ATA Environmental - MRA · ATA Environmental _____ 4. Localised SVCH impact in the SSA (including...

ATA Environmental _______________________________________________________________________________

TABLE OF CONTENTS

1. INTRODUCTION .............................................................................................................1 1.1 Objectives..................................................................................................................1 1.2 Regulatory Framework .............................................................................................1

2. BACKGROUND INFORMATION ..................................................................................3

2.1 Overview of Proposed Site Remediation Works.......................................................3 2.2 Geological and Hydrogeological Overview..............................................................3 2.3 Groundwater Effluent Quantity.................................................................................4 2.4 Groundwater Quality.................................................................................................4 2.5 Surface Water Quality...............................................................................................6

3. ASSESSMENT OF POTENTIAL IMPACTS ..................................................................8 4. KEY PERFORMANCE INDICATORS ...........................................................................9 5. GROUNDWATER EFFLUENT MANAGEMENT STRATEGY..................................10

5.1 Roles and Responsibilities ......................................................................................10 5.2 Stakeholder Consultation ........................................................................................11 5.3 Effluent Extraction..................................................................................................11 5.4 Effluent Treatment ..................................................................................................13 5.5 Proposed Method of Effluent Disposal ...................................................................14 5.6 Alternative Effluent Disposal Methods...................................................................14

6. GROUNDWATER EFFLUENT DISCHARGE CRITERIA..........................................16 7. MONITORING AND REPORTING...............................................................................18

7.1 Monitoring of General Groundwater Effluent Extraction and Treatment Operations .................................................................................................................................18 7.2 Monitoring of Groundwater Effluent Quality Discharge........................................18 7.3 Infiltration Basin Decommissioning .......................................................................19 7.4 Other Monitoring Works.........................................................................................20 7.5 Reporting.................................................................................................................20 7.6 Regulatory Approval...............................................................................................20

8. CONTINGENCY MEASURES ......................................................................................21

________________________________________________________________________________ MRA-2005-004-DESI_033_JL_V1: Groundwater Effluent Management Plan, Helena East & i Southern Embankment Former Railway Workshops, Midland Version 2: 7 August 2007


LIST OF TABLES

1. Summary of Contamination Concentrations Within the Shallow Superficial Aquifer (SSA)

2. Summary of Surface Water Quality: Helena River 3. Assessment of Potential Impacts 4. Proposed Groundwater Effluent Discharge Criteria for Onsite Disposal 5. Contingency Response Measures

LIST OF FIGURES 1. Current Site Condition and Layout 2. Inferred Point Source Contamination Hotspots 3. Inferred Extent of Groundwater Contamination Plumes (Hydrocarbon, Solvent and

Pesticides)

LIST OF APPENDICES Appendix A Groundwater Effluent Volume Estimate Calculations Appendix B Swan River Trust Correspondence

________________________________________________________________________________ MRA-2005-004-DESI_033_JL_V1: Groundwater Effluent Management Plan, Helena East & ii Southern Embankment Former Railway Workshops, Midland Version 2: 7 August 2007


1. INTRODUCTION The Midland Redevelopment Authority (MRA) proposes to remediate and redevelop 17ha of land referred to as Helena East and the Southern Embankment, located within the former Midland Railway Workshops site (Figure 1). During soil remedial works it is possible that the extraction of groundwater and other water inflows from within excavations will be required to facilitate those remedial excavation works and/or subsequent ground reinstatement. The extraction of groundwater and other water will inturn result in the need to manage the effluent in an environmentally responsible and safe manner. This Groundwater Effluent Management Plan (GEMP) forms part of the overall environmental management Program (EMP) for Helena East and the Southern Embankment and complements the Surface and Groundwater Management Plan (ATA 2006a) appended to the ATA (2006b) Public Environmental Review (PER) document (see Section 1.2). This GEMP has been developed in accordance with best practise guidelines including those publications contained within the Department of Environment and Conservation (DEC) Contaminated Sites Management Series. Consideration is also given to guidance provided in the Department of Water [(DoW) 2006] Dewatering of Soils at Construction Sites publication, particularly in the development of an appropriate groundwater effluent discharge strategy. 1.1 Objectives The objective of the GEMP is to set out management strategies for the extraction, treatment and disposal of groundwater effluent and other effluent which, with the implementation of management measures and safeguards, can be undertaken in an environmentally responsible and safe manner that will not adversely impact on the environment or human health. In order to achieve the above objective, the GEMP will address the following key elements: • Probable groundwater effluent quality and quantity; • Potential environmental hazards and impacts and key environmental performance

indicators; • Review of possible groundwater effluent extraction, treatment and disposal methods;

and • Development of monitoring & reporting programs 1.2 Regulatory Framework The Helena East and Southern Embankment remediation and redevelopment proposal was formally assessed under the Environmental Protection Act 1986, and a PER of the proposal was prepared and released for public comment in March 2006. Commitments were made by the MRA in the ATA (2006b) PER to rehabilitate the site to be compatible with the proposed future land uses, and to do so in a manner that would not adversely impact on the environment or human health. The PER proposal has since been conditionally approved by the Minister for the Environment (Climate Change; Peel) by the issue of Ministerial Statement No. 742 on 6 June 2007. The GEMP has not been prepared to satisfy any one Ministerial condition but instead has been prepared to satisfy a commitment of the Surface and Groundwater Management Plan (ATA 2006a) in relation to potential groundwater dewatering during remedial works.

________________________________________________________________________________ MRA-2005-004-DESI_033_JL_V1: Groundwater Effluent Management Plan, Helena East & 1 Southern Embankment Former Railway Workshops, Midland Version 2: 7 August 2007


In accordance with DEC (2006) Contaminated sites auditors: guidelines for accreditation, conduct, and reporting, this GEMP is submitted to the appointed Contaminated Sites Auditor for this site, Mr Jeremy Hogben of Environmental Resources Management (Australia) Pty Ltd, for his consideration and endorsement prior to its implementation.



2. BACKGROUND INFORMATION In order to establish an understanding of the likely quantity and quality of groundwater effluent that may require management during remedial works, a review of relevant background information promulgated in the ATA (2006b) PER has been undertaken. The actual extent of subsurface remedial excavation works relative to the depth and nature of the groundwater system beneath the site is considered a key factor in determining the likely quantity of groundwater effluent requiring management and these factors are reviewed below in Section 2.1 and Section 2.2 and evaluated in Section 2.3. Analytical data obtained from groundwater investigation works performed to date (Section 2.4) provides an indication into the probable quality of groundwater effluent. Further detail and supporting information applicable to the proposed site remedial works and the environmental setting of the site can be found in the ATA (2007) Remediation and Validation Plan (RVP) and the ATA (2006b) PER, respectively. 2.1 Overview of Proposed Site Remediation Works The proposed remedial works will involve the excavation of significant quantities of contaminated waste fill material and the excavation of inferred point-source contamination ‘hotspots’. It is the excavation of these point-source contamination hotspots, particularly deeper hotspots such as the hydrocarbon-based hotspots in the surrounds of the element shop [~5m below ground level (mBGL)], water tank (~8mBGL) and within the Southern Embankment (~9.5mBGL), that are most likely to intersect groundwater and in turn, potentially lead to the need to manage groundwater effluent. The location of inferred contamination hotspots are shown in Figure 2. 2.2 Geological and Hydrogeological Overview The uppermost occurrence of groundwater beneath the site, termed the ‘shallow superficial aquifer’ (SSA), has been encountered at depths ranging from approximately 1.5mBGL to 6.5mBGL (7mAHD-12mAHD). The SSA is a complex flow system perched within the ‘Upper Clay’ unit of the Guildford Formation. Overall, the effective porosity and specific yield of the SSA is considered to be low due to its predominantly clay-rich geology. However, local hydrogeological variations are expected, particularly where the SSA occurs in relatively more sand-rich lenses. Based on the anticipated depth of subsurface disturbance discussed in Section 2.1, the SSA is considered likely to be intersected during areas of deeper site remedial works exceeding 7mAHD-12mAHD. At depths ranging from 9.0mBGL-10.5mBGL (3.0mAHD-4.5mAHD), a deeper groundwater system, termed the lower superficial aquifer (LSA) has been encountered beneath the site. The LSA occurs within the Lower Sands unit of the Guildford Formation and Henley Sands and comprises unconsolidated sand lenses, minor silt and slightly indurated sandstone. Groundwater investigation works undertaken to date suggests that the LSA may be mildly confined/semi-confined beneath the site. In addition, due to its sand rich nature, the effective porosity and specific yield of the LSA as a whole is considered to be higher than the overlying SSA. Based on the anticipated maximum site remedial excavation depth of 9.5mBGL (~4mAHD), and a measured LSA standing water level (SWL) of approximately 2.5mAHD in this corresponding area, it is considered unlikely that management of the groundwater effluent associated with the LSA will be required. In the event that contaminated soil does extend into the LSA, it is unlikely that it will be practicable to remove this material given the difficultly in excavating to such a significant depth below site surface levels as well the likely need to



actively dewater the LSA which would prove complicated given the semi-confined properties of the LSA. Environmental safeguards to avoid the interception of LSA during general remedial excavation works are provided in Section 5.3. In the event that the LSA is intercepted, contingency measures have been outlined in Section 8. It is noted that environmental safeguards for remediation of the localised semi-volatile chlorinated hydrocarbon impacted (SVCH) area will be included in a separate management plan in order to satisfy Condition 9-2 of Ministerial Statement No. 742. 2.3 Groundwater Effluent Quantity With consideration to the physiological setting of the site discussed above, an estimate of groundwater flow that may seep into excavations during the remediation of three deeper contamination hotspots most likely to intersect the SSA (as depicted in Figure 2) has been calculated. Calculation worksheets are provided in Appendix B. By applying a site-specific hydraulic conductivity value of 3.47x10-6 m/sec as published in ENV (2003) Hydrogeological Investigation, the estimated volume of groundwater inflow into site excavations is approximately 18KL. In contrast, by applying a literature hydraulic conductivity value of 1.57x10-5 m/s for unconfined clay superficial groundwater systems as published in Davidson (1995), an estimate of 80KL is calculated. As illustrated by the application of different hydraulic conductivity values above, it is difficult to define with a high level of confidence an estimate of the volume of groundwater effluent that will arise through site remedial works. In addition to groundwater seepage rates, other factors that have the potential to significantly influence the volume of groundwater effluent include final pit dimensions, rainfall events, surface runoff and the overall time that such excavations remain open. Bearing these uncertainties in mind, it may be necessary to revise some elements of the GEMP should significantly higher volumes of groundwater effluent require management during site remedial work. Such revisions and other contingency measures are addressed in Section 8 of the GEMP. 2.4 Groundwater Quality Groundwater investigation works that have been performed to date have identified four broad types of groundwater impact beneath Helena East and the Southern Embankment. The nature and extent of groundwater impact, as detailed in the ATA (2006b) PER, can be summarised as follows: 1. Widespread marginal elevations of metals (particularly zinc and copper) in the SSA

across much of the site that may be a regional phenomenon; 2. Localised nickel contamination hotspot in the SSA that is likely to be associated with the

former Plating Shop; 3. Localised hydrocarbon contamination hotspots in the SSA that are likely to be

associated with diesel and solvent spills, mainly in the vicinity of the Power House [including a Light Non-Aqueous Phase Liquid (LNAPL)] and south of the Tarpaulin Shop; and



