MAJOR ROAD PROJECTS VICTORIA

TECHNICAL REPORT J - GROUNDWATER IMPACT ASSESSMENTYan Yean Road Upgrade – Stage 2: Kurrak Road to Bridge Inn RoadFINAL

15 JULY 2020

CONTACT

SELINA MOKArcadis P&E Lead

T 03 8623 4118E selina.mok@arcadis.com

ArcadisLevel 32/140 William StreetMelbourne VIC 3000

Copyright © 2020 Arcadis. All rights reserved.  arcadis.com

MAJOR ROAD PROJECTS VICTORIATECHNICAL REPORT J - GROUNDWATER IMPACT ASSESSMENT

Yan Yean Road Upgrade – Stage 2: Kurrak Road to Bridge Inn Road

FINAL

Author Lena Chang; Sarah Sawyer

Checker Karen Kataguiri

Approver Dave Adams

Report No AA009647-N-GW-R01-P32_YanYeanEES_Final

Date 15/07/2020

Revision Text 01

This report has been prepared for Major Road Projects Victoria in accordance with the terms and conditions of appointment as Technical Advisor dated 14 October 2016. Arcadis Australia Pacific Pty Limited (ABN 76 104 485 289) cannot accept any responsibility for any use of or reliance on the contents of this report by any third party.

REVISIONSRevision Date Description Prepared by Approved by

00 26.06.2020 Final SS DA

01 15.07.2020 Final – minor edits SS DA

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CONTENTSEXECUTIVE SUMMARY..................................................................................................1Methodology.............................................................................................................................................................1Existing Conditions................................................................................................................................................. 1Impact Assessment................................................................................................................................................. 2Environmental Performance Requirements..........................................................................................................2

1 INTRODUCTION.........................................................................................................41.1 Background........................................................................................................................................................ 41.2 Project Description............................................................................................................................................4

1.2.1 Yan Yean / Bridge Inn / Doctors Gully Road Intersection.................................................................................6

1.2.2 Construction Activities......................................................................................................................................6

1.3 Project Objectives.............................................................................................................................................7

2 EES SCOPING REQUIREMENTS....................................................................................8

3 METHODOLOGY.........................................................................................................93.1 Study Area.......................................................................................................................................................... 93.2 Existing Conditions...........................................................................................................................................93.3 Risk Assessment.............................................................................................................................................10

3.3.1 Risk Assessment Process..............................................................................................................................12

3.4 Impact Assessment.........................................................................................................................................143.5 Environmental Performance Requirements..................................................................................................143.6 Assumptions.................................................................................................................................................... 15

4 LEGISLATION, POLICIES AND GUIDELINES.................................................................164.1 Commonwealth Legislation............................................................................................................................164.2 State Legislation..............................................................................................................................................164.3 Groundwater Licencing...................................................................................................................................18

5 EXISTING CONDITIONS.............................................................................................195.1 Data Sources.................................................................................................................................................... 195.2 Location, Topography and Drainage.............................................................................................................195.3 Climate.............................................................................................................................................................. 205.4 Regional Geology............................................................................................................................................215.5 Hydrogeological Units.....................................................................................................................................225.6 Groundwater Levels and Flow Direction.......................................................................................................23

5.6.1 Site-Specific and Local Groundwater Level Data...........................................................................................23

5.6.2 Regional Groundwater Level Data..................................................................................................................24

5.7 Hydraulic Properties........................................................................................................................................245.8 Groundwater Quality.......................................................................................................................................245.9 Recharge and Discharge.................................................................................................................................265.10 Groundwater Quality Restricted Use Zones...............................................................................................265.11 Sensitive Receptors......................................................................................................................................26

5.11.1 Registered Groundwater Users....................................................................................................................26

5.11.2 Groundwater Dependent Ecosystems..........................................................................................................27

6 RISK ASSESSMENT...................................................................................................28

7 IMPACT ASSESSMENT..............................................................................................307.1 Construction Impacts......................................................................................................................................307.2 Operational Impacts........................................................................................................................................30

8 ENVIRONMENTAL PERFORMANCE REQUIREMENTS.....................................................32

9 CONCLUSIONS.........................................................................................................339.1 Existing Conditions.........................................................................................................................................339.2 Impact Assessment.........................................................................................................................................33

10 LIMITATIONS.........................................................................................................35

11 REFERENCES.........................................................................................................36

TABLESTable 3.1: Risk significance matrix.......................................................................................................12Table 3.2: Likelihood criteria................................................................................................................. 13Table 3.3: Generic consequence criteria..............................................................................................13Table 3.4: Groundwater consequence categories................................................................................14Table 4.1: Protected uses – SEPP (Waters)........................................................................................17Table 5.1: Hydrogeological units..........................................................................................................22Table 5.2: Bore yields (L/s) for groundwater bores within the study area.............................................24Table 5.3: Groundwater quality data for relevant groundwater bores within the study area.................25Table 5.4: Groundwater bore details for the Project area (within approx. 500 m of the Project area)...27Table 6.1: Summary of groundwater risk assessment..........................................................................29Table 8.1: Environmental Performance Requirements.........................................................................32

FIGURESFigure 1.1: Project area..........................................................................................................................5Figure 1.2: Bridge Inn Road intersection design.....................................................................................6Figure 3.1: Environmental risk process................................................................................................11Figure 5.1: Average monthly rainfall for the 1856 to 2018 period (Yan Yean)......................................20Figure 5.2: Long-term annual rainfall and CDFM curve (Yan Yean).....................................................21Figure 5.3: Piper diagram of groundwater data from within the study area..........................................26

APPENDICES

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APPENDIX A PROJECT DESCRIPTION: YAN YEAN ROAD UPGRADE – STAGE 2

APPENDIX B FIGURES

APPENDIX C GROUNDWATER RISK REGISTER

APPENDIX D GROUNDWATER RESOURCE REPORTS

APPENDIX E GEOTECHNICAL BORE LOGS

APPENDIX F DEPARTMENT OF ENVIRONMENT, LAND, WATER AND PLANNING WMIS DATABASE

APPENDIX G RELEVANT BACKGROUND DATA FROM PLENTY LANDFILL AFTERCARE MANAGEMENT PLAN

Glossary

Term Description

Adit An adit is a horizontal passage leading into a mine for the purposes of access, drainage or mineral prospecting.

Alluvium General term for unconsolidated deposits of inorganic materials (clay, silt, sand, gravel, boulders) deposited by flowing water.

Aquifer Rock or sediment in a formation, group of formations or part of a formation that is saturated and sufficiently permeable to transmit economic quantities of water to wells and springs.

Aquitard Saturated geological unit with a relatively low permeability that can store large volumes of water but does not readily transmit or yield significant quantities of water to bores or springs. An aquitard can sometimes, if impermeable, be called an aquiclude.

Australian Height Datum (AHD) A level datum, uniform throughout Australia, that generally approximates mean sea level.

Beneficial reuse An alternative reuse for a material such as coal seam water or salt residues that changes the status of the material from a waste to a resource that can be used for a beneficial purpose.

Bore Artificially constructed or improved groundwater cavity used for the purpose of accessing or recharging water from an aquifer.

Interchangeable with borehole, piezometer, monitoring well.

Borehole Includes a well, excavation, or other artificially constructed or improved groundwater cavity which can be used for the purpose of intercepting, collecting or storing water from an aquifer; observing or collecting data and information on water in an aquifer; or recharging an aquifer. Interchangeable with bores, wells, piezometers.

Clay Deposit of particles with a diameter less than 0.002 mm, typically contain variable amounts of water within the mineral structure and exhibit high plasticity.

Coal Carbon-based sedimentary rock formed by the accumulation and decomposition of plant material in layers, which can be used as a combustible fuel. Main types, in order of highest rank to lowest rank, are black coal (anthracite, bituminous, sub-bituminous), brown coal (lignite) and peat (considered to be a precursor of coal).

Colluvium Term for deposits or sediment which is deposited at the base of steep inclines by erosion and downslope creep.

Confined aquifer An aquifer bounded above and below by impervious (confining) layers. In a confined aquifer, the water is under sufficient pressure so that when bores are drilled into the aquifer, measured water levels rise above the top of the aquifer.

Dewatering Draining, permanently or temporarily, a wet area of land or an aquifer.

Dissolved solids Minerals and organic matter dissolved in water; a measure of salinity.

Drawdown The change in groundwater level in a bore, or the change in water table elevation in an unconfined groundwater system, due to the extraction of groundwater.

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Term Description

Ecosystem An organic community of plants, animals and bacteria and the physical and chemical environment they inhabit.

Fault Zone of displacement in rock formations resulting from forces of tension or compression in the earth’s crust.

Formation General term used to describe a sequence of rock layers.

Fracture Break or defect in a rock including cracks, joints, and faults.

Groundwater Water found in the subsurface in the saturated zone below the water table or piezometric surface i.e. the water table marks the upper surface of groundwater systems.

Groundwater flow The movement of water through openings and pore spaces in rocks below the water table i.e. in the saturated zone.

Groundwater resource Groundwater available for beneficial use, including human usage, aquatic ecosystems and the greater environment.

Hydraulic conductivity Measure of the ease with which water will pass through earth material; defined as the rate of flow through a cross-section of one square metre under a unit hydraulic gradient at right angles to the direction of flow (metres per day).

Hydraulic gradient Change in the hydraulic head over a certain distance.

(Hydraulic) head Elevation to which water will rise in a borehole connected to a point in an aquifer.

Hydrogeology The study of the interrelationships of geological materials and processes with water, especially groundwater.

Impact An event that disrupts ecosystem, community, or population structure and alters the physical environment, directly or indirectly.

Infiltration The downward movement of water from the atmosphere into the ground; not to be confused with percolation.

Lithology The physical character of rocks.

Monitoring bore A bore used to monitor groundwater levels or quality.

Permeability The ease with which a fluid can pass through a porous medium and is defined as the volume of fluid discharged from a unit area of an aquifer under unit hydraulic gradient in unit time (metres per day).

pH Absolute value of the decimal logarithm of the hydrogen-ion concentration (activity). Used as an indicator of acidity (pH < 7) or alkalinity (pH > 7).

Recharge Recharge is defined as the process by which water is added from outside to the zone of saturation of an aquifer, either directly into a formation, or indirectly by way of another formation.

Salinity The concentration of dissolved salts in water, usually expressed in electrical conductivity (EC) units (µS/cm) or total dissolved solids (TDS) units (mg/L TDS).

Sediment Particles derived from rocks or biological materials that have been transported by air or water.

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Term Description

Semi-confined aquifer An aquifer that is partly confined by layers of lower permeability material through which recharge and discharge may occur, also referred to as a leaky aquifer.

Shale Finely laminated and fissile sedimentary rock composed primarily of consolidated mud and clay.

Siltstone Consolidated silt; fine-grained sedimentary rock.

Spring Natural discharges of groundwater at the surface or within stream beds.

Spring vents are a single point in the landscape where groundwater is discharged at the surface. Recharge (reject) springs occur where rates of recharge are greater than rates of water infiltration; thus, ‘rejection’ of water causes seepage of water at the surface from exposed formations. Recharge springs are commonly an ephemeral feature in a local aquifer and not necessarily connected to the water table aquifer. Discharge springs occur where faulting or rapid thinning occur against basement highs disrupting lateral through-flow of groundwater or where aquifers approach the ground surface and pressurised groundwater breaks through fractures in thin confining beds.

Watercourse springs are a section of a watercourse where groundwater enters the stream from an aquifer through the streambed. These springs occur where an outcropping aquifer has been eroded to create a depression in the surface of sufficient depth to reach the water table.

Strata Single bed of sedimentary rock, generally consisting of one kind of matter representing continuous deposition.

Stratigraphy Branch of geology dealing with the classification, nomenclature, correlation, and interpretation of stratified rocks.

Water balance An equation that expressed the conservation of mass of water, to account for inflows and outflows of a particular system.

Water table The surface in an unconfined aquifer or confining bed at which the pore water pressure is atmospheric; it can be measured by installing shallow wells extending a few feet into the zone of saturation and then measuring the water level in those wells.

Watercourse A river, creek or other stream, including a stream in the form of an anabranch or a tributary, in which water flows permanently or intermittently, regardless of the frequency of flow events:

In a natural channel, whether artificially modified or not

In an artificial channel that has changed the course of the stream

It also includes weirs, lakes and dams.

Well A structure that is designed to bore through the earth’s surface in order to extract resources.

Wetland Victoria State Government describes wetlands in the Healthy Waterways Strategy 2018 (Government of Victoria, 2018) as “areas, whether natural, modified or artificial, subject to permanent or temporary inundation, that hold static or very slow-moving water and develop, or have the potential to develop, biota adapted to inundation and the aquatic environment. They may be fresh or saline. Examples of wetlands include swamps or billabongs.”

Yield The quantity of water removed from a water resource e.g. yield of a borehole.

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Abbreviations

Acronym Meaning

AHD Australian Height Datum

ANZECC Australian and New Zealand Environment Conservation Council

ARMCANZ Agriculture and Resources Management Council of Australia and New Zealand

BOM Bureau of Meteorology

CDFM Cumulative deviation from mean

DELWP Victoria Department of Environment, Land, Water & Planning

EC Electrical conductivity

EE Act Environment Effects Act 1978

EP Act Environment Protection Act 1970

EES Environment Effects Statement

EMF Environmental Management Framework

EPA Environment Protection Authority

EPBC Act Environment Protection and Biodiversity Conservation Act 1999 (Commonwealth)

EPR Environmental Performance Requirements

ERA Environmental Risk Assessment

GDE Groundwater dependent ecosystem

GMA Groundwater Management Area

GMU Groundwater Management Unit

GQRUZ Groundwater Quality Restricted Use Zone

HGU Hydrogeological Unit

km kilometre

L/s Litre per second

m metre

mAHD metres Australian Height Datum

mbgl metres below ground level

mg/L milligrams per litre

m/day metres per day

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Acronym Meaning

ML megalitre

MNES Matters of National Environmental Significance

MRPV Major Road Projects Victoria

NHMRC National Health and Medical Research Council

NRU Northern Roads Upgrade

OH&S Occupational Health and Safety

PCV Permissible Consumptive Volumes

SCO Specific Controls Overlay

SEPP State Environment Protection Policy

TDS Total Dissolved Solids

TRG Technical Reference Group

UA Unincorporated area

WMIS Water Measurement Information System

WSPA Water Supply Protection Area

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EXECUTIVE SUMMARYMajor Road Projects Victoria (MRPV) proposes to duplicate Yan Yean Road from Kurrak Road to Bridge Inn Road as part of the Yan Yean Road (Stage 2) Upgrade (the Project).

On 14 October 2018, the Minister for Planning decided that an Environment Effects Statement (EES) is required under the Environment Effects Act 1978 (EE Act) to assess the potential environmental effects of the Project. The EES process provides for identification and analysis of the potential environment effects of the Project and the means of avoiding, minimising and managing adverse effects. It includes public involvement and allows stakeholders to understand the likely environmental effects of the Project and how they will be managed.

This groundwater impact assessment report has been prepared for the EES in accordance with the Scoping Requirements released by the Minister for Planning in June 2019

Arcadis Australia Pacific Pty Ltd (Arcadis) has been engaged as the sub-consultant to WSP Australia Pty Ltd (WSP) in a joint engagement with MRPV. Acting as the Technical Advisor for the Project, Arcadis is responsible for undertaking a desktop Groundwater Impact Assessment to characterise the groundwater systems of the footprint and surrounding areas of the Project.

MethodologyAn assessment of the existing conditions was undertaken by reviewing limited site-specific information from the geotechnical investigations completed within the Project area and publicly available data from the surrounding area. This data included:

Water Measurement Information System (WMIS) bore database

BOM climate and rainfall data

BOM groundwater dependant ecosystems database

Plenty Landfill Aftercare Management Plan prepared by Golder Associates for Nillumbik Shire Council (provided by Nillumbik Shire Council)

EPA Victoria audit records and licencing documentation

Mining and Geological Journal papers from 1940 to 1955

Hydrogeological publications

Melbourne Water documentation detailing the Plenty River Water Supply Protection Area Stream Flow Management Plans

Melbourne Water Local Management Plans

Geological mapping from the Geological Survey of Victoria and subsequent updates.

Existing ConditionsThe Project area can be characterised by the following key geological and hydrogeological characteristics:

the Project area is underlain by the Murrindindi Supergroup (Melbourne Formation) of Mesozoic/Paleozoic age bedrock comprising sandstone, siltstone, mudstone and shale. Igneous (fractured rock) formations are also present in the region

the bedrock aquifer is regionally extensive; however, it is not considered significant in terms of regional groundwater flow and is generally of low permeability and low quality due to the nature of the soil and the presence of weathered mudstones

groundwater in the area is characterised by salinity (as total dissolved solids) concentrations of between 2,170 to 6,870 mg/L and is conservatively classified as Segment B under the State Environment Protection Policy (SEPP Waters) 2018

groundwater was not identified in two bores drilled as part of the geotechnical assessment which were extended to a maximum depth of 7.5 m below ground level

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a review of the WMIS maintained by the Department of Environment, Land, Water and Planning (DELWP) revealed two registered groundwater bores within 500 m of the Project area one of which is registered for domestic uses and the other is registered for domestic and stock uses. Depth to groundwater in these bores is not reported

groundwater is present at a depth of more than 60 metres below ground level at the southern end of the Project area

the Project area is located within the East Port Phillip Bay Groundwater Catchment and within the Plenty River Water Supply Protection Area

seven ecosystems which rely on the subsurface presence of groundwater were identified within the broader study area

Plenty River, Scrubby Creek, Sawpit Creek and Dry Creek are located within the study area and rely on the surface expression of groundwater and have a moderate potential for groundwater interaction.

Impact AssessmentThe design includes a number of cuttings and retaining walls (north of Jorgensen Avenue and south of Bannons Lane); this includes provision for one piled shotcrete wall and three post and panel retaining walls supported by bored piles. No other structures are proposed which would require significantly deep excavations, deep piling or dewatering activities. Groundwater is likely to be more than 60 metres deep in this area of the Project therefore it is considered unlikely that groundwater would be intersected during construction or that dewatering would be required.

Yan Yean Road (Stage 1) Upgrade is located south of Yan Yean Road (Stage 2) Upgrade and is in a similar geological setting. Groundwater was not intersected during construction of Stage 1 to a maximum depth of 8 metres below ground level.

Therefore, the risk of groundwater levels being reduced or a reduction in groundwater availability for Groundwater Dependent Ecosystems (GDE), baseflow or for registered or unregistered users is considered to be low.

The potential of groundwater being impacted by fuel or chemical spills during construction or operation is also considered unlikely given the depth to groundwater and the nature of the surrounding geological formation which typically comprise sandstones, siltstones and mudstones. The aquifer is not considered to be significant in terms of regional groundwater flow and is noted to be of low permeability. Therefore, the risk of groundwater being impacted by fuel or chemical spills is considered to be low.

Based on the Project description, impacts to groundwater during construction and operation are considered low if managed in accordance with the standard controls. If piling depths exceed the design depths, the following assessments should be considered:

assess if excavations will penetrate the water table and therefore experience groundwater inflows

conduct a site-specific intrusive groundwater investigation to assess structures that will intersect the groundwater table to confirm or otherwise the potential impacts identified during the assessment

estimate the quantity and quality of the groundwater inflows

produce a dewatering management plan to safely manage inflows and minimise groundwater impacts (if required).

Environmental Performance RequirementsThe proposed Environmental Performance Requirements (EPR) requires preparation and implementation of a Construction Environmental Management Plan (CEMP). The CEMP will detail actions to be implemented in the unlikely event that groundwater is unexpectedly encountered during construction activities and actions to be implemented to protect groundwater from spills generated during operation of the road.

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The EPRs also require management of any potential impacts during operation and maintenance in accordance with the Department of Transport’s Environmental Management System and standards for managing declared roads in Victoria.

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The EPRs are presented below:

Performance Objective

Applicable Legislation, Policy and Guideline

EPR Code

Risk No.

Environmental Performance Requirement

Project Phase

Effects on physical environment - Identify other potential adverse environmental effects of the project, such as on social and community amenity canvass an environmental management approach and performance measures to ensure any effects are identified and avoided, minimised or mitigated

Groundwater

To protect beneficial uses of groundwater

State Environment Protection Policy (Waters)

EPA Publication 480 (EPA Environmental Guidelines for Major Construction Sites)

Water Industry Regulations 2006 (Vic)

National Environment Protection (Assessment of Site Contamination) Measures 2013

GW1 9, 29, 49, 69

Groundwater management

The CEMP must include measures to manage groundwater impacts in accordance with the relevant water objectives set out in the State Environment Protection Policy (Waters), Water Industry Regulations 2006 (Vic) and other relevant statutory requirements.

Design and construction

Environmental Management Framework

To provide a transparent framework with clear accountabilities for managing and monitoring the environmental effects associated with the Project

Legislation and policy as identified in all EPRs

EMF5 89, 109

Any potential impacts during operation and maintenance would be managed in accordance with the Department of Transport’s environmental management system and standards for managing declared roads in Victoria.

Operation and maintenance

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1 INTRODUCTIONMajor Road Projects Victoria (MRPV) proposes to duplicate Yan Yean Road from Kurrak Road to Bridge Inn Road as part of the Yan Yean Road (Stage 2) Upgrade (the Project).

On 14 October 2018, the Minister for Planning decided that an Environment Effects Statement (EES) is required under the Environment Effects Act 1978 (EE Act) to assess the potential environmental effects of the Project. The EES process provides for identification and analysis of the potential environment effects of the Project and the means of avoiding, minimising and managing adverse effects. It includes public involvement and allows stakeholders to understand the likely environmental effects of the Project and how they will be managed.

This groundwater impact assessment report has been prepared for the EES in accordance with the Scoping Requirements released by the Minister for Planning in June 2019.

1.1 BackgroundYan Yean Road is a primary north-south arterial road and connects the growth suburb of Doreen, with major east west arterials such as Bridge Inn Road, Kurrak Road and Diamond Creek Road. The road runs through the townships of Yarrambat and Plenty and connects with established areas of Diamond Creek and Greensborough. There is a high demand for north-south travel from Doreen and surrounding towns to established northern suburbs for employment and services.

Stage 1 of the Yan Yean Road upgrade (Diamond Creek Road to Kurrak Road) was completed in 2019, and construction on Stage 2 (this Project) is due to be completed by 2025.

1.2 Project DescriptionThe Project would duplicate a 5.5 kilometre (km) portion of Yan Yean Road between Kurrak Road and Bridge Inn Road increasing the existing two lanes to four lanes (comprising two lanes in each direction). The design speed along Yan Yean Road is 70 km/h, with the exception of north of Bridge Inn Road which is 80 km/h. The design for the Project has 3.5 metre (m) wide lanes with the majority of the Project using a 2.2 m wide central median. This cross section was adopted in design due to various constraints ranging from road safety issues, steep and rolling terrain, high cut and fill batters and subsequent retaining walls at certain locations, as well as seeking to limit impacts to existing properties, local accesses and trees along Yan Yean Road.

The Project will include:

two new roundabouts (at Heard Avenue, and Youngs Road)

five new signalised intersections (Bannons Lane, Jorgensen Avenue, North Oatlands, Orchard and Bridge Inn Roads)

upgrades to one existing signalised intersection, including an additional right hand turning lane, slip lane, and traffic island (Ironbark Road)

new street lighting at all intersections, road signage and landscaping.

The Project will also include a new 3 m wide shared user path on the western side and 1.2 m wide footpath on the eastern side of Yan Yean Road. The paths links Diamond Creek to Doreen and would improve safety and connectivity for pedestrians and cyclists.

Continuous safety barriers would run along the Project’s length and are proposed in the median and behind outer kerbs along the mid-block sections of the carriageways.

The Project area and key Project components are shown in Figure 1.1.

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Figure 1.1: Project area

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1.2.1 Yan Yean / Bridge Inn / Doctors Gully Road IntersectionThe Bridge Inn Road / Yan Yean Road / Doctors Gully Road intersection has been designed to retain the two Doreen River Red Gums, General Store and Pet Supply/Stockfeed business situated adjacent to the current Doctors Gully and Yan Yean Road intersection by shifting the whole intersection to the north east (see Figure 1.2). This intersection design has been developed following community consultation and in response to arboricultural advice on the Doreen River Red Gums.

Figure 1.2: Bridge Inn Road intersection design

1.2.2 Construction ActivitiesProposed construction activities would likely be standard road construction activities to be undertaken in accordance with the Environmental Performance Requirements (EPR) for the Project. These construction activities would include:

tree clearance and vegetation lopping and removal

establishment of construction site compounds

clearing and grubbing, temporary sediment and erosion control works

establishment of environmental and traffic controls

earthworks, including:

– remediation of any existing contamination and removal of any hazardous material

– protecting and relocating services7

– widening of existing rock cuttings (approximately 750 m of existing cut along the Project would be widened by approximately 20 m)

– new cuttings (approximately 1300 m of new rock cut would be required to a width of approximately 5 m along the Project)

– bulk earthworks and haulage.

civil and structure works, including:

– roundabouts and intersection upgrades

– shared user path and pedestrian path construction and connections

– retaining walls

– drainage works

– pavement works.

30-36 metre high fence along the edge of the Yarrambat Park Golf Course to avoid golf ball collisions with pedestrians, cyclists or vehicles

traffic management systems and landscaping.

A detailed Project description of the Yan Yean Road Upgrade is provided in Appendix A.

1.3 Project ObjectivesThe Project aims to improve travel times and reliability to and from growing residential areas in Doreen and Mernda, enhance north-south travel in the area, and improve safety along the corridor. The objectives of the Project are set out below:

To improve road safety: The Project will achieve this by isolating road users from hazards and improving access control through signalised intersections. Congestion and the complex road environment (poor sight lines due to undulating linear / perpendicular grades and adjacent terrain) are presently contributing to the poor safety record on Yan Yean Road.

To improve the customer experience: The Project will achieve this by improving access, improving network connectivity, opportunities for active transport, and providing more road capacity.

To improve network efficiency: The Project will achieve improved traffic flow and a reduction in travel times by increasing road capacity and reducing congestion.

To maintain environmental and amenity values: The Project will achieve this by managing environmental effects to acceptable levels and ensuring that impacts are avoided, minimised and mitigated to the extent practicable.

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2 EES SCOPING REQUIREMENTSThe Scoping Requirements for Yan Yean Road (Stage 2) Upgrade Environment Effects Statement (June 2019) have been prepared by DELWP on behalf of the Minister for Planning. The Scoping Requirements set out the specific environmental matters to be investigated and documented in the EES, which informs the scope of the EES technical studies.

The following matters of the Scoping Requirements are relevant to the groundwater impact assessment:

Draft evaluation objective

to avoid or, at least, minimise adverse effects on native vegetation (including remnant, planted, regenerated and large old trees), listed migratory and protected species/ecological communities and then to address offset requirements consistent with relevant state and commonwealth policies

– potential impacts to Matter of National Environmental Significance (MNES) through erosion, sedimentation and contamination of watercourses and groundwater near and downstream from the Project site resulting from the construction and operation of the Project

Environmental management framework (EMF)

management measures proposed in the EES to address specific issues, including commitments to mitigate adverse effects and enhance environmental outcomes should be clearly described in the EMF. The EMF should describe proposed objectives, indicators and monitoring requirements, including for (but not limited to) managing or addressing:

– surface runoff, flood potential and groundwater.

The EMF will outline how potential adverse effects on groundwater will be avoided, minimised or mitigated.

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3 METHODOLOGYThis assessment has been completed to assess the environmental impacts of the Project on the local groundwater environment and to recommend appropriate mitigation and management measures, if required. Groundwater investigations were completed during the geotechnical assessments to adequately assess the potential for impacts to groundwater.

3.1 Study AreaThis desktop Groundwater Impact Assessment has been undertaken to characterise the groundwater systems of the footprint and surrounding areas of the Project. This assessment was based on a review of readily available desktop information with regards to geology, groundwater levels, groundwater quality and groundwater flow.

A 2 km study area has been applied to this assessment to provide a broad understanding of the area surrounding the proposed Project with reference to drainage features, geology, registered bores and Groundwater Dependent Ecosystems (GDE). The study area is principally a function of the area required to characterise existing conditions that may influence the impact assessment. The extent of the Project area and the study are presented on Figure 1, Appendix B.

This assessment has been limited to a desktop study with the inclusion of some site-specific data from adjacent sites which have historically investigated groundwater, the geotechnical assessments along the alignment of Yan Yean Road and publicly available data sets.

3.2 Existing ConditionsIn order to satisfy the Project and assessment objectives and to guide the environmental studies, the following scope of work was completed to establish the existing conditions:

a search of the Water Measurement Information System (WMIS) bore database (Victoria Department of Environment, Land, Water & Planning, 2019b)

a search of the Bureau of Meteorology (BOM) groundwater dependant ecosystems database

review of readily available data/reports from previous and current studies in the Project area including:

– Plenty Landfill Aftercare Management Plan prepared by Golder Associates for Nillumbik Shire Council (provided by Nillumbik Shire Council)

– Environment Protection Authority Victoria (EPA Victoria) audit records.

characterisation of the hydrogeological environment in the Project area including:

– aquifer and aquitard layers

– groundwater flow paths

– groundwater quality and beneficial use

– sensitive receptors, including groundwater users and GDEs.

preparation of a desktop Groundwater Impact Assessment comprising the following:

– potential impacts on groundwater levels, quality and sensitive receptors were assessed in accordance with legislative and policy requirements

– direct and indirect impacts associated with the construction and operational phases of the Project

– standard controls to avoid or mitigate impacts and assessment of residual impacts on groundwater following implementation of measures

– details of ongoing monitoring and assessment in accordance with any recommended EPRs, if required.

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3.3 Risk AssessmentAn environmental risk assessment (ERA) has been completed to identify environmental impacts associated with construction and operation of the Project. The risk-based approach shown in Figure3.3 is integral to the EES as required by Sections 3.1 and 4 of the Scoping Requirements and the Ministerial guidelines for assessment of the environmental effects under the Environment Effects Act 1978. The groundwater risk register is provided in Appendix C and the key impacts are presented in Section 7.

Primary environmental impact pathways were identified for groundwater and initial risk ratings were assessed by considering likelihood and consequence categories (Table 3.2, Table 3.3 and Table 3.4) and applying the risk significance matrix (Table 3.1). The initial risk ratings were assessed assuming the implementation of standard controls. Standard controls include compliance with legislative requirements and best practice requirements typically incorporated into the construction contracts for the delivery of road Projects. The standard controls do not include any Project-specific controls or requirements.

EPRs have been informed by the ERA, to set the minimum outcomes necessary to avoid, mitigate or manage environmental impacts and reduce environmental risks during delivery of the Project. The development of the proposed EPRs was an iterative process with input from the technical specialists and MRPV. Section 8 provides further detail of the specific EPRs developed for groundwater.

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Figure 3.3: Environmental risk process

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3.3.1 Risk Assessment ProcessThe ERA has guided the environmental studies for the Project. The objectives of the ERA are to:

identify primary environmental risks that relate to the construction and operation of the Project

guide the level and extent of investigation and data gathering necessary for accurately characterising the existing environment and assessing the Project's environmental effects

help identify performance requirements to avoid, minimise and mitigate environmental risks

inform assessment of likely residual effects that are expected to be experienced after standard controls and proposed EPRs have been implemented.

The risk assessment process for the EES incorporates risk management requirements as detailed in MRPV’s Environmental Risk Management Guideline. The process includes:

an approach to environmental management which is aligned with ISO 31000 Risk Management – Guidelines

systems used to manage environmental risk and protect the environment, and how these are implemented at different stages of road construction, operation and maintenance

tools and reporting requirements which provide guidance in managing environmental issues throughout the Project.

The ERA identifies impact events for each relevant element of the environment, details the primary risks and has informed the level and range of technical reporting required to address predicted impacts. The ERA utilises a risk matrix approach where likelihood and consequence of an event occurring are considered (Table 3.1, Table 3.2 , Table 3.3 and Table 3.4). Throughout the preparation of the EES, the likelihood and consequence categories were updated to ensure currency, as required.

Table 3.1: Risk significance matrix

Likelihood Consequence Level

Insignificant Minor Moderate Major Critical

Almost Certain Medium Significant High High High

Likely Medium Medium Significant High High

Possible Low Medium Medium Significant High

Unlikely Low Low Medium Medium Significant

Rare Low Low Low Medium Medium

Likelihood and generic consequence criteria, informed by the MRPV corporate risk matrix, are shown in Table 3.2, Table 3.3 and Table 3.4.

Risk ratings were then reassessed following risk evaluation and risk treatment to generate a 'residual' risk rating. Both initial and residual risk ratings are documented in the risk register attached in Appendix C.

Table 3.2: Likelihood criteria13

Likelihood Description

Almost certain

76-99% Has occurred before and is expected to occur again

Is expected to occur each year or more frequently

All of the controls associated with the risk are extremely weak/non-existent. Without control improvement there is almost no doubt that the risk will eventuate

Likely

51-75% Has occurred before with a chance of it occurring again

Has occurred several times at the Department, Group, Division, Program or Project before

The majority of the controls associated with the risk are weak. Without control improvement it is more likely than not that the risk will eventuate

Possible

26-50% Has occurred before with a chance of occurring again

Has occurred at the Department, Group, Division, Program or Project once before

There are some controls that need improvement, however unless there is improvement the risk may eventuate

Unlikely

6-25% Has occurred elsewhere before, therefore a small chance of occurring

The majority of controls are strong with no control gaps. The strength of this control environment means that is likely that the risk eventuating would be caused by external factors not known to the organisation

Rare

0-5% Has never occurred but may occur

Is expected to occur 1/100 or more years

All controls are strong with no control gaps. The strength of this control environment means that if this risk eventuated, it is most likely as a result of external circumstances outside of the control of the organisation

Table 3.3: Generic consequence criteria

Consequence Description

Critical A critical degree of impact on an environmental asset, value or use of moderate or higher significance

Major A high degree of impact on an environmental asset, value or use of moderate or higher significance

Moderate A moderate degree of impact on an environmental asset, value or use of moderate or higher significance

Minor A low degree of impact on an environmental asset, value or use

Insignificant A very low degree of impact on an environmental asset, value or use

Table 3.4: Groundwater consequence categories

Aspect Insignificant Minor Moderate Major Critical

Groundwater Changes to groundwater levels or flows, or release or movement of contaminants

Changes to groundwater levels or flows, or release or movement of contaminant is

Changes to groundwater levels or flows, or release of contaminants into the environment

Changes to groundwater levels or flows, or release of contaminants into the environment

Changes to groundwater levels or flows, or release of contaminants into the environment

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Aspect Insignificant Minor Moderate Major Critical

have no measurable effect for groundwater uses.

measurable but is within range of typical natural variation or does not result in a loss of one or more beneficial uses of the groundwater.

causes temporary and reversible loss of one or more beneficial uses of the groundwater.

causes permanent loss of one or more beneficial uses of the groundwater on a localised scale.

causes permanent loss of one or more beneficial uses of the groundwater across a large geographic area.

3.4 Impact AssessmentLikely impacts during construction and operation have been identified by assessing existing groundwater conditions primarily through review of desktop information and review of available data sources from nearby sites and publicly available data.

Construction impacts have been identified by assessing potential construction methods which are likely to be employed along the alignment based on the design specified in Appendix A. This takes into consideration the need for piling and cut and fill activities along the central section of the alignment between Jorgensen Avenue and Bannons Lane.

The impact assessment considered potential intersection of groundwater by piling and excavation activities and the potential for changes to groundwater level (from dewatering) and groundwater quality (from run-off or infiltration of impacted surface soils or surface water).

Operational impacts have been identified by assessing how the proposed works could permanently alter the groundwater regime. Potential impacts from spills during maintenance works which could impact groundwater quality have also been assessed.

Several standard strategies are available for management of groundwater during construction and operation and these are based on the mitigation techniques provided in the Best Practice Environmental Management: Environmental Guidelines for Major Construction Sites (EPA Publication 480).

3.5 Environmental Performance RequirementsThe environmental outcomes that must be achieved during design, construction and operation of the Projects are referred to throughout the EES as Environmental Performance Requirements (EPR). EPRs must be achieved regardless of the construction methodology or design solutions adopted. Measures identified in this EES to avoid, reduce or environmental impacts have formed part of the recommended EPRs for the Projects.

The development of a final set of EPRs for the Project has been iterative and considers inputs from technical specialists and MRPV.

EPRs were identified to inform the assessment of initial risk ratings (where appropriate). These initial EPRs were based on compliance with legislation and standard requirements that are typically incorporated into the delivery of construction contracts for road Projects.

As outlined in Section 3.3 the risk assessment methodology has been designed to confirm if the developed EPRs are adequate or require further refinement.

The EPRs recommended for the groundwater component of the Project are outlined in Section 8 and are included in the EES Environmental Management Framework. The EPRs are applicable to the final design, construction approach and operation and provide certainty regarding the environmental performance of the Project.

3.6 AssumptionsThis impact assessment has been predominantly based on publicly available data sources. Data from the drilling of two geotechnical bores has been included to provide limited site-specific data.

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The extent of the assessment is considered to satisfy the EES scoping requirements based on the findings of the ERA, the desktop review and the nature of the Project.

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4 LEGISLATION, POLICIES AND GUIDELINESThis section assesses the Project against the Commonwealth and State legislation, policies and guidelines relevant to the groundwater assessment.

4.1 Commonwealth LegislationCommonwealth guidelines relevant to the management of groundwater include:

Australian and New Zealand Guidelines for Fresh and Marine Water Quality 2018 (ANZG 2018). These guidelines replace the Australian and New Zealand Guidelines for Fresh and Marine Water Quality 2000 (ANZECC, 2000) and provide for the sustainable use of Australia’s water resources by protecting and enhancing quality, while maintaining economic and social development. These guidelines are used as groundwater quality criteria for assessing beneficial uses, as outlined in the State Environmental Protection Policy, SEPP (Waters) 2018

Australian Drinking Water Guidelines (NHMRC, 2011). These guidelines provide guidance to the Australian community and the water supply industry on what constitutes good quality drinking water. These guidelines are used as groundwater quality criteria for assessing beneficial uses outlined in the SEPP (Waters).

The Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) prescribes the Commonwealth’s role in environmental assessment, biodiversity conservation and the management of protected areas and species, population and communities and heritage items.

Impacts on MNES are assessed through a referral process to the Commonwealth Department of the Environment. If the Commonwealth Minister for the Environment determines that a Project is likely to have a significant impact on MNES, then the Project becomes a controlled action and approval of the Commonwealth Minister for the Environment would be required before construction works can commence.

The Project was referred to the Commonwealth Department of the Environment and Energy, who determined under Section 75 of the EPBC Act that the proposed action is a controlled action and, as such, it requires assessment and a decision about whether approval for it should be given under the EPBC Act. The controlled action considered the proposed action likely to have significant impacts on listed threatened species and communities (sections 18 & 18A) (WSP, 2020).

4.2 State LegislationThe framework for the management of groundwater in Victoria is established primarily through the:

Water Act 1989

Environment Protection Act 1970.

The Water Act 1989 deals with the sustainable, efficient and equitable management and allocation of groundwater resources.

The Environment Protection Act 1970 (EP Act) empowers the Environment Protection Authority Victoria (EPA Victoria) to implement regulations, maintain State Environment Protection Policies (SEPP), manage wastes and protect the environment from pollution. The Act also regulates the discharge or emission of waste to water, land or air by a system of Works Approvals and licences.

The Environment Protection Amendment Act 2018 is proposed to take effect in 2021 and provides a risk-based preventative approach to environmental management through a general environmental duty and strengthening of EPA Victoria’s compliance and enforcement powers. Until the Environment Protection Amendment Act 2018 comes into effect the subordinate legislation remains unchanged.

A number of subordinate legislation and guidelines exist which further expand on the Water Act 1989 and the EP Act. SEPPs set out Victorian Government policies that control and reduce environmental pollution and have been formulated for discharges to land, water, atmosphere and noise emissions. These policies protect the environment and human activities (beneficial uses) from pollution caused by waste discharges and noise and are subordinate documents to the EP Act.

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SEPP (Waters) was gazetted (S499) on 19 October 2018. It replaces the SEPP (Waters of Victoria), its regional Schedules, and SEPP (Groundwaters of Victoria) and was made following an extensive review and consultation process.

The policy provides that groundwater is categorised into segments, with each segment having particular identified uses. Groundwater with higher concentrations of salinity (measured as mg/L of Total Dissolved Solids, TDS) is deemed to have fewer beneficial uses. The segment categories and their beneficial uses are summarised in Table 4.5.

The most up to date version of legislation at the time will be used once construction commences.

Table 4.5: Protected uses – SEPP (Waters)

Beneficial Use

Water Quality Segments (mg/L TDS)

A1 A2 B C D E F

0 - 600 601 – 1,200

1,201 – 3,100

3,101 - 5,400

5,401 - 7,100

7,101 - 10,000

>10,001

Water Dependent Ecosystems and Species

Potable Water Supply – desirable

Potable Water Supply – acceptable

Potable Mineral Water Supply

Agriculture and Irrigation (Irrigation)

Agricultural and Irrigation (Stock Watering)

Industrial and Commercial

Water Based Recreation (Primary Contact Recreation)

Traditional Owner Cultural Values

Cultural and Spiritual Values

Buildings and Structures

Geothermal Properties

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4.3 Groundwater LicencingIn Victoria, groundwater resource units are identified as Groundwater Management Areas (GMA) and Water Supply Protection Areas (WSPA). These areas are collectively known as Groundwater Management Units (GMU).

