16.3 Assessment of potential construction impacts

The project has the potential to generate contamination during construction and operation, including the potential to disturb existing contaminated lands at surface works locations.

16.3.1 Construction ancillary facilities

The assessment of impacts for surface works during construction is presented in Table 16-23. Site layouts showing construction work areas are shown in Chapter 6 (Construction work).

Table 16-23 Risk assessment for potential construction impacts
Area Construction works Potential contamination impacts Likelihood of
contamination Consequence Risk1
Wattle Street civil and tunnel site (C1a) at Haberfield

Stockpiling within cut-andcover structure
Excavations and tunnelling for ramps using roadheaders
Minor civil and finishing (pavement and line-marking)
works

The demolition of former buildings and use of lead paint which may have resulted in localised areas of asbestos containing material (ACM) and lead paint flakes in soil. If present and not appropriately controlled, there is potential for:

Inhalation and/or ingestion risk to site workers of hazardous building materials via dust
Cross contamination associated with the incorrect handling or disposal of spoil/unexpected finds
Accidental leaks and spills from the use of the site as a construction ancillary site.

The site would be demobilised and earthworks carried out by the M4 East contractor to provide finished levels that are consistent with the original ground surface before being handed over to the M4-M5 Link contractor.
Very unlikely and limited in extent
Exposure pathway likely to be present
Low
Haberfield civil and tunnel site (C2a) at Haberfield

Minor civil construction and shallow excavation associated with the substation
Demolition activities and use of plant and machinery
Use of existing M4 East facilities (currently under construction)

Historical land uses of former dry cleaners, workshops associated with former car dealerships and mechanics may have caused soil and groundwater contamination at the western end of the site. Isolated soil contamination may be present from demolition or construction of former buildings and use of lead paint which may have resulted in localised areas of ACM and lead paint flakes in surface soil. If present and not appropriately controlled, there is potential for:

Accidental leaks and spills from the use of the site as a construction ancillary site
Demolition activities to mobilise contaminants.

Very unlikely and limited in extent Exposure pathway likely to be present Low

Northcote Street civil site (C3a) at Haberfield

Use of existing M4 East facilities (currently under construction)
Demolition activities and use of plant and machinery

Historical land uses within the site may have caused soil and potentially groundwater contamination (potential former petrol station and workshops). If present and not appropriately controlled, there is potential for:

Accidental leaks and spills from the use of the site as a construction ancillary site
Demolition activities to mobilise contaminants.

Parramatta Road West civil and tunnel site (C1b) at Ashfield

Demolition of existing buildings and structures
Utility works
Establishment of site offices, amenities and temporary infrastructure
Laydown and storage of materials Delivery of materials, plant and equipment
Construction of an acoustic shed
Construction of a temporary access tunnel
Tunnel excavation, stockpiling of excavated material and spoil haulage
Mechanical installation and fitout of the tunnels
Finishing works
Demobilisation

Historical and current land uses including car servicing, potential USTs, former dry cleaner, workshops associated with former car dealerships and mechanics may have resulted in soil and groundwater contamination. Soil contaminations (PAHs) have also been previously identified to the east of the site (GHD 2015). If present and not appropriately controlled, there is potential for:

Demolition activities to mobilise contaminants (ACM and lead paint)
Inhalation and/or ingestion risk to site workers from hazardous building materials and PAHs in excavated soil via dust
Cross contamination associated with the incorrect handling or disposal of spoil/unexpected finds
Accidental leaks and spills from the use of the site as a construction ancillary site.

Potentially present and widespread Exposure pathway likely to be present Medium

Haberfield civil site (C2b) at Haberfield

Establishment of site offices, amenities and temporary infrastructure
Delivery, laydown and storage of materials
Civil works
Landscaping
Demobilisation

Historical land uses of potential former dry cleaners and workshops associated with former car dealerships and mechanics at the western end of the site may have caused soil and groundwater contamination. The remainder of the site was historically residential therefore no other outstanding areas of concern were identified. Isolated soil contamination may be present from demolition or construction of former buildings and
use of lead paint which may have resulted in localised areas of ACM and lead paint flakes in surface soil.

Demolition activities, use of plant and machinery and excavation activities are proposed which could result in:

Inhalation and/or ingestion risk to site workers from hazardous building materials (if present) and PAHs in surface soil via dust
Accidental leaks and spills from the use of the site as a construction ancillary site.