4. Localised SVCH impact in the SSA (including trichloroethene, tetrachloroethene, vinyl chloride and other associated degradation products) which has in turn migrated through overlying clay-rich strata into the LSA as a result of its chemical and physical characteristics.

Table 1 compares the contamination profile of the SSA (being the most likely groundwater system to be intersected during remedial excavation works) against default water quality guidelines including the DoE (2003) draft drinking water and freshwater guideline levels and also the ANZECC (2000) irrigation short-term trigger values (STVs).. The water quality criteria adopted in Table 1 are default criteria and do not necessarily reflect the groundwater effluent discharge criteria which will vary depending on the adopted method of discharge and in some cases, will be limited by the level of detection achievable by commercial analytical laboratories (see also Section 6). The water quality of the SSA (and in turn the probable water quality of groundwater effluent) will be used to evaluate and prioritise appropriate effluent treatment and disposal strategies. Further groundwater analytical detail and supporting information can be found within the ATA (2006b) PER.

TABLE 1 SUMMARY OF PEAK CONTAMINATION CONCENTRATIONS WITHIN THE

SHALLOW SUPERFICIAL AQUIFER (SSA)

Relevant Water Assessment Criteria SSA Peak

Concentrations1 Drinking Water4 Freshwater4 Irrigation STVs3

Contaminant

mg/L Cadmium 0.0005 0.002 0.0002 0.05 Copper 0.010 2 0.0014 5 Manganese 0.92 0.5 1.9 10 Mercury 0.0004 0.001 0.00006 0.002 Nickel 10.0 0.02 0.011 2 Zinc 0.65 3 0.008 5 Naphthalene 0.12 NV 0.016 NV Total PAHs 0.25 NV 0.003 NV Aldrin 0.00014 0.0003 0.00001 NV DDT 0.0029 0.02 0.000006 NV Chlordane 0.000131 0.001 0.00003 NV Benzene 0.009 0.001 0.95 NV m & p-Xylenes 0.670 0.2 NV o-Xylene 0.580 0.6 0.35 NV Vinyl chloride 0.470 0.0003 0.00072 NV Carbon tetrachloride 0.590 0.003 NV NV Dichloromethane 0.098 0.004 NV NV 1,2-Dichloroethane 0.085 0.003 NV NV Trichloroethene 4.1 0.07 0.52 NV Tetrachloroethene 31.0 0.05 0.042 NV

1: Data reproduced from ATA (2006b) PER 2: Dutch (2000) Intervention Level adopted in the absence of DoE (2003) draft guidelines 3: Short-Term Irrigation Values adopted from ANZECC (2000) 4: DoE (2003) Drinking Water and Freshwater Assessment Levels Shaded Cell: Contaminant concentration exceeds guideline value NV: No Value



It is noted that the contamination concentrations summarised in Table 1 above are peak concentrations that have been recorded from groundwater investigation wells representative of the SSA and therefore, in addition to the presence of the localised LNAPL plume in the vicinity of the Power House, are likely to be a conservative indication of the quality of the SSA across the broader site. As such, the groundwater contaminant concentrations summarised in Table 1 are a conservative reference to the potential quality of groundwater effluent that may require management during remedial works. 2.5 Surface Water Quality Helena River is the nearest and receiving water body for stormwater discharged from the site. Whilst the discharge of treated groundwater effluent into the stormwater system is not currently the preferred groundwater effluent disposal option (effluent disposal strategy is discussed in Section 5.5), background surface water quality is provided for completeness should this disposal option require further consideration during remedial works. Surface water sampling has been undertaken at different locations within the Helena River as part of the ATA (2006b) PER, with subsequent samples since collected in accordance with Proponent Commitment Item 6 of the ATA (2006b) PER. A summary of peak contaminant concentrations detected within the Helena River is provided in Table 2. Further detail and supporting information can be found within the ATA (2006b) PER.

TABLE 2 SUMMARY OF SURFACE WATER QUALITY: HELENA RIVER

Relevant Water Assessment Criteria Helena River

Peak Concentrations1

Drinking Water3 Freshwater3 Contaminant

mg/L Arsenic 0.001 0.007 0.013 Cadmium <0.0001 0.002 0.0002 Chromium 0.007 0.05 0.01 Copper <0.001 2 0.0014 Mercury <0.0002 0.001 0.00006 Nickel 0.001 0.02 0.011 Lead 0.001 0.01 0.0034 Zinc 0.008 3 0.008 TPHs (C6-C9) <0.02 NV NV TPHs (>C9) <0.1 NV NV Benzene <0.001 0.001 0.95 Toluene <0.001 0.8 0.3 Ethylbenzene <0.001 0.3 NV Xylenes <0.003 0.6 0.2 Vinyl chloride <0.001 0.0003 0.00072 1,2-Dichloroethane <0.001 0.003 NV Trichloroethene <0.001 0.07 0.52 Tetrachloroethene <0.001 0.05 0.042 Total PAHs <0.0025 NV 0.003

1: ATA (2006b) PER and ATA (2007) Helena River Water and Sediment Sampling 2: Dutch (2000) Intervention Level adopted in the absence of DoE (2003)draft guidelines 3: DoE (2003) Drinking Water and Freshwater Assessment Levels Shaded Cell: Contaminant concentration equal to or exceeds DoE (2003)draft Guidelines NV: No Value



Other than the presence of marginally elevated zinc concentrations [equivalent to DoE (2003) Freshwater guidelines], background concentrations of the contaminants of concern are below the applicable DoE (2003) draft assessment criteria. The ongoing water and sediment sampling program within the Helena River will continue to monitor the contaminants of concern, including the validity of the marginally elevated zinc concentration.



3. ASSESSMENT OF POTENTIAL IMPACTS There are a number of potential adverse environmental impacts and other impacts that could potentially occur as a result of the extraction and disposal of groundwater effluent. A review of the more significant potential impacts and the likelihood of these occurring at the site and its surrounds are provided below in Table 3.

TABLE 3 ASSESSMENT OF POTENTIAL IMPACTS

Action Potential Impact Risk Potential

Reduced groundwater yield in offsite supply bores

Considered a very low risk since the SSA is a low yielding, discontinuous groundwater system. There is no known usage of the SSA as source of irrigation or the like.

Reduce surface water body level and flow

Considered a very low risk since the interconnection between the SSA and the Helena River is limited with the SSA flow inferred to migrate vertically into the LSA.

Land subsidence and damage to buildings and structures

Considered a potential risk. A number of buildings and structures of heritage value exist onsite and in close vicinity to areas potentially requiring extraction of groundwater effluent.

Disturbance of acid sulphate soils

Considered a very low risk since geologies indicating the presence of acid sulphate soils have not been encountered onsite. Acid sulphate soil mapping (WAPC, 2003) indicates the site is within an area of ‘no known risk’.

Groundwater Extraction

Alter the profile and extent of groundwater contamination plume(s)

Considered a potential risk since groundwater within the SSA is polluted.

Flooding and erosion of land and surface water bodies

Considered a potential risk, however discharge rates would need to be significant and greater than that experienced during standard storm water discharge events.

Pollution of land and surface water bodies Damage to native vegetation

Considered a potential risk since groundwater within the SSA is polluted.

Sediment build-up in drains and wetlands

Considered a potential risk.

Offsite groundwater effluent discharge

Release of aesthetically offensive effluent

Considered a potential risk since groundwater within the SSA is polluted and contains some localized phase separated hydrocarbons (PSH).

Contamination of land

Release of aesthetically offensive effluent

Considered a potential risk since groundwater within the SSA is polluted and contains some PSH.

Damage to native vegetation Considered a low risk since the presence of native vegetation onsite is for the most part limited to the Southern Embankment.

Onsite groundwater effluent discharge

Flooding and erosion of land Considered a potential risk since infiltration of effluent may be limited by the low permeability and effective porosity of the Upper Clay unit.

An assessment of potential impacts that may result through extraction and disposal of groundwater effluent has identified a number of risks that will need to be managed through a combination of the design of groundwater effluent extraction and disposal strategy including treatment of groundwater effluent along with operational safeguards to mitigate these risks.



4. KEY PERFORMANCE INDICATORS Bearing in mind the potential impacts associated with the extraction and disposal of groundwater effluent that have been identified in Section 3, the key performance indicators (KPIs) that are set for the effective performance of the GEMP are as follows: 1. Disposal of groundwater effluent offsite does not adversely affect the condition of the

Helena River floodplain through erosion, siltation, flooding, pollution or any other adverse environmental or social impact;

2. Disposal of groundwater effluent onsite does not adversely affect the condition of the

site through the contamination or re-contamination of land, flooding, water logging, erosion or any other adverse environmental or social impact;

3. Extraction of groundwater effluent does not adversely affect the profile and extent of the

groundwater contamination plumes beneath the site; and 4. Extraction of groundwater effluent does not adversely affect building or structure

stability through land subsidence or soil erosion.