In Victoria there are 44 GMAs in which groundwater has been extensively developed or has the potential to be developed. They are geographically defined as such for the purposes of ongoing management of the aquifer and are carefully monitored via the Department of Environment, Land, Water and Planning (DELWP) State Observation Bore Network.

WSPAs are areas declared by the Minister for Water under the Water Act 1989 to protect stressed groundwater or surface water resources through the implementation of a statutory Groundwater Management Plan for the area.

Unincorporated Areas are areas where no significant development of the groundwater resource has occurred. This is usually because the resource is low yielding, or its quality has traditionally severely limited its use. They exist outside of GMU boundaries, although they will be defined within a GMU in the next few years.

Groundwater extraction is managed through licensing and is allocated under the Water Act 1989:

to drill a bore a Bore Construction License is required under Section 67 of the Act

to extract groundwater for commercial purposes (not including domestic and stock users) a ‘Take and Use Licence’ is required under Section 51 of the Act.

Rural Water corporations are responsible for assessing licence applications, deciding whether to issue licences and the terms and conditions on which the licence is issued. The licence will specify the exact location and depth from which groundwater can be extracted, the annual volume of water that can be pumped and the rate at which the pumping can occur.

Permissible Consumptive Volumes (PCV) have been set by the Minister for Water, which detail the maximum volume of water that can be allocated in an area. Many areas have been allocated to their PCV limit, meaning no new licences can be issued in these areas. The only way to acquire new groundwater licences in these areas is to trade with an existing groundwater licence holder. PCVs are imposed to protect the resource and prevent depletion. PCVs do not apply to UAs.

The Project is located in the East Port Phillip Bay Groundwater Catchment and within the Plenty River Water Supply Protection Area, as presented in Figure 2, Appendix B. The Diamond Creek Water Supply Protection Area is to the east of the Project (Melbourne Water, 2007 & 2016). No PCVs were identified within the Plenty River Water Supply Protection Area (Melbourne Water, 2007). The site is reportedly not located within a GMU (Groundwater Resource Report, DELWP, 2020).

Where excavations penetrate the water table and dewatering is required, a licence to take groundwater must be sought from the rural water corporation. An analysis may need to be carried out to estimate the required dewatering rate and volume.

The discharge of dewatered groundwater to the environment or to drainage infrastructure will need to be licensed by the relevant authority, water disposal to a licensed facility will not require a licence. Should discharge of groundwater be required, an assessment of volume and water chemistry would be required to assess the most appropriate discharge method and obtain the relevant approvals.

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5 EXISTING CONDITIONS

5.1 Data SourcesA variety of data sources have been used to assess the existing groundwater conditions within the study area. Data sources range in quality and quantity and therefore the level of reliance on each data source is variable.

The following data sources have been used to assess groundwater conditions as noted in Section 3.2:

WMIS bore database

BOM climate and rainfall data

BOM groundwater dependant ecosystems database

Plenty Landfill Aftercare Management Plan prepared by Golder Associates for Nillumbik Shire Council (provided by Nillumbik Shire Council)

EPA Victoria audit records and licencing documentation

Mining and Geological Journal papers from 1940 to 1955

Hydrogeological publications

Melbourne Water documentation detailing the Plenty River Water Supply Protection Area Stream Flow Management Plans

Melbourne Water Local Management Plans

Geological mapping from the Geological Survey of Victoria and subsequent updates.

Due to the variable data sets available more weight is given to site-specific field data or site-specific data from nearby sites, such as the geotechnical investigation works completed along the alignment, historical contaminated land audit reports for adjacent sites and parcels of land and reports associated with the Plenty Landfill. The historical Mining and Geological Journal papers were also used within this assessment due to the quality of the documentation of the mining works completed within the study area and the relevance to assessing depth to groundwater.

Geological maps are also considered a high-quality data resource.

The WMIS bore database, the hydrogeological publications and the Melbourne Water management plan data has been used to assess regional trends and quality where data is available. The data sources are variable in quality and are not complete in some instances.

Where variable or conflicting data has been identified, a judgement on the quality of the data set and the regional scale of the data set has been made and this is clearly documented in this assessment of existing conditions.

A full reference list which details the data sources is provided in Section 11 of this report.

5.2 Location, Topography and DrainageThe Project area is characterised by urban and rural land features and is located within the East Port Phillip Bay groundwater catchment and within the Plenty River Water Supply Protection Area. The location of the Project is presented in Figure 1, Appendix B and the water management areas are presented in Figure 2, Appendix B.

The local topography within the Project area ranges from approximately 165 to 200 metres Australian Height Datum (mAHD). The road elevation is at its peak between the intersections of Ironbark Road / Yan Yean Road and Orchard Road/Yan Yean Road, and slopes downwards to the north and southwest.

The closest named surface water receptors to the road alignment are the Doctors Gully Road Drain and Plenty River, which are located to the east (approximately 380 m) and west (approximately 1 km) of the road alignment, respectively. Unnamed tributaries are located to the east and west of the road alignment. An unnamed dam is located approximately 75 m west of Yan Yean Road, south of the

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Yarrambat Harness Track. The local surface drainage is likely to be collected at the creeks, by infiltration through the soil profile and overland flow during heavy rain events.

5.3 ClimateMeteorological data were obtained from the closest BOM weather station, Yan Yean (086131) located approximately 6 km to the north west of the Project area. In the Project area, most rainfall occurs from August to December whilst January to March have the lowest long-term monthly averages. Figure 5.4 presents the average monthly rainfall for Yan Yean. Historical data shows that the region receives on average approximately 658 millimetres (mm) per year based on rainfall data from 1856 to 2019 (BOM, 2020).

The long-term annual cumulative deviation from mean (CDFM) rainfall for the 1920 to 2018 period at the Yan Yean station is plotted in Figure 5.5. The long-term cumulative rainfall residual plots provide an indication of the broad scale trends in rainfall pattern behaviour and are formulated by subtracting the average annual rainfall for the recorded period from the actual annual rainfall and then accumulating these residuals over the assessment period. Periods of below average rainfall are represented as downward trending slopes while periods of above average rainfall are represented as upward trending slopes.

The lowest annual rainfall of 372 mm was in 1945 and the highest annual rainfall of 1049 mm occurred in 1872.

Janu

ary

Febru

ary

March

April

MayJu

ne July

Augus

t

Septem

ber

Octobe

r

Novem

ber

0

10

20

30

40

50

60

70

Average Monthly Rainfall (mm)

Figure 5.4: Average monthly rainfall for the 1856 to 2018 period (Yan Yean)

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Figure 5.5: Long-term annual rainfall and CDFM curve (Yan Yean)

5.4 Regional GeologyThe Department of Economic Development, Jobs, Transport and Resources (Geological Units 1:50,000) indicates that the Yan Yean Road (Stage 2) Upgrade lies within geological deposits of the Murrindindi Supergroup (Melbourne Formation). The Melbourne Formation is made up of Mesozoic/Paleozoic age bedrock comprising shale, mudstone, siltstone and sandstone with undisturbed Bouma sequences. Igneous (fractured rock) formations are also present in the region, including granites, granodiorites and igneous intrusions (dykes). No superficial Quaternary deposits are reportedly present in the area. The Doreen Syncline and an unnamed anticline transects the Project area.

Review of the Geological Survey of Victoria, 1:63,360 Yan Yean map sheet, 1972 and the GeoVic database (GeoVic, 2015) indicate historical mining activities in the area of North Oatlands Road. Several historical gold mines are present in this area; however, no current operations are reported to be present.

Small scale gold mining activities were undertaken mainly from the 1920s to the 1950s in the area west of the current Yan Yean Road and north and south of Oatlands Road. In addition, three shafts were recorded in the area of the Plenty Landfill located to the south of Yan Yean Road. Gold bearing ore was extracted from narrow quartz veins, breccias and dykes that had intruded the basement siltstones.

The historical records, geological plans and cross sections indicate several mine shafts and adits associated with 5 mines were located west of Yan Yean Road, either side of North Oaklands Road (Kenny, 1940 and Whiting, 1955).

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The superficial geology within the Project area and the location of the mine shafts are presented in Figure 3, Appendix B.

The interpreted locations relative to the current Yan Yean Road indicate the following:

Golden Stairs – approximately 250 m west, several shafts are present to 60 m with associated adits at 30 m and 60 m depth below the surface

Golden Crown – approximately 140 m west, several shafts are present to an approximate depth of 91 m below surface. Adits are present trending north between the shafts with adits extending west from the shafts

Golden Gate – approximately 290 m west, shaft approximately 42 m deep with adit extending approximately 55 m west

Golden King – approximately 125 m west, several shafts present to an approximate depth of 30 m. Several short adits 15 m to 22 m below surface extending east of the shaft

Golden Step – approximately 250 m west

Three unnamed shafts – approximately 725 m south east of Yan Yean Road, east of Plenty Landfill.

Mining operations scaled down in the late 1970s. The Golden King mine closed in 1984 and the main shafts were filled in and capped in 1994.

It is considered that there is a low risk of historical mining activities impacting the Project as the proposed road alignment is greater than 100 m from the shafts and adits.

Groundwater intrusion into the mines was not reported within the Mining Journal indicating that groundwater was unlikely to have been intersected above the deepest point of the mines (approximately 90 m below ground surface).

5.5 Hydrogeological UnitsGroundwater Resource Reports were sourced from DELWP (2020). The Groundwater Resource Reports are provided in Appendix D. The Project is located in the East Port Phillip Bay groundwater catchment and the Plenty River Water Supply Protection Area (Melbourne Water, 2007).

The Hydrogeological Units (HGU) detailed in Table 5.6 below are based on the Victorian Aquifer Framework prepared for Department of Sustainability and Environment (now DELWP) in 2012 (GHD, 2012).

Table 5.6: Hydrogeological units

Hydrogeological Unit (HGU) Estimated Depth Below Surface (m)

Groundwater Salinity (mg/L) Characteristics

BSE Mesozoic and Paleozoic Bedrock (basement) sedimentary (fractured rock): Sandstone, siltstone, mudstone, shale. Igneous (fractured rock): includes volcanics, granites, granodiorites

(Murrindindi Supergroup with Melbourne Formation as the relevant formation)

0-200 1,001-3,500

Widespread subsurface low permeability aquifer, generally with low yields and poor water quality.

Unincorporated Area

The Melbourne Formation was deposited during the Silurian Period, however the Victorian Aquifer Framework (DSE, 2012) includes the Melbourne Formation within the Mesozoic and Paleozoic Bedrock Aquifer.

