the Environment (Operations) Act (May 1999) and Guidelines on the Assessment, Classification and Management of Liquid and Non-Liquid Wastes.

• Any proposal to dispose of contaminated soil off-site shall be carried out in accordance with these guidelines, including adequate validation of the environmental quality of the soil to determine how and where it should be disposed.




• Any excavated contaminated soils will be kept separate from stockpiles of other materials and be appropriately labelled (i.e. contaminated, imported clay, topsoil etc, date of placement). Material tracking forms will be used to track the movement of the soil until it reaches its destination.

• To prevent cross contamination of underlying soils, hardstand areas should be used to stockpile contaminated soil. If hardstand areas are unavailable a low permeability liner should be placed underneath stockpiles. Appropriate diversion berms or bunding should be constructed around any contaminated soil stockpiles and they should be covered to prevent contamination of surface waters and runoff.

• All vehicles in contact with contaminated materials must be washed prior to leaving the site and any wastewater generated from the cleaning of these vehicles should either be used to control dust or discharged to sewer under an appropriate licensing agreement. Since this washdown water may contain contaminants, the preference should be to use it to wet-down contaminated material, or otherwise consult a land contamination expert prior to using it for dust control on non-contaminated areas.

• All soil / fill materials requiring offsite disposal will be transported and disposed of at an appropriate location or waste facility in accordance with statutory regulations and EPA guidelines. These include, but are not limited to:

• Control of the Environment (Operations) Act.

• NSW EPA (May 1999), Guidelines on the Assessment, Classification and Management of Liquid and Non-Liquid Wastes

• Any other pertinent legislation, guidelines or practices.

• All soil materials(crushed rock sub-base, foundation and landscaping soil) imported to the site to be used as clean fill will be required to be sampled and classified according to the NSW EPA (May 1999), Guidelines on the Assessment, Classification and Management of Liquid and Non-Liquid Wastes, NSW EPA (September 1995), Sampling Design Guidelines, NSW EPA Guidelines for Consultants Reporting on Contaminated Sites (NSW EPA, 1998) and EPAV Bulletin 448, Classification of Wastes (EPAV, 1995)


Adequate characterisation of any areas proposed for excavation where known or suspected contamination may be present.

Re-evaluate existing investigation results and supplement those if necessary with additional soil sampling.

As required

Classification and appropriate management of soil materials requiring offsite disposal

Sampling and analysis As required

D2.10.5 Reporting • Documentation will be kept to record adequate characterisation of any area proposed for

excavation or other remedial process.

• A comprehensive and professional health and safety plan will be prepared in the event that excavation of any soil found to be contaminated (in excess of NEPM F levels) is proposed.

• Documentation will be retained relating to contaminated soil transport off-site (such as waste transport certificates and disposal receipts etc).

• Validation reporting in the event that excavation is proposed as a remediation measure and soil sampling is carried out to confirm that the works have successfully remediated the target area.




D2.11 CONTAMINATED GROUNDWATER MANAGEMENT

D2.11.1 Issues Long-term management of groundwater contamination is addressed in the body of the CMP report and in the Long-Term Environmental Management Plan, Appendix D.1. Within this REMP, the scope of contaminated groundwater management is concerned only with excess water from groundwater sampling, hydrogeological pumping tests or other activities that might require abstraction of potentially contaminated groundwater.

D2.11.2 Objectives To ensure that any risks to human health and the environment due to extracted contaminated groundwater is minimised during any contamination management and remediation activities.

D2.11.3 Management Strategy / Actions Any groundwater extracted for sampling, hydrogeological pumping tests or other activities associated with contamination management or remediation activities shall be managed according to the known level of contamination in the bore based on the most recent sampling of the bore concerned. Groundwater that is below the stock watering guidelines (400 mg / L nitrate and 1,000 mg / L) may be disposed of to grassed areas or stormwater drainage. Groundwater that exceeds the stock watering guidelines must be collected in a water tanker, transported to the ADI facility and disposed of appropriately via the site effluent treatment facility. Any off-site water disposal must be undertaken in accordance with the NSW EPA (May 1999), Guidelines on the Assessment, Classification and Management of Liquid and Non-Liquid Wastes, Protection of the Environment Operations (POEO) Act (1997) and the Contaminated Land Management (CLM) Act (1997).