5. GROUNDWATER EFFLUENT MANAGEMENT STRATEGY The proposed groundwater effluent management strategy put forward assumes that the extraction of groundwater will be limited to localised areas of the site and the quantity of effluent will not be significant and similar to that estimated in Section 2.3. Revision and refinement of some elements of the groundwater effluent management strategy may be required to suit the actual quantity and quality of groundwater effluent encountered and this respect, a number of alternative methods of groundwater effluent disposal have been provided in Section 5.5 and the revision to elements of the GEMP has been recognised as a contingency measure in Section 8. The primary elements of the groundwater effluent management strategy, along with the roles and responsibilities in the implementation of the GEMP are outlined in separate subsections below. 5.1 Roles and Responsibilities The Environmental Supervisor and the Earthworks Contractor are considered to be the primary parties responsible for the implementation of the GEMP and its ongoing management. A description of key roles and responsibilities for the Environmental Supervisor and the Earthworks Contractor and other key members of the project works group (PWG) in relation to the GEMP are summarised separately below. Environmental Supervisor (ATA Environmental/Coffey Environments) • Oversee general conformance of extraction, treatment and disposal of groundwater

effluent and other effluent with environmental management measures through site inspections, review of site records and communication with the Earthworks Contractor;

• Perform groundwater effluent monitoring and, with consideration to analytical results

and other factors, provide advice to the Earthworks Contractor on groundwater effluent compliance with groundwater effluent disposal criteria;

• Assist as needed the Earthworks Contractor / Superintendent in the resolution of issues

related to extraction, treatment and discharge of groundwater effluent or other effluent; and

• Respond to any environmental complaints and non-conformances and as applicable,

communicate such issues with the PWG, regulatory bodies and its representatives (including the Contaminated Sites Auditor).

Earthworks Contractor (Georgiou Group) • Obtain licences, approvals and/or permits applicable to the extraction, treatment and

disposal of groundwater effluent and other effluent; • Implement groundwater effluent management measures in accordance with the GEMP,

relevant environmental laws, codes of practice, guidelines, standards and any specific contractual and legislative requirements;

• Review and monitor compliance of site team and contractors/subcontractors to project

standard requirements such as implementation of engineering, procurement, safety and environmental activities and safe practices;



• Assist as needed the Environmental Supervisor/ Superintendent in the resolution of issues related to extraction, treatment and discharge of groundwater effluent or other effluent; and

• Notify the Environmental Supervisor and the PWG of any environmental complaints and

non-conformances using an Environmental Incident & Hazard Form. Client [Midland Redevelopment Authority (MRA)]. • Provide guidance to the Environmental Supervisor and the PWG on the consistency of

the GEMP (and any subsequent revisions) with respect to the objectives of the MRA and its environmental, social and economic priorities; and

• Inform the community of any potential disruptions and address community complaints

and queries in accordance with ATA (2006a) Community Consultation Plan. Project Superintendent/Project Engineer [Wood & Grieve Engineers (WGE)]. • Provide engineering advice to the Earthworks Contractor and the PWG with respect to

engineering and design elements of the GEMP (and any subsequent revisions) including groundwater extraction (and risk to buildings and structures), groundwater effluent storage and groundwater effluent disposal facilities;

• Oversee general project management of the development works and ensure that works

are being conducted in accordance with contract specifications, regulations; and • Regularly inform the Client of the project status. 5.2 Stakeholder Consultation To evaluate the feasibility of implementing the groundwater effluent management strategy, key stakeholders have been consulted during its development. The Earthworks Contractor, Project Engineer and the Client have reviewed critical elements of the GEMP and feedback obtained through this process has been incorporated into the finalised GEMP. Endorsement of the GEMP by the appointed Contaminated Sites Auditor will also be requested prior to implementing the GEMP. The Swan River Trust (SRT) has been consulted with respect to the regulatory requirements associated with the discharge of groundwater effluent into the SRT-managed Helena River and/or the onsite surface waterbody known as the Helena West Coal Dam. The SRT has confirmed that the discharge of groundwater effluent into the existing stormwater system which flows into the Helena River, would be subject to the approval of an application under Part 5 (Development Control) of the Swan River Trust Act 1988. Clarification by the SRT with respect to the regulatory requirements (if any) applicable to the discharge of groundwater effluent into the Coal Dam was pending at the time of finalisation of the GEMP. SRT correspondence has been included in Appendix B. 5.3 Effluent Extraction Under the Rights in Water and Irrigation Act 1914, depending on the nature of the groundwater system along with the rate and length of groundwater extraction, a Groundwater Dewatering License may need to be issued by the Department of Water (DoW). Accordingly, prior to commencement of effluent extraction works the Earthworks Contractor should consult



the DoW and confirm the applicability of any licensing requirements to the extraction operation in question. Notwithstanding any potential Groundwater Dewatering License conditions that may apply, the following groundwater effluent extraction strategy is proposed. • Contaminated soils will be excavated to the greatest depth achievable before

groundwater effluent extraction is required but not to within 1.0m of the LSA as guided by the Environmental Supervisor. This environmental safeguard will allow for ponding of groundwater from the SSA at the base of the excavation and avoid potential cross-contamination with the deeper LSA. Where phase-separated hydrocarbons (PSH), surface scum or other floating matter are identified within excavations, absorbent pads and/or a liquid waste contractor will be engaged to remove the layer from the ponded water. Any contaminated absorbent pads will be disposed offsite as controlled waste to a licensed disposal facility and any disposal documentation retained for record-keeping purposes.

• Land subsidence/movement and subsequent damage to buildings and structures has been

identified as a potential risk associated with groundwater extraction activities (Table 3). In order to manage this risk, the Project Engineer will be consulted where groundwater dewatering is required to complete excavation works that are in the vicinity of buildings and structures. Depending on the particular circumstance, the Project Engineer may deem dewatering (and further excavation) requires specific engineered safety precautions be applied (such as sheet piling, etc).

• A mobile liquid vacuum pump or similar will be used to pump groundwater effluent that

has ponded within the excavation. Passive dewatering of groundwater by only extracting pit seepage will minimise the potential to adversely alter the hydrogeological regime beneath and beyond the site or cause land subsidence.

• All groundwater effluent extracted from within known or inferred SSA hydrocarbon

plumes (as depicted in Figure 3) will be treated and discharged into a holding tank or similar for analytical verification prior to disposal.

• In areas outside of known or inferred groundwater hydrocarbon plumes, or where

ponded water within excavations may not be representative of groundwater quality (i.e. contains surface runoff, rainfall, etc) and does not demonstrate any field evidence of contamination, in consultation with the Environmental Supervisor, groundwater effluent or other effluent may be discharged directly into holding tanks or similar without pre-treatment. In such instances, untreated effluent should be stored separately from treated effluent until analytical verification has been obtained. Groundwater effluent discharge criteria and monitoring requirements and for treated and untreated groundwater effluent are outlined in Section 6 and Section 7, respectively.

• Where large volumes of groundwater effluent are extracted, storage of groundwater

effluent in a lined containment pond or similar may be required. In this respect, a waste water storage tank located at the base of the Southern Embankment (Figure 1) has been identified as potentially suitable storage vessel for extracted groundwater effluent. Appropriate positioning of the containment pond should be agreed in consultation with the Environmental Supervisor and the appointed Contaminated Sites Auditor. The containment pond or other storage vessel should be watertight and of a sufficient size so as to contain the forecast volume of groundwater effluent and any potential surface runoff that may occur during a storm event or similar.

Alternative groundwater effluent extraction methodologies, such as active dewatering through dewatering spears, will need to be carefully reviewed in consultation with key stakeholders to evaluate potential risks, particularly those associated with land subsidence and groundwater contamination plumes (see contingency measures in Section 8).



5.4 Effluent Treatment Based on the nature and concentration of a number of contaminants that have been detected within the SSA (as summarised in Table 1), it is likely that a combination of active and passive treatment of contaminated groundwater effluent will be required to enable the preferred disposal option of onsite reuse to occur in an environmentally safe and responsible manner. It is also noted that the treatment of contaminated groundwater that accumulates within excavations forms part of the groundwater remediation strategy proposed in the ATA (2006b) PER and is referred to in Ministerial Statement 742 (although not forming a specific ministerial condition). The following treatment methodology is proposed: • A mobile water treatment vessel will be used to treat effluent contamination

concentrations in excess of the effluent discharge criteria. A treatment vessel offered by Hydrocarbon Remedial Services has shown effective performance in past remedial projects in reducing hydrocarbon and metal concentrations by up to 98%. Typically, effluent that enters the treatment vessel will first be directed into a column filled with activated carbon granules. Water flows countercurrent to the weight of the activated carbon, ensuring that channel bypasses are not formed. Water then flows directly into a buffer tank that allows air sparging/ventilation of any residual volatile hydrocarbon fractions;

• The Earthworks Contractor through its subcontractor will be responsible for maintaining

correct operation of the vessel including replacement and recharging of activated carbon treatment columns as required;

• Effective operation of the treatment vessel should be verified through laboratory analysis

of both influent and effluent prior to reusing treated groundwater onsite. Effluent monitoring programs are outlined in Section 7; and

• In conjunction with active remedial treatment methods, the disposal of groundwater

effluent onsite through controlled irrigation (i.e. dust suppression) or infiltration ponds will assist in passively remediating minor contaminant concentrations (particularly metals) within groundwater effluent. This is due to natural filtration processes such as adsorption and absorption and precipitation of suspended sediments for which clay-rich soils, such as that found at the site, are typically effective.

It is noted that for some alternative disposal options, such as the disposal of groundwater effluent as liquid waste through a liquid waste contractor or disposal into the waste water system (subject to any trade waste permit requirements), groundwater effluent may require little or no pre-treatment. Further discussion of alternative effluent disposal options is provided in the following section.



5.5 Proposed Method of Effluent Disposal With consideration to DoW (2006) Dewatering of Soils at Construction Sites, disposal of groundwater effluent onsite is proposed in favour of offsite disposal. Possible onsite uses for groundwater effluent may include use for dust suppression water supply purposes or disposal to ground via infiltration basins. Offsite disposal options may include disposal to sewer or stormwater, or removal of groundwater effluent by liquid waste contractors. Management measures for the preferred disposal of groundwater effluent onsite are outlined below. • Where used for dust suppression purposes, groundwater effluent will be applied in a

manner that is consistent with safeguards and measures included in the ATA (2007) Dust and Air Quality Management Plan and the ATA (2006a) Site Environmental Management Plan. In particular, the irrigation of groundwater effluent should not cause any appreciable surface runoff and erosion.

• Where groundwater effluent is disposed to ground via infiltration ponds, the treatment

ponds should be sized in accordance with Guidance for Groundwater Management in Urban Areas on Acid Soils (DoE, 2004) so as to enable precipitation of any suspended sediment within groundwater effluent. In addition, any infiltration pond in itself should not be within direct contact of the uppermost groundwater system so as to enable any attenuation process through contact with clay-rich soils to occur. The positioning of infiltration ponds should be evaluated in consultation with the Environmental Supervisor and agreed to by the appointed Contaminated Sites Auditor. Alternative disposal options will need to be considered where infiltration ponds lead to the prolonged presence of stagnant surface water and/or waterlogged soils (see contingency measures in Section 8).

• At the completion of groundwater effluent disposal operations, the base of each

infiltration pond should be validated for potential impact from the contaminants of concern in accordance with procedures and methods detailed in the ATA (2007) Remediation and Validation Plan and Section 7.3.

5.6 Alternative Effluent Disposal Methods In consultation with key stakeholders (Section 5.2), it is acknowledged that there may construction and engineering constraints or other constraints that may hinder the disposal of groundwater effluent onsite where effluent volumes are significant. Accordingly, a number of alternative offsite disposal options (in no particular order) and the potential implications of each are outlined below. Alternative disposal options will require consultation with the Environmental Supervisor and agreement by the appointed Contaminated Sites Auditor. 1. Discharge to Sewer. Disposal to the waste water network would require the approval of

the Water Corporation and the effluent would be required to meet Trade Waste acceptance criteria as well as any other specific conditions that may apply to the issued Industrial Waste Permit. It is likely that this disposal option will require some level of treatment such as removal of immiscible liquids (i.e. PSH) in order to comply with the requirements of an Industrial Waste Permit. The current capability of the waste water network to accommodate groundwater effluent flows has been estimated at up to 5L per second by the Project Engineer and the Earthworks Contractor will need to assure itself of the practicability of this method of disposal.



2. Offsite Disposal via Liquid Waste Contractors. Offsite disposal of contaminated groundwater effluent as contaminated waste may be considered an appropriate management option for small volumes of waste and/or highly contaminated waste such as PSH, or in situations where prompt disposal is required. The typically high cost involved in disposing groundwater effluent as liquid waste is likely to prohibit the suitability of this option where large volumes of extracted groundwater effluent require management.

3. Discharge to Helena River. As indicated in Section 5.2, correspondence with the Swan

River Trust (SRT) (included in Appendix B) has confirmed that the discharge of groundwater effluent into the existing stormwater system which flows into the Helena River, would be subject to the approval of an application under Part 5 (Development Control) of the Swan River Trust Act 1988. This approval process is understood to take several months and on this basis is not considered a practical option for the discharge of groundwater effluent at this time.

4. Discharge to an Onsite Surface Waterbody (‘Helena West Coal Dam’). The Coal Dam

has an approximate capacity of 120ML and is fed via a combination of incidental rainfall, untreated stormwater, and extraction from the Leederville Formation under licence from the Department of Water. The Coal Dam is used as a water supply for the irrigation of public open space within the Helena West Precinct. The Coal Dam may also be used to supply water for dust suppression works during remedial works at Helena East. It is likely that in the event groundwater effluent was discharged into the Coal Dam, the equivalent volume of water would be more than that re-extracted from the Coal Dam for dust suppression works which may in effect reduce the volume of water extracted from the Leederville Formation. On its merits, discharging into the Coal Dam would appear to have a number of benefits, however due to time constraints, this option is subject to SRT confirmation that an application under Part 5 (Development Control) of the Swan River Trust Act 1988 is not required. Correspondence with the SRT is provided in Appendix B.



6. GROUNDWATER EFFLUENT DISCHARGE CRITERIA For the proposed method of groundwater effluent storage and discharge (i.e. dust suppression and/or infiltration basins, as discussed in Section 5.5) and also the alternative option of discharging/storing effluent into the Helena West Coal Dam, it is considered appropriate to adopt the ANZECC (2000) irrigation short-term trigger values (STVs) as the groundwater effluent discharge criteria. The application of the ANZECC (2000) irrigation STVs as the groundwater effluent discharge criteria is considered appropriate based on the following considerations: • Groundwater effluent extraction and discharge operations will operate over a relatively

short period of time and can therefore be considered a short-term use (less than 20 years) rather than a long-term use (up to 100 years) which is applicable to the DoE (2003) long-term irrigation values;

• Whilst the protection of surface water bodies (namely the Helena River) is considered a

relevant and protected beneficial use, reinfiltration of groundwater effluent onsite via infiltration basins or general dust-suppression irrigation works that is below the adopted discharge criteria is unlikely to compromise this use. This is due to the dilution and attenuation processes that could reasonably be expected to occur through infiltration of the clay-rich upper geology and the SSA, and any potential discharge from the SSA into the indirectly connected Helena River;

• It is not anticipated that the application of the proposed groundwater effluent discharge

criteria will contaminate or re-contaminate onsite soils since at these levels the overall mass of contaminants is extremely low and unlikely to exceed relevant background levels and/or ecological and health-based soil assessment criteria. As an additional precaution, the base of each infiltration pond and any accumulated sediment will be validated for potential impact prior to decommissioning (see Section 7.3);

• If groundwater effluent was to be discharged into the Helena West Coal Dam, (currently

an alternative method of groundwater effluent discharge), the adopted groundwater effluent discharge criteria would not comprise the primary beneficial use of the Coal Dam as a reservoir for irrigation water. The volume of groundwater effluent that may result through site remedial works estimated at 18KL-80KL (see Section 2.3) is relatively insignificant in the context of the Coal Dam, equating to less than 1% of the Coal Dam holding capacity and therefore unlikely to alter background water quality within the Coal Dam or the indirectly connected Helena River.

Where ANZECC (2000) irrigation STVs have not been specified, the DoE (2003) Freshwater assessment levels, Dutch Intervention values (NMSP&W, 2000) and DoE (2003) Drinking Water assessment levels have been adopted in preferential order. The adoption of the stringent DoE (2003) freshwater assessment levels and the Dutch Intervention values as the groundwater effluent discharge criteria for the majority of organic compounds will ensure that where these site-sourced contaminants accumulate in excavations, they are remediated to the extent practicable in accordance with ATA (2006) PER commitments. The adopted groundwater effluent discharge criteria are summarised in Table 4. No groundwater effluent discharge criteria have been specified for TPHs C6-C9 with the assessment of BTEX commonly applied as an indicator for any risk that may be associated with the detection of such lighter fuel fraction hydrocarbons. It is noted that for some analytes where an extremely low discharge criteria has been set (such as dieldrin), it is anticipated that the discharge criteria will be below the laboratory limit of reporting (LOR). For such analytes, lowest possible detection limits will be requested and, with consideration to DoE (2003), the LOR set as the groundwater effluent discharge criteria for these analytes.



TABLE 4

PROPOSED GROUNDWATER EFFLUENT DISCHARGE CRITERIA FOR ONSITE DISPOSAL AND DISPOSAL TO HELENA WEST COAL DAM

Water Quality Assessment Criteria Adopted Discharge Acceptance Criteria1 Drinking

Water2 Freshwater2 Irrigation STV3

Contaminant

mg/L Arsenic 2 0.007 0.013 2 Cadmium 0.05 0.002 0.0002 0.05 Chromium 1.0 0.05 0.01 1.0 Copper 5 2 0.0014 5 Manganese 10 0.5 1.9 10 Mercury 0.002 0.001 0.00006 0.002 Nickel 2 0.02 0.011 2 Lead 5 0.01 0.0034 5 Zinc 5 3 0.008 5 TPHs (C6-C9) NV NV NV NV TPHs (>C9) 0.6 NV 0.64 NV Benzene 0.95 0.001 0.95 NV Toluene 0.3 0.8 0.3 NV Ethylbenzene 0.3 0.3 NV NV Xylenes 0.2 0.6 0.2 NV Vinyl chloride 0.0007 0.0003 0.00074 NV 1,2-Dichloroethane 0.003 0.003 NV NV

Trichloroethene 0.5 0.07 0.54 NV Tetrachloroethene 0.04 0.05 0.044 NV Benzo(a)pyrene 0.00001 0.00001 NV NV Total PAHs 0.003 NV 0.003 NV Aldrin 0.00001 0.00001 NV Dieldrin 0.000002 0.0003 0.000002 NV Chlordane 0.00003 0.001 0.00003 NV DDT 0.000001 0.02 0.000001 NV pH 6.5-8.5 6.5-8.5 6.5-8.5 NV

1: For metals, the adopted discharge criteria apply to total metal concentrations rather than dissolved metal concentrations.

2: DoE (2003) draft assessment levels 3: ANZECC (2000) Irrigation Short-Term Trigger Values 4: Dutch (2000) Intervention Level adopted in the absence of DoE (2003) draft guidelines Shaded Cell: Adopted Groundwater Effluent Discharge Criteria NV: No Value For some alternative methods of groundwater effluent disposal such as direct disposal into the Helena River or direct groundwater recharge (such as through groundwater reinjection or similar), there are a number of chemical and physical criteria for which the effluent would be required to satisfy. In the case of toxicants, DoW (2006) prescribes that groundwater effluent discharge quality would need to cause no more than a maximum increase in the ‘seasonal background concentration’ of any toxicant of ten percent, and cause a maximum rise in the receiving water’s seasonal background concentration of any toxicant to the lesser value of 75% of the ANZECC (2000) Freshwater Quality Guidelines and NHRMC (2004) Drinkwater Guidelines or ecosystem protection criterion for 90 percent of existing ecosystem species. It is emphasised that irrespective of compliance with DoW (2006) dewatering criteria, the direct discharge of groundwater effluent into the Helena River would be subject to approval by the DEC and the Swan River Trust.



