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February 2019

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GroundwaterRay Hatley

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Qualifications•Ray has 34 years of pertinent experience providing geological, hydrogeological, geotechnical and environmental services to road, rail and tunnel infrastructure projects, as well as, projects for land development, construction, mining, energy, industrial, state and federal government clients in project director, project manager, coordinator, advisory or technical review, and Independent Certifier roles.

•He has completed work covering major Victorian, NSW, and Queensland transport infrastructure projects. Work Ray undertook included groundwater related inflow and dewatering assessments for road and rail tunnels, caverns and dive structures; road and rail cutting/embankment pore pressure assessments, dewatering monitoring and management; environmental impact of road and rail alignments on groundwater users, vulnerable ecological communities and GDE’s, risk assessment (review, methodology development and management/mitigation decision-making); acid sulphate soil, metals and nutrient runoff management; contaminant mobilisation assessment, monitoring and management; and design evaluation, input and adequacy review. Key transport infrastructure projects Ray has had substantial involvement in include:

� LXRA Cheltenham and Mentone;

� Beaufort Bypass Project;

� MRPV – Suburban Road Upgrades;

� EastLink Freeway;

� WestConnex (NSW);

� M5 East Motorway (NSW);

� Pacific Highway Upgrade - Tintenbar to Ewingsdale (T2E)(NSW);

� Pacific Highway Upgrade - Warrell Creek - Nambucca Heads – Urunga (NSW); and

� Toowoomba Second Range Crossing (Qld);

� Other works completed cover water resources, water supply schemes, and groundwater works for water conveyance, defence, industrial, commercial and petrochemical facilities (contaminated land assessment and remediation), oil and gas projects, and mining and mineral process operations.

Introduction Ray Hatley

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EES Studies

• Preliminary Assessment / Risk Assessment

• EPBC Act Referral

• Confirmation of controlled action

• Finalisation of Scoping Requirements

• Methodology

• Existing conditions

• Impact assessment

• Risk assessment

• Environmental Performance Requirements (EPRs)

Response to submissions

• Submissions received

• Submission responses

• Response to other experts

Groundwater Impact Assessment -Presentation Overview

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Location

• new freeway connecting the Dingley Bypass with the Mornington Peninsula Freeway

Key Features

• The project comprises a 9 kilometre freeway with bridges over wetland areas, embankment structures, several grade-separated interchanges and a cycling and walking path

• Passes between the western boundary of Braeside Park and the eastern boundary of the Woodlands Industrial Estate constructed wetlands, crosses constructed wetlands at Waterways, and passes within 1 km of the Ramsar-listed Edithvale–Seaford Wetlands.

NOTES

• Assessment of the landfill/s located on the northern portion of the alignment is dealt with in the Environmental Site Assessment (Appendix L) and are addressed by the expert evidence of Helen Jones in contaminated land who will cover contaminated land impacts issues (incl. soil and groundwater contamination and acid sulfate soils are addressed)

The Mordialloc Bypass Freeway Project

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Preliminary assessments

Preliminary groundwater impact

assessments, largely desktop

Preliminary GWIA Report

Initial EES investigations

Establishment of groundwater

monitoring network

Baseline groundwater / surface water

sampling

Aquifer testing and water level logging

Embankment consolidation study

EPBC Act referral

(13/09/17)

Characterisation of existing conditions

Identified potential risks associated

with embankments to groundwater flow

Recommendation for a numerical

groundwater model

Controlled action

Controlled action

(8/1/2018)

Wetland sensitive receptor list expanded to include Waterway Wetlands, Woodlands Industrial Estate

Wetlands and Braeside Park Wetlands.

Risk assessment

Risk identification Risk workshopsQuantitative risk

assessment

Impact assessment

Expansion of groundwater

monitoring network

Development and calibration of

numerical groundwater model

Numerous technical studies to assess impacts to sensitive receptors

Groundwater Impact Assessment Methodology

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Jun

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7 Preliminary Groundwater Impact Assessment

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7 Groundwater Impacts to Edithvale Wetlands –Assessment and Mitigations Report

Sep

tem

ber

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18 Groundwater

Impact Assessment (EES Groundwater Technical Report)

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18 Groundwater

Modelling Report

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18 Edithvale

Wetland Water Balance Modelling

Groundwater Technical Reports Completed

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Total of 15 submissions with concerns to groundwater

Key Submission concerns

� Impacts to groundwater

� Baseline / ongoing groundwater monitoring input to Environmental Performance Requirements (EPRs)

� Cumulative impacts to sensitive receptors arising from both the proposed Mordialloc Freeway and Level

Crossing Removal Authority (LXRA) Edithvale – Bonbeach project

� Groundwater – surface water interaction, and groundwater dependant ecosystems

� Climate change.

