INFORMATION REGARDING...Revised page issued 21 November 2011 V Table 1.1: Summary of Audit...

INFORMATION REGARDING ENVIRONMENTAL AUDIT REPORTS August 2007

VICTORIA’S AUDIT SYSTEM An environmental audit system has operated in Victoria since 1989. The Environment Protection Act 1970 (the Act) provides for the appointment by the Environment Protection Authority (EPA Victoria) of environmental auditors and the conduct of independent, high quality and rigorous environmental audits.

An environmental audit is an assessment of the condition of the environment, or the nature and extent of harm (or risk of harm) posed by an industrial process or activity, waste, substance or noise. Environmental audit reports are prepared by EPA-appointed environmental auditors who are highly qualified and skilled individuals.

Under the Act, the function of an environmental auditor is to conduct environmental audits and prepare environmental audit reports. Where an environmental audit is conducted to determine the condition of a site or its suitability for certain uses, an environmental auditor may issue either a certificate or statement of environmental audit.

A certificate indicates that the auditor is of the opinion that the site is suitable for any beneficial use defined in the Act, whilst a statement indicates that there is some restriction on the use of the site.

Any individual or organisation may engage appointed environmental auditors, who generally operate within the environmental consulting sector, to undertake environmental audits. The EPA administers the environmental audit system and ensures its ongoing integrity by assessing auditor applications and ensuring audits are independent and conducted with regard to guidelines issued by EPA.

AUDIT FILES STRUCTURE Environmental audit reports are stored digitally by EPA in three parts: the audit report (part A), report appendices (part B) and, where applicable, the certificate or statement of environmental audit and an executive summary (part C). A report may be in colour and black-and-white formats. Generally, only black-and-white documents are text searchable.

Report executive summaries, findings and recommendations should be read and relied upon only in the context of the document as a whole, including any appendices and, where applicable, any certificate or statement of environmental audit.

AUDIT REPORT CURRENCY

Audit reports are based on the conditions encountered and information reviewed at the time of preparation and do not represent any changes that may have occurred since the date of completion. As it is not possible for an audit to present all data that could be of interest to all readers, consideration should be made to any appendices or referenced documentation for further information.

When information regarding the condition of a site changes from that at the time an audit report is issued, or where an administrative or computation error is identified, environmental audit reports, certificates and statements may be withdrawn or amended by an environmental auditor. Users are advised to check EPA’s website to ensure the currency of the audit document.

PDF SEARCHABILITY AND PRINTING EPA Victoria can only certify the accuracy and correctness of the audit report and appendices as presented in the hardcopy format. EPA is not responsible for any issues that arise due to problems with PDF files or printing.

Except where PDF normal format is specified, PDF files are scanned and optical character recognised by machine only. Accordingly, while the images are consistent with the scanned original, the searchable hidden text may contain uncorrected recognition errors that can reduce search reliability. Therefore, keyword searches undertaken within the document may not retrieve all references to the queried text.

This PDF has been created using the Adobe-approved method for generating Print Optimised Output. To assure proper results, proofs must be printed, rather than viewed on the screen.

This PDF is compatible with Adobe Acrobat Reader Version 4.0 or any later version which is downloadable free from Adobe’s Website, www.adobe.com.

FURTHER INFORMATION For more information on Victoria’s environmental audit system, visit EPA’s website or contact EPA’s Environmental Audit Unit.

Web: www.epa.vic.gov.au/envaudit

Email: [email protected]

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http://www.epa.vic.gov.au/envaudit/environmental_audits.asphttp://www.adobe.com/http://www.epa.vic.gov.au/envauditmailto:[email protected]?subject=Electronic Audit Report Enquiry - PDF Info Sheet

EXECUTIVE SUMMARY

Coffey Environments GEOTABTF16430AA_R09.docx Revised page issued 21 November 2011

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Table 1.1: Summary of Audit Information

EPA file reference no. 57386-1 Auditor Phil Sinclair Auditor term of appointment 2 December 2009 – 30 November 2011 Name of Person Requesting Audit: Mr Renzo Negrelli Relationship to premises/location On behalf of SP AusNet, the site owner Date of Request 9 February 2005 Date EPA notified of Audit 10 February 2005 Completion date of the audit 14 November 2011 Reason for audit Clean Up Notice, dated 3 April 2007 Current land use zoning Public Use Zone 1 (PUZ1) EPA region North West Municipality Mount Alexander Shire Council Lot on Plan Volume 10541 Folio 901 and Lot 1 of Title Plan TP019291TStreet No. 98 Street Name Forest Street Type Street Street Suffix N/A Suburb Castlemaine Postcode 3450 GIS coordinate of site centroid: Longitude GDA94 144.2223 Latitude GDA94 37.0678 Site area (hectares) 0.406 ha Members and categories of support team utilised

Sarah Richards (Contaminant transport and assessment of exposure pathways and risk) Tim Marshall (Peer review) Michael Blackam (Hydrogeology)

Outcome of the audit Statement of Environmental Audit indicating suitability for high density residential, commercial and industrial uses

Further works or requirements Implementation of Environmental Management Plan and Groundwater Management Plan attached to the Statement of Environmental Audit

EXECUTIVE SUMMARY

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EXECUTIVE SUMMARY

Coffey Environments GEOTABTF16430AA_R09.docx 14 November 2011

VI

Nature and Extent of Continuing risk Continuing risks present at the site consist of: Groundwater impacted with TPH C10-C36, Naphthalene,

MAHs, free cyanide, metals (arsenic, cadmium, copper, manganese, nickel, lead and zinc), ammonia, nitrate and organic compounds commonly detected in coal tar;

Remnant gasworks waste is present as tar layers (1-2mbgl) along the northern and southern boundaries, and as a PAH and TPH impacted band between 3 – 4mbgl along the central portion of the northern boundary;

DNAPL is present in the centre of the site within the siltstone,

There is a continuing risk to construction and maintenance workers at

EXECUTIVE SUMMARY

Coffey Environments GEOTABTF16430AA_R09.docx 14 November 2011

VII

Physical site information

Site aquifer formation Alluvium/Fill underlain by Ordovician Siltstone Average depth to groundwater 3.5 mbgs Groundwater segment Segment B Groundwater flow direction South-west Past use/site history

The site was formerly a gasworks manufacturing plant. Gas was manufactured at the site from 1859 to 1962 via coal carbonisation. Tempered Liquid Petroleum Gas was produced at the site from 1962 to 1973. Following decommissioning in 1973 the site was used as a mains and service depot until remediation commenced in 2005. Remedial works were completed in July 2007. The site is currently vacant.

Surrounding land use North: Forest Street (Pyrenees Highway) and Primary School; South: Residential; East: Duke Street (Pyrenees Highway) and Commercial (Motel); West: Urquhart Street and Residential

Proposed future use Commercial/industrial

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Appendix A Statement of Environmental Audit

Environmental Audit Report Former Castlemaine Gasworks

98 Forest St, Castlemaine

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ENVIRONMENT PROTECTION ACT 1970

STATEMENT OF ENVIRONMENTAL AUDIT

Revised page dated 21 November 2011

I, Phillip Leigh Sinclair, of Coffey Environments Australia Pty Ltd, a person appointed by the Environment Protection Authority (“The Authority”) under the Environment Protection Act 1970 (“the Act”) as an environmental auditor for the purposes of the Act, having:

1. been requested by Mr Renzo Negrelli on behalf of the SP AusNet Pty Ltd, to issue a certificate of environmental audit in relation to the property located at 98 Forest Street, Castlemaine and known as the Former Castlemaine Gasworks, Castlemaine, Victoria, being Volume 10541 Folio 901, with the boundaries defined on Lot 1 of Plan TP019291T, located where shown in Figure 1 attached to this Statement (‘the site’) owned by the SPI Networks (Gas) Pty Ltd.

2. had regard to, amongst other things,

i. guidelines issued by the Authority for the purposes of Part IXD of the Act;

ii. the beneficial uses that may be made of the site; and;

iii. relevant State environment protection policies/industrial waste management policies and regulations, namely

SEPP Groundwaters of Victoria SEPP Waters of Victoria SEPP Ambient Air Quality and Air Quality Management SEPP Prevention and Management of Contamination of Land IWRR Industrial Waste Resources Regulation

in making a total assessment of the nature and extent of any harm or detriment caused to, or the risk of any possible harm or detriment which may be caused to, any beneficial use made of the site by any industrial processes or activity, waste or substance (including any chemical substance), and

3. completed an environmental audit report in accordance with Section 53X of the Act, a copy of which has been sent to the Authority and the relevant planning and responsible authority.

HEREBY STATE that I am of the opinion that:

The site is suitable for the beneficial uses associated with High Density Residential, Commercial and Industrial land uses, subject to the following conditions attached thereto:

a. The site must be developed to provide levels of site coverage (in terms of building elements, paving etc.) that prevent access to underlying soils as far as practicable.

b. Garden beds or other landscaping elements should be designed and constructed to prevent access to underlying soils as far as practicable.

c. Site development protocols and management must take into account the requirements of the Environmental Management Plan (EMP) that forms part of this Statement of Environmental Audit and the presence of aesthetically-impacted material at the site.

d. Any fill or soil removed from the site should be assessed to determine its contamination status and managed in accordance with EPA requirements, and where appropriate, disposed of to a suitably licensed EPA waste treatment or disposal facility.

e. The owner / occupier shall notify EPA and the responsible authority of any significant revision to the EMP.

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f. Groundwater at the site and downgradient is polluted. Groundwater within the Groundwater Quality Restricted Use Zone (GQRUZ) must not be used for Stock Watering, Industrial Water Use, Agriculture, Parks and Gardens and Primary Contact Recreation.

g. Groundwater within the GQRUZ is required to be managed until such time that the Authority determines that the management may cease. Groundwater is to be managed in accordance with the Groundwater Management Plan (GMP) that forms part of this Statement of Environmental Audit. The GMP contains a groundwater monitoring program, trigger levels for groundwater contaminant concentrations, a contingency plan for groundwater remediation in the event that groundwater conditions change such that trigger levels are exceeded, controls on groundwater extraction and use, and a program for review of the Plan. Responsibility for implementation of the GMP shall be maintained by the current owner of the site, SP AusNet, or its successors and assignees with the agreement of future owners. To cease groundwater monitoring and management, where all beneficial uses of groundwater have not been restored, a 53V audit must be undertaken.

The condition of the site is detrimental or potentially detrimental to any (one or more) beneficial uses of the site. Accordingly, I have not issued a Certificate of Environmental Audit for the site in its current condition, reasons for which are presented in the environmental audit report. The terms and conditions that need to be complied with before a Certificate of Environmental Audit may be issued are set out as follows:

a. Material containing contaminant concentrations above human health-based criteria considered protective of sensitive land uses and above ecologically-based criteria considered protective of ecosystems would need to be removed or remediated.

b. Removal of material with aesthetic limitations would need to occur.

c. All relevant beneficial uses of groundwater would need to be restored.

OTHER RELATED INFORMATION

a. The Environment Protection Agency (EPA) advised in correspondence dated 16 May 2011, that it had determined that groundwater beneath the site has been cleaned up to the extent practicable, and identified that the site is within a GQRUZ.

b. Concentrations of TPH C10-C36 , naphthalene, benzo(a)pyrene, benzene, toluene, xylene, styrene, phenols, cyanide, DEHP, ammonia, arsenic, iron and manganese are present at levels that preclude one or more of the beneficial uses of groundwater; i.e. agriculture, parks and gardens, stock watering, primary contact recreation and industrial use.

c. Elevated concentrations of metals, chloride, sodium and sulfate are present in groundwater but are considered to be naturally occurring or to have been leached from natural site soils;

d. Soils at depths typically greater than 1m are not considered aesthetically acceptable for Sensitive Use (low, medium or high density residential use);

e. There is some remnant soil contamination exceeding all NEPM HIL and EIL criteria for Total PAHs, BaP, Total Phenols, benzene, ethylbenzene and xylenes is present at some locations at the site. With the exception of BaP, the remnant soil contamination found at

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concentrations exceeding the above criteria was at depths greater than 1m below the site surface.

f. The relevant planning and responsible authority has advised that that the conditions of the Statement of Environmental Audit are likely to be incorporated in any planning approval issued by the Mount Alexander Shire Planning Authority for development of the site

g. The uses for which the land is considered suitable in this Statement of Environmental Audit may not be allowed under the existing zoning of the Mount Alexander Shire Planning Scheme.

This Statement forms part of environmental audit report entitled ‘Environmental Audit Report: Former Gasworks, 98 Forest Street, Castlemaine, Victoria‘ (Coffey Environments Australia Pty Ltd, Ref. GEOTABTF16430AA-R09, dated 14 November 2011). Further details regarding the condition of the site may be found in the environmental audit report.

Signed

Phil Sinclair

Environmental Auditor (Appointed Pursuant to the Environment Protection Act 1970)

Attachments: Environmental Management Plan, including Figures.

(ref. GEOTABTF16430AA-R011) Groundwater Management Plan, including Figures

(ref: GEOTABTF16430AA-R08)

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GEOTABTF16430AA-R11.doc

Reviewed/Approved by:

Phil Sinclair Environmental Auditor (Appointed Pursuant to the Environment Protection Act 1970)

ENVIRONMENTAL MANAGEMENT PLAN FORMER GASWORKS SITE 98 FOREST STREET CASTLEMAINE, VICTORIA

Prepared for:

SPAusNet Level 32, 2 Southbank Boulevard Southbank, Victoria, 3006

Report Date: 10 November 2011 Project Ref: GEOTABTF16430AA

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CONTENTS

Coffey Environments GEOTABTF16430AA-R11.doc 10 November 2011

ABBREVIATIONS II

1 INTRODUCTION 4

1.1 Objectives 4

1.2 Responsibility 4

2 SITE DESCRIPTION 5

2.1 Brief Site History 5

3 SITE SOIL AND GROUNDWATER CONTAMINATION STATUS 6

3.1 Groundwater 6 3.1.1 Final Groundwater Condition 6

4 HEALTH RISK ASSESSMENT 7

5 MINIMISATION OF POTENTIAL RISK TO HEALTH OF SITE WORKERS 8

5.1 During Site Redevelopment 8

5.2 After Site Redevelopment 9

5.3 Garden Beds 9

6 EXPOSURE CONTROL MEASURES 10

6.1 Soil Contamination 10

6.2 Groundwater Contamination 10

6.3 Surface Water Contamination 10

6.4 Vapour Contamination 11

7 MINIMISATION OF POTENTIAL ENVIRONMENTAL IMPACTS 12

7.1 Soil Excavation and Management 12 7.1.1 Movement of Soil on Site 13 7.1.2 Off-site Disposal of Soil 13 7.1.3 Managing Unexpected Contamination 13

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CONTENTS


7.1.4 Managing Unexpected Services 14 7.1.5 Importation of Fill Material 14 7.1.6 Management of Stockpiles 14

7.2 Dust Control 14

7.3 Odour Control 15

7.4 Extraction of Groundwater 15

7.5 Off-Site Disposal of Water 16 7.5.1 Surface Water 16 7.5.2 Groundwater 16

7.6 Erosion Control 16

7.7 Stormwater Management and Sediment Control 16

7.8 Road Cleaning 17

7.9 Noise Control 18

8 EMP SURVEILLANCE AND REVISION 19

8.1 Surveillance 19

8.2 Review 19

9 REPORTING 20

10 OTHER INFORMAITON 21

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LIST OF ATTACHMENTS


EMP I

Figures

Figure 1: Site Location

Figure 2: Site Plan with Historical Features & Remediation

Figure 3: Boundary Sampling Locations and Exceedances

Appendix

Appendix A: Groundwater Management Plan (GMP)

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ABBREVIATIONS


EMP II

ANZECC Australian and New Zealand Environment and Conservation Council

C6-C36 hydrocarbon chainlength fraction

BaP benzo(a)pyrene

BH borehole

BTEX benzene, toluene, ethylbenzene and xylenes

COPC chemicals of potential concern

CUTEP clean up to the extent practicable

EES Environmental and Earth Sciences Pty Ltd

EIL Ecological Investigation Level

EMP environmental management plan

EPAV Environment Protection Authority Victoria

HIL Health Based Investigation Levels

km kilometre

LPG liquid petroleum gas

µg/L micrograms per litre

mbgl metres below ground level

mg/kg milligrams per kilogram

mg/L milligrams per litre

MW monitoring well

NATA National Association of Testing Authorities

NEPC National Environmental Protection Council

NEPM National Environment Protection Measure

NSW EPA Environment Protection Authority of New South Wales

ABBREVIATIONS

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ABBREVIATIONS


EMP III

PAH polycyclic aromatic hydrocarbon

SEPP State Environment Protection Policy

TDS total dissolved solids

TLPG tempered liquid petroleum gas

TPH total petroleum hydrocarbon

UCL upper confidence level

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Environmental Management Plan

98 Forest Street, Castlemaine, Victoria


EMP 4

1 INTRODUCTION

This Environmental Management Plan (EMP) has been prepared as a condition of the Statement of Environmental Audit issued for the former Gasworks site located at 98 Forest Street, Castlemaine (Figure 1) (Coffey 2010). The EMP should be read in concordance with the Environmental Audit Report.

1.1 Objectives

The purpose of this EMP is to minimise risks to future on-site construction and maintenance workers, future site users and the environment associated with redevelopment of the site.

The EMP includes information and guidance in relation to:

Advising future site occupants (including contractors engaged in ground maintenance or construction work and/or excavation) of the environmental issues and potential hazards associated with the reported site contamination;

Limiting extraction and use of potentially contaminated groundwater;

Identifying measures to minimise environmental impacts during site construction works;

Outlining procedures to be followed relating to deep excavations during redevelopment and future use of the site; and

Providing information relating to off-site disposal of soil and groundwater.

1.2 Responsibility

The implementation of this EMP is the responsibility of the owner of the site at the time that construction or maintenance works are undertaken.

Compliance with the guidance within this EMP should be followed by all persons involved in works or other activities at the site that may result in disturbance and/ or excavation of soil or access to underlying groundwater.

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EMP 5

2 SITE DESCRIPTION

The site is located at 98 Forest Street, Castlemaine in north central Victoria and is located within a commercial and residential area (Figure 1). The site is currently vacant land and is proposed to be developed for commercial or industrial use. A detailed description of the site setting, history, local geology and hydrogeology is provided in the CUTEP and the Environmental Audit Report. During remediation of the site, EES (the site assessment and remediation consultant) divided the site into five zones and provided a grid layout. These are presented in Figure 2 and 3 and have been used in this report as points of reference.

2.1 Brief Site History

Gas was manufactured at the site from 1859 to 1962 via coal carbonisation in retorts. In 1962, TPLG production commenced, and site features then included LPG vessels, high pressure vessels, a buffer vessel and pumps. The tar wells associated with the first 100 years of gas manufacture were filled with gasworks waste consisting of bricks, concrete and coke. The TPLG Plant was decommissioned in 1973 and rubble from the partial site demolition was used to fill the gas holders. After decommissioning, the site was used as a mains and service depot. Demolition of above ground structures was commissioned by SP AusNet in 2004/2005.

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EMP 6

3 SITE SOIL AND GROUNDWATER CONTAMINATION STATUS

The site was previously impacted by gas manufacturing by-products which contained elevated levels of chemicals of concern, in particular Polycyclic Aromatic Hydrocarbons (PAHs). A summary of the final contamination status of soil is provided below.

Tar Layers

A secondary sources of PAH contamination is present along the northern and southern boundary in the south-eastern corner of the site between 1 – 2 mbgl in the form of a layer of tar. Samples taken above and below the layer of impacted material indicated that the vertical extent of the impact was less than 1 m on the southern boundary. On the northern wall, impact was still present at 2 mbgl. Analysis of this material indicates that the PAHs were leachable to some degree. Based on the analytical data, the depth at which samples were collected, and the minimum recorded depth to water of 1.64 mbgl in BH1 (adjacent to the boundary), the auditor considers that the tar layers on the boundaries of the site have the potential to both leach to groundwater and pose a soil vapour risk to users of the site if contamination migrates onto the site.

DNAPL

DNAPL was visually identified in BH13, which is screened within siltstone in the middle of the site. Groundwater analytical results identified soluble coal tar constituents such as naphthalene, carbazole and dibenzofuran in this well, which is also consistent with free phase tar being present. The DNAPL occurrence is considered to be limited to the siltstone and does not appear to extend offsite.

Northern Wall Impact

EES validation sampling undertaken during the remediation process identified high concentrations of PAHs and TPHs on the northern wall.

Reinstated Fill Quality

PAHs, BaP and TPH C10-C36 soil concentrations exceeding the adopted screening criteria were identified in 4 of the 5 zones. To identify the level at which the remaining impact was present, the data was analysed for compounds exceeding the criteria over 3 depth ranges; 0 – 1mbgl, 1 – 2.5 mbgl and >2.5 mbgl. The mean and 95% upper confidence level (UCL) on the mean exceeded the adopted criteria for PAH, BaP and TPH in Zone B at depths of >2.5mbgl. The 95% UCL for BaP in Zone B between 1.0 – 2.5 mbgl also exceeded the adopted criterion. Although there are individual exceedances of the adopted criteria elsewhere at the site, the population statistics indicate that the mean and 95% UCL concentrations of chemicals of potential concern (COPCs) elsewhere onsite are acceptable.

3.1 Groundwater

3.1.1 Final Groundwater Condition

The final condition of groundwater at the site is provided in the CUTEP report (Coffey November 2010) and in the Environmental Audit Report (Coffey November 2011). Due to the likelihood of inorganic and organic contamination in groundwater to be, at least in part, sourced from the leaching of onsite soil, groundwater extraction at the site should be managed through a conditional audit statement for the site which restricts groundwater extraction through a groundwater quality restricted use zone (GQRUZ). As such, the potential extraction and subsequent use of groundwater must be managed appropriately and not used for any purpose without testing of its suitability for the proposed use.

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EMP 7

4 HEALTH RISK ASSESSMENT

A health risk assessment (HRA) has been conducted for the site and is included within the Audit report. Based on the outcome of the HRA, the auditor considers that, while some outstanding issues such as ongoing management to prevent contact with groundwater and soil remain, these do not affect the finding that there is no significant vapour risk to site users for the areas assessed for soils on the site.

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EMP 8

5 MINIMISATION OF POTENTIAL RISK TO HEALTH OF SITE WORKERS

Work procedures conducted on the site should be in accordance with relevant Occupational Health and Safety (OH&S) Regulations. The site owner should ensure all site maintenance or construction workers are aware of OH&S issues at the site.

5.1 During Site Redevelopment

During construction works, engaged companies or contractors should prepare a site specific Health and Safety Plan covering their workers at the site. The plan should specify the risk of exposure to the contaminants identified at the site and how site workers are to be protected. An OH&S Specialist or an Occupational Hygienist may be engaged to ensure OH&S measures are implemented on site.

Potential hazards for site workers associated with the presence of contaminants during the construction phase of site development should be considered as part of the overall Health and Safety Plan for the site, including:

Ingestion of contaminated soil and water;

Inhalation of dust;

Inhalation of vapours from impacted media; and

Dermal (skin) contact.

Personnel working at or visiting the site during construction works should be provided with an induction briefing that informs those personnel about the potential risks associated with the site. The induction briefing should ensure that workers:

Understand the hazards and risks associated with work on a contaminated site;

Are not likely to cause harm to themselves or others; and

Know how to use any mobile plant and equipment and personal protective equipment and clothing.

During construction works, site visitors who do not complete the induction briefing should be accompanied at all times by a nominated representative who is familiar with the site and associated risks.

Measures that can be undertaken to assist in minimising exposure of site maintenance or construction workers to soil and water contaminants include the following:

Avoid handling of potentially contaminated soil or groundwater;

Wash hands before eating, drinking or smoking;

Store and consume food and drink in a designated, dust free, clean area;

Remove soiled clothing and footwear before entering a designated clean area and before leaving the site;

Use personal protective equipment as required. In addition to hard hats, safety boots, safety glasses and hearing protection, this equipment may include:

o Impermeable gloves, if handling potentially contaminated soil or water;

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EMP 9

o Long sleeved shirt and long trousers; and o Dust masks. o Respirators and appropriate cartridges

Store personal protective equipment in a clean place to avoid contamination;

Ensure all personal protective clothing and equipment is regularly cleaned, maintained and inspected to ensure it remains effective; and

Replace gloves and masks regularly, and other equipment as required.

During construction, site workers and visitors should be provided with:

A site induction briefing;

Adequate hand washing facilities;

A designated clean area for storage and consumption of food and drink; and

Adequate personal protective equipment.

5.2 After Site Redevelopment

After construction of infrastructure and / or building(s) at the site:

maintenance workers conducting intrusive works likely to extend to a depth of more than 1 m below the current site surface (RL ) shall follow the procedures outlined above; and

there is no requirement for special protective measures to be taken to protect other users of the site along the northern and southern boundary in the south-eastern corner of the site.

5.3 Garden Beds

Although it is likely that the site will be developed for commercial or industrial purposes with minimal soil contact, there is the potential for garden beds to be created. The health risk to future workers associated with maintaining the garden may be managed through the excavation of contaminated fill and backfilling with clean fill in garden bed areas during the site development stage.

Construction of the garden beds should be undertaken following the measures outlined above to ensure that the potential risk to construction workers is minimised.

Material excavated during the construction of garden beds should be managed according to the guidelines provided in Section 7.1.1 and 7.1.2.

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EMP 10

6 EXPOSURE CONTROL MEASURES

The main principles to be applied to protect the users of the site from exposure to contaminated soil and groundwater at the site are:

Developing the property to provide levels of coverage (in terms of building elements, paving, etc.) that prevent access to underlying soils as far as practicable;

Garden beds or other landscaping elements being designed and constructed to prevent access to underlying soils as far as practicable (see Section 5.3); and

Preventing the use of groundwater at the property1.

6.1 Soil Contamination

On-site exposure to soil contamination should be controlled by:

Implementing the measures outlined in Section 6 of this report, during excavation, construction and maintenance works, including the appropriate use of personal protective equipment.

6.2 Groundwater Contamination

On-site exposure to groundwater contamination should be controlled by:

Excluding extraction and the use of groundwater;

Implementing the measures outlined in the Section 6, during excavation, construction and maintenance works; and

The use of personal protective equipment outlined in Section 6, during excavation, construction and maintenance works.

For further details of groundwater management, please refer to the Groundwater Management Plan, attached to the Statement of Environmental Audit.

6.3 Surface Water Contamination

On-site exposure to surface water contamination should be controlled by:

Implementing the stormwater management measures outlined in Section 7.7; and

Installing drainage and/or grade soil surfaces to minimise pooling of water on exposed soils.

Off-site exposure to surface water contamination should be controlled by:

Implementing the stormwater management measures outlined in Section 7.7; and

1 Note that there is a Groundwater Quality Restricted Use zone within which groundwater should not be used, for land located between the site and Forest Creek.

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EMP 11

Collecting stormwater on-site and disposing of it in accordance with EPAV and/or local water authority requirements.

6.4 Vapour Contamination

On-site exposure to vapour contamination should be controlled by:

Monitoring site excavations for the presence of odours or visibly contaminated materials;

Monitoring works that generate dust or vapours and ensuring any exposure is being adequately controlled to protect workers; and

Usage of personal protective equipment outlined in Section 5.1, when working in site excavations.

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EMP 12

7 MINIMISATION OF POTENTIAL ENVIRONMENTAL IMPACTS

Potential environmental impacts during any subsurface or construction works and / or subsequent excavations may be associated with:

Soil excavation and management;

Movement of soil on site;

Off-site disposal of soil;

Importation of fill material;

Stockpile management;

Extraction of groundwater;

Off-site disposal of water;

Dust and odour controls;

Erosion control;

Stormwater and sediment management; and

Noise.

To minimise potential environmental impacts, all work should be conducted in accordance with relevant EPA guidelines and the guidance set out in this EMP.

7.1 Soil Excavation and Management

The following procedures must be undertaken prior to, during and following any significant soil and/or surface cover disturbance, or excavation at the site.

Contractors and workers must be made aware of the presence of soil contamination and be familiar with the requirements of the EMP;

Contractors must prepare a site specific Health and Safety Plan covering their workers at the site;

Soil contamination status of any soil to be removed from the site must be established and appropriate disposal undertaken in accordance with EPAV guidelines;

All potentially contaminated soil excavated must be stockpiled separately and securely from uncontaminated soil (fill material) to prevent cross contamination and restrict public access;

Soil stockpiles must be managed in accordance with best practice and EPAV guidelines in order to prevent the loss of soil caused by wind (dust) or stormwater run-off, including protection of nearby stormwater drains and waterways;

The source area of any soil excavated from the site and the location of any stockpiled soil must be noted on a plan for reference to ensure soil is accurately tracked on-site;

Following appropriate sampling and classification, stockpiles should be re-instated or removed off-site. Stockpiles of fill should be managed carefully and be removed or re-instated as soon as possible; and

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EMP 13

Equipment used for excavation of potentially contaminated soil must be cleaned of loose soil prior to use in another area.

7.1.1 Movement of Soil on Site

All movement of soil at the site should be tracked to ensure its origin, contamination status and fate is documented. During the environmental site assessment and remediation, the site was divided into five zones (Zones A – E) and 15 grid locations (C1 – C15). Figure 2 of this EMP provides the locations of these zones and a full description of the condition of these zones is provided in the Environmental Audit Report. For ongoing soil tracking purposes Zones A – E and the grid locations should be used to describe and reference the source and destination of soil movement around the site or off-site.

7.1.2 Off-site Disposal of Soil

Where activities on the site generate excess soil, which requires off-site disposal or reuse, the material must be classified in accordance EPAV (2007a) “Classification of Wastes” and transported in accordance with EPAV requirements.

If observations of the soil condition on site indicate significant difference from the conditions noted in the previous assessment, the material is to be assessed on site to determine the requirement for further testing.

A suitably qualified environmental consultant must conduct the sampling and analysis.

Soil containing contaminant concentrations above EPAV fill material criteria (EPAV 2007a) and which is being taken off-site, must be transported in an EPA permitted vehicle with an EPA Transport Certificate and disposed of at a suitably licensed site in accordance with EPAV (June 2009) “Environment Protection (Industrial Waste Resource) Regulations 2009”.

7.1.3 Managing Unexpected Contamination

In some instances, site contamination is not expected and is detected after work commences. Given the extensive excavation that has occurred on the former gasworks site, the risk of finding unidentified ‘hot-spots’ of contamination is low, however, it should still be considered.

Measures that can be undertaken include:

Ensuring all workers are trained to recognise signs of potential contamination such as odours or soil discolouration; and

Ensuring there is a response plan that can be activated if contamination hot spots are found, such as:

o Stop work o Report signs to the site supervisor immediately o Isolate the area with a physical barrier o Assume the area is contaminated until an assessment proves otherwise o Assess the area to identify contaminants in the soil or spoil.

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EMP 14

7.1.4 Managing Unexpected Services

Although the majority of the site has been excavated to greater than 0.7 mbgs, with deeper excavations in areas of known gasworks features, it is possible that there are undiscovered services, pipework or similar on the site. In the event that such services are discovered during site development works they should be removed according to the current guidelines and legislation for the material involved.

7.1.5 Importation of Fill Material

All fill imported to the site should meet EPA Victoria “Fill Material” criteria as outlined in the Soil Hazard Categorisation and Management, Publication No. IWRG 621 (EPAV July 2009) and should be sampled and analysed in accordance with EPAV guidelines to demonstrate it meets the criteria prior to import to the site. An environmental consultant shall assess the source location of the fill material and undertake sampling and analysis.

If the fill is obtained from a known commercial quarry there is no mandated sampling frequency. The relevant regulations or guidelines in force at the time of importation should be used to assess whether the imported soil is likely to give rise to environmental or health impacts. When not sourced from a commercial quarry, fill material should be sampled and analysed at a minimum rate of one sample per 100 m3 of bulk soil volume if sourced from a naturally occurring greenfield site, or one sample per 50 m3 of bulk soil volume if source from brownfield or previously developed sites, as required by EPA Victoria Publication 1178.

7.1.6 Management of Stockpiles

Stockpile areas are a potential source of dust and sediment run-off and should be managed to minimise environmental impacts. If soil stockpiles are to be stored on site for extended periods of time, they should be covered with netting, matting, or plastic sheeting, if necessary, to minimise generation of dust and to limit runoff of contaminated sediment. Other stockpile management measures are outlined below.

Minimise the number and size of stockpiles;

Locate stockpiles where they are protected from wind and away from drainage lines;

Keep topsoil separate from underburden when stockpiling soil;

Construct the stockpile with no slope greater than 2:1 (horizontal to vertical). A less steep slope may be required where the erosion risk is high;

Establish sediment controls around non-stabilised stockpiles and batters; and

Suppress dust on stockpiles and batters, as circumstances require.

7.2 Dust Control

Generation of dust at the site can pose a risk to the health of on-site workers and to people off-site. This is of particular concern at the former gasworks site because of the presence of contaminants such as TPH and PAHs within the soil. Dust emissions can also affect the visual amenity at the site and surrounding areas. Measures that can be undertaken to assist in the minimisation of dust generation include:

Minimising movement and speed of vehicles on the site;

25




EMP 15

Minimising excavation and movement of soils;

Using a water spray to dampen vehicle tracks, if excess dust is generated;

Using a water spray to dampen soil prior to and during excavation, if excess dust is generated;

Avoiding soil excavation during gusty or windy weather; and

Minimising the extent and duration of stockpiling of soil.