7. MONITORING AND REPORTING 7.1 Monitoring of General Groundwater Effluent Extraction and Treatment

Operations In accordance with the roles and responsibilities outlined in Section 5.1, the Earthworks Contractor will be responsible for monitoring the general operations associated with the extraction, treatment and disposal of groundwater effluent. As part of its quality assurance program, the Earthworks Contractor has developed an internal Environmental Management Plan (EMP) as its working document for Helena East and the Southern Embankment. The Environmental Supervisor will review the specifications and commitments contained within the Earthwork Contractor’s EMP to ensure compliance with the GEMP and other environmental management commitments form part of the overall EMP for this site. In undertaking general operational monitoring, the Earthworks Contractor should monitor and record the following information: • Monitor all effluent extraction, treatment and disposal events by keeping a logbook or

similar. As a minimum, the location of effluent extraction and disposal, the estimated volume of extracted effluent and the method of effluent discharge should be recorded. The waste tracking system outlined in the ATA (2006a) Waste Management Plan will adopted for verifying the disposal of groundwater effluent; and

• Any unplanned discharge or spill that could impact the environment or human health

onsite or offsite, along with any complaints should be reported to the Environmental Supervisor as soon as possible along with the corrective action taken. Such incidents should be recorded on an Environmental Incident and Hazard Form in accordance with Section 9.4 of ATA (2006a). The Environmental Supervisor will endeavour to notify the appointed Contaminated Sites Auditor and any applicable bodies within 24 hours of the incident occurring.

The Environmental Supervisor will undertake random checks to ensure conformance with this GEMP. Any non-conformances will be discussed with the Earthworks Contractor and noted in an Environmental Field Activity Sheet that is completed at the end of each day of attendance by the Environmental Representative. 7.2 Monitoring of Groundwater Effluent Quality Discharge In order to ensure compliance with groundwater effluent discharge criteria and the overall GEMP key performance indicators, monitoring of groundwater effluent quality is proposed prior to its discharge onsite. Environmental sampling will be undertaken by the Environmental Supervisor in accordance with the roles and responsibilities outlined in Section 5.1. Groundwater effluent monitoring will be undertaken in the following instances: • For each individual excavation where groundwater extraction is undertaken, monitoring

of that effluent will be required. Where the effluent is to be actively treated, both the influent and the effluent should be monitored to ensure effective operation of the treatment system;



• Should continuous active groundwater effluent extraction extend for more than a week in any one excavation, groundwater influent and effluent monitoring will be undertaken on a minimum weekly basis, and more frequently where field evidence and/or analytical evidence suggest an adverse change in the groundwater effluent quality and in consultation with the appointed Contaminated Sites Auditor; and

• Where discharge of groundwater effluent onsite inadvertently leads to a effluent surface

runoff into the Helena River, in accordance with the Surface and Groundwater Management Plan [ATA (2006b) Site Environmental Management Plans], discharge effluent and/or surface water monitoring works may be initiated depending on the nature and magnitude of the discharge and in consideration of guidance provided by the appointed Contaminated Sites Auditor and the DEC;

For the proposed discharge of groundwater effluent onsite, including discharge into the Helena West Coal Dam, laboratory analysis will be performed for the contaminants of concern as follows: • Total Petroleum Hydrocarbons (TPHs); • Monocyclic Aromatic Hydrocarbons (MAHs); • Polycyclic Aromatic Hydrocarbons (PAHs); • Semi-volatile Chlorinated Hydrocarbons (SVCHs); • Organochlorine Pesticides; • Metals (As, Cd, Cu, Cr, Hg, Mn, Ni, Pb, Zn); and • pH value Sample collection (including collection of quality control samples) and analysis will be performed in accordance with the Department of Environmental Protection [DEC (2001)] Development of Sampling and Analysis Programs and other best practice guidelines contained within the DEC Contaminates Sites Management Series. The analytical results will be compared against the adopted groundwater effluent discharge criteria specified in Section 6 and reported in accordance with Section 7.5. 7.3 Infiltration Basin Decommissioning Should the disposal of groundwater effluent be undertaken using infiltration basins, the base of each basin will be validated for the presence of contaminated sediments at the completion of groundwater effluent disposal works. The Environmental Supervisor will inspect the infiltration basin and obtain at least one validation surface sample from the centre of each infiltration basin and submit the sample for the groundwater effluent contaminants of concern, as listed above in Section 7.3. Sampling and analysis methodologies (including collection of quality control samples) will be undertaken in accordance with procedures detailed in the ATA (2007) RVP and DEC (2001) Development of Sampling and Analysis Programs. The analytical results will be compared against the adopted remediation criteria adopted in ATA (2007) RVP and reported in accordance with Section 7.5. Where contaminated sediment is identified at the base of an infiltration basin, a specific remedial workscope will be developed in consultation with the appointed Contaminated Sites Auditor.



7.4 Other Monitoring Works No specific groundwater or surface water monitoring program will be undertaken as part of the GEMP. The proposed groundwater effluent extraction and disposal methodologies in themselves have been designed to minimise the potential adverse impacts identified in Table 3. Where alternative GEMP methodologies are implemented, such as active groundwater dewatering and/or offsite groundwater effluent discharge, or an environmental incident or hazard occurs, then in accordance with contingency measures (Section 8), active groundwater and surface water monitoring programs may be implemented in consultation with key stakeholders. Monitoring of potential land subsidence and risk to buildings and structures will be the responsibility of the Earthworks Contractor in consultation with the Project Engineer. 7.5 Reporting GEMP reporting will be undertaken in two formats as follows: • Incident Report: Where an incident occurs that results or may result in an adverse impact

to the environment or human health, in addition to contingency response measures outlined in Section 8, an incident report and/or Environmental Incident & Hazard Form will be submitted to the Auditor. The incident report will include the nature of the incident, causal factors, and corrective action in accordance with ATA (2006a); and

• GEMP Closure Report. At the completion of remedial works, all groundwater effluent

discharge monitoring information, infiltration basin decommissioning information will be incorporated into a GEMP Closure Report and/or incorporated into the Remediation and Validation Report for submission to the appointed Contaminated Sites Auditor. Verification documents such as operation logs, disposal dockets (if applicable), laboratory certificates and field activity records will be appended to the GEMP Closure Report.

7.6 Regulatory Approval Extraction of groundwater effluent will not commence until the GEMP has been formally endorsed by the Contaminated Sites Auditor. It envisaged that the endorsed GEMP along with other management plans that form the site EMP will be published on the MRA website (www.mra.wa.gov.au) in accordance with in the ATA Community Consultation Plan (2006a).


http://www.mra.wa.gov.au/


8. CONTINGENCY MEASURES Table 5 below identifies primary incidents/hazards and the proposed corrective action strategy. It is noted that the GEMP has been designed to wherever possible avoid unsafe environmental and social incidents or hazards from arising in the first place.

TABLE 5 CONTINGENCY RESPONSE MEASURES

Nature of Non-Conformance Corrective Action

Ineffective groundwater effluent extraction methodology

• Avoid further excavation works which are likely to result in the need to further manage groundwater effluent;

• In consultation and agreement with key stakeholders, review and implement alternative groundwater effluent extraction methods.

Ineffective groundwater effluent treatment methodology

• Review operational performance of treatment vessel including influent and effluent analytical data;

• In consultation and agreement with key stakeholders, assess alternative groundwater disposal options that may require a lower standard of treated effluent such as disposal to sewer or disposal as contaminated waste;

• In consultation with the Contaminated Sites Auditor, review alternative treatment methodologies.

Ineffective groundwater effluent disposal methodology

• In consultation with key stakeholders, review and revise onsite groundwater disposal methodology;

• In consultation and agreement with key stakeholders, review and implement alternative groundwater effluent extraction methods.

Uncontrolled groundwater effluent discharge event

• Contain any further discharge and cease any effluent extraction and disposal operations;

• Record event on a Environmental Incident/Hazard Form; • In consultation with key stakeholders, identify causal factors

and immediately rectify; • In consultation with the Contaminated Sites Auditor, review

or initiate monitoring program. Interception of the LSA • Avoid further excavation works which are likely to result in

the need to further manage groundwater effluent; • Record event on a Environmental Incident/Hazard Form; • In consultation with the Contaminated Sites Auditor, review

location-specific data and agree on appropriate action to avoid potential cross contamination of the separate groundwater systems.

In accordance with reporting requirements, the appointed Contaminated Sites Auditor and relevant regulatory bodies will be notified in writing by the Environmental Supervisor within 24 hours of an incident or hazard associated with the GEMP or the EMP in general that may present an adverse risk to human health and/or the environment.



REFERENCES ANZECC & ARMCANZ (2000) Australian and New Zealand Guidelines for Fresh and

Marine Water Quality. Volume 1, The Guidelines (Chapters 1 to 7). National Water Quality Management Strategy Paper No 4, Australian and New Zealand Environment and Conservation Council (ANZECC) & Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ), Canberra.

ATA (2006a) Site Environmental Management Plans, Remediation of Helena East Precinct,

Former Railway Workshops, Midland, Version 2, Report No. 2005/219. Prepared for the Midland Redevelopment Authority (MRA). ATA Environmental (ATA), March 2006.

ATA (2006b) Helena East Precinct, Remediation and Redevelopment: Public Environmental

Review, Version 3. Prepared for the Midland Redevelopment Authority (MRA). ATA Environmental (ATA), March 2006.

ATA (2007) Remediation and Validation Plan, Helena East and the Southern Embankment,

Version 3, Report No 2007/111. Prepared for the Midland Redevelopment Authority (MRA). ATA Environmental (ATA), July 2007.

ATA (2007) Results of Helena River Water and Sediment Sampling, Midland Redevelopment

Authority, Letter to Environmental Protection Authority. ATA Environmental (ATA), 7 February 2007.