� Groundwater modelling, impact predictions and their confidence levels

� Landfill matters

Response to Submission

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Groundwater Levels

• Potential for mounding / drawdown

• Potential impacts to beneficial users

Groundwater Quality

• Potential impacts to water quality (particularly salinity)

Sensitive Receptors

• Potential impact to sustaining groundwater flow to Edithvale-Seaford Wetlands

Identification of Risks - Basis for groundwater aspects of EES and EPBC Act Referral

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• Potential impact to GDEs (Edithvale and other wetlands)

• Potential interference with water users (registered bores)

• Acid sulfate soil exposure (oxidation)

Groundwater drawdown

• Potential impact to GDEs

• Potential water logging

Groundwater mounding

EES Groundwater Impact assessment

� Requirement for numerical groundwater model

� Quantification of impacts required

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The Scoping Requirements objectives provide a framework in which potential impacts from the project can be assessed in accordance with the Ministerial guidelines for the assessment of environmental effects under the Environment Effects Act 1978

� The Ministers EES Scoping requirements with regard to groundwater are to examine:

‘Potential effects on water environments and related beneficial uses, including as a result of

changes to hydrology and groundwater’.

� Therefore: the primary objective of the groundwater impact assessment and its

associated numerical impact modelling was to quantify impacts to groundwater resources

and associated environmental values, in particular the Edithvale Wetlands in response to

the proposed embankments for the Project.

� Ref: Department of Environment, Land Water and Planning (DELWP) (2018).

Scoping Requirements for Mordialloc Bypass Environment Effects Statement.

Melbourne.

EES Scoping Requirements - Groundwater

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Desktop assessment and conceptualisation

• Identification of data gaps

• Regional conceptualisation

Intrusive Investigations

• Establishment of groundwater monitoring network

• Aquifer testing

• Baseline sampling / water level monitoring

Initial Impact Assessment

• Geotechnical assessment of change in permeability due to embankment loading

• Initial Impact Assessment

Conservatisms Incorporated

Initial Impact Assessment- Embankment consolidation and permeability reduction modelling

• Media: defined as 100% compressible clay

• Embankment height set at 10 m high

• Sensitivity tested to 15 m high (150%)Modelling Method Reference: Boussinesq, M. J. (1885)

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Governor Road

• Height 0 - 8 m above grade

• Length = 1300 m

Springvale Road

• Height = 0 - 9 m above grade

• Length = 800 m long

Conservativeness

• Geotechnical assessment of change in permeability due to embankment loading

Embankment Locations and Specifications

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Groundwater Existing Conditions -Recap

• Groundwater system: 2 key aquifers present - shallow

Quaternary aquifer and deeper Upper-Tertiary aquifer

• Groundwater Levels: Shallow, seasonally variable with

levels fluctuation range from 0.5 to 1.0 m.

• Groundwater Flow: To the south-south west, Edithvale

Wetlands influence as acts as a discharge feature.

• Groundwater Quality: highly variable, fresh to saline.

• Wetland Recharge/Discharge: Complex GW-SW

interaction at Edithvale Wetlands. Other wetlands appear

to be SW dependant only (urban run-off sustained).

• Environmental Values: wetlands, and wetlands

ecosystems, water users

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Drilling program

• A total of 35 boreholes drilled and monitoring bores installed - in both the QA and UTAF aquifers

• Aquifer testing of 35 monitoring bores

Baseline monitoring

• Quarterly sampling to capture seasonal variability (both surface and groundwater)

• Installation of groundwater level loggers (6 hour interval continual monitoring)

Geochemical Investigation

• Isotopic sampling and analysis, including within Edithvale Wetlands

• Water source investigation

EES site investigations - best practice approach

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Groundwater quality

• Completed four rounds of quarterly sampling to capture seasonal variability

Groundwater levels

• Installed groundwater level loggers are still collecting data at 6 hour intervals. First loggers commenced August 2017

• Most recent download occurred Jan 2019

Baseline data will be used in the establishment of monitoring criteria within the Water Management and Monitoring Plan (EPR W5)

NOTE: The Natural groundwater fluctuation range of 0.5 – 1.0 m

Baseline Monitoring

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Refinement of conceptual groundwater model - East – West Cross Section

Edithvale Wetlands are below sea level and act as a discharge feature influencing both local and regional groundwater flow

