of Power Supply

15.0 Summary of effects of Power Supply

of Power Supply

15.0 Summary of effects

Volume 1 Volume 2 Volume 3 Volume 4 Volume 5 Technical

Project and its Environmental Environmental Environmental Environmental Appendix

Effects Effects of Effects of Effects of Effects of

Marine Structures Desalination Plant Transfer Pipeline Power Supply









Chapter 15

Summary of

effects of the

Power Supply









15 Summary of effects of Power Supply

The Desalination Plant and Transfer Pipeline will require an average electricity

requirement of approximately 92 megawatts for a 150 GL Plant. As the existing

electricity network in the Bass Coast region is unable to meet this demand, a

new power supply is required. The Reference Project includes connection to the

existing transmission network via grid connection infrastructure. This would

include connection to existing 220 kV lines via a new terminal station at Tynong

North, a double circuit 220 kV overhead transmission line approximately 60

kilometres long to a new terminal station in Woolamai and three 66 kV

underground lines approximately 10 kilometres long installed to the Desalination

Plant.







15.1 Assessment methodology

The key effects of the Power Supply were identified taking into account

legislative and policy obligations, community and stakeholder concerns and

guidance from the Scoping Requirements. Environmental effects from

construction and operation of the grid connection were considered through an

environmental impact and risk assessment process.









Chapter 15 Summary of effects of the Power Supply 15-1

Project controls — expressed as Performance Requirements in the

Environmental Management Framework — were developed following a detailed

risk assessment of the effects of the Power Supply on the environment,

community and local economy. The Performance Requirements form an

envelope to guide the Project Company in the design, construction and

operation of the Desalination Plant and its components, including the Power

Supply. This will prevent any adverse impacts to the environment and the

community, whilst allowing the Project Company to create an innovative design

for the Desalination Project.







15.2 Existing environment

The grid connection would cross a range of distinct environments, including the

coastal plain between Kilcunda and Wonthaggi, the Strzelecki foothills, Bass

Valley and the alluvial plain between Nyora and Tynong. The transmission line

alignment has been selected to avoid townships and relevant environmental

constraints as far as possible and therefore land use largely comprises cleared

agricultural land. Beef and dairy are the dominant agricultural land uses along

the alignment. The notable exception to this is the Koo Wee Rup Horticultural

Preservation Area, defined in the Cardinia Planning Scheme as the Special Use

Zone (SUZ1). Within this zone and where irrigation is available, there is heavy

cropping, most notably potatoes. The potato pathogen, the Potato Cyst

Nematode (PCN), is also known in this area. The area has been declared a PCN

Control Area under the Plant Health and Plant Products Act 1995. Within this

Control Area there are strict protocols in place for the movement of soil and

plant materials.



Some indigenous remnant vegetation is present in road reserves, along

waterways and in occasional patches within paddocks or windrows. The

Strzelecki foothills comprise steeply sloping hills as well as stream sides and

soaks, and these areas may provide habitat for the EPBC-listed Giant Gippsland

Earthworm. The EPBC-listed Dwarf Galaxias and Australian Grayling are likely to

be present in waterways crossed by the transmission line, including the Bass

River and Powlett River. Other EPBC-listed fauna species that may occur along

the grid connection corridor include the Powerful Owl, Southern Brown

Bandicoot, Swamp Skink and Growling Grass Frog. Potential habitat for three

EPBC-listed flora species has been identified along the grid connection corridor;

these include River Swamp Wallaby Grass and Strzelecki Gum.









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Aboriginal sites are scattered across the region, with areas of cultural heritage

sensitivity including waterways, the Koo Wee Rup Plain and coastal dunes.

Isolated artefact sites or small scatters are likely to occur in all landforms along

the alignment, but they are more likely to occur where landforms change or

along waterways and the edges of former swamplands or floodplains.



Aboriginal archaeological sites previously recorded, and those recorded during

field investigations to date, consist largely of isolated artefacts or low density

artefact sites of low scientific significance. Post contact historical archaeological

sites within the investigation corridor include the Eastern Railway Like (RNE

103345) and the Woodleigh Hall (H0179). Further sites of historical

archaeological significance within the corridor have also been recorded during

field investigations to date, including former house sites and timber bridges.



Towns in the vicinity of the grid connection corridor include Dalyston, Kilcunda,

Woolamai, Almurta, Glen Forbes and Kernot. A number of community facilities

are present in the region, including the Bass Coast Rail Trail, Williamsons Beach

and Kilcunda Beach, Woolamai Racecourse, recreation reserves, community

halls, schools and a church. The transmission line would also be constructed

near some residential dwellings.