7.3 Odour Control

In the event that odorous soils are encountered on site, measures that can be undertaken to assist in minimising the generation of odour include the following:

Minimising excavation and movement of soils where possible;

Limiting or scheduling excavation or movement of potentially odorous soil to short and/or pre-determined time periods, cognisant of nearby sensitive receptors;

Conducting vapour monitoring and regular site surveillance during activities which have the potential to generate odour;

Spraying a suitable vapour suppressant during odour-generating excavation works if required;

Avoiding extended stockpiling of odorous soils on site;

Covering stockpiles of odorous soils with clean soil or plastic sheeting; and

Capping odorous areas where practicable.

7.4 Extraction of Groundwater

The range of contaminant concentrations that exceeded relevant criteria during the most recent groundwater monitoring round conducted by the assessor (EES 2009c, provided in Appendix D of the Audit report) and auditor validation sampling (April and August 2010) is summarised below.

Groundwater remains contaminated with:

Metals: arsenic, cadmium, copper, iron, manganese, mercury, nickel, lead and zinc;

Organic Contaminants: BTEX, styrene, naphthalene, benzo(a)pyrene, phenols and hydrocarbons; and

Inorganic Contaminants: cyanide, sodium, chloride, sulfate, ammonia and nitrate.

As such, a GQRUZ has been placed on groundwater use at the site. Groundwater extraction for any beneficial use should not be conducted until such time that the identified contaminant concentrations comply with appropriate guidelines. For further details on the management of site groundwater, refer to the attached GMP (attached to the Statement of Environmental Audit.

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EMP 16

7.5 Off-Site Disposal of Water

7.5.1 Surface Water

After heavy rain events, pooled surface water is often pumped off construction sites to allow for construction works to recommence. This water may contain high levels of suspended sediments. If off-site disposal of stormwater is required, it should be conducted in accordance with EPA requirements. To ensure that de-watering operations do not result in turbid water entering natural waterways, the following management options are provided:

Treat contaminated water before it is pumped into the stormwater system or a natural waterway to remove excess sediments and ensure water quality meets EPAV guidelines;

Ensure that the level of suspended solids in water pumped into natural waterways never exceeds the regulatory water quality standard;

De-water by pumping water, wherever practical, on to vegetated areas with sufficient sediment control capacity; and

Monitor the turbidity of the water at least once per hour during pumping.

7.5.2 Groundwater

Groundwater at the site was encountered at depths of approximately 2.2- 4.8 mbgl. Groundwater extraction should be minimised during any construction works. However, where groundwater is encountered and extracted or pumped from excavations it should be collected and disposed of in accordance with EPAV and local water authority requirements.

Testing and assessment of the quality of the extracted groundwater should be undertaken prior to disposal. A suitably qualified environmental consultant should conduct sampling and analysis.

7.6 Erosion Control

Where soil is disturbed through excavation or the removal of vegetation, soil becomes vulnerable to erosion. Soil removed by erosion may become airborne and create a dust problem. To minimise the quantity of soil lost during construction due to land-clearing, the following measures should be considered:

Keep vehicles to well-defined haul roads;

Minimise the areas of land cleared and the period of time areas remain cleared; and

Revegetate and mulch progressively as each section of works is completed.

7.7 Stormwater Management and Sediment Control

Soil eroded during land disturbance can wash away and contaminate stormwater. If contaminated stormwater enters a drainage line or stormwater drainage system it will eventually discharge into an adjacent waterway and pollute it. This is of particular concern for the former gasworks site because of the presence of contaminants such as TPH, PAH, BTEX and metals in the soil on some parts of the site. These contaminants, attached to soil particles, can ultimately be transferred to waterways through sedimentation of stormwater.

27




EMP 17

Measures to minimise the potential for stormwater sedimentation include the following:

Install drainage and/or grade soil surfaces to minimise pooling of water on exposed soils;

Minimise the quantity of stormwater entering areas where there is exposed soil (using intercept drains);

Use swales or other techniques to reduce the velocity of stormwater over areas of exposed soil;

Collect stormwater on-site and allow suspended solids to settle before disposal in accordance with EPAV and/or local Water Authority requirements;

Place sediment control devices around stormwater drains and stockpiles as required;

Ensure vehicles are free from excess soil when leaving the site, to avoid tracking soil off-site;

Clean up any soil spilt on roads adjoining the site;

Establish a vehicle wash down area, if necessary;

Avoid extended stockpiling of soil;

Cover soil stockpiles during heavy rain, if necessary (refer to Management of Stockpiles above);

Avoid conducting vehicle or machinery maintenance on-site;

Ensure any fuel, oil or other chemicals are stored safely and securely and are prevented from leaking;

Repair or remove any leaking containers or machinery from the site;

Clean up any spilt fuel, oil or other chemicals;

Check sediment control measures regularly (at least daily) and clean and maintain as necessary; and

Inspect sediment control measures more frequently during rain periods, to check they are adequate.

7.8 Road Cleaning

Where it is required that vehicles move on and off site regularly, it is possible that these vehicles will transport soil off the site and deposit it on adjacent roads. This can lead to increased dust created by other vehicles driving over deposited soil, sedimentation of stormwater from the roads and contamination of other vehicles using the road. To minimise the incidence of soil being tracked onto surrounding roads, the following options should be considered:

Install wheel washes and rumble grids at all main exits from the site;

Ensure that roads are swept at least once per day on uncontrolled road crossings when construction vehicles are travelling off the site;

Install litter traps lined with filter cloth in all road drainage in proximity to road crossings; and

Cover all loads of soil being taken off-site for disposal.

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EMP 18

7.9 Noise Control

Measures that can be undertaken to assist in minimising the generation of noise beyond the site boundaries include:

Maintaining vehicles and equipment in good working order;

Minimising loud activities such as the use of excavators, construction equipment and vehicles;

Ensuring that all noise emissions comply with relevant guidelines such as the Environment Protection (Residential Noise) Regulations (EPAV 2008) and the Interim Guidelines for Control of Noise from Industry in Country Victoria, N3/89 (1998); and

As a minimum, avoid loud activities before 7 am and after 8 pm Monday to Friday and before 9 am and after 8 pm on weekends and public holidays (or as per operating hours stipulated within planning/building permits).

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EMP 19

8 EMP SURVEILLANCE AND REVISION

8.1 Surveillance

It is recommended that a mechanism for surveillance and internal reporting of EMP compliance performance by all stakeholders be implemented by the site owners for site construction and maintenance works. This may include the following components:

Appointment of a representative (e.g. project manager or site foreman) who has responsibility for controlling all construction, maintenance and / or excavation works at the site;

Maintaining a log of all construction, maintenance and excavation work carried out, which includes confirmation that in each case, the purchaser, current owner or subsequent site owners of the site and their contractors have met the requirements outlined in this EMP;

Maintaining a log that records any breaches of the requirements of the EMP and outlines actions taken to prevent recurrence of the breach; and

Maintaining a record of site inspections by the purchaser, current owner or subsequent site owners of the site to confirm compliance with the requirements of the EMP by site workers.

8.2 Review

It is recommended that this EMP be reviewed by a competent person prior to the commencement of development works and prior to any intrusive works conducted after site development and that suitability be assessed against any changes in site conditions, work requirements, legislation, environmental conditions and other relevant factors. The EMP should be revised to reflect any changes and provide adequate procedures for ensuring continued public and environmental safety and compliance with legislation.

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EMP 20

9 REPORTING

It is recommended that the site owners maintain documentation demonstrating that the requirements of this EMP have been met.

Such documentation is likely to include site survey levels, soil tracking records, volumes of fill removed or imported onto the site, evidence that imported fill met EPAV fill material criteria and evidence that excavated fill was disposed of in accordance with EPAV requirements.

Any significant changes to the EMP should be notified to the responsible authority (Mount Alexander Shire Council) and EPAV.

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EMP 21

10 OTHER INFORMATION

Further information on this site and the relevant regulatory documents can be found below:

ANZECC 1992, Australian Water Quality Guidelines for Fresh and Marine Waters. Australian and New Zealand Environment & Conservation Council. ISBN 0-642-18297-3.

ANZECC 2000, Australian and New Zealand guidelines for Fresh and Marine Water Quality, National Water Quality Management Strategy Paper No 4, Australian & New Zealand Environment and Conservation Council & Agriculture and Resource management Council of Australia and New Zealand, October 2000.

CMPS&F 1997, Department of Treasury & Finance Site Investigation, Castlemaine Depot, Forest St, Castlemaine, Victoria.