D2.11.4 Monitoring None required.





D2.12 NOISE CONTROL PLANNING

D2.12.1 Issues Avoiding excessive noise during contamination management and remediation activities will assist to avoid inconvenience for neighbours and compliance with noise limitations of ADI’s licence for the facility.

D2.12.2 Objectives To ensure compliance with appropriate noise guidelines during contamination management and remediation activities and in particular with the existing licence (EP Licence No. 4848) for the ADI facility.

D2.12.3 Management Strategy / Actions The noise levels during and contamination management and remediation works are not to exceed the criteria outlined in Section L6 of the Environment Protection Licence for the ADI facility. This states that noise from the premises must not exceed: • an LA10 (15 minute) noise emission criterion of 55 dB(A) 7am to 6pm Monday to Friday and

7am to 1pm Saturday; and

• an LA10 (15 minute) noise emission criterion of 45 dB(A) during the evening (6pm to 10pm) Monday to Friday; and

• at all other times, an LA10 (15 minutes) noise emission criterion of 40 dB(A), except as expressly provided by this licence.

The Licence also requires that noise from the premises is to be measured at the nearest or most affected noise sensitive area to determine compliance with this condition. Construction activities will cause a temporary increase in noise levels. Therefore, noise control measures should be implemented to reduce the impact upon the beneficial use of surrounding land(s) and ensure compliance with licence requirements. The noise associated with construction can be controlled by the following means: • Ensuring that all equipment and vehicles are fitted with effective exhaust mufflers; and

• Activities generating high noise levels are to be constrained to daylight hours between (7am to 6pm Monday to Friday and 7am to 1pm Saturday; and





Noise monitoring during remediation activities.

ADI to commission acoustics consultant.

At the commencement of works and once a month thereafter during the anticipated noisiest activities.

D2.12.5 Reporting During any contamination management and remediation activities, ADI will keep records of acoustics monitoring results and discuss a summary of those results, including any exceedence of guidelines, as a recurring agenda item at community liaison meetings.




D2.13 DUST CONTROL PLANNING

D2.13.1 Issues Remediation operations on site have the potential to generate dust during dry weather periods. The activities that may cause problems include traffic movement on unsealed roads and on working areas, vehicles transporting soils and construction materials, excavation works, drilling, earthworks and movement of stockpiles.

D2.13.2 Objectives To minimise visible dust during any contamination management and remediation activities in accordance with NSW EPA (1999), Environmental Guidelines: Assessment, Classification & Management of Liquid & Non-Liquid Wastes, June 1999.

D2.13.3 Management Strategy / Actions Dust control planning should consider seasonal weather conditions and schedule works for months with low wind prevailing winds. Measures to minimise the potential for dust generation may include:

• Covering and / or revegetating any soil stockpiles that are to remain for extended periods, or if weather forecasts predict strong winds;

• Keeping a water cart on site throughout the remediation operations to wet down access roads, working areas and exposed soil surfaces as required, using water obtained from clean sources such as mains water;

• Covering loads of soil or rock during transport to or from the site; and

• Where practicable high traffic access roads should be surfaced with gravel. The Contractor for any activity that could potentially generate dust shall prepare a dust management plan to minimise any dust generated, that will consider human health and environmental aspects.

D2.13.4 Monitoring None required unless large scale earthworks result in frequent visible dust and/or complaints are received or visible dust indicates the potential for worker exposure. If either of these circumstances occurs, the dust management plan shall include a program of daily or weekly dust monitoring.





D2.14 ODOUR CONTROL PLANNING

D2.14.1 Issues Odour control is not anticipated to be a likely or significant issue based on the nature of the proposed contamination management and remediation activities. However this section is included to address odour if it becomes an issue. One possibility for generating odours is if break-down of sulphate due to carbon source addition remediation activities causes the generation of H2S gas in existing groundwater abstraction bores.

D2.14.2 Objectives To minimise any inconvenience to neighbours and bore owners due to odour issues and comply with the existing Licence (No. 4848) for the facility.