The Melbourne Formation is described as steeply dipping sandstones and siltstones with minor occurrences of limestone. The Formation has been subject to folding events and is broken by faulting

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in certain areas. Shallow saturated zones would be expected to be encountered within the shallow weathered/residual soil formation, these zones may be transient saturation and are likely to be relatively limited in horizontal and vertical extent. The deeper saturated zones would be classified as a fractured rock formation with majority of aquifer storage associated with secondary porosity.

Where the Mesozoic and Paleozoic Bedrock Aquifer outcrops, the groundwater would likely occur in an unconfined state. Elsewhere it may be confined by overlying strata. The depth of weathering is highly variable ranging from a few metres to more than 50 m (Leonard, 2006).

Although regionally extensive, the bedrock aquifers are not considered significant in terms of regional groundwater flow as they are generally of low permeability with low yields and poor water quality (GHD, 2012).

5.6 Groundwater Levels and Flow DirectionGroundwater flow direction within the Project area is likely to follow the local topography and be consistent with the regional flow direction. In some cases, however there may not be a correlation between topography and groundwater flow, and in these cases, it is generally relatively localised. Regional topography would be expected to dominate the flow direction in the deep bedrock aquifers.

Several sources of information were reviewed during this assessment including site-specific data, local investigation data from nearby sites and regional scale desktop information. Groundwater depth is variably recorded within these data sources, therefore more weight is given to the site-specific data and local data points than the desktop regional data.

5.6.1 Site-Specific and Local Groundwater Level DataGroundwater was not identified in the two geotechnical bores installed as part of the site-specific investigation to assess ground conditions along the proposed alignment. These bores are located to the south of Orchard Road (WSP, 2018). Bore B17-68317 was extended to a maximum depth of 4.86 metres below ground level (mbgl) which indicates that regional groundwater level is below 198 m AHD. Bore B17-68318 was extended to a maximum depth of 7.5 mbgl, indicating that regional groundwater level is below 194 m AHD in this area.

Bore logs from the geotechnical investigation are presented in Appendix E and the bore locations are presented on Figure 4, Appendix B.

The Plenty Landfill is located to the south of Yan Yean Road as presented in Figure 4, Appendix B. The Plenty Landfill After Care Management Plan (Golder, 2015) was prepared for Council to address a Pollution Abatement Notice issued by EPA (PAN90003408). The report indicates that 12 groundwater monitoring bores are located across the landfill site. Two of these groundwater monitoring bores are located adjacent to Yan Yean Road as follows:

BH7 is located 80 m north east of the intersection of Yan Yean Road and Kurrak Road, approximately 10 m north of Yan Yean Road

BH8 is located 80 m south west of the intersection of Yan Yean Road and Worns Lane, approximately 10 m north of Yan Yean Road.

The location of all of the groundwater monitoring bores are presented on Figure 4, Appendix B.

Groundwater was measured at depths greater than 70 mbgl at BH7 and below 64 mbgl at BH8. This is considered to be consistent with the depth to regional groundwater level and also indicates that the groundwater flow direction is generally to the west which is consistent with the regional topography.

Yan Yean Road (Stage 1) Upgrade is located south of Yan Yean Road (Stage 2) Upgrade and is present in a similar geological setting but is located at a lower topographical elevation. Groundwater was not intersected during construction of Yan Yean Road Stage 1 structures (pers. comms MRPV to WSP dated 6 December 2018). Piles were constructed to a depth of 8 m below ground surface within Stage 1.

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Based on the information above, it is considered unlikely that groundwater will be intersected during Project works due to the depth of groundwater being more than 60 mbgl at the southern end of the alignment and the elevated ground level towards the central area of the site where the shallow piling and cut works will be completed (between Bannons Lane and Jorgensen Avenue).

It is noted that groundwater sampling and assessment was not completed during this assessment, as groundwater was not intersected during the drilling works along the Stage 2 alignment and the bores were dry following installation.

5.6.2 Regional Groundwater Level DataThe Victorian Groundwater Resource Reports (DELWP, 2020) provide a high-level assessment of depth to groundwater and groundwater quality within the HGU below the Project area. The report indicates that the Mesozoic and Paleozoic Bedrock is present and that depth to groundwater is estimated to be between 5 and 50 m below ground surface. Three Groundwater Resource Reports are provided in Appendix D. Less reliance is placed on this data set due to the regional scale.

The WMIS bore database contains some information on screened depths of regional bores, however no specific groundwater elevation data is provided within the database.

5.7 Hydraulic PropertiesA summary of bore yields for bores located within the study area is presented in Table 5.7 below (DELWP, 2020).

Table 5.7: Bore yields (L/s) for groundwater bores within the study area

Parameter No. Observations Minimum Maximum Average

Bore Yields (L/s) 3 0.51 3.03 1.54

Aquifer hydraulic characteristics within the Murrindindi Supergroup (Melbourne Formation) are not well known. Hydraulic conductivities of 0.56 m/day for fractures and 0.014 m/day for the rock matrix were derived from pumping tests conducted on the Melbourne Formation at two sites in King's Domain (Robinson and Kenna, 1992). Hancock (1992) reported hydraulic conductivity values between 0.001 m/day and 0.3 m/day along the Melbourne Warp. Yields from bores are generally less than 0.6 L/sec.

Higher yields are obtained where the rocks are highly fractured and/or deeply weathered. Yields of up to 6.0 L/sec have been obtained from bedrock underlying the Tertiary sediments underlying the south-eastern suburbs of Melbourne (Leonard, 2006). No hydraulic testing was completed during the Plenty Landfill investigation works due to the slow recharge observed during drilling and groundwater sampling (Golder, 2015) indicating low hydraulic conductivities.

Data reviewed from the Victorian WMIS database (DELWP, 2020) is presented in Appendix F.

5.8 Groundwater QualityLimited regional groundwater quality data is available in the Yan Yean area. Groundwater quality data is available for groundwater bore 66398 (DELWP, 2020) located approximately 2 km to the east of the Project and groundwater bores installed as part of the Plenty Landfill Aftercare Management Plan (Golder, 2015) located at the southern end of the Project.

Review of the Plenty Landfill Aftercare Management Plan indicates that a total of 12 groundwater bores are associated with the landfill. However, only BH7 and BH8 are considered appropriate for inclusion in this assessment, as these two groundwater bores are located up hydraulic gradient of the landfill. Inclusion of the remaining bores within the monitoring network is considered inappropriate due to the potential for contamination from the landfill.

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Available and appropriate groundwater quality data is presented in Table 5.8 below and Appendix F and has been used to assess the beneficial use under the SEPP (Waters).

Table 5.8: Groundwater quality data for relevant groundwater bores within the study area

Bore ID Field pH

Field Dissolved Oxygen (mg/L)

Field Redox Potential (uncorrected) (mV)

Field Electrical Conductivity (uS/cm)

Estimated TDS (mg/L)

Beneficial Use Segment

66398 8.5 - - 3,300 2,170 B

BH7^ 6.6 0.59 60 10,564 6,870 D

BH8^ 5.9 0.67 72 5,747 3,740 C

* TDS = EC*0.65

^ Data for BH7 and BH8 is from Plenty Landfill Aftercare Management Plan (Golder, 2015) and is from the October 2014 sampling event (most recent event).

Based on the available TDS data for the Project area the Mesozoic and Paleozoic Bedrock Aquifer is conservatively defined as Segment B (SEPP Waters). This beneficial use assessment is consistent with the groundwater resource reports and is considered to be representative of the regional aquifer.

The beneficial uses to be protected under each Segment are presented in Table 4.5 A classification of Segment B of the Mesozoic and Paleozoic Bedrock Aquifer indicates that the following beneficial uses are to be protected:

Water Dependent Ecosystems and Species

Potable Mineral Water Supply

Agricultural and Irrigation (Irrigation)

Agricultural and Irrigation (Stock Watering)

Industrial and Commercial

Water Based Recreation (Primary Contact Recreation)

Traditional Owner Cultural Values

Cultural and Spiritual Values

Buildings and Structures

Geothermal Properties.

It should be noted however, that the relevance of some beneficial uses that are protected under Segment B are unlikely to be realised, including:

Potable Mineral Water Supply: there are no known mineral or spring groundwater sources in the study area

Industrial and Commercial: expected bore yields are likely to be too low to maintain the yields typically required for commercial or industrial processes

Geothermal Properties: there are no known geothermal properties associated with groundwater within the study area.

The major ion characteristics of the groundwater samples at three groundwater bores within the study area are shown on the piper diagram in Figure 5.6. A piper diagram is a graphical representation of the relative concentrations of major ions (Ca2+, Mg2+, Na+, K+, Cl-, HCO3

- and SO42-), and is used to

26

distinguish the chemical profile of major water types. The groundwater bores are all screened within the Mesozoic and Paleozoic Bedrock Aquifer.

Based on the limited data available groundwater below the Project is likely to be dominated by sodium, carbonate and bicarbonate species.

Figure 5.6: Piper diagram of groundwater data from within the study area

5.9 Recharge and DischargeThe primary recharge mechanism to the groundwater systems is considered to be direct rainfall infiltration. The proportion of net rainfall recharging the groundwater systems depends largely on the characteristics of the surface geology, soils, land use and depth to the water table.

Recharge also may occur via leakage from surface water features in areas where the groundwater table is below the stream water level. Recharge rates will largely depend on the river stage and hydraulic characteristics of the riverbed material and underlying geology. The Mesozoic and Paleozoic Bedrock Aquifer would be recharged locally through direct rainfall infiltration in the absence of an overlying confining layer or Quaternary Aquifer in this area.

Groundwater can also discharge from shallow perched groundwater into creeks or drains depending on the porosity of the geological units in the aquifer and the hydraulic gradients.

Evapotranspiration from the water table is another mechanism of groundwater discharge. The evapotranspiration rate depends on land use and depth to groundwater. In areas where the water table is shallow and within the rooting depth of vegetation evapotranspiration can be a significant component of the water balance.

5.10 Groundwater Quality Restricted Use ZonesNo sites adjacent to the Project area are listed on the EPA Groundwater Quality Restricted Use Zones (GQRUZ) database (accessed March 2020). An assessment of potentially contaminated sites along the alignment has been completed as an independent assessment (Arcadis, 2020).

5.11 Sensitive Receptors

5.11.1 Registered Groundwater UsersRegistered groundwater bores located within the study area were identified using the WMIS (Appendix F). A total of eight groundwater bores were listed in the search.