The site would be demobilised and earthworks carried out to provide finished levels that are consistent with the original ground surface before
Very unlikely and limited in extent Exposure pathway likely to be present Low

Parramatta Road East civil site (C3b) at Haberfield

Demolition of existing structures
Establishment of site offices, amenities and temporary infrastructure including temporary noise barriers
Utility works
Establishment of site offices and workforce amenities
Civil works
Landscaping
Demobilisation

Historical and current land uses for car servicing, USTs, former dry cleaner, workshops associated with former car dealerships and mechanics may have caused soil and groundwater contamination. Isolated soil contamination may be present from demolition or construction of former buildings and use of lead paint which may have resulted in localised areas of ACM and lead paint flakes in surface soil. Soil contaminations (PAHs) have also been previously identified to the east of the site (GHD 2015).

Demolition activities, use of plant and machinery and excavation activities are proposed which could result in:

If present and not appropriately controlled, there is
potential for:

Inhalation and/or ingestion risk to site workers from hazardous building materials (if present) and PAHs in surface soil via dust
Cross contamination associated with the incorrect handling or disposal of spoil/unexpected finds
Accidental leaks and spills from the use of the site as a construction ancillary site.

Known to be present Exposure pathway potentially present Medium

16.3.2 Tunnelling

A review of potential contamination sources along the tunnel alignment identified the presence of potential, current and former contamination sources. These are summarised in Appendix R (Technical working paper: Contamination).
During tunnel construction, groundwater would be extracted from the tunnelling process, which would subsequently require disposal. The extracted water would be either:

Treated onsite and then discharged to stormwater under an EPL or to sewer under a trade waste agreement
Transported to a liquid waste facility.

Potential impacts on receiving water bodies associated with the construction of new drainage outlets and drainage infrastructure adjustments and upgrades could occur at the following locations:

Rozelle Bay
Iron Cove
Whites Creek
Easton Park drain
Receiving waters of Sydney Harbour.

Potential pre-mitigation impacts on workers could include exposure to extracted contaminated groundwater from either direct contact or inhalation of vapours, or vapours encountered during tunnelling.
There is potential for shallow tunnelling, such as near portals, temporary access tunnels or cut-andcover tunnels, to encounter groundwater that is impacted from contamination from sources such as petrol stations with dissolved and undissolved petroleum hydrocarbon plumes or other industrial sources. The identified highest risk locations are considered to be:

Parramatta Road, Annandale: The temporary access tunnel connecting the mainline tunnel to the Pyrmont Bridge Road tunnel site (C9) passes directly south of the 7 Eleven service station that is presently under assessment by the NSW EPA under section 60 of the CLM Act. The temporary access tunnel may be relatively shallow as it passes the service station and could potentially intercept a dissolved or undissolved (ie LNAPL) petroleum plume
Wattle Street, Haberfield: The Wattle Street entry and exit ramps are located in an area historically occupied for residential land use in the suburb of Haberfield. There is potential for ACM and lead paint to be present in surface soils
Darley Road, Leichhardt: The temporary access tunnel to the Darley Road civil and tunnel site (C4) passes between former manufacturing businesses and former steel manufacturers and boiler makers. There is potential for metals, PAHs, TPH, asbestos, VOCs, SVOCs to be present in shallow surface soils and/or groundwater
Parramatta Road west, Ashfield: The temporary access tunnel to the Parramatta Road West civil and tunnel site (C1b) is generally located within the northern portion of the site and traverses north along Parramatta Road. There is potential for ACM (from demolition and redevelopment works along Parramatta Road and associated filling) and PAHs to be present in shallow surface soils and/or groundwater
Rozelle Rail Yards, Rozelle: previously identified LNAPL within the Rozelle civil and tunnel site (C5) could be impacted by dewatering for tunnelling around the Rozelle interchange and is likely to be encountered during future tunnelling/portal construction, if not remediated prior
Victoria Road, Rozelle: The Iron Cove Link tunnel between Darling Street and Terry Street passes beneath or directly adjacent to several service stations, some of which are presently under assessment by the NSW EPA under section 60 of the CLM Act, as well as several former dry cleaners
Campbell Road, St Peters: The tunnel portal area and temporary access tunnel within the former Alexandria Landfill at the New M5 St Peters interchange due to leachate and landfill gases. The tunnel at this section is shallow and would be exposed to landfill leachate if appropriate mitigation measures are not implemented.