D2.14.3 Management Strategy / Actions Remedial activities conducted at the site will be controlled such that all equipment used and all facilities constructed are designed and operated to control the emission of smoke, fumes and vapour into the atmosphere. Emissions and odour levels should comply with the Environment Protection Licence for the site and Control measures may include:

• Construction equipment will be properly maintained so that exhaust emissions comply with the Clean Air Regulations issued under the Protection of the Environment Operations Act 1997.

• Cleared vegetation, demolition materials and other combustible waste will not be burned onsite.

The geochemistry of the groundwater will be monitored carefully during any carbon source addition trials and associated remediation activities. In the event that H2S gas is generated in any groundwater abstraction bores, measures may be required to reverse or alleviate the geochemical imbalance to avoid such odours.


Recording of any odour from bores during groundwater monitoring

ADI to continue recording this observation during the groundwater monitoring program

During every groundwater monitoring event (currently every 6 months)





D2.15 OCCUPATIONAL HEALTH AND SAFETY PLANNING

D2.15.1 Issues The Contractor is responsible for the health and safety of its personnel and is responsible for complying with all of the requirements that ADI has for the site, as well as implementation of the requirements of the Contractor’s own Health and Safety Management System.

D2.15.2 Objectives Zero injuries, fatalities and near misses during all contamination management and remediation activities.

D2.15.3 Management Strategy / Actions All personnel will be given a site induction before commencing works or accessing the site to cover site occupational health and safety requirements and make personnel aware of the site OH&S plan. Contractors who work on this site remain responsible for all health and safety issues associated with their activities and must take account of the presence of the potentially contaminated material present onsite. The Contractor is responsible for preparing its own Health and Safety Plan. The requirements discussed in this REMP are intended only as a guide for the minimum precautions and the Contractor is responsible for identifying more comprehensive protective measures associated with the specific activities it is commissioned to carry out. As discussed above, based on the nature of the contaminants, the nitrate and sulphate impacted soil is unlikely to represent a significant exposure risk to workers at the site. However in the event that any excavation of soil is carried out in areas known or suspected to contain contamination, it is important to re-evaluate and ensure that the extent of investigation in the area concerned is sufficient to characterise the soil for exposure risk to workers (more so due to potential low pH and metals etc, than nitrate and sulphate). Occupational Health and Safety planning will be done in accordance with statutory regulations and EPA guidelines. These include, but are not limited to:

• NSW Occupational Health and Safety Regulation 2001. • Any other pertinent legislation, guidelines or practices. As a minimum, the precautions should include (but not be limited to) the following:

• There is potential for exposure to contaminants via inhalation as a result of dust creation during the excavation process. Dust masks should be made available on site should these conditions arise, creating a potential (local) exposure to site staff;

• Potential exposure pathways for contaminants include dermal absorption (skin contact, ingestion) of dust. All workers should wear long sleeve trousers/shirts on-site. Gloves and safety glasses shall be worn by all workers involved in handling of potentially contaminated soils;

• All workers involved in excavation activities should be attired with hard hats;

• Protective footwear (steel capped boots) to be worn on site at all times;

• Hearing protection should be worn when working in the vicinity of heavy plant/machinery;

• Limit unauthorised access by ensuring that security gates are locked at the completion of each days work;




• All open excavations to be barricaded in accordance with the NSW Occupational Health and Safety Act; Clause 16 (1) and the Construction Safety Regulation Section 73, as administered by WorkCover NSW;

• Excavations greater than 1.5m depth need to be “stepped” by the appointed civil contractor;

• Personnel are not to enter excavations (>1m depth) at any time unless appropriate shoring is in place;

• Install warning signs on/adjacent to all access points, including but not limited to: Danger: Open Excavations; Danger: Contaminated Soil;

• Undertake underground and overhead services location for the area in the immediate vicinity of the proposed excavation areas;

• Personal protective equipment (PPE) noted above shall be provided in sufficient quantities to provide for the duties of each on-site individual; and

• Workers coming into direct contact with the soil during excavation or construction activities will wear clothing, which prevents skin contact with the soil including gloves, full-length trousers and sleeves, or overalls;

• Workers in contact with the soil will wash their hands and face prior to drinking, eating or smoking;

• Food shall not be consumed in or around areas of exposed soil, inside buildings or proximal to any other suspect material; and

• Smoking shall only be permitted in designated areas.