Six of these bores have a registered use of groundwater as detailed below:

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4 Domestic and Stock

1 Domestic

1 Irrigation.

Two of these bores have no registered use or are listed as a non-groundwater use.

Two bores with registered groundwater uses within approximately 500 m of the Project are presented in Table 5.9 below.

Table 5.9: Groundwater bore details for the Project area (within approx. 500 m of the Project area)

Bore ID Distance from Site and Direction Use Depth of

Bore (mbgl) Lithology Date Installed

WRK983650352 m north of Yan Yean / Worns Lane intersection

Domestic 147Mudstone, sandstone, grey siltstone

21/06/2008

WRK990779100 m north of the northern end of the Project

Domestic & Stock 59 Clay and

siltstone 05/08/2009

Twelve bores are also associated with the Plenty Landfill site. Bore construction data from the Aftercare Management Plan is presented in Appendix G.

All registered bores and bores associated with the Plenty Landfill site are presented in Figure 4, Appendix B.

5.11.2 Groundwater Dependent EcosystemsGDEs are communities of plants, animals and other organisms that depend on groundwater for survival (Department of Land and Water Conservation, 2002). A GDE may be either entirely dependent on groundwater for survival or may use groundwater opportunistically or for a supplementary source of water (Hatton and Evans, 1998).

GDEs include wetlands, vegetation, mound springs, river base flows, cave ecosystems, playa lakes and saline discharges, springs, mangroves, river pools, billabongs and hanging swamps and near-shore marine ecosystems. The GDE Atlas (BOM, 2018b) categorises GDEs into three classes:

Ecosystems that rely on the surface expression of groundwater – this includes all the surface water ecosystems which may have a groundwater component, such as rivers, wetlands and springs

Ecosystems that rely on the subsurface presence of groundwater – this includes all vegetation and ecosystems

Subterranean ecosystems – this includes cave and aquifer ecosystems.

Groundwater discharge can be important in maintaining baseflow in rivers and streams, and ecosystems associated with these discharge areas may have a high dependency on groundwater for their water requirements. It should be noted however that some of these ecosystems rely on perched aquifer systems that are shallow, surficial and are largely not connected to the deep regional groundwater system. These ecosystems are largely sustained by recharge/discharge processes associated with rainfall infiltration which typically characterise the behaviour of shallow perched water systems.

GDEs within the vicinity of the Project are identified in Figure 5, Appendix B.

No GDEs that are reliant on the surface presence of groundwater were identified within the Project area. However, the GDE Atlas identified Plenty River, Scrubby Creek, Sawpit Creek and Dry Creek as GDEs reliant on surface presence of groundwater within the study area.

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Seven ecosystems rely on the subsurface presence of groundwater within the study area. Further investigation of the ecosystems has been completed and reported as an independent biodiversity assessment (WSP, 2020).

No Ramsar Wetlands are present within the study area.

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6 RISK ASSESSMENTThe residual environmental risks identified for groundwater are provided in Table 6.10.

The residual risk ratings consider the standard controls and proposed EPRs. The proposed EPRs are set out in Table 8.11 in Section 8.

The purpose of the risk assessment was to assess the residual risk levels and whether the calculated risk levels were supported by the technical information and to determine if additional studies are required. The groundwater risk register provided in Appendix C is summarised below.

Following identification of potential risks to groundwater, industry best practice controls were identified and standard mitigation controls intrinsic to the Project were identified, including requirements under relevant sections of the Department of Transport (DoT) Standard Specifications, including requirements under EPR GW1 that are outlined in Section 8.

Relevant Standards and Policies including:

State Environment Protection Policy (SEPP Waters)

EPA Victoria’s Environmental Guidelines for Major Construction Sites.

Risks were assessed during the site establishment, construction and operation and maintenance phases of the Project. Details of what is included within the construction and operation phase of the Project are summarised in the Environmental Risk Assessment Report.

The following potential risk were considered during this assessment:

potential impacts to groundwater level from abstraction of groundwater for piling or dewatering activities, thereby reducing groundwater availability for GDEs, surface water baseflow and registered or unregistered users of groundwater

potential contamination of groundwater from fuel and chemical spills from vehicles and equipment during construction or operation and maintenance of the Project.

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Table 6.10: Summary of groundwater risk assessment

Risk No.

Aspect Impact PathwayMitigation Measures to Inform Environmental Performance Requirements

EPRResidual Risk Rating

Construction

9 Groundwater

Potential changes to groundwater levels or flows from excavation works, resulting in impacts on groundwater quality and / or beneficial uses (from site establishment).

The Construction Environmental Management Plan will include processes and measures to manage groundwater in accordance with the relevant water objectives set out in the Environmental Reference Standard under the Environment Protection Amendment Act 2018 and Water Industry Regulations 2006 (Vic).

GW1 Low

29 Groundwater

Potential changes to groundwater levels or flows from piling and excavation works, resulting in impacts on groundwater quality and / or beneficial uses (from earthworks).

The Construction Environmental Management Plan will include processes and measures to manage groundwater in accordance with the relevant water objectives set out in the Environmental Reference Standard under the Environment Protection Amendment Act 2018 and Water Industry Regulations 2006 (Vic).

GW1 Low

49 Groundwater

Potential changes to groundwater levels or flows from piling and excavation works, resulting in impacts on groundwater quality and / or beneficial uses (from civils and structures).

The Construction Environmental Management Plan will include processes and measures to manage groundwater in accordance with the relevant water objectives set out in the Environmental Reference Standard under the Environment Protection Amendment Act 2018 and Water Industry Regulations 2006 (Vic).

GW1 Low

69 Groundwater

Potential changes to groundwater levels or flows from excavation works, resulting in impacts on groundwater quality and / or beneficial use (from reinstatement).

The Construction Environmental Management Plan will include processes and measures to manage groundwater in accordance with the relevant water objectives set out in the Environmental Reference Standard under the Environment Protection Amendment Act 2018 and Water Industry Regulations 2006 (Vic).

GW1 Low

Operations

89 Groundwater

Potential changes to groundwater levels or flows from operation, resulting in impacts on groundwater quality and / or beneficial uses.

Mitigation measures have been applied during the design and construction phases. As such, the risk of impact on groundwater during operation of Yan Yean Road is considered to be low.

Any potential impacts during operation and maintenance will be managed in accordance with the Department of Transport’s standards for managing declared roads in Victoria.

EMF5

Low

Maintenance

109 Groundwater

Potential changes to groundwater levels or flows from maintenance, resulting in impacts on groundwater quality and / or beneficial uses.

Any potential impacts during operation and maintenance will be managed in accordance with the Department of Transport’s standards for managing declared roads in Victoria.

EMF5

Low

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7 IMPACT ASSESSMENT

7.1 Construction ImpactsThe review of site specific and local data sources indicates that the depth to groundwater within the Project area is likely be present in the regional aquifer at depths of 60 m below the ground surface.

Works completed at Stage 1 did not intersect groundwater at a depth of 8 m below the ground surface. Stage 2 is similar in terms of the topography, geology and hydrogeological setting.

The design for the Project does not involve any bridge structures or other structures that would require significantly deep excavations, deep piling or dewatering activities. Road cuttings and retaining walls with piled foundations are present in some areas, however groundwater is likely to be more than 60 m deep in the area of the Project therefore it is considered unlikely that groundwater would be intersected during construction or that dewatering would be required.

Dewatering of excavations along the alignment is not anticipated to be required and therefore impact to surrounding users (registered or unregistered users) or GDE from lowering of the water table or reducing the quality of the groundwater is considered unlikely.

Should shallow perched groundwater be unexpectedly identified during construction works, these minor seepages would be managed using standard controls in accordance with Best Practice Environmental Management: Environmental Guidelines for Major Construction Sites (EPA Publication 480).

The potential for regional groundwater to be impacted by fuel or chemical spills during construction is also considered unlikely given the depth to groundwater and the nature of the surrounding geological formation which typically comprise sandstones, siltstones and mudstones. The aquifer is not considered to be significant in terms of regional groundwater flow and is noted to be of low permeability and low quality. The application of standard controls during construction activities, are considered to be sufficient to prevent impact by fuels or chemicals on groundwater. Standard controls to assist in managing spills may include:

refuelling in designated areas where hardstand is present

use of bunded tanks and bunded refuelling areas

removal of impacted soils following minor spills

drain standing water from the site to prevent infiltration of potentially contaminated water

avoid stockpiling of contaminated soils and place sheeting below stockpiles to prevent infiltration of precipitation.

Should the design change from that specified in Appendix A, the following assessments should be considered, and this impact assessment should be re-evaluated:

assess if excavations will penetrate the water table and therefore experience groundwater inflows

conduct site specific intrusive groundwater investigation to assess structures that will intersect the groundwater table to confirm or otherwise the potential risk and impacts

estimate the quantity and quality of the groundwater inflows

produce a dewatering management plan to safely manage inflows and minimise groundwater impacts (if required).

EPR GW1 presented in Section 8 requires preparation of a Construction Environmental Management Plan (CEMP). The CEMP will detail actions to be implemented in the unlikely event that groundwater is unexpectedly encountered during construction activities.

7.2 Operational ImpactsSimilar to the construction impact, potential impacts to groundwater during operation and maintenance of the road are considered unlikely due to the depth to groundwater.

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The potential for regional groundwater to be impacted by fuel or chemical spills during operation or maintenance is also considered unlikely given the depth to groundwater and the nature of the surrounding geological formation. The aquifer is not considered to be significant in terms of regional groundwater flow and is noted to be of low permeability and low quality. The application of standard controls during operation activities, are considered to be sufficient to prevent impact by fuels or chemicals. Standard controls to assist in managing spills during operation and maintenance may include:

avoid refuelling equipment during maintenance and operational tasks, unless in a bunded area

removal of impacted soils following minor spills

avoid stockpiling of contaminated soils during maintenance works and place sheeting below stockpiles to prevent infiltration of precipitation.

The proposed EPR (EMF5) presented in Section 8 requires management of any potential impacts during operation and maintenance in accordance with the Department of Transport’s Environmental Management System and standards for managing declared roads in Victoria.

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8 ENVIRONMENTAL PERFORMANCE REQUIREMENTS

Table 8.11 presents the proposed EPRs relevant to the groundwater assessment.

Table 8.11: Environmental Performance Requirements

Performance Objective

Applicable Legislation, Policy and Guideline

EPR Code

Risk No.

Environmental Performance Requirement

Project Phase

Effects on physical environment - Identify other potential adverse environmental effects of the project, such as on social and community amenity canvass an environmental management approach and performance measures to ensure any effects are identified and avoided, minimised or mitigated

Groundwater

To protect beneficial uses of groundwater

State Environment Protection Policy (Waters)

EPA Publication 480 (EPA Environmental Guidelines for Major Construction Sites)

Water Industry Regulations 2006 (Vic)

National Environment Protection (Assessment of Site Contamination) Measures 2013

GW1 9, 29, 49, 69

Groundwater management

The CEMP must include measures to manage groundwater impacts in accordance with the relevant water objectives set out in the State Environment Protection Policy (Waters), Water Industry Regulations 2006 (Vic) and other relevant statutory requirements.

Design and construction

Environmental Management Framework

To provide a transparent framework with clear accountabilities for managing and monitoring the environmental effects associated with the Project

Legislation and policy as identified in all EPRs

EMF5 89, 109

Any potential impacts during operation and maintenance would be managed in accordance with the Department of Transport’s environmental management system and standards for managing declared roads in Victoria.

Operation and maintenance

The initial risk ratings for the Project consider standard inherent controls in accordance with the relevant standards and guidelines provided in Section 7 above. No additional controls above those listed as standard controls are required to minimise the primary environmental risks. The full technical discipline risk assessment is presented in Appendix C.

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9 CONCLUSIONSA groundwater impact assessment has been completed for the Yan Yean Road (Stage 2) Upgrade to assess potential impacts to groundwater as a result of Project site establishment, construction work and operation and maintenance and to identify management options to reduce potential risks.

9.1 Existing ConditionsThe Project area and wider study area can be characterised by the following geological and hydrogeological characteristics:

the Project area is underlain by the Murrindindi Supergroup (Melbourne Formation) of Mesozoic/Paleozoic age bedrock comprising sandstone, siltstone, mudstone and shale. Igneous (fractured rock) formations are also present in the region, including granites, granodiorites and igneous intrusions (dykes)

the bedrock aquifer is regionally extensive; however, it is not considered significant in terms of regional groundwater flow and is generally of low permeability

groundwater is present at a depth of greater than 60 mbgl at the southern end of the Project area

located within the East Port Phillip Bay Catchment and the Plenty River Water Supply Protection Area

groundwater in the area is characterised by salinity concentrations of between 2,170 to 6,870 mg/L.

Sensitive receptors identified within the study area are:

two registered bores specifying groundwater use are present within approximately 500 m of the Project area

seven ecosystems which rely on the subsurface presence of groundwater were identified within the study area. These ecosystems were identified as having potential for groundwater interaction.

Plenty River, Scrubby Creek, Sawpit Creek and Dry Creek are within the study area and rely on the surface expression of groundwater and have a moderate potential for groundwater interaction.

9.2 Impact AssessmentThe design as detailed in Appendix A includes a number of cuttings and retaining walls (north of Jorgensen Avenue and south of Bannons Lane); this includes provision for one piled shotcrete wall and three post and panel retaining walls supported by bored piles.

Yan Yean Road (Stage 1) Upgrade is located south of Yan Yean Road (Stage 2) Upgrade and is in a similar geological setting. Groundwater was not intersected during construction of the Stage 1 structures (pers. comm. MRPV to WSP dated 6 December 2018) to a depth of 8 mbgl.

Review of the Management Plan for Plenty Landfill located south of Yan Yean Road (Stage 2) Upgrade indicates groundwater is located more than 60 m below ground level and confirms the risk of groundwater impacts from the Project construction or operation are likely to be low.

The initial risk ratings for the Project consider standard inherent controls in accordance with the relevant standards and guidelines. No additional controls above those listed as standard controls are required to minimise the primary environmental risks.

This desktop groundwater impact assessment concludes that the potential impacts to groundwater and associated GDEs either from reduction in groundwater elevation by dewatering or reduction in groundwater quality are low. It is considered unlikely that groundwater would be intersected by construction activities due to the depth to groundwater.

Should the detailed design change from that specified in Appendix A, the following assessments should be considered, and this impact assessment should be re-evaluated:

assess if excavations will penetrate the water table and therefore experience groundwater inflows

conduct site specific intrusive groundwater investigation to assess structures that will intersect the groundwater table to confirm or otherwise the potential risk and impacts

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estimate the quantity and quality of the groundwater inflows

produce a dewatering management plan to safely manage inflows and minimise groundwater impacts (if required).

EPR GW1 requires preparation of a CEMP that will detail actions to be implemented in the unlikely event that groundwater is unexpectedly encountered during construction activities and actions to be implemented to protect groundwater from spills generated during operation of the road.

EPR EMF5 requires management of any potential impacts during operation and maintenance in accordance with the Department of Transport’s Environmental Management System and standards for managing declared roads in Victoria.

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10 LIMITATIONSThe findings of this report are based on the Scope of Work described in this report. Arcadis Australia Pacific Pty Limited (Arcadis) performed the services in a manner consistent with the level of care and expertise exercised by members of the environmental profession.

No warranties, express or implied, are made. Subject to the Scope of Work, Arcadis’ assessment is limited strictly to identifying typical environmental conditions associated with the subject property.

While normal assessments of data reliability have been made, Arcadis assumes no responsibility or liability for errors in any data obtained from regulatory agencies, statements from sources outside of Arcadis, or developments resulting from situations outside the scope of this Project

Arcadis prepared this report for the sole and exclusive benefit and use of the client. Notwithstanding delivery of this report by Arcadis or the client to any third party, any copy of this report provided to a third party is provided for informational purposes only, without the right to rely.

Information from samples collected by Arcadis personnel relating to soil, groundwater, waste, air or other matrix conditions in this document is considered to be accurate at the date of issue. Surface, subsurface and atmospheric conditions can vary across a particular site or region, which cannot be wholly defined by investigation. As a result, it is unlikely that the results and estimations presented in this report will represent the extremes of conditions within the site that may exist. Subsurface conditions including contaminant concentrations can change in a limited period of time and typically have a high level of spatial heterogeneity.

From a technical perspective, there is a high degree of uncertainty associated with the assessment of subsurface, aquatic and atmospheric environments. They are prone to be heterogeneous, complex environments, in which small subsurface features or changes in geologic conditions or other environmental anomalies can have substantial impact on water, air and chemical movement.

Arcadis’ professional opinions are based upon its professional judgment, experience, and training. These opinions are also based upon data derived from the limited testing and analysis described in this report. It is possible that additional testing and analysis might produce different results and/or different opinions. Arcadis has limited its investigation(s) to the scope agreed upon with its client.

That standard of care may change and new methods and practices of exploration, testing and analysis may develop in the future, which might produce different results.

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11 REFERENCESArcadis (2020). Yan Yean Road Upgrade, Limited Environmental Site Assessment.

ANZECC (2000). Australian and New Zealand Guidelines for Fresh and Marine Water Quality.

ANZG 2018. Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australian and New Zealand Governments and Australian state and territory governments, Canberra ACT, Australia. 

Bureau of Meteorology, BOM weather station, Yan Yean (086131) Climate Data, Accessed: 2020.

Bureau of Meteorology, Atlas of Groundwater Dependent Ecosystems, Accessed: 2018.

GHD, 2012. Department of Sustainability and Environment (2012), Victorian Aquifer Framework Updates for Seamless Mapping of Aquifer Surfaces. May 2012.

Department of Economic Development, Jobs, Transport and Resources (Geological Units 1:50,000).

DELWP (2020). Victorian Groundwater Resource Reports, Department of Environment, Land, Water and Planning (2020), accessed March 2020.

DELWP (2019). Water Management Information System, Department of Environment, Land, Water and Planning (2019), accessed March 2020.

Geological Survey of Victoria, 1972. Yan Yean map sheet, 1:63,360.

Golder Associates, 2015. Plenty Landfill Aftercare Management Plan. Prepared for Nillumbik Shire Council. Ref: 147615003-026-R-Rev0. June 2015.

Government of Victoria (2018). State Environment Protection Policy (SEPP Waters), Government of Victoria S499.

Government of Victoria (2002). State Environment Protection Policy (Prevention and Management of Contamination of Land) S95.

Hatton, T. & Evans, R. (1998), Dependence of ecosystems on groundwater and its significance to Australia, Land and Water Resources Research and Development Corporation, Canberra.

Kenny, J. P. L. 1940. Golden Gate Mine, Yarrambat, Mining and Geological Journal V2. Pt 2, p77.

Kenny, J. P. L. 1940. Golden Crown Mine, Yarrambat, Mining and Geological Journal V2. Pt 2, p77

Leonard, J.G. (2006). Hydrogeology of the Melbourne area, published in the Australian Geomechanics Vol 41, No 3, September 2006.

Melbourne Water (2007). Plenty River Water Supply Protection Area Stream Flow Management Plan 2007.

Melbourne Water (2016). Diamond Creek, Local Management Plan 2016.

NHMRC, NRMMC (2011) Australian Drinking Water Guidelines Paper 6 National Water Quality Management Strategy. National Health and Medical Research Council, National Resource Management Ministerial Council, Commonwealth of Australia, Canberra.

Southern Rural Water (2014). Port Phillip and Western Port Groundwater Atlas.

State government of Victoria, 1996-2015. GeoVic Earth Resources. Department of Jobs, Precincts and Regions, Victoria, Australia.

Department of Transport (2016). 177 Environmental Management (Major). Accessed 7/2/17 from: http://webapps.vicroads.vic.gov.au/VRNE/csdspeci.nsf/webscdocs/D8CBB019CA9E4C64CA257FAF0002B324?OpenDocument

Whiting, R. G. 1955. Report on the Golden Crown Mine, Yarrambat. Mining and Geological Journal V5. Pt 6, p32-34.

WSP (2018). Geotechnical Report, Yan Yean Road Upgrade.

WSP (2020) Yan Yean (Stage 2) Upgrade Flora and Fauna Impact Assessment.

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APPENDIX A PROJECT DESCRIPTION: YAN YEAN ROAD UPGRADE – STAGE 2

Insert Project Description

APPENDIX B FIGURES

Insert Appendix B Figures

APPENDIX C GROUNDWATER RISK REGISTER

Insert GW Risk Register

APPENDIX D GROUNDWATER RESOURCE REPORTS

APPENDIX E GEOTECHNICAL BORE LOGS

Insert Geotechnical Bore Logs

APPENDIX F DEPARTMENT OF ENVIRONMENT, LAND, WATER AND PLANNING WMIS DATABASE

Appendix F – WMIS DatabaseYan Yean Road (Stage 2) Upgrade

APPENDIX G RELEVANT BACKGROUND DATA FROM PLENTY LANDFILL AFTERCARE MANAGEMENT PLAN