Alkimos Seawater Desalination Plant

What is being planned?

Water Corporation is investigating the establishment of a possible future seawater desalination plant on land adjacent to its wastewater treatment plant in Alkimos. The investigations are part of long term planning to secure Perth’s water supply.

The possible future Alkimos Seawater Desalination Plant is proposed to be delivered in stages. Initially a 25GL/year plant, with supporting intake, outfall and pipeline infrastructure, with a further 25GL/year expansion to follow.

We are also investigating a possible future desalination plant near operating plant in Kwinana and pursuing other water source solutions including expansion of groundwater replenishment.


What is a feasibility investigation?

A feasibility investigation, or study, assesses whether a project is viable and takes into consideration a range of factors including the likely environmental, social, technical and financial outcomes of what is being considered. A feasibility study can include applying for some approvals before a project is decided to proceed.


Why is it needed?

Water Corporation is planning ahead to secure water supplies in our drying climate for a growing city. Streamflow into dams has reduced from an average of 394 billion litres per year pre-1975 to an average of 50.6 billion litres over the past five years.  This represents an 87 per cent reduction in average streamflow to our dams.  In 2015, Perth’s dams received their worst streamflow on record. 

By 2030, we expect a further 70 to 100 gigalitres of additional climate independent water will be required to support Perth’s water needs, providing our targets for water use reduction and recycling are met.

Why Alkimos and not elsewhere?

Establishing a desalination plant north of Perth has been a key consideration in our long term planning and is included in our ‘Water Forever’ 10 year plan (released in 2012). A range of land options were considered. We have operated our wastewater treatment plant in Alkimos for a number of years and are pursuing the financial and environmental benefits of collocating our assets at the site.

When will the plant be built?

We are completing early investigations for a number of new water sources (including the possible future desalination plants) as part of our long-term planning. No firm timing is known for when a new source will be required, however we do not expect to require a major new source to be required for at least five years.

How does desalination work?

Why desalination and not other options (such as groundwater replenishment)?

More than 40% of Perth’s water supply is from our two desalination plants (in Kwinana and Binningup). Desalination is a proven and trusted water supply solution that does not depend on climate. We will continue to deliver a range of water sources (including expanding our groundwater replenishment scheme) to secure Perth’s water supply.

Why can’t you expand the existing desalination plants (in Kwinana and Binningup)?

Our desalinations plants are operating at capacity and will continue to produce a significant portion of Perth’s baseload supply during the delivery of a new source, without major interruption. The new plant(s) are planned to be independent to the existing plants to further secure Perth’s water supply.

What will it cost?

A desalination plant is a significant State asset. The focus of our current work in relation to the new desalination plant is on feasibility in relation to plant design, environmental impact assessment and engaging with stakeholders. Costs in relation to construction and operations will be considered closer to when the new plant is needed.

What will the plant’s energy requirements be?

Every effort is being taken to ensure the future plant’s design is energy efficient. The expected plant performance will match or exceed industry benchmarks for energy efficiency.

Instead of a major new water source, shouldn’t we be concentrating on reducing and recycling water?

New water sources are only a part of the picture and we will continue to invest in programs to encourage efficient water use – this will help to defer the need for new water sources for as long as reasonably possible.

Will the desalination plant have an effect on the value of my home?

Response prepared by Lendlease:

The location of the proposed plant would be within the Water Corporation’s existing infrastructure land to the north. This site has an existing buffer of regional open space separating the facility from the community. 

Any Water Corporation construction and operational trucks for the facility now also have their own access point directly off Marmion Avenue and no longer drive through the residential area.

Part of initial planning for the plant includes sinking the possible future plant into the Water Corporation site, where it will be sheltered from community view to the north and south by large dunes.

For more information please contact Lendlease.

Will our 6star Green Star rating for Alkimos Beach estate be affected by a desalination plant?

Response provided by Lendlease:

No, the vision of the Alkimos Beach development partners, LandCorp and Lend Lease, is to create a sustainable and carbon neutral community and this remains unchanged. Alkimos Beach was awarded Australia’s first 6 Star Green Star community based on the physical implementation of infrastructure and fostering community initiatives

For more information contact Lendlease.