D2.15.4 Monitoring

None required

D2.15.5 Reporting

As required under the OH&S




D2.16 DATA AND INFORMATION MANAGEMENT

D2.16.1 Issues It is important for information obtained from any contamination management and remediation activities (e.g. validation sampling and groundwater monitoring results) to be of an acceptable level of quality, to be accessible for ADI and compatible with existing information. To ensure this is the case it is necessary to specify minimum requirements and formats for any environmental data that is generated. It is also important to control copies of the applicable environmental management plans so that personnel are not in a position where they are using a superseded document.

D2.16.2 Objectives To ensure compatibility of new information with the existing data that ADI holds and to ensure an acceptable level of data quality for any information generated during the proposed contamination management and remediation activities.

D2.16.3 Management Strategy / Actions

D2.16.3.1 Document Control All aspects of the remediation should be documented and a copy of all correspondence kept on site at the facility for inspection by the stakeholders at any period of time. All documents should be given a unique document number and a register kept on file with the documents to ensure that all communications are retained as a record of the activities undertaken at the site.

D2.16.3.2 Data Collection and Storage It is recommended that all electronic data (i.e. analytical laboratory results) collected during the remediation be maintained in an electronic database system (i.e. Access). Transfer of the data to the system should be automated to ensure that a known level of quality of the data is retained and minimise the possibility of transcription errors generated as a result of manual data entry.

D2.16.3.3 Data Verification and Data Validation All information collected should be evaluated for completeness, correctness, and conformance/compliance against the method, procedural, or contractual requirements. The process should ensure that all data collected during the remediation is of known quality. Any restrictions or limitations associated with the use of the data should be understood to enable easy identification and rejection of the data if it cannot be used fulfil the overall project objectives.









D2.17 GENERAL REPORTING REQUIREMENTS

D2.17.1 Issues Apart from the specific reporting requirements outlined for each of the issues addressed in this REMP, there are general progress and project reporting requirements that must be implemented.

D2.17.2 Objectives To ensure an adequate level of reporting and project information provision to ADI during any contamination management and remediation works and to ensure adequate reporting to meet the needs of the Auditor.

D2.17.3 Management Strategy / Actions The following reporting requirements are for general reporting of the works. Special reporting requirements on environmental issues or OH&S issues / incidents are to be performed in accordance with the Environment Protection Licence for the site and the site OH&S requirements. The general reporting schedule will be established to include daily progress reporting and fortnightly project reporting. Reporting of remedial work conducted at the site shall be managed in accordance with the following guidelines as a minimum: • NSW EPA (1998), Guidelines for Consultants Reporting on Contaminated Sites, February

1998. • Any other pertinent legislation, guidelines or practices.

D2.17.3.1 Progress Reporting Daily worksheets will be established for contractors working onsite to capture the following:

• General information including contractors onsite, hours of work, future induction requirements etc;

• Work activities;

• Deliveries received on site and the transfer of materials around site, including volumes and locations of stockpiles;

• Special requirements; and

• Environmental and Health and safety issues and actions. The daily worksheets will be filled out by the site supervisor at the end of each days works and will be filed for inclusion in the fortnightly project reporting.




D2.17.3.2 Project Reporting Project reporting will be completed fortnightly and will include progress updates on remediation activities against project schedules. It will include:

• A summary of works completed;

• Locations of stockpiles around the site clearly identifying stockpiles of contaminated soil and clean stockpiles;

• Cost tracking against project budgets, volumes of consumables, offsite disposal of water / soil etc;

• Reporting on environmental and health and safety issues; and

• Forecast requirements for the following 12 day period.




D006005_RPT236Rev03_17Dec03

Appendix D3 Contingency Management Plan

ADI Mulwala Contamination Management Project CONTAMINATION MANAGEMENT PLAN Appendix D3 – Contingency Management Plan 17 December 2003 Prepared for: Department of Defence and ADI Limited Bayley Street, Mulwala, NSW 2647 Report by: HLA-Envirosciences Pty Limited ABN: 34 060 204 702 46 Clarendon Street Melbourne VIC 3205 Australia Ph: +61 3 8699 2199 Fax: +61 3 8699 2122 HLA Ref: D006005_RPT236Rev03_17Dec03_AppendixD3


Appendix D3 – Contingency Management Plan

D006005_RPT236Rev03_17Dec03_AppendixD3 i

CONTENTS D3 APPENDIX D3 - CONTINGENCY MANAGEMENT PLAN...........................................1

D3.1 SCOPE AND OBJECTIVES..........................................................................1 D3.2 SOURCES FOR BACKGROUND INFORMATION .......................................1 D3.3 TRIGGER LEVELS .......................................................................................2 D3.4 CONTINGENCY MANAGEMENT PLANNING PROCESS ...........................2





D3 APPENDIX D3 - CONTINGENCY MANAGEMENT PLAN

D3.1 SCOPE AND OBJECTIVES In accordance with the NSWEPA Guidelines for Consultants Reporting on Contaminated Sites (NSWEPA, 1997), a contingency plan is a description of the response in the event of ‘trigger levels’ being reached. It may involve the implementation of an alternative clean up technology or simple modification of the selected clean up technology. Contingency plans should be prepared at the time of the initial technology selection and should be flexible, allowing for the incorporation of new information (for example, advances in clean up technologies or toxicological data used to estimate the risk to groundwater receptors). Triggers adopted for this Contingency MP are discussed in Section D3.1.2 below. The extent of the area that this Contingency MP refers to (noting that the plan is concerned only with impact sourced from the ADI facility) is depicted on Figure 1 attached. It includes the ADI site and extends from the site south to the Murray River and west from the site to the Murray River billabong system. It is recommended that this document be referenced in conjunction with the following:

• Appendix D1 – Long Term Environmental Management Plan (LTEMP);

• Appendix D2 – Remediation Environmental Management Plan (RMP);




ADI undertakes to review and if necessary update this Contingency MP every five years and/or if either of the triggers for contingency in Section D3.2 occur or in the event that circumstances relating to the known impact change for any reason.

The objective of this Contingency MP is to document triggers for implementing contingency measures for protection of the environment and providing procedures for implementing those measures should they be required.

D3.2 SOURCES FOR BACKGROUND INFORMATION Since the late 1980s several investigations have been conducted to date on the groundwater contamination and impacted soil on-site beneath the facility, culminating in the CMP that is the main body of this report. Pertinent background information on the site and the contamination, such as the regulatory framework, extent of contamination and planned measures to manage the contamination is provided either within the body of the CMP report or in the documents listed in Appendix B of the CMP document.

1 ADI Mulwala Environmental Management System Manual - 2000




D3.3 TRIGGER LEVELS The NSWEPA Guidelines for Consultants Reporting on Contaminated Sites (NSWEPA, 1997), state that trigger levels specify a concentration of contaminant that is unacceptable at a critical location. These “triggers” may signal unsatisfactory performance of the clean up/management by indicating:

• Insufficient reduction in contaminant concentration;

• Increase in contaminant concentration (possibly indicating a new release); or

• Migration and/or expansion of the plume. This Appendix D3 Contingency Management Plan (Contingency MP) is concerned with the following potential triggers for possible contingency requirements: • If groundwater quality decreases to the extent that garden irrigation becomes impractical

due to plant stress and/or contamination levels in existing domestic groundwater abstraction bores exceed stock watering guidelines (in which case the groundwater would not be considered suitable for any use in accordance with the AWQG guidelines). This situation would constitute an “increase in contaminant concentration” trigger.

• If it becomes evident during implementing measures outlined in the Contamination Management Plan (CMP) that remediation using the preferred carbon source addition, or other methodologies are “impracticable”. This situation would constitute an “insufficient reduction in contaminant concentration” trigger. If this occurs, the Remediation Feasibility Study and the CMP have outlined a prioritised approach whereby substitute technologies and approaches are adopted if the preferred technology is found to be impracticable or a Practicability of Clean-Up study is implemented. These are included in the body of the CMP and are not therefore required within this Contingency MP.

• If the monitoring programme shows that the contamination plumes are continuing to expand

or migrate into areas that affect other groundwater users (i.e. a “migration or expansion of the plume” trigger).

D3.4 CONTINGENCY MANAGEMENT PLANNING PROCESS If the monitoring programme shows a trend (i.e. interpreted to be more than just a fluctuation during one monitoring episode) of increasing contamination, to the extent that garden irrigation or stock watering uses are impacted, ADI undertakes to implement the following contingency measures:

• Individual discussions will be held with any groundwater users whose irrigation or stock watering resource is impacted. ADI will discuss with the groundwater users the extent of any inconvenience and possible solutions or alternative water supplies.