Coffey 2010, CUTEP Submission, Former Gasworks Site, 98 Forest Street, Castlemaine, Victoria, 10 November 2010.

DNRE 1995, North Western Victoria Water Table Aquifers. Victorian Groundwater Beneficial Use Map Series. Department of Natural Resources.

Environmental and Earth Sciences (April 2007) Remediation Action Plan, Former gasworks site, 98 Forest St, Castlemaine, Victoria.

Environmental Earth Sciences (October 2007) Hydrogeological assessment of the former Castlemaine gas-works site, 98 Forest St, Castlemaine, Victoria.

Environmental Earth Sciences (February 2009) Stage 2 Hydrogeological Assessment of the Former Castlemaine Gas Works Site, 98 Forest St, Castlemaine, Victoria

Environmental Earth Sciences (October 2009) Validation Report, Castlemaine Former Gasworks Site, 98 Forest Street, Castlemaine, Victoria.

Environmental Earth Sciences (December 2009) Stage 3 Hydrogeological Assessment of the Former Castlemaine Gas Works Site, 98 Forest St, Castlemaine, Victoria

EPAV 1996, Environmental Guidelines for Major Construction Sites, Publication No. 480, EPA Victoria, February 1996.

EPAV 2002, Groundwater Sampling Guidelines, Publication 669, Environment Protection Authority Victoria, April 2000.

EPAV 2002, Clean up and Management of Polluted Groundwater, Publication 840, Environment Protection Authority Victoria, April 2002.

EPAV 2005, Reducing Stormwater Pollution From Construction Sites, Publication No. 981, EPA Victoria, May 2005;

EPAV 2008, Environment Protection (Residential Noise) Regulations 2008, EPA Victoria, October 2008.

EPAV 2009, Environment Protection (Industrial Waste Resource) Regulations 2009, EPA Victoria, S.R. No. 77/2009, June 2009.

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EMP 22

EPAV (June 2009) Sampling and Analysis of Waters, Wastewaters, Soils and Wastes, Publication No. IWRG701. Environment Protection Authority Victoria.

EPAV (July 2009) Soil Hazard Categorisation and Management, Publication No. IWRG 621. Environment Protection Authority Victoria.

IT Environmental 2003, Groundwater Monitoring Event, Former TXU Gasworks Site, 98 Forest St, Castlemaine, Victoria, June 2003.

Land Remediation Department (LRD) (July 1994) Site description of the Castlemaine ex GMPS.

Land Remediation Department 1994, Potential of offsite migration of residuals from the former gas manufacture plant site, September 1994.

Land Remediation Unit (GSB) 1998, Groundwater monitoring results at the former gas manufacture plant site, Forest St, Castlemaine, August 1998.

Land Remediation Unit (GSB), 1999, Environmental site report, Westar depot, 98 Forest St, Castlemaine, January 1999.

NEPC 1999, National Environment Protection (Assessment of Site Contamination) Measure, National Environment Protection Council.

NSW EPA 1994, Guidelines for Assessing Service Station Sites. ISBN 0-7310-3712-X.

Netherlands 2000, Circular on Target Values and Intervention Values for Soil Remediation, Ministry of Housing, Spatial Planning and the Environment, Netherlands Government.

State Government of Victoria 1970, Environment Protection Act 1970.

State Government of Victoria 1989, State Environmental Protection Policy (Control of Noise from Commerce, Industry and Trade), No. N-1, No. S31, 16/5/1989, Gazette 15/6/1989 and relevant amendments.

State Government of Victoria 1997, State Environment Protection Policy (Groundwaters of Victoria), No. S160, Gazette 17/12/1997 As varied 19/3/2002, No. G12, Gazette 21/3/2002.

State Government of Victoria 1998, State Environment Protection Policy (Waters of Victoria), Gazette 23/2/1988 – and relevant amendments (most recently dated 5/10/2004).

State Government of Victoria 2002, State Environment Protection Policy (Prevention and Management of Contamination of Land), No. S95, Gazette 4/6/2002.

WorkSafe Victoria 2005, Industry Standard Contamination Construction Sites, First Edition, June 2005.

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EMP 23

Figures Environmental Management Plan


34

SWAN HILL

BENDIGO

GEELONG

WARNAMBOOL

BALLARAT

HORSHAM

MILDURA

MORWELL

MELBOURNE

SHEPPARTON

ECHUCA

SEYMOUR

WODONGA

ALBURY

SCALE

0 200

KMS

COOMA

coffey

environments

SPECIALISTS IN ENVIRONMENTAL,

SOCIAL AND SAFETY PERFORMANCE

Fax: (03) 9473 1450

126 Trenerry Crescent

Abbotsford VIC 3067

Ph: (03) 9473 1400

SITE

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(A3)

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Coffey Environments Pty Ltd

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Revision DetailsDateRev Drn

Client:

Project:

Location:

Drawing Title:

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Project - Drawing No. Figure No. Rev.

A3

SITE LOCATION

98 FOREST STREET

CASTLEMAINE, VICTORIA

FORMER CASTLEMAINE GASWORKS

ENVIRONMENTAL MANAGEMENT PLAN

SP AUSNET

SITE

35

Former Residence

Former Coal Shed

Retort House

Former

Purifier

Condenser

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Former Workshop

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coffey

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Abbotsford VIC 3067

Ph: (03) 9473 1400

ADAPTED FROM EES REPORT 205019 (DEC 2009) FIGURE 12

Former structures

South School Reserve

Residential

36

Zone A

Zone D

Zone E

Zone C

Zone B

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C

coffey

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Ph: (03) 9473 1400

ADAPTED FROM EES REPORT 205019 (DEC 2009) FIGURE 12

+

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37

GEOTABTF16430-R08.docx

Approved by:

Phil Sinclair Environmental Auditor appointed pursuant to the Environment Protection Act 1970

GROUNDWATER MANAGEMENT PLAN FORMER CASTLEMAINE GASWORKS SITE, 98 FOREST STREET, CASTLEMAINE

Prepared for:

SP Ausnet Level 32, 2 Southbank Boulevard SOUTHBANK 3006

Report Date: 10 November 2011 Project Ref: GEOTABTF16430-R08

38

RECORD OF DISTRIBUTION

Coffey Environments GEOTABTF16430-R08.docx 10 November 2011

See Distribution List for Environmental Audit Report of which this forms a part

39

CONTENTS


LIST OF ATTACHMENTS I

1 INTRODUCTION 1

1.1 Background 1

1.2 Objective 1

2 GEOLOGY AND HYDROGEOLOGY 2

2.1 Geology – Regional/Local 2 2.1.1 Hydrogeology – Regional/Local 2 2.1.2 Hydrogeology – Regional Groundwater Use 3

3 ENVIRONMENTAL MANAGEMENT AT THE SITE 4

3.1 Environmental Issues at the Site 4 3.1.1 Soil Issues 4 3.1.2 Groundwater Issues 4 3.1.3 Risk to Beneficial Uses of Land 8

3.2 Regulatory Requirements 8

4 GROUNDWATER ENVIRONMENTAL MANAGEMENT PLAN 10

4.1 Purpose and Scope of Plan 10

4.2 Life of Plan 10

4.3 Implementation of Groundwater Management Plan 10

4.4 Reporting 11

5 GROUNDWATER MANAGEMENT 13

5.1 General 13

5.2 Controls on Groundwater Extraction and Use 13

5.3 Groundwater Monitoring 13 5.3.1 Monitoring Frequency and Procedures 13 5.3.2 Groundwater Analytical Plan 14 5.3.3 QC Procedures 15

40

CONTENTS


5.4 Monitoring Data Review 15 5.4.1 Compliance Targets 16 5.4.2 Groundwater Trigger Levels 16

5.5 Groundwater Management during Construction 20

6 REVIEW OF GMP 21

7 SUMMARY 22

8 REFERENCES 23

41


I

Tables

Table 3-1 – Summary of Groundwater Contaminant Concentrations Exceeding Screening Criteria. ...................................................................................................... 6

Table 4-1 – GMP Tasks and Responsibilities .......................................................................... 11 Table 5-1 – Groundwater Monitoring Bores to be Retained ..................................................... 14 Table 5-2 – Groundwater Monitoring Bores to be Retained ..................................................... 15 Table 5-3 – Health Risk Trigger Values (mg/L) ........................................................................ 17 Table 5.4 Plume Stability Trigger Values (mg/L) ...................................................................... 19