ATA (2007) Dust and Air Quality Management Plan, Helena East and the Southern

Embankment, Version 6, Report No 2005/221. Prepared for the Midland Redevelopment Authority (MRA). ATA Environmental (ATA), June 2007.

Davidson (1995) Hydrogeology and groundwater resources of the Perth region Western

Australia, Geological Survey of Western Australia. DEC (2006) Contaminated Sites Auditors: Guidelines for Accreditation, Conduct and

Reporting. Contaminated Sites Management Series, Department of Environment and Conservation, Perth. August 2006.

DEP (2001) Development of Sampling and Analysis Programs. Contaminated Sites

Management Series, Department of Environmental Protection (DEP), Perth. DoE (2003) Assessment Levels for Soil, Sediment and Water (Draft). Version 3. Contaminated

Sites Management Series, Department of Environment (DoE), Perth. DoE (2004) Guidance for Groundwater Management in Urban Areas on Acid Sulphate Soils.

Acid Sulphate Soils Guideline Series, Department of Environment (DoE), Perth. DoW (2006) Water Quality Protection Note, Dewatering of Soils at Construction Sites.

WQPN13. Department of Water, Government of Western Australia, April 2006. ENV (2003) Hydrogeological Investigation, Helena West, Midland Railway Workshops. NHMRC/ARMCANZ (2004) Australian Drinking Water Guidelines. National Health and

Medical Research Council/Agriculture and Resource Management Council of Australia and New Zealand.



NMHSP&E (2000). Environmental Quality Objectives in the Netherlands. Netherlands Ministry of Housing, Spatial Planning and the Environment, 2000.

WAPC (2003) Planning Bulletin No. 64: Acid Sulphate Soils. Western Australian Planning

Commission (WAPC), Perth.


FIGURES

12.5

13.0

13.50

13.25

13.25

13.50

13.75

13.7514.00

13.75

14.00

14.25

13.25

13.75

13.0

13.213.4

13.6

13.8

14.0

12.8

12.6

4.0

5.0

5.0

5.0

5.0

6.0

6.0

6.0

6.0

6.0

6.0

7 .0

7.0

7.0

7.0

8.0

8.0

8.0

8.0

8.0

8.0

10.011.0

11.0

12.0

12.0

13.0

13.0

13.0

13.0

5.0

6.0

5.0

10.09.0

11.0

13.0

13.0

HELENA WESTHELENA WEST

HELENA EASTHELENA EAST

AREA EAREA E

HELENAHELENAEASTEAST

AREAS A, B, C & DAREAS A, B, C & D

EXTENT OF SOUTHERNEXTENT OF SOUTHERNEMBANKMENTEMBANKMENT

Element ShopElement Shop

PowerPowerHouseHouse

BLOCK 3BLOCK 3

BLOCK 2BLOCK 2

BLOCK 1BLOCK 1

FoundryFoundry

DRIVEDRIVE

YELVERTON

YELVERTON

PLA

CE

PLA

CE

CE

NTE

NN

IAL

CE

NTE

NN

IAL

RAILWAYRAILWAY

Helena

Helena

RiverRiver

Chief Mechanical

Chief MechanicalEngineers Building

Engineers Building

BoilerBoilerHouse/CopperHouse/CopperShopShop

FP

OILSTORE

War MemorialWar Memorialand Gardenand Garden

GATEKEEPER’S

GATEKEEPER’SOFFICEOFFICE TIME KEEPER’S

TIME KEEPER’SOFFICEOFFICE

Workers WallWorkers Wall

(Loco)(Loco)Weighbridge

Weighbridge

Old TarpaulinOld TarpaulinShopShop

Elevated CircularElevated CircularTankTank

MAIN STOREMAIN STORE

AMBULANCE BUILDING

AIR COMPRESSORS

AMBULANCE GARAGE

PatternPatternStore (&

Store (&WaterWaterTank)Tank) PatternPatternShopShop

HELENA STHELENA STEXTENSIONEXTENSION

RAILWAYRAILWAYINSTITUTE

INSTITUTE


0 25

metres

50 75 100

SCALE 1 : 2 250 @ A3

environmental scientistsEnvironmental

ATA

FIGURE 1

LEGEND

CURRENT SITE CONDITION AND LAYOUT

Fri

22 J

un 0

7P

RIN

TE

D:

GROUNDWATER EFFLUENT MANAGEMENT PLANFORMER RAILWAY WORKSHOPS, MIDLAND

Disused Waste WaterTreatment Plant Tank

(Possibly Suitable as anEffluent Holding Tank)

FOUNDRYFOUNDRY

ROADROAD

RAILWAY PARADE

RAILWAY PARADE

RESERVERESERVE

Eas

emen

t

Eas

emen

t

CLAYTON STREET

Eas

emen

t

HOT & COLDWELLS

HE

LEN

A

S

TRE

ET

HE

LEN

A

S

TRE

ET

Easement

Midland Redevelopment Area Boundary

Helena East Area Boundary

Cadastral Boundary, Proposed Lot Number

Easement Boundary

Service Tunnel

Topographic Contours (0.5m interval)

Temporary Fence

Temporary Stockpile Footprint

Existing Building / Structure Outline

8.0

MR

A-2

005-

004/

DE

SI/2

7_12

9F1.

dgn

D

AT

UM

: MG

A50

DR

AW

N:

GLM

21-

6-07

C

HE

CK

ED

: JL

RO

AD

RO

AD

WAL

LSEN

D

WAL

LSEN

D

Coal DamPark

L a k e

Eas

emen

t

Eas

emen

t

Easement

SOURCES:- BASE: McMULLEN & NOLAN, 1-06-2007SOURCES:- BASE: McMULLEN & NOLAN, 1-06-2007BUILDING LAYOUT: WOOD & GRIEVE, May 2007BUILDING LAYOUT: WOOD & GRIEVE, May 2007