• If clean up to the practicable extent has not been completed at the time that these contingency measures are triggered, ADI will implement a review to investigate opportunities to complete the process more expediently. As part of this process ADI may for example re-evaluate the expected fate and transport of the groundwater contamination under the known conditions at the time, taking into account monitoring results, natural attenuation and any clean up measures in progress or completed.


D006005_RPT236Rev03_17Dec03

Appendix E Gantt Chart

ID Task Name1 IMPLEMENTATION OF GROUNDWATER MANAGEMENT2 Prepare Tender Documentation3 Request Proposals from Environmental Consultants4 Review Proposals5 Engage Environmental Consultant6 Seek Aproval to Undertake Works7 Referral to Environment Australia for consideration under the EPBC Act8 Off-site Groundwater Plume Management9 Monitoring Natural Attenuation

10 Prepare Monitoring Plan11 Auditor Review12 Auditor Aproval 13 Groundwater Sampling and Reporting14 February 200415 July 200416 Management of Current Groundwater Uses17 Stakeholders Meeting and Community Presentations (2004)18 February 200419 May 200420 August 200421 November 200422 Stakeholders Meeting and Community Presentations (2005)23 February 200524 May 200525 August 200526 November 200527 Source Area Management28 Source Management Area A29 Proof-of-Concept Trial30 Carbon Source Addition to Groundwater31 Hydrogeological Pump Testing and Reporting32 Groundwater Modelling and Reporting33 Carbon Source Addition to Soil34 Laboratory Testing35 Design of Works36 System Design37 Request for Tender38 Review Proposals39 Engage Contractor40 Commission Works41 Implementation of Remediation System42 Monitoring and Reporting43 Source Management Area B44 Undertake Inspection of Effluent Drain45 Conduct Necessary Remedial Works to Improve the Integrity of the Drain (if necessary)46 Design of Capping Works47 System Design48 Request for Tender49 Review Proposals50 Engage Contractor51 Commission Works52 Implementation of Capping for Source Management53 Monitoring and Reporting54 Source Management Area C55 Determine Soil Volumes for Excavation

19-05

Month 1 Month 2 Month 3 Month 4 Month 5 Month 6 Month 7 Month 8 Month 9 Month 10 Month 11 Month 12 Month 13 Month 14 Month 15 Month 16 Month 17November 2003 December 2003 January 2004 February 2004 March 2004 April 2004 May 2004 June 2004 July 2004 August 2004 September 2004 October 2004 November 2004 December 2004 January 2005 February 2005 March 2005

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Rolled Up Split

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Implementation of Groundwater Management

Page 1

Project: project.timeframeDate: Fri 21-11-03

ID Task Name56 Establish On-site Landfill57 Design of Capping Works for Landfill58 System Design59 Request for Tender60 Review Proposals61 Engage Contractor62 Commission Works63 Consolidation of Soil and Waste Materials64 Landfilling of Waste and Soil65 Monitoring and Reporting66 Capping of Source Area67 Design of Capping Works68 System Design69 Request for Tender70 Review Proposals71 Engage Contractor72 Commission Works73 Implementation of Capping for Source Management74 Monitoring and Reporting75 Source Management Area D76 Determine Soil Volumes for Excavation77 Establish On-site Landfill78 Design of Repository79 System Design80 Request for Tender81 Review Proposals82 Engage Contractor83 Commission Works84 Consolidation of Soil and Waste Materials85 Landfilling of Waste and Soil86 Monitoring and Reporting87 Capping of Source Area88 Design of Capping Works89 System Design90 Request for Tender91 Review Proposals92 Engage Contractor93 Commission Works94 Implementation of Capping for Source Management95 Monitoring and Reporting96 Source Management Area E97 Capping of Source Area98 Design of Capping Works99 System Design

100 Request for Tender101 Review Proposals102 Engage Contractor103 Commission Works104 Implementation of Capping for Source Management105 Monitoring and Reporting