15.3 Construction of the Power Supply

Construction activities for the grid connection would largely include vegetation

clearance, earthworks, trenching, stockpiling, excavation, truck movements, use

of machinery and some chemical storage and hazardous materials handling. The

transmission line would require construction of towers or poles and stringing of

conductors between these structures. The 66 kV lines would be installed as

underground cables between the Woolamai terminal station and the

Desalination Plant site. As well as the Woolamai terminal station, one more

terminal station will be constructed at Tynong North. The Tynong North terminal

station will connect to the existing transmission network and the Woolamai

terminal station will be used to step down the voltage for the Desalination Plant.









Chapter 15 Summary of effects of the Power Supply 15-3

Ground disturbance during construction has the potential to disturb both

Aboriginal and historical cultural heritage sites. A number of previously recorded

and newly discovered Aboriginal and historical sites have been identified along

the grid connection corridor. Further sites are expected to be discovered as part

of detailed surveys for development of the Cultural Heritage Management Plan

(CHMP). Works could potentially disturb a number of these sites.



Firstly, most of the excavation required for the construction of the overhead

transmission line would be restricted to the immediate area for each tower or

pole. With less ground disturbance than trenching, there is the flexibility to

avoid known sites through siting of transmission structures and there is a lower

probability of encountering undiscovered Aboriginal sites. A Cultural Heritage

Management Plant (CHMP) would be developed, in consultation with the

Registered Aboriginal Party (RAP) applicants, to avoid, minimise and manage

impacts to Aboriginal cultural heritage. The CHMP must be submitted to and

approved by Aboriginal Affairs Victoria before works commence. Additionally,

the PRs require protection of sites at risk of accidental damage during

construction and require implementation of design to avoid sites of high

significance. Application of the PRs is expected to minimise any impacts on

Aboriginal cultural heritage sites.



Historical sites are likely to be far fewer in number than Aboriginal sites and are

easier to avoid during construction, as they are typically infrequent, more

discrete entities. As with Aboriginal cultural heritage, impacts to historical sites

will be minimised through application of the PRs, including a requirement to

design the extent of works to avoid known sites and protect sites that are at risk

of accidental damage during construction.









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Similar to other linear infrastructure construction projects, construction of the

grid connection will create some noise, vibration, dust and vehicular emissions.

In general, these emissions are expected to be within the range expected for

construction projects of this scope. Specialist investigations have been

conducted to characterise these emissions and to confirm that these emissions

will be temporary and restricted in extent. For example, modelling of possible

dust emissions during construction of the transmission line shows that dust

levels will be below the critical level for nuisance dust complaints beyond 175

metres from the construction site. Although some emissions would be produced

during construction, these activities will be short-term in any one location (since

construction will move through the corridor) and any effects on people and the

environment will be minimal and temporary. Furthermore, the PRs will be

implemented to minimise the effects of noise, vibration, dust and other air

emissions on all receptors.



During excavation activities, potential acid sulfate soils may be encountered in

limited areas along the grid connection corridor: along the Powlett River and in

areas of drained swamp east of Koo Wee Rup, though this risk is considered to

be unlikely. Management of acid sulfate soils is common for construction

projects of this nature and will be managed through the PRs.



Giant Gippsland Earthworm habitat has been identified along the grid connection

corridor and therefore excavation has potential to directly affect this species.

However, it is considered unlikely that works will impact this species as Giant

Gippsland Earthworm habitat is generally located within 40 metres of streams

and waterways, and the transmission structures would be located to span

waterways and areas of suitable habitat. Since the corridor crosses

predominately agricultural land dominated by introduced vegetation, which is

unlikely to support threatened fauna species, construction is unlikely to affect

other EPBC or FFG listed species. Final design of the grid connection would aim

to avoid impacts to significant species, and any potential impacts would be

managed through the PRs. The PRs require implementation of methods to

manage stormwater, noise, light spill, vehicle movements, dust, and weeds and

open trenching in order to limit impacts on flora and fauna.









Chapter 15 Summary of effects of the Power Supply 15-5

Construction of the grid connection, particularly the underground cables, may

require some interactions with surface waters and groundwaters. Construction

could require some dewatering, but this is likely to be localised and temporary.

As already noted, the transmission line would span waterways with minimal

interactions between transmission line construction and surface water. Poles /

towers will be offset from waterways as agreed with the relevant water

authorities. Pursuant to the Performance Requirements, the Project will develop

and implement construction methods and site rehabilitation plans to the

satisfaction of the relevant water authority that seek to protect habitat values of

designated waterways under the Water Act 1989 and waterways that play an

important role in flood mitigation.