EasementEasementEasement

R a i l w a y L i n e s


TunnelTunnelPortalPortal


Helena

Helena

RiverRiver

H1B-22H1B-22 H1B-60H1B-60

H1B-61H1B-61

H1B-62H1B-62

H1B-63H1B-63

H1B-29H1B-29

H1B-24H1B-24

H1B-25H1B-25

H1B-26H1B-26

H1B-27H1B-27H1B-28H1B-28

H1B-65H1B-65

H1B-65H1B-65

H1B-66H1B-66

B-1B-1 B-2B-2 B-3B-3

B-4B-4

B-5B-5B-6B-6

B-7B-7 B-8B-8

H4-1H4-1

H4-4H4-4

H4-7H4-7

H4-8H4-8

H4-9H4-9H4-10H4-10

H4-11H4-11

H4-12H4-12 H4-13H4-13H4-14H4-14

H4-15H4-15

H4-16H4-16H4-17H4-17

H4-18H4-18

H4-19H4-19

H4-20H4-20

H4-5H4-5

A-3A-3A-4A-4

A-5A-5

A-6A-6

A-7A-7A-9A-9

A-10A-10

A-11A-11

A-13A-13

A-14A-14

A-17A-17

J-1J-1J-2J-2

J-3J-3

J-4J-4

J-5J-5J-6J-6

J-7J-7

J-8J-8J-9J-9

N-1N-1

N-2N-2

N-3N-3

N-4N-4

N-6N-6N-5N-5

N-7N-7

N-8N-8

A-3A-3

A-4A-4

E-2E-2

E-3E-3E-4E-4

E-5E-5D-2D-2

D-4D-4

D-5D-5

K-1K-1 K-2K-2

K-3K-3

K-4K-4

K-5K-5M-1M-1

M-2M-2

M-3M-3M-4M-4

M-5M-5

F-1F-1F-2F-2

G-2G-2

G-6G-6

G-7G-7

G-10G-10

G-12G-12

G-13G-13

L-1L-1L-2L-2

L-3L-3

L-4L-4L-5L-5

L-6L-6

L-7L-7

L-8L-8L-9L-9

I-3I-3

I-6I-6

I-8I-8

C-2C-2C-4C-4

C-5C-5 C-6C-6

B1-1B1-1 B1-2B1-2

B1-3B1-3

B1-4B1-4

B2-2B2-2

B2-6B2-6

B2-7B2-7

B2-8B2-8

H5-1H5-1

H5-2H5-2

H5-3H5-3H5-4H5-4

H5-5H5-5

H5-8H5-8

H5-9H5-9H5-10H5-10

H5-11H5-11

H5-12H5-12

H5-13H5-13

H5-14H5-14

A-2A-2

A-3A-3

A-4A-4

A-5A-5

A-6A-6

A-7A-7

A-9A-9

A-10A-10A-11A-11

A-12A-12

A-14A-14

A-15A-15

A-16A-16

A-17A-17 A-18A-18

S-2S-2

S-1S-1

B-1B-1

B-2B-2

B-3B-3

B-4B-4

B-5B-5

W3-1W3-1

W3-2W3-2

W3-3W3-3W3-4W3-4

W3-6W3-6

W3-5W3-5

W3-7W3-7

W3-8W3-8

W3-9W3-9

W1-1W1-1

W1-2W1-2

W1-3W1-3W1-4W1-4

W1-5W1-5

W1-7W1-7

W1-8W1-8

W2-1W2-1

W2-2W2-2

W2-3W2-3

W2-4W2-4

W2-5W2-5

W2-6W2-6

W2-7W2-7

W2-8W2-8

H6-1H6-1

H6-2H6-2

H6-3H6-3

H6-4H6-4

H6-5H6-5

H6-6H6-6

H6-7H6-7

H6-8H6-8

H6-9H6-9

H6-10H6-10

H6-11H6-11

H6-12H6-12

H6-13H6-13

H6-14H6-14

H6-15H6-15

H6-16H6-16

C-1C-1

H1B-23H1B-23

A-1A-1

E-1E-1

F-4F-4

G-1G-1G-3G-3G-4G-4

I-1I-1

I-2I-2

C-3C-3

C-7C-7

C-8C-8

A-1A-1

A-2A-2

A-8A-8

A-12A-12

A-2A-2 A-5A-5

D-3D-3

D-1D-1

F-5F-5

G-5G-5

G-8G-8

G-9G-9

G-11G-11

G-14G-14

I-4I-4

I-5I-5

I-7I-7

C-1C-1

B2-1B2-1

B2-3B2-3

B2-4B2-4B2-5B2-5

A-8A-8

A-13A-13

S-3S-3

W1-6W1-6

H3-6H3-6

H3-3H3-3H3-1H3-1

H3-2H3-2

H3-8H3-8

A3-3A3-3

A3-4A3-4

A3-5A3-5

A3-6A3-6

A3-7A3-7

A3-8A3-8

A3-9A3-9

A3-10A3-10

A3-11A3-11

A3-12A3-12

A3-13A3-13

A3-14A3-14

A3-15A3-15

A3-16A3-16

A3-17A3-17

A3-18A3-18

A3-19A3-19

A3-20A3-20

A3-21A3-21

A3-22A3-22

A3-23A3-23

A3-24A3-24

A3-25A3-25

A3-26A3-26A3-27A3-27

A3-28A3-28

A3-29A3-29

A3-46A3-46

A3-47A3-47

A4-13A4-13

A4-14A4-14

A4-15A4-15

A4-16A4-16

A4-17A4-17

A4-18A4-18

A4-19A4-19

A4-20A4-20

A4-21A4-21

A4-22A4-22

A4-23A4-23

A4-24A4-24

A4-32A4-32

A4-33A4-33A4-34A4-34

A4-35A4-35

A4-36A4-36A4-37A4-37

HR32HR32

HR33HR33

HR34HR34HR35HR35

H5HH5H

HE-15HE-15

H5BH5B

HE-16HE-16

HE1HE1HE2HE2

HE3HE3

HE4HE4

HE5HE5

HE6HE6

HE7HE7

HE8HE8

HE9HE9

HE12HE12

HWMW1HWMW1

HR12HR12

B3B3

B4B4

HP1HP1

HP9HP9

HP10HP10

HP11HP11

HP13HP13

HP14HP14

HP15HP15

HP16HP16

MB10MB10

RivbedRivbed

HE14HE14

HE11HE11

HE12HE12

HE13HE13

HE-17HE-17 F-3F-3

6161

6363

6565

6868

66666464

6767

6969 7070

62625252

20201919

1818

1313

1616

5353

1717

99

1515

1212

44

55

1414

11

22

6677

33

88

2222 2323 2525

2626

3030 31312929

2424

28282727

3232

3737

4545

484849494747

3838

4040

4242

5454

4141

3535

3636

3333

4343

3939

5050

5151

4444

5656

5959

55555757

5858

10101111

2121

3434

ATA-1ATA-1

ATA-2ATA-2

ATA-3ATA-3

ATA-4ATA-4ATA-5ATA-5

ATA-6ATA-6

ATA-7ATA-7

ATA-8ATA-8

ATA-10ATA-10

ATA-11ATA-11

ATA-12ATA-12 ATA-13ATA-13

ATA-14ATA-14

ATA-15ATA-15

ATA-16ATA-16

F1F1

F2F2

F3F3F4F4

F5F5

F6F6

F7F7F8F8

F9F9

F10F10

F11F11

F12F12

F13F13

F14F14

7474

7878

7171

ATA72ATA72

ATA73ATA73ATA76ATA76


ATAS-88ATAS-88

ATAS-89ATAS-89

ATAS-90ATAS-90

ATAS-91ATAS-91

ATAS-92ATAS-92

4646

A-1A-1

0 25

metres

50 75 100

SCALE 1 : 2 250 @ A3

LEGEND


ATA

HW1HW1

H3-24H3-24

2929

ATA-9ATA-9

ENV Sample Locations

ATA Sample Locations

Soil Sampling Location

Groundwater Monitoring Well

Groundwater Monitoring Bores

Soil Sample Locations

FIGURE 2

DRIVEDRIVE

YELVERTON

YELVERTON

PLA

CE

PLA

CE

CE

NTE

NN

IAL

CE

NTE

NN

IAL

RAILWAYRAILWAY

RESERVERESERVE

Fri

22 J

un 0

7P

RIN

TE

D:

TPHs0-9.5m

1

1234567891011

?

?

?

?

?

?

?

?

?

??

?

?

?

?

??

?

?

?

PAH

PAHTPHs

Xylenes

PAHTPHs

PAHTPHs

PAH

PAHTPHs

TPHs

TPHs

TPHs

0.8-1.5m(?)

0-1m

0.2-2m 0-1m

0-1mPAH

1.5-2m

1.5-2m(?)

0.5-8m

0-1m

TPHs0.8-1m(?)

0.5-9.5m

0.4-2m(?)

PAHTPHs

Solvents

PAHTPHs

Solvents1-2m

11

10

12

3 4

5

6

6

68

8

9

ATA-81LSA-2ATA-81LSA-2

ATA-9 LSA 1-3ATA-9 LSA 1-3

ATA-80 LSA-1-3ATA-80 LSA-1-3

ATA-79 LSA 1-4ATA-79 LSA 1-4



BLOCK 3BLOCK 3

BLOCK 2BLOCK 2

BLOCK 1BLOCK 1

FoundryFoundry

Chief Mechanical


Engineers Building


War MemorialWar Memorialand Gardenand Garden GATEKEEPER’S





Weighbridge






INSTITUTE

HOT ANDCOLD WELLS

AMBULANCE GARAGE

AIR COMPRESSORS

OILOILSTORESTORE

12

INFERRED POINT SOURCECONTAMINATION HOTSPOTS

ATAS46Pb

0.0-0.5m

ElevatedElevatedCircular TankCircular Tank

A3-16

0.0-3.0m

AS, Cr, CuPb & Zn

12Cyanide

1.5m

ATA-81ATA-81LSA-1LSA-1

12Cr, Cyanide

12Cyanide

0.5m

A3-20Cd, Pb0.0-1.0m

1.5-2.5m

27Cu

2-5mTPHs

7

1-2m(?)TPHs

8

PbATA4

0.25-0.5m

H6-8Cd, Cu

Pb & Zn


AREA EAREA E







0.4-1.8m(?)

0.3-1.1m(?)

ATAS-86ATAS-86

ATAS-85ATAS-85

ATAS-84ATAS-84

ATAS-83ATAS-83ATAS-87ATAS-87

ATAS-82ATAS-82

MR

A-2

005-

004/

DE

SI/2

7_12

9F2.

dgn

D

AT

UM

: MG

A50

DR

AW

N: G

LM 2

2-6-

07

C

HE

CK

ED

: JL


RAILWAY PARADE

RAILWAY PARADE


Cadastral Boundary, Proposed Lot #

Easement Boundary

Building Outline

Hotspot Identification:

Inferred Point Source ContaminationHotspot

Potential Groundwater Effluent ExtactionZone

Hotspot Identification (see below)Contaminant TypeApproximate Depth Interval

Foundry WestGeneral FoundryFoundry SouthFoundry EastBlock 1Block 2Copper Shop SurroundsDiesel Shop SurroundsMain Stores SouthWater TankElectroplating Shop Waste DumpFormer Wastewater Treatment Facility

HE

LEN

A

S

TEE

T

HE

LEN

A

S

TEE

T

FOUNDRYFOUNDRY

ROADROAD

SOURCES:- BASE: McMULLEN & NOLAN, 1-06-2007SOURCES:- BASE: McMULLEN & NOLAN, 1-06-2007SAMPLING DATA: ENV Australia, April 2005SAMPLING DATA: ENV Australia, April 2005BUILDING LAYOUT - WOOD & GRIEVE ENGINEERS, May 2007BUILDING LAYOUT - WOOD & GRIEVE ENGINEERS, May 2007



CLAYTON ST

CLAYTON ST

AMBULANCEBUILDING

Tunnel PortalTunnel Portal



BLOCK 3BLOCK 3

BLOCK 2BLOCK 2

BLOCK 1BLOCK 1

FoundryFoundry

Chief Mechanical


Engineers Building



GATEKEEPER’S





Weighbridge


Elevated CircularElevated CircularTankTank





INSTITUTE



TunnelTunnelPortalPortal

AIR COMPRESSORS

AIR COMPRESSORS

AMBULANCE BUILDING

AMBULANCE BUILDINGAMBULANCE GARAGE

AMBULANCE GARAGE

HOT & COLDHOT & COLDWELLS

WELLS

Disused Waste WaterDisused Waste WaterTreatment Plant TankTreatment Plant Tank

(Possibly Suitable as an(Possibly Suitable as anEffluent Holding Tank)Effluent Holding Tank) OILOILSTORE

STORE

H5HH5H

HE-15HE-15

H5BH5B

HE-16HE-16

HE1HE1HE2HE2

HE3HE3

HE4HE4

HE5HE5

HE6HE6

HE7HE7

HE8HE8

HE9HE9

HE11

HE12HE12

HWMW1HWMW1

HW1W1

HW2HW2

HR10

HR11

HR12HR12

B1

B2B2

B3B3

B4B4

HP1HP1

HP2HP2

HP3HP3

HP4

HP6

HP7

HP8HP8

HP9HP9

HP10HP10

HP11HP11

HP12a12aHP12

HP13HP13

HP14HP14

HP15HP15

HP16HP16

MW1MW1

MW2

MW3

MW4

MW15

MW16MW16

B5B5 B6B6

B7

MB1MB1

MB2MB2

MB3MB3

MB4

MB10MB10

MB11

CD2

CD3

CD5

CD7CD7

CD8CD8

RivbedRivbed

HE14HE14

HE11HE11

HE12HE12

HE13HE13

HE-17HE-17

MW21

r Monitoring Bores

Locations

ATA-1ATA-1

ATA-2ATA-2

ATA-3ATA-3

ATA-4ATA-4

ATA-5ATA-5

ATA-6ATA-6

ATA-7ATA-7

ATA-8ATA-8

ATA-9ATA-9

ATA-10ATA-10

ATA-11ATA-11

ATA-12ATA-12

ATA-13ATA-13

ATA-14ATA-14

ATA-15ATA-15

ATA-16ATA-16

ring Bores updated 1-9-05 from survey by MAPS

ATA72ATA72





AREA EAREA E








Helena

Helena

RiverRiver

L a k e

0 25

metres

50 75 100

SCALE 1 : 2 250 @ A3


ATA

Fri

27 J

ul 0

7P

RIN

TE

D:

> DWGOCs

?

?

?

?

?? ??

?

? ? ?

??

?

?

?

?

??

?

?

?

?

?

?

FIGURE 3


INFERRED EXTENT OFGROUNDWATER CONTAMINATION PLUMES

(HYDROCARBON, SOLVENT AND PESTICIDES)

BLOCK 1BLOCK 1

BLOCK 2BLOCK 2

BLOCK 3BLOCK 3

RAILWAYRAILWAY

PLA

CE

PLA

CE

CE

NTE

NN

IAL

CE

NTE

NN

IAL

YELVERTON

YELVERTON

DRIVEDRIVE

FoundryFoundry

PatternPatternStoreStore

PatternPatternShopShop

CopperCopperShopShop

Weigh BridgeWeigh Bridge

TarpaulinTarpaulinShopShop



HE

LEN

A

S

TRE

ET

HE

LEN

A

S

TRE

ET

RAILWAY PARADE

RAILWAY PARADE

RESERVERESERVE

FOUNDRYFOUNDRY

ROADROAD

WAL

LSEN

D

WAL

LSEN

D

RO

AD

RO

AD

Benzene, Toluene, Ethylbenzene, Xylenes

Polycyclic Aromatic Hydrocarbons

Organochlorine Pesticides

Volatile Organic Compounds

BTEX

PAHs

OCs

VOCs

Fresh Waters Guidelines

Drinking Water Guidelines

FWGs

DWGs

ABBREVIATIONS

SOURCES:- BASE: McMULLEN & NOLAN, 1-06-2007SOURCES:- BASE: McMULLEN & NOLAN, 1-06-2007BUILDING LAYOUT: WOOD & GRIEVE, May 2007BUILDING LAYOUT: WOOD & GRIEVE, May 2007SAMPLING DATA SOURCE: ENV Australia, April 2005SAMPLING DATA SOURCE: ENV Australia, April 2005




STOREOILElevated CircularElevated Circular

TankTank

Chief Mechanical


Engineers Building



TIME KEEPER’S


GATEKEEPER’S

GATEKEEPER’SOFFICEOFFICE


INSTITUTE

Helena

Helena

RiverRiver

L a k e

Coal DamPark

LEGEND

HW1HW1

ATA-9ATA-9

Groundwater Monitoring Well

Groundwater Monitoring Bores

ENV Sample Locations

ATA Sample Locations

Contamination

VOCs Detected < DWGs/FWGs

VOCs > FWGs and/or DWGs

BTEX > FWGs and/or DWGs

PAHs > FWGs

TPHs Detected (no guidelines available)

Active Groundwater Effluent TreatmentLikely to be Required whereGroundwater is Extracted


CLAYTON ST

CLAYTON ST

Ambulance Building

Ambulance BuildingAmbulance Garage

Ambulance Garage

Air Compressors

Air Compressors

Tunnel PortalTunnel Portal


Cadastral Boundary, Proposed Lot #

Easment Boundary

Building Outline

MR

A-5

-4/D

ES

I/27_

129F

3.dg

n

DA

TU

M: M

GA

50

D

RA

WN

: G

LM 2

2-6-

07

CH

EC

KE

D: J

L 27

-7-0

7

APPENDICES

APPENDIX A

GROUNDWATER EFFULENT VOLUME ESTIMATE CALCULATIONS

Estimate of Groundwater Flow - Electroplating Shop Waste Dump Hotspot

Width of Excavation (m)

Length of Excavation

(m)

Watertable = h (mBGL)

Excavation Depth = H

(mBGL)

Average dewatering depth = h

(m)

time (days)Hydraulic

Conductivity = K (m/sec)

40 50 6 9.5 3.5 35 3.47E-06 ENV (2003) 1

1.57E-05 Davidson (1995) 2

Radius of Pit (r) = √(a.b/π) Radius of influence (R0) = C.h.√K

= 25.2377233 m = 13.04372987 m

R = r + R0

= 38.2814531 m

Flow rate (Q) = K(H2-h2)/2R Flow rate (Q) = K(H2-h2)/2R

= 2.4603E-06 m3/sec = 1.11534E-05 m3/sec

= 0.2125703 m3/day = 0.963649535 m3/day

= 212.570301 L/day = 963.6495354 L/day

Total flow = 7439.96 L Total flow = 33727.73 LUsing site-specific K value 1 Using Literature K Value 2

Key Calculation Assumptions:

Pit dimensions are as estimated

Local watertable height is as estimated

Excavation remains open for timeframe as estimated

Local hydraulic conductivity is equivalent to ENV (2003)

Cone of Depression is negligible (not calculated)

Rainfall and surface water runoff is neglligible (not calculated)

1: ENV (2003) Hydrogeological Investigation, Helena West, Midland Railway Workshops .

2: Davidson (2005) Hydrogeology and groundwater resources of the Perth region Western Australia , Geological Survey of Western Australia. (Adopted K-Value of 1m/day for unconfined superficial groundwater systems in clay)

MRA-2005-004-DESI_110a_bc.xls

Estimate of Groundwater Flow - Water Tank Hotspot



(m)



(mBGL)


(m)



40 20 6 8 2 35 3.47E-06 ENV (2003) 1

1.57E-05 Davidson (1995) 2


= 15.9617377 m = 7.453559925 m

R = r + R0

= 23.4152976 m


= 2.076E-06 m3/sec = 9.41136E-06 m3/sec

= 0.17936992 m3/day = 0.813141521 m3/day

= 179.369917 L/day = 813.1415211 L/day












Estimate of Groundwater Flow - Coppershop and Surrounds Hotspot



(m)



(mBGL)


(m)



40 20 2 5 3 35 3.47E-06 ENV (2003) 1

1.57E-05 Davidson (1995) 2


= 15.9617377 m = 11.18033989 m

R = r + R0

= 27.1420776 m


= 1.3432E-06 m3/sec = 6.08934E-06 m3/sec

= 0.11605596 m3/day = 0.526119012 m3/day

= 116.055965 L/day = 526.1190121 L/day












APPENDIX B

SWAN RIVER TRUST CORRESPONDENCE

Justin Lumsden

From: Justin Lumsden

Sent: Monday, 30 July 2007 2:49 PM

To: '[email protected]'

Cc: Greg Milner; 'Bridget Nichols'

Subject: FW: SRT Queries relating to the Remediation and Redevelopment of Helena East Former Railway Workshops Site

Importance: High

Attachments: MRA-2005-004-DESI_091_JL.pdf

Page 1 of 2

2/08/2007

Carissa, Thankyou for providing clarification to my previous queries. From our discussion, it is understood that the discharge of groundwater effluent from Helena East and directly into the Helena River will require Ministerial Approval under Part 5 of the Swan River Trust Act 1988. Furthermore, approval under Part 5 of the act is likely to take up to 4-5 months. Bearing in mind the above and as discussed, I would confirmation from the SRT that the storage of groundwater effluent within an onsite water body is exempt from the above approval process. I have prepared a letter to assist the SRT in providing advice on this matter (attached and posted). I look forward to your prompt reply. Regards, JUSTIN LUMSDEN Environmental Scientist Coffey Environments Pty Ltd Dilhorn House, 2 Bulwer Street Perth WA 6000 T (+61) (8) 6462 7900 F (+61) (8) 6462 7936 M 0418 914 967 www.coffey.com.au/environments

From: Justin Lumsden Sent: Friday, 6 July 2007 2:41 PM

To: '[email protected]'

Subject: SRT Queries relating to the Remediation and Redevelopment of Helena East Former Railway Workshops Site

Importance: High Rachel, Further to our telephone discussion of last week and in preparation for the forthcoming remedial works within the MRA Helena East former railway workshops, as a stakeholder in the management of the Helena River floodplain which abuts the site (figure attached), clarification is sought from the SRT on the following matters: 1) Discharge of groundwater effluent into the Helena River

a) Bearing in mind that the proposal to remediate and redevelop the site has been conditionally approved by the issue of Ministerial Statement 742, should an application be made directly to SRT to

seek permission to discharge groundwater effluent into the Helena River and if so, how long may this process take? I note that the Helena River Floodplain is also a CCW and as such I understand separate approval and/or SRT referral may also be required through the DEC?

b) Subject to the above and on a conceptual basis, if it can be demonstrated that groundwater effluent

satisfies those water quality criteria contained in SRT Policy DE6.2, would the SRT object to its discharge into the Helena River via an existing site stormwater network?

2) Remedial Work Environmental Management Plans

a) A number of EMPs were developed in support of a Public Environmental Review of the proposal to remediate and redevelop the MRA Helena East site, and following the issue of Ministerial Statement 742, additional EMPs have since been prepared to address specific Ministerial Statement Conditions. Other than the potential discharge of treated groundwater effluent into the Helena River (potential contingency discharge option, as discussed above) and discharge of surface runoff via the existing stormwater system, no discharge or emission is envisaged into the Helena River. Bearing this in mind, can you confirm that the SRT does not have an active role in endorsing or commenting on any Post-Ministerial Statement EMPs prepared at this site? It is noted that in order to purely satisfy Ministerial Statement Conditions, EMPs will require endorsement by the appointed Contaminated Sites Auditor and approval by the Minister of the Environment (on the advice of the DEC CEO).

I trust I have provided sufficient information to enable the SRT to provide advice on the above matters. Should you wish to discuss my queries further, please do not hesitate to contact me on 6462 7900. Regards, JUSTIN LUMSDEN Environmental Scientist Coffey Environments Pty Ltd Dilhorn House, 2 Bulwer Street Perth WA 6000 T (+61) (8) 6462 7900 F (+61) (8) 6462 7936 M 0418 914 967 www.coffey.com.au/environments

Page 2 of 2

2/08/2007

Date post:	24-Jun-2020
Category:	Documents
Upload:	others
View:	0 times
Download:	0 times

ATA Environmental - MRA · ATA Environmental _____ 4. Localised SVCH impact in the SSA (including...

Documents