Surface and ground water replace evaporation losses to deeper wetland cells

Evidence of saline intrusion observed through water quality samples adjacent Edithvale Wetlands

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Refinement of conceptual groundwater model

Local Wetlands are largely recharged surface water run-off from urban catchments

Evaporation dominates discharge from wetlands

Dominant UTAF regional groundwater flow direction is from the north-north east to south south west

Water balance modelling indicates that there was little sensitivity to groundwater inflows

Local groundwater flow dominated by groundwater ‘sink’ effect of wetlands

Key requirements for the EES is to examine:

• “Potential effects on water environments and related beneficial users, including as a result of changes to hydrology and groundwater”

Objectives

• The primary objective of the Mordialloc Bypass (MB) groundwater modelling is to quantify impacts to groundwater resources and associated environmental values, in particular, for the Edithvale, Braeside Park, Waterways, Woodlands Industrial Estate Wetlands in response to the proposed embankments for the Mordialloc Bypass Project

• The modelling also aimed to quantify cumulative impacts associated with other projects in the area, in particular, the Edithvale-Bonbeach level crossing removal project (LXRA)

EES Impact Estimation –using

Numerical Groundwater Modelling

The modelling approach to achieve these objectives has been independently reviewed and is considered fit-for-purpose and is commensurate with the inferred impacts: ie. those arising out of compaction effects and their inferred reduction hydraulic conductivity characteristic in the shallow aquifer beds underlying the embankment structures.

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Numerical Groundwater Impact Modelling

- specifications A Class 2 predictive groundwater model was developed using the control-volume finite difference code: MODFLOW-USG.

Model inputs – Water levels, stratigraphy, hydraulic conductivity (K) etc.:

• 35 project groundwater monitoring bores (groundwater levels, stratigraphy, K)

• 20 LXRA groundwater monitoring bores (groundwater levels, stratigraphy)

• Climate data (BOM rainfall, evaporation)

• The Victorian Aquifer Framework (VAF) hydro-stratigraphy

• LiDAR – land surface elevation

• Embankment surcharge permeability values

• Designed to meet a Class 2 model resolution in accordance with Australian Groundwater Modelling Guidelines (2012)

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Important features

• Topographic high in the north

• Costal dune system

• Topographic low at Edithvale Wetlands and Centre Main Drain

• Former Carrum-Carrum Swamp outline

Surface Elevation

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The model domain is 8km by 10.35 km.

4 model layers (QA, UTAF, UMTD, LTA)

Cell size is 50 x 50 m over most of the model and 12.5 x 12.5 around embankment areas and wetland / drainage lines -

Total number of cells after refinement is 138,860 (34,715 per layer)

Model Domain

The model domain is centred on the Springvale Road and Governor Road embankment structures - from which impacts arise

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Modelled groundwater table –calibrated to observed conditions

Groundwater levels largely topographically controlled.

Larger hydraulic gradients in the north with flow generally south and south-west

Lower hydraulic gradients within the former Carrum Carrum Swamp with flow controlled locally by wetlands (generally south and west).

Key: the significant influence of Edithvale Wetlands and Centre Main Drain (being below sea level) on flow.

Designed and calibrated to meet a Class 2

model resolution in accordance with

Australian Groundwater Modelling

Guidelines (2012)

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Predicted water level changes due to embankments

(95% Confidence Level)

Steady State Model Run:

• Maximum predicted drawdown observed in steady state scenario is:

• 6 cm at the southern end of embankment and

• 11 cm at northern embankment with change only observed beneath the embankment itself.

• Negligible drawdown outside of the embankment footprint.

Transient Model Runs:

•Maximum predicted drawdown observed in transient scenario (June / December 2020) were:

•3.6 cm (June 2020) and 11 cm (December 2020) for southern embankment; and

•5.1 cm rise (June 2020) and 13 cm rise (December 2020) for northern embankment.

•Negligible drawdown outside of the embankment footprint.

Outcome: Most of predicted changes occur beneath the embankment footprint itself and within the project boundaries.

Impacts are well within the natural groundwater fluctuation range of 0.5 – 1.0 m

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Winter vs Summer Predictions

June Predictions – Winter Months December Predictions – Summer Months

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Cumulative Impacts associated with LXRA Edithvale-Bonbeach

The LXRA indicated that changes to the water table caused by the LXRA trenches do not extend to Edithvale Wetlands.

The Mordialloc Bypass model predicts changes to groundwater do not extend past the alignment boundary

Therefore no cumulative impacts to the wetlands are expected as a result of Mordialloc Bypass or LXRA projects at Edithvale / Bonbeach

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Groundwater – surface water interaction a key focus of the EES and characterised through:

• Literature review – well understood through previous investigations.

• Geochemical analysis – Ionic composition comparison, isotopic analysis, and chloride-bromide mass ratio.

• Edithvale north wetland cells display groundwater contributions.

• Woodlands Industrial Estate Wetlands, Braeside Park Wetlands, Waterway Estate Wetlands and Mordialloc Creek are chemically distinct and not considered groundwater dependant.

Groundwater – Surface Interaction

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Ca Na+K HCO3+CO3 Cl

Mg SO4

<=C

a +

Mg

Cl + S

O4=>

Rainfall

Waterways Wetland

Edithvale Wetland

BPWIEW

Port Phillip Bay

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Water balance modelling

• Developed from existing LXRA water balance model (GHD-AECOM JV) using SOURCE modelling platform incorporating Mordialloc Bypass project requirements

• Project-only impacts evident for Edithvale South catchment (no significant GW inflows for ES1)

• Wetland inflows consist of direct rainfall, stormwater runoff and groundwater discharge.

• Wetland discharge consists of evapotranspiration and outflow to Centre Main Drain

• Water balance model consisted of three scenarios:

•Base case (current conditions);

•Proposed case with no change to groundwater inflow (as modelled in the groundwater model); and

•Proposed case with 10% reduction to groundwater flow (considered an extreme scenario)

• Climate change conditions run for all three scenarios for 2040 and 2065

Water balance modelling indicates that there was little sensitivity to groundwater inflows between the model scenarios

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Numerical Modelling Sensitivity

• The sensitivity analysis assessed the impact of:

• Increasing/decreasing the horizontal and vertical hydraulic conductivity of all hydraulic conductivity zones by a lower multiplier of 0.1 and an upper multiplier of 10

• Increasing/decreasing the leakage streambed from Patterson River by a 0.1 and 10

• Increasing/decreasing recharge by a multiplier of 0.1 and 10

• Increasing/decreasing evapotranspiration by a 0.1 and 10.

• The results indicate the most sensitive parameters to be:

• Horizontal hydraulic conductivity of layer 1, the Quaternary Alluvium

• Evapotranspiration

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Conservatism

• Compaction modelling used the most compressible lithology (plastic clay) to assess permeability reduction factors

• Compaction modelling included a sensitivity run using embankment height of 150% greater than planned (9m, versus +15m)

• Numerical groundwater impact model incorporated Climate Change Scenarios using CSIRO predictions

• Climate change scenario results imply that groundwater impacts to the Edithvale Wetlands as a result of the embankments is unlikely to be significant under the currently accepted climate change scenarios.

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The development of a:

Water Management and Monitoring Plan (WMMP)(EPR reference W5):

Prepared to the satisfaction of the EPA,

WMMP will encompass both surface and groundwater aspects and allows for the

verification of predicted impacts to both surface and groundwater resources:

• The WMMP will form part of the Environment Management Plan (EMP) for construction and operation, and is of satisfactory standing requiring approval EPA Victoria.

• The WMMP incorporates baseline data acquired through the pre-development quarterly monitoring. This baseline data allows for the development of:

• Site specific trigger levels for water quality of surface and groundwater

• Details what parameters are to be monitored

• Monitoring frequency (scheduled and event based)

• Duration of monitoring obligations – being 5 years post construction.

Environmental Performance Requirements

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At a glance

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• GWIA OBJECTIVE: the groundwater impact modelling was set-up to quantify impacts to groundwater resources and associated environmental values, in particular for the Edithvale Wetlands, Braeside Park Wetlands, Waterways Wetlands and Woodlands Estate Wetlands; and

• The risk of leachate migration from closed landfills in the northern section of the alignment and risks related to soil and groundwater contamination and acid sulfate soils are addressed by the expert evidence of Helen Jones in contaminated land

• WSP consider that the specific requirements, defined in the groundwater modelling guidelines (2012), for the model to be considered a Class 2 model, have been met.

• The model has been independently peer reviewed by Dr Tony Smith of CDM Smith, who determined the model to be fit-for-purpose and to not contain significant technical flaws or errors.

• Flux to wetlands has been provided within the Mordialloc Bypass Edithvale Wetland Water Balance Modelling report (WSP, 2018. Mordialloc Bypass – Edithvale Wetland Water Balance Modelling.

• The ANZECC 95% protection criteria were used based on local ecosystems being classified as slightly to moderately disturbed (consistent with Melbourne Water’s management plans)

Response to Other Experts – City of KingstonClarifications

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Thank you –

Any questions