Month 1 Month 2 Month 3 Month 4 Month 5 Month 6 Month 7 Month 8 Month 9 Month 10 Month 11 Month 12 Month 13 Month 14 Month 15 Month 16 Month 17November 2003 December 2003 January 2004 February 2004 March 2004 April 2004 May 2004 June 2004 July 2004 August 2004 September 2004 October 2004 November 2004 December 2004 January 2005 February 2005 March 2005

Task

Split

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Rolled Up Split

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ID Task Name1 IMPLEMENTATION OF GROUNDWATER MANAGEMENT2 Prepare Tender Documentation3 Request Proposals from Environmental Consultants4 Review Proposals5 Engage Environmental Consultant6 Seek Aproval to Undertake Works7 Referral to Environment Australia for consideration under the EPBC Act8 Off-site Groundwater Plume Management9 Monitoring Natural Attenuation

10 Prepare Monitoring Plan11 Auditor Review12 Auditor Aproval 13 Groundwater Sampling and Reporting14 February 200415 July 200416 Management of Current Groundwater Uses17 Stakeholders Meeting and Community Presentations (2004)18 February 200419 May 200420 August 200421 November 200422 Stakeholders Meeting and Community Presentations (2005)23 February 200524 May 200525 August 200526 November 200527 Source Area Management28 Source Management Area A29 Proof-of-Concept Trial30 Carbon Source Addition to Groundwater31 Hydrogeological Pump Testing and Reporting32 Groundwater Modelling and Reporting33 Carbon Source Addition to Soil34 Laboratory Testing35 Design of Works36 System Design37 Request for Tender38 Review Proposals39 Engage Contractor40 Commission Works41 Implementation of Remediation System42 Monitoring and Reporting43 Source Management Area B44 Undertake Inspection of Effluent Drain45 Conduct Necessary Remedial Works to Improve the Integrity of the Drain (if necessary)46 Design of Capping Works47 System Design48 Request for Tender49 Review Proposals50 Engage Contractor51 Commission Works52 Implementation of Capping for Source Management53 Monitoring and Reporting54 Source Management Area C55 Determine Soil Volumes for Excavation

Month 18 Month 19 Month 20 Month 21 Month 22 Month 23 Month 24 Month 25 Month 26 Month 27 Month 28 Month 29 Month 30 Month 31 Month 32 Month 33 Month 34April 2005 May 2005 June 2005 July 2005 August 2005 September 2005 October 2005 November 2005 December 2005 January 2006 February 2006 March 2006 April 2006 May 2006 June 2006 July 2006 August 2006

Task

Split

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Rolled Up Split

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ID Task Name56 Establish On-site Landfill57 Design of Capping Works for Landfill58 System Design59 Request for Tender60 Review Proposals61 Engage Contractor62 Commission Works63 Consolidation of Soil and Waste Materials64 Landfilling of Waste and Soil65 Monitoring and Reporting66 Capping of Source Area67 Design of Capping Works68 System Design69 Request for Tender70 Review Proposals71 Engage Contractor72 Commission Works73 Implementation of Capping for Source Management74 Monitoring and Reporting75 Source Management Area D76 Determine Soil Volumes for Excavation77 Establish On-site Landfill78 Design of Repository79 System Design80 Request for Tender81 Review Proposals82 Engage Contractor83 Commission Works84 Consolidation of Soil and Waste Materials85 Landfilling of Waste and Soil86 Monitoring and Reporting87 Capping of Source Area88 Design of Capping Works89 System Design90 Request for Tender91 Review Proposals92 Engage Contractor93 Commission Works94 Implementation of Capping for Source Management95 Monitoring and Reporting96 Source Management Area E97 Capping of Source Area98 Design of Capping Works99 System Design

100 Request for Tender101 Review Proposals102 Engage Contractor103 Commission Works104 Implementation of Capping for Source Management105 Monitoring and Reporting

Month 18 Month 19 Month 20 Month 21 Month 22 Month 23 Month 24 Month 25 Month 26 Month 27 Month 28 Month 29 Month 30 Month 31 Month 32 Month 33 Month 34April 2005 May 2005 June 2005 July 2005 August 2005 September 2005 October 2005 November 2005 December 2005 January 2006 February 2006 March 2006 April 2006 May 2006 June 2006 July 2006 August 2006

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Page 4


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