Figures

1: Site Location Plan

2: Site Plan & Monitoring Well Locations, Showing Transects

3: Conceptual Cross Section A-A’

4: Conceptual Cross Section B-B’

5: Groundwater Level Contours (August 2009)

6: Groundwater Monitoring Bores to be Retained

LIST OF ATTACHMENTS

42

ABBREVIATIONS


II

AHD Australian Height Datum

ANZECC Australian and New Zealand Environment and Conservation Council

C6-C36 Hydrocarbon chainlength fraction

bgl Below ground level

BH Borehole

BTEX Benzene, Toluene, Ethylbenzene and Xylenes

COC Chain of Custody

CUTEP Clean Up To Extent Practicable

DNAPL Dense Non Aqueous Phase Liquid

DO Dissolved Oxygen

EC Electrical Conductivity

Eh Oxidation/Reduction Potential

EES Environmental Earth Science

EPA Environment Protection Authority

ESA Environmental Site Assessment

GMP Groundwater Management Plan

GQRUZ Groundwater Quality Restricted Use Zone

HRA Health Risk Assessment

LOR Limit of Reporting

µg/L micrograms per litre

mg/kg milligrams per kilogram

mg/L milligrams per litre

MW Monitoring Well

NATA National Association of Testing Authorities

NEPM National Environment Protection Measure

PAH Polycyclic Aromatic Hydrocarbons

QA Quality Assurance

QC Quality Control

43

ABBREVIATIONS


III

RL Reduced Level

SMP Site Management Plan

SWL Standing Water Level

TDS Total Dissolved Solid

TOC Top of Casing

TPH Total Petroleum Hydrocarbon

UCL average Upper Confidence Level of average

WHO World Health Organisation

44

Groundwater Management Plan Former Castlemaine Gasworks Site


1

1 INTRODUCTION

1.1 Background

This Groundwater Management Plan (GMP) has been prepared as part of the environmental audit conducted by Phil Sinclair of Coffey Environments for the former Castlemaine Gasworks site located at 98 Forest Street, Castlemaine (“the site”). Compliance with this GMP forms part of the conditions in the Statement of Environmental Audit issued for the site.

This GMP is needed because there is polluted groundwater present beneath and adjacent to the site that could affect proposed uses of the site and adjacent land. The groundwater pollution is due to past use of the site as a manufacturing gasworks.

There are measures contained in a separate Site Management Plan (SMP) to manage hazards from contaminated soil during any excavation, maintenance, dewatering and construction works at the site.

The location of the site is shown on Figure 1. Groundwater monitoring well locations and groundwater contours are shown on Figures 2 and 5 respectively.

1.2 Objective

The purpose of the GMP is to outline ongoing groundwater management requirements for the former Castlemaine Gasworks site, located at 98 Forest Street, Castlemaine.

This plan provides a summary of site conditions and does not attempt to reproduce large quantities of data and information contained in the previous site assessment reports and the environmental audit report for the site. For a more complete description of all site conditions and environmental issues that created a need for this GMP, refer to the audit report (ref. GEOTABTF16430AA-R09).

Closure of this GMP must involve completion of an environmental audit conducted in compliance with S. 53V of the Environment Protection Act 1970, which requires the appointment of an Environmental Auditor appointed pursuant to the Environment Protection Act 1970.

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2

2 GEOLOGY AND HYDROGEOLOGY

2.1 Geology – Regional/Local

The site is located in an alluvial valley in the Central Victorian Highlands. According to Willman (1994), the surficial geology of the site is Quaternary through to early Tertiary (Holocene, Pleistocene and Pliocene epochs, 0-5Myo) Shepparton Formation described as non-marine gully alluvium; imbricated pebble and cobble gravels overlain by pebbly sand and clay. Haydon and Allfra (2002) also describe the geology in the vicinity of the site as Recent Quaternary age Shepparton Formation consisting of gravel, sand silt and clay.

To the south of the site, beyond Forest Creek, the geology is identified as Ordovician aged Castlemaine Group “sandstones fine to very coarse grained with interbedded siltstone and shale; quartz rich, turbidic, marine. Colour varies from grey to yellow-brown in sandstone and siltstone and grey-green to purple in shale” (Willman 1994).

Cross-sections generated based on borelogs recorded during monitoring well establishment are consistent with stream deposited alluvial material consisting of clay, sand, silt and gravel or fill, sitting on Ordovician bedrock (see Figures 3 and 4).

Visual observations during excavation confirmed that bedrock was encountered at approximately 6 - 8 metres below ground level (mbgl) on the northern half of the site, with siltstone bedrock rising steeply in the centre of the site and outcropping beneath the residences beyond the southern boundary.

2.1.1 Hydrogeology – Regional/Local

The regional aquifers of significance are identified as pre-Cainozoic bedrock aquifers, the Ordovician Castlemaine Group in this case, with an expected TDS of between 1,001-3,500mg/L based on publicly available hydrogeological information (DNRE 1995a and DNRE 1995b). According to Weaver et al (2006) the salinity range for spring discharges from Ordovician sediments ranges between 720-3,000 mg/L TDS, with discharge flow rates of between 0.02 and 0.37 L/sec. The TDS values at the site averaged 2,758 mg/L.

Reported salinity ranges in the Shepparton Formation range from 300 to 9,850 mg/L TDS. It is however noted that, based on regional beneficial use maps (DNRE 1995b), this aquifer is considered effectively absent, and therefore unlikely to be a significant source of groundwater in the vicinity of Castlemaine. Additional local information related to regional aquifers is available in Appendix A (EES 2007, EES 2009a, EES 2009c).

Based on the standing water level (SWL) reported in monitoring wells included in the site assessment, two stratigraphic units are associated with the site; one within the fill onsite and alluvial material of the Shepparton Formation (unconsolidated material), where it still exists offsite, and the other within the fractured Ordovician siltstone and sandstone bedrock. The Ordovician siltstone aquifer outcrops to the south of the site. Two conceptual cross sections of the subsurface, including groundwater levels and stratigraphic detail from borelogs are presented as Figure 3 and Figure 4 of this report. The alignment of the cross sections is shown on Figure 2 of this report.

46



3

Groundwater contouring of gauging data shows the flow direction was typically to the southwest. Immediately post remediation, a groundwater depression was apparent in the centre of the site (BH13), possibly due to dewatering of tight fractures within the siltstone during the remediation process. By 2009, two years after site re-instatement, the groundwater was less depressed (Figure 6); however the time taken for the groundwater gradient to re-establish across the site is consistent with the observed tightness of the fractures within the siltstone and low yields noted during purging.

The nearest down gradient water body is Forest Creek, which is approximately 100 metres to the south of the site. The Forest Creek can act as either a losing or gaining stream. Figure 2 shows the current and historic locations of the Forest Creek. It is likely that the historic creek bed will also act as a high permeability groundwater conduit.

Based on site specific hydraulic conductivity testing and average hydraulic gradients across the site post remediation, the seepage velocity is estimated to range from 0.3 m/year to 11 m/year in the siltstone, and 0.3 m/year to 3.8 m/year in the upper unconsolidated material.

2.1.2 Hydrogeology – Regional Groundwater Use

A total of 20 registered bores are located within a 2 km radius of the site. Of these, two (2) were nominated as investigation wells, two (2) for commercial use, one (1) for irrigation use and 15 for stock and domestic use.

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4

3 ENVIRONMENTAL MANAGEMENT AT THE SITE

3.1 Environmental Issues at the Site

3.1.1 Soil Issues

Following excavation of contaminated material at the site, validation sampling indicated that high concentrations of PAHs and TPH, and in some cases tar, remain along the northern and southern boundaries of the site and in the south eastern corner. The auditor noted that contaminant migration from the boundaries of the site is a potential future source of contamination.

During EES’s remediation program, contaminated soil was excavated and remediated. Approximately 75% of the material excavated was disposed off-site. The remaining 25% was re-instated at the site following bioremediation of impacted material. Analysis of the results from the reinstated materials indicated that PAHs, BaP and TPH C10-C36 soil concentrations exceeding the adopted screening criteria in 4 of the 5 zones. The population statistics indicate that the mean and 95% UCL average concentrations of COPCs on the site are acceptable with the exception of the material placed at depth in Zone B. The auditor considers it is appropriate to recommend the implementation of a site management plan (SMP) to control access to the contaminated material. The proposed elements of the SMP will be included in the audit report.

Therefore, potentially contaminated soil within zone B and around the site boundaries may act as an ongoing source of groundwater pollution.

