Navigate home logo

Alkimos seawater desalination
plant project

Project goal:

Deliver a new seawater desalination plant at Alkimos - WA's next major water source.

Status:

In design

Delivery Date:

First production in 2028

What’s happening?

A reduction in rainfall and an increase in population means Western Australia needs a new water source. The Alkimos Seawater Desalination Plant will be WA’s next major water source. At completion of stage 1 the plant will supply up to 50 billion litres of clean, safe drinking water to millions of Western Australians each year. With further investment and construction, stage 2 will increase the plant capacity to 100 billion litres per year.

What is the scope of the project?

The desalination plant in Alkimos will include:

  • A 50 billion litres per year desalination plant within the Alkimos Water Precinct, with the possibility of a future 50 billion litres per year expansion
  • An ocean intake pipeline below the seabed that brings seawater into the plant
  • An ocean discharge pipeline below the seabed that safely takes brine (salty water) away from the plant
  • Built-up, vegetated sand dunes on the western side of Alkimos Water Precinct. We will incorporate this into the existing natural dune system to minimise potential visual and noise impacts from the plant.
  • Provision for a 4.9 billion litres per year groundwater treatment plant and local bores. 
  • A 33.5-kilometre pipeline to convey drinking water produced by the plant to Wanneroo Reservoir for supply into Perth’s Integrated Water Supply Scheme (IWSS).
  • A number of smaller projects will be delivered across Perth under the ‘Alkimos Seawater Desalination Plant Conveyance Program’ which will upgrade the capacity of the existing IWSS to support the bulk transfer of water throughout the network to homes and businesses across the region.  

Site construction plan incorporated into the existing natural dune system.
Alkimos Seawater Desalination Plant concept illustration showing the plant incorporated into the natural dune system.

 

Where will the new plant be built?

The plant will be built within an area known as Alkimos Water Precinct, between Marmion Avenue and the coast. Water Corporation is the proprietor of the land and already operates a wastewater treatment plant at the precinct.

view image

Map showing the Alkimos Water Precinct and the location of the future desalination plant.

When will we need a new desalination plant?

Based on current trends, we will need an extra 75 to 125 billion litres of water per year by 2035. Alkimos Seawater Desalination Plant will be the first new water source to help make up this shortfall. 

Who will build and operate the plant?

Water Corporation has formed an alliance with Acciona and Jacobs Group to design, construct and operate the desalination plant. Known as the Alkimos Seawater Alliance, the group brings together experts in the delivery and operation of water infrastructure including seawater desalination plants.    

Working with the community

In 2018, we consulted with the local community about a potential seawater desalination plant in Alkimos. There is a high level of support from locals and the Perth community for desalination as a rainfall independent water source in Alkimos.

We invited the community to learn about the project and provide feedback. This was through a series of local face-to-face events and our online platform.

We have taken your feedback and ideas into consideration and completed additional studies to refine potential construction methods and precinct designs. We are dedicated to minimising any potential disruption to the local community. We have already used initial feedback to reduce potential visual and noise impacts.

For regular updates, go to our Updates section or subscribe for email updates. We will provide written updates to the local community about work that affects them and opportunities for face-to-face engagement.

A Community Reference Panel has been established to provide local residents and stakeholders with opportunities to participate in two-way consultation. The panel's first meeting was held in July 2023. Panel meetings are held quarterly to keep stakeholders informed as we move forward with this exciting infrastructure project.

Protecting the environment

We have conducted extensive research to minimise environmental impacts.

We've investigated the location and methods for constructing the ocean pipelines. These pipelines will bring seawater in and safely remove brine from the plant. The ocean pipelines will be tunnelled underground to protect the dunes and marine environment. 

Diagram showing the pipelines will be deep underneath the seabed to avoid impacting the reef and marine life.
The pipelines will be tunnelled deep underneath the seabed to avoid impacting the reef and marine life.

Another important way we will reduce our impact on the environment is by minimising our construction footprint and revegetating areