Feedback invited for desalination plant environmental assessment

A model of the desalination plant proposed for Alkimos.
A model of the desalination plant proposed for Alkimos.

PLANS for what could be the first northern suburbs seawater desalination plant are out for public consultation.

The Federal Department of Environment and Energy has invited feedback until August 14 for its environmental impact assessment of a Water Corporation proposal to build a 100GL per annum seawater desalination plant and groundwater treatment plant in Alkimos.

The proposal would include marine intake and outfall pipelines that extend 4km offshore, treatment plants with a 29ha footprint and a 35km pipeline from Alkimos to Wanneroo Reservoir.

According to Water Corporation, the desalination plant could be built in four 25GL stages and timing would depend on growth in water demand, potential groundwater allocation reduction and stream flow conditions.

It could also depend on timing of other water source option development, such as another desalination plant at Kwinana or groundwater replenishment.

Alignment and dimensions of the proposed subsea tunnels and existing waste water pipeline.

Dozens of files relating to the proposal’s environmental review document, which was also referred to the State Environmental Protection Authority (EPA), can be found online.

The document said the environmental impact assessment process needed to consider the connections and interactions between parts of the environment to inform a holistic view of impacts to the whole environment, including in a regional context.

“Due to a combination of drying climate and increasing demand, Water Corporation needs to be prepared to enable the supply of sufficient water to meet Perth (and surrounds) long-term requirements,” it said.

The document said the proposal could help reduce Perth’s future water supply gap and increase the supply capacity of the integrated water supply scheme.

“The environmental studies commissioned for this proposal have considered and assessed potential proposal impacts at both a local and regional scale, as well as cumulative impacts,” it said.

“Key and other environmental factors have been considered against EPA objectives and relevant guidelines.

“Water Corporation considers the potential impacts for the preliminary key environmental factors can be appropriately managed through the implementation of specific mitigation measures.

“Based on the mitigation measures proposed and the use of management measures, the proposal is considered to meet the EPA’s objective for each environmental factor.”

In June, the EPA published its plans to assess the proposal, which would be located in the Alkimos water precinct beside the waste water treatment plant .

Water Corporation undertook community consultation on the proposal in 2018 and did offshore testing from late 2018 to early 2019.

The proposed Alkimos seawater desalination plant site.