With the exception of the former Alexandria Landfill (assessed as part of the New M5 project), other sections of the tunnel are at depths greater than 30 metres and therefore the likelihood of encountering plumes with high concentrations of contaminants is low given that deep contamination (greater than 30 metres below ground level) has generally not been identified along the proposed M4- M5 Link tunnel alignment. However, the extracted groundwater is likely to contain concentrations of metals and nutrients above background concentrations and low concentrations of chemical and petroleum hydrocarbon contaminants from the types of sources listed in the previous table. Notwithstanding, tunnels would be drained to construction water treatment facilities prior to discharge to receiving surface water bodies.
Dewatering during construction works may cause changes in the migration of plumes of contaminated groundwater by changing groundwater gradients and drawing the contamination towards the tunnel. This is most likely in areas where the tunnels are shallow and approaching the surface such as the temporary access tunnel at Parramatta Road, Annandale, and the Iron Cove section near and beneath Victoria Road at Rozelle. This is discussed further in Appendix T (Technical working paper:
Groundwater).
Temporary construction water treatment plants would be located at each construction ancillary facility where tunnelling would occur, and would be designed to treat construction water and groundwater inflows encountered during construction. The level of treatment would consider the characteristics of the water requiring treatment, operational constraints or practicalities, and associated environmental impacts. The treatment would be developed in accordance with ANZECC (2000) and with consideration to the relevant NSW Water Quality Objectives as discussed in Appendix Q (Technical working paper: Surface water and flooding).

16.4 Assessment of potential operational impacts

16.4.1 Permanent operational facilities

Potential contamination impacts associated with the presence of roads and permanent operational infrastructure is presented in Table 16-24. Leachate within the former Alexandria Landfill would be treated by the existing water treatment plant constructed for the New M5 project and discharged to sewer under the existing trade waste agreement with Sydney Water. Therefore, leachate within the former Alexandria Landfill does not form part of this assessment.

The Parramatta Road ventilation facility located adjacent to Parramatta Road between Wattle Street and Walker Avenue has been assessed as part of the M4 East project. The M4-M5 Link project includes the internal fit out of this structure.

The construction ancillary facilities that are not anticipated to be used for permanent operational infrastructure would be rehabilitated at the end of construction. Construction facilities that will not include new operational infrastructure are:

Northcote Street civil site (C3a)
Parramatta Road West civil and tunnel site (C1b)
Parramatta Road East civil site (C3b)
Pyrmont Bridge Road tunnel site (C9).

At the completion of M4-M5 Link construction the landscaping (where applicable) and residual land obligations as detailed in the M4 East and New M5 conditions of approval would be carried out by these respective projects. As such there are no anticipated operational impacts of these construction ancillary facilities during operation and these are not discussed further in this section.

Table 16-24 Risk assessment for potential operational impacts

Wattle Street at Haberfield

Roadway

Accidental leaks and spills on constructed roadways from vehicles and vehicle accidents.
Very unlikely and limited in extent
Exposure pathway may be present, if leaks and spills occur
Low

Parramatta Road at Haberfield

Parramatta Road ventilation facility

Minimal soil or groundwater contamination impacts would be expected from the operation of the ventilation facility. Sources of contamination could be from small volumes of oils, fuels, solvents and other chemicals used for operation and maintenance if not stored and handled in accordance with regulations.
Very unlikely and limited in extent Exposure pathway may be present Low

16.4.2 Tunnels

During operation, groundwater seepage would need to be extracted from the tunnels, treated and discharged to receiving water bodies. As part of the tunnel design, some sections would be lined to reduce the ingress of groundwater into the tunnels.
Groundwater quality may be impacted along parts of the tunnel alignment due to overlying contamination sources impacting groundwater. An assessment of the expected groundwater seepage rates and groundwater drawdown which may have an effect on existing groundwater contamination plumes is provided in Chapter 19 (Groundwater).
The extracted groundwater could contain concentrations of metals and nutrients above background concentrations and low concentrations of chemical and petroleum hydrocarbon contaminants. Water collected from within the tunnels would be treated to an appropriate standard to prevent environmental harm prior to discharge (refer to Chapter 15 (Soil and water quality)). If not treated adequately, the discharge of the groundwater to receiving water bodies could contribute to poor water quality. However, the potential for this to occur is considered to be extremely low.
Tunnel drainage infrastructure would be designed to accommodate a combination of contaminated water ingress events including groundwater ingress, stormwater ingress at portals, tunnel wash-down water, fire suppressant deluge or fire main rupture and spillage of flammable and other hazardous materials. Separate sumps would be provided at tunnel sags, one to collect groundwater ingress and one to collect the other potential water sources. The two tunnel drainage streams from the mainline works would be pumped to a water treatment facility at Darley Road, Leichhardt. Potential discharge
and disposal options for treated flows from the facility are discussed in Chapter 15 (Soil and water quality).
Tunnel drainage for Rozelle would be pumped to a water treatment facility and constructed wetland at the Rozelle Rail Yards, with treated flows ultimately discharged to Rozelle Bay. Tunnel drainage from around one kilometre of the northbound and 600 metres of the southbound tunnel would be captured by the New M5 drainage system and conveyed to the New M5 operational water treatment plant at Arncliffe, which ultimately drains to the Cooks River.