3.1.2 Groundwater Issues

Based on the results of groundwater monitoring conducted at the site, BH13 in the centre of the site is impacted by residual tar material. Tar was reported in the base of monitoring well BH13 in three consecutive sampling rounds, and contamination concentrations in this well have remained relatively stable while groundwater concentrations in other locations have decreased. Based on the most recent round of groundwater sampling, BH13 is impacted by TPH, BTEX, phenols and PAHs including naphthalene. Historically, a groundwater plume of dissolved phase contaminants extended from BH12, which is up-gradient on the northern boundary, toBH6 which is down-gradient and adjacent to Forest Creek. The range of organic contaminant concentrations detected, and wells exceeding the adopted criteria, are summarised in Table 3-1 below. Temporal TPH C6 to C36 and naphthalene data (Figures 10 and 11 of the CUTEP report (Coffey 2010)) indicates the dissolved phase plume is stable or reducing. Based on these trends, and the absence of impact above screening criteria hydraulically downgradient of the site, the auditor considers it unlikely that the beneficial use of maintenance of ecosystems would be affected by the organic contaminants discussed above.

Metals identified above the relevant criteria were: arsenic, cadmium, copper, iron, manganese, mercury, nickel, lead and zinc. Metals concentrations in groundwater exceeded screening criteria for the beneficial uses of maintenance of ecosystems, agriculture, parks and gardens, stock watering and primary contact recreation. Metals concentrations in upgradient monitoring well BH16 were lower than concentrations detected on-site, and hydraulically downgradient of the site, indicating the site is likely to be the source of the elevated metals concentrations. This observation is consistent with the leachability of metals noted in stockpiles used to backfill the site, and the increased biological activity on-site due to residual organic impact. While biological activity is enhanced on-site, leaching and mobilisation of metals is expected to continue. It is noted that metal concentrations in groundwater have generally

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decreased post remediation, consistent with the removal of the majority of degradable impact from the site. In addition, although metal concentrations are elevated above maintenance of ecosystem criteria, they are either below, or only slightly exceed other criteria.

A number of other organic compounds (carbazole, dibenzofuran, di-(2-ethylhexyl) phthalate, and endosulfan) were detected in monitoring wells BH13, BH6, BH7, BH8 and BH12. These contaminants have been considered in the CUTEP report and are considered to be either decreasing, representative of degradation of PAHs, relatively easily degraded and/or of limited extent. Thus none of these chemicals are considered to be an ongoing concern at the site.

Cyanide concentrations reported onsite and immediately downgradient of the site have sporadically exceeded the adopted maintenance of ecosystems criteria (0.007 mg/L); however concentrations in groundwater wells adjacent to the creek have consistently been below the level of reporting. In addition, free cyanide concentrations on-site (BH13), which reported concentrations four times the criteria in 2008 and 2009, appear to be decreasing. Therefore, it is considered unlikely the concentrations of free cyanide flowing from the site into Forest Creek will increase in the future or impact on the beneficial use of maintenance of ecosystems. Note that analysis of free cyanide by ion-selective electrode method, rather than colorimetric methods is stipulated in Section 5.3 of this plan to reduce the impact of interfering compounds.

Elevated concentrations of sodium, chloride and sulfate were recorded above the adopted screening criteria in samples collected across the site. These are considered to be representative of background conditions in the region, and are not considered to be a concern.

In the majority of groundwater monitoring wells located hydraulically down gradient of the site ammonia has been detected at concentrations exceeding the screening criteria for the beneficial of maintenance of ecosystems and primary contact recreation. The highest concentration detected in recent sampling events was 9.8 mg/L in BH11(s). Limited nitrate concentration data was available prior to remediation. However, upgradient concentrations (BH16) have ranged from 20g/L to 490g/L. Following remediation works in 2007, nitrate concentration exceeding the reported criteria was observed in the majority of monitoring wells (refer to Figure 12). Subsequent groundwater monitoring events indicated nitrate concentrations have reduced to below the screening criteria in all monitoring wells, with the exception of on-site well BH13(s). Based on the trends observed across the site, it is expected that nitrate concentrations are returning to background levels and are unlikely to impact on the beneficial use of maintenance of ecosystems.

The range of contaminant concentrations that exceeded relevant criteria during the most recent groundwater monitoring round conducted by the assessor (EES Report 209050, December 2009) and auditor validation samples (April and August 2010) are summarised in Table 3-1 below.

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Table 3-1 – Summary of Groundwater Contaminant Concentrations Exceeding Screening Criteria.

Analyte

Concentration Range Reported

* ( µg/L)

Wells exceeding criteria Screening Criteria (µg/L)

(Shading indicates an exceedance was recorded)

On-site Off-site Maintenance

of Ecosystems1

Agriculture, Parks and Gardens2

Stock Watering3

Primary Contact

Recreation4

TPH C6 – C9



7

Analyte

Concentration Range Reported

* ( µg/L)

Wells exceeding criteria Screening Criteria (µg/L)

(Shading indicates an exceedance was recorded)

On-site Off-site Maintenance

of Ecosystems1

Agriculture, Parks and Gardens2

Stock Watering3

Primary Contact

Recreation4

Copper

1 - 25

BH13(s), BH14, BH15, MW4

BH1, BH3, BH6, BH9, BH10,

BH10(s), BH11(s), BH12,

BH16

1.4 * 5,000 500 1000

Iron



8

^ Low reliability figure adopted based on ANZECC (2000) Section 8.3.4. ^^ Moderate reliability figure adopted based on ANZECC (2000) Section 8.3.7 * Criteria not hardness modified. Conservative assumption based on groundwater alkalinity range from >1mg/L to >1,000mg/L, @ Concentration converted from N03 to N to using a dividing factor of 4.43 where applicable.

3.1.3 Risk to Beneficial Uses of Land

A health risk assessment was undertaken to assess the potential human health risks to on-site and off-site receptors associated with impact currently identified in soil, groundwater and soil vapour (Health Risk Assessment (HRA), Coffey, October 2010). The findings of the HRA are summarised as follows:

Based on available data, exposure assumptions and constraints of the exposure assessment model, the COPC concentrations identified in groundwater and soil vapour via vapour inhalation, as presented in the HRA are not considered to present an unacceptable health risk to onsite commercial, construction and maintenance workers, off-site residential occupants and maintenance workers. The assessment is based on the future commercial land use onsite, and residential use of properties located hydraulically down gradient of the site.

Based on the presence of tar in the saturated zone, and exceedances of the ANZECC (2000) Primary Contact Recreation Guidelines, groundwater in the vicinity of the site, and immediately downgradient, is not suitable for extractive use. Potential extraction and subsequent use of the groundwater requires management.

Published modelling of contaminant migration of gasworks coal tar, suggests that the tar is likely to act as a source of pollution for 100 – 1,000 years, with detectable groundwater concentrations decreasing over time as the leachable fraction of the tar becomes depleted.

Impact detected in soil may pose an unacceptable direct contact health risk to future on-site maintenance and construction workers conducting sub-surface works, where no management controls are implemented. The auditor will recommend the implementation of a site management plan to control access to residual impacted material.

This summary should be read in conjunction with the fill HRA Report. Limitations and assumptions used to reach the conclusions of the HRA are contained within the report.

3.2 Regulatory Requirements

The regulations, legislation and policies that are most applicable to the management of groundwater at the site are considered to be:

Environment Protection Act (1970).

State Environment Protection Policy (Waters of Victoria), No: S107, State of Victoria, Environment Protection Act, as varied 4 June 2003.

State Environment Protection Policy (Groundwaters of Victoria), No S160, 1997 as amended on 19 March 2002 (Special Gazette G12).

State Environment Protection Policy (Prevention and Management of Contamination of Land)”, No: S95, State of Victoria, Environment Protection Act, 4 June 2002.

Guidelines for the Issue of Certificates and Statements of Environmental Audit, No. 759b EPA Victoria (June 2002).

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In relation to this site, EPA Victoria on 11 March 2011 determined that groundwater Clean Up to the Extent Practicable (CUTEP) has been achieved in accordance with EPA Publication 759a. The EPA determination included identification of the area of the site to be in a Groundwater Quality Restricted Use Zone (GQRUZ) pursuant to Clause 19 of State Environment Protection Policy (Groundwaters of Victoria), as amended in March 2002.

In EPA’s letter to the auditor of 16 May 2011, it advised that it had determined that:

1. groundwater pollution at the site has been cleaned up to the extent practicable; and

2. the site is within a Groundwater Quality Restricted Use Zone (GQRUZ).

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INFORMATION REGARDING...Revised page issued 21 November 2011 V Table 1.1: Summary of Audit...

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