WATER Corporation has trimmed back plans to clear native vegetation as part of a proposed seawater desalination plant in Alkimos.
The Environmental Protection Authority this month approved changes to the Alkimos Seawater Desalination Plant referral, submitted in 2019.
Proposed changes to the pipeline route from Alkimos to Wanneroo Reservoir would reduce the overall development envelope by 10 per cent, from 155.7ha to 140.5ha.
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READ NOWKey changes to the development envelope would remove the Nowergup tank farm pipeline spur and realign 2km of pipeline near the plant.
They would also reduce the overall extent of native vegetation clearing by 4 per cent, from 46.5ha to 44.5ha, as a result of changes along the proposed 33.5km pipeline route.
An EPA notice said the changes would decrease the impact on foraging habitat for black cockatoos and increase impact on potential breeding trees, although none were known to contain hollows.
“The extent of clearing to potential black cockatoo breeding trees will increase from 65 trees to 77 trees as a result of the increase in the pipeline construction footprint to 30m,” it said.
“The number of areas containing black cockatoo breeding trees has been reduced overall by the removal of the Nowergup tank pipeline spur.”
The notice said widening the pipeline construction footprint to 30m for safety reasons would increase impact on Bush Forever from 4.8ha to 9.5ha.
It said flora and fauna surveys identified impacts on tuart woodlands, which have been listed as threatened ecological communities since the 2019 referral.
The notice said a northern option for the pipeline alignment east of Marmion Avenue could affect the Alkimos dune system, which was a listed geoheritage area, and building the desalination plant could affect Quindalup dunes.
The EPA said the proposed changes were unlikely to significantly increase the proposal’s overall impact on the environment.
Water Corporation started consultation on the proposed facility in 2018, and a drilling barge did offshore investigations in 2018-19.
If the State Government decides to fund the facility, it would be built beside the Alkimos Wastewater Treatment Plant.
Earlier this year, a consultant did surveys around the existing plant to investigate ground conditions for enabling infrastructure and surveys for access road improvements.
Water Corporation has focused investigations on building a 100GL per annum seawater desalination plant in four stages, co-located with a 6GL/a Eglinton groundwater treatment plant at the site.
It would have two ocean pipelines, below the seabed, that bring seawater to and take brine away from the plant.
The pipeline to Wanneroo Reservoir would transfer desalinated water to Perth’s main water supply.
Water Corporation has also investigated the possibility of building another desalination plant in Kwinana.