Construction activities for the grid connection could cause a temporary and

localised disruption to some roads and recreational areas. Any interactions will

be minimal since construction would move progressively along the corridor and

rehabilitation would occur in the wake of grid connection installation. Overall,

any impact on facilities and recreational activities is likely to be minor due to the

short time period of construction and since the PRs specify development of a

traffic management strategy, a rehabilitation plan and a construction workforce

accommodation strategy.



The potential impacts of construction on farming activities include temporary

loss of production, severance where the construction corridor isolates an area

for use, capital improvements loss, spread of soil borne pathogens such as the

Potato Cyst Nematode (PCN) and inadequate rehabilitation. Impacts to farming

activities will be managed through implementation of relevant Project

Requirements (PRs) which require design to minimise impact through detailed

siting of infrastructure, compliance with protocols to prevent the spread of PCN

and appropriate site rehabilitation.









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15.4 Operation of the Power Supply

Operational activities for the Power Supply would mainly involve maintenance

activities, which could require some truck and vehicle movements. The terminal

stations for the grid connection will generate some noise and vibration, but

other emissions such as dust are expected to be minimal since truck movements

would be infrequent and any dust would be much less than emissions generated

during construction. The terminal stations would be located and designed to

comply with EPA noise guidelines and modelling already shows that by locating

and designing the stations, operational noise would be below the operational

noise goals for the EPA Victoria guidelines for noise in Country Victoria at all

nearby properties. Therefore, noise and vibration are not expected to be an

ongoing issue for the Power Supply.



Since the environmental disturbance will be mostly restricted to the construction

period, it is expected that there will be no ongoing effects on terrestrial

ecosystems, aquatic ecosystems and cultural heritage during operation.

Maintenance activities will need to be managed to limit the potential impact to

terrestrial flora and fauna, including vehicle movements, dust, noise and the

introduction of weeds and pests. Appropriate management during construction

would minimise any possible impacts on surface water and groundwaters

including a rehabilitation plan to restore the pre-construction landscape.



The transmission line will include permanent infrastructure on the landscape

including poles or towers, powerlines and terminal stations. This will change the

amenity of the area. The alignment has been selected to avoid dense

populations of people and sensitive land uses. A visual impact assessment

concludes that the transmission line would be visible from a number of publicly

accessible viewpoints and residencies along the alignment. The impact on visual

amenity from the transmission line depends on the type of infrastructure and

the adjacent land use. Steel poles have been considered as an alternative to

steel towers which would lower the visual impact in sensitive landscapes. The

assessment of residential properties shows that the grid connection would have

a moderate to high impact on the visual amenity of residents. The PRs address

this possible change in amenity by requiring design and siting of the grid

connection to limit visual impacts on residential properties and publicly

accessible locations.









Chapter 15 Summary of effects of the Power Supply 15-7

An easement will be acquired for the transmission line and subtransmission

cables, and land acquisition will be required for the terminal stations. The

transmission line alignment would intersect some highly productive agricultural

land in the Koo Wee Rup area. The alignment across this area has the potential

to compromise irrigation efficiency as it may restrict irrigation within the

easement. As a result, some land may be removed from irrigation and suffer a

loss in productivity, the potential earning rate and ultimately in land value.



Compensation (including disruption costs) is payable under the Land Acquisition

Compensation Act 1986 (Vic) for acquired easements. Some activities would be

largely unaffected by the easement; livestock grazing and other typical

agricultural activities that do not require irrigation methods discussed above

should be able to resume once construction and rehabilitation have been

completed. Cropping which requires irrigation could still be undertaken, provided

modifications were undertaken to practices and equipment. The PRs require

development of rehabilitation planning with individual private landowners prior

to disturbance of private land. In general, the transmission line corridor will be

progressively rehabilitated and any potential impacts on land use of the

easement after construction will be managed through the PRs and the Land

Acquisition and Compensation Act 1986 (Vic).







15.5 Conclusions

The grid connection would involve construction and operation of infrastructure

that is common in Victoria. Firstly, sites and alignments have been sited and

designed to avoid areas of sensitivity. Construction impacts would be short lived

and similar to those for other linear infrastructure projects. These will be

managed through the PRs and will conform to all applicable policies, legislation

and guidelines, as well as implementing best practice measures to further

reduce the construction impact.



Once constructed, the transmission line corridor would be rehabilitated.

Operational activities would largely be restricted to routine maintenance. Any

potential impacts on land use within the easement will be appropriately

managed through PRs and the Land Acquisition and Compensation Act 1986. As

the Power Supply would be designed in accordance with legislation, and in

particular EPA policies relating to noise, it is expected that there will be minimal

impact on the surrounding environment and community.









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