An assessment of the potential impacts on the receiving bodies is provided in Chapter 15 (Soil and water quality).

16.5 Management of impacts

The mitigation and management measures provided in Table 16-25 would be implemented during construction and operation of the project to reduce or minimise the potential impacts created by contamination risks. These measures are expected to make the land to be used as part of the project suitable for the proposed end use. Potentially contaminated sites identified in section 16.2.14 would be subject to further investigation, remediation and/or management. Further details on the environmental management measures are provided in Appendix R (Technical working paper: Contamination).

An UDLP would be prepared for the project. Areas of land not required for the construction or
operation of the project but that have been identified as being subject to the UDLP would be
rehabilitated and landscaped to be consistent with the UDLP. Remaining project land would be rehabilitated and returned to finished levels generally consistent with the original ground surface. The future use of remaining project land would be outlined in the Residual Land Management Plan to be prepared for the project.
Wattle Street civil and tunnel site (C1a), Haberfield civil and tunnel site (C2a) and Northcote Street civil site (C3a) would be developed in accordance with the conditions of approval for the M4 East project. The Campbell Road civil and tunnel site (C10) would be developed consistent with the conditions of approval for the New M5 project.
Table 16-25 Environmental management measures – contamination
Impacts on site workers and/or local community through disturbance and mobilisation of contaminated material
CM01 Potentially contaminated areas directly affected by the project will be investigated and managed in accordance with the requirements of guidance endorsed under section 105 of the CLM Act.

This includes further investigations in areas of potential contamination identified in the project footprint. If contamination posing a risk to human or ecological receptors is identified, a Remediation Action Plan will be prepared.

Construction
CM02 Asbestos handling and management will be undertaken in accordance with an Asbestos Management Plan (as part of the Work Health and Safety Plan) as described in Chapter 23 (Resource use and waste minimisation).
Construction
CM03 A hazardous materials assessment will be carried out prior to and during the demolition of buildings. Demolition works will be undertaken in accordance
with the relevant Australian Standards and relevant NSW WorkCover Codes of Practice, including the Work Health and Safety Regulation 2011 (NSW).
Construction
CM04 The Construction Waste Management Plan for the project, prepared as described in Chapter 23 (Resource use and waste minimisation), will include procedures for handling and storing potentially contaminated substances.
Construction

CM05 Stockpile management procedures will be implemented to control dust, odour and cross contamination.
Construction
CM06 The discovery of previously unidentified contaminated material will be managed in accordance with an unexpected contaminated lands discovery procedure, as outlined in the Guideline for the Management of Contamination (Roads and Maritime 2013) and
detailed in the CEMP. The procedure will include:

Cease work in the vicinity
Initial assessment by an appropriately qualified environmental consultant
Further assessment and management of contamination, if confirmed, in accordance with section 105 of the CLM Act.
Construction

Impacts on soil and water quality through incorrect handling of contaminated material
CM07 A Construction Soil and Water Management Plan will be prepared for the project including procedures to manage potentially contaminated stormwater runoff and acid sulfate soils, as described in Chapter 15 (Soil and water quality).
Construction
CM08 Measures identified in Chapter 25 (Hazard and risk) will be implemented to appropriately store dangerous goods and reduce the potential for environmental contamination due to spills and leaks.
Construction
Accidental spills during operation

OCM09 Procedures to address spills, leaks and tunnel washing will be developed as part of an Operational Environmental Management Plan (OEMP) and implemented during operation of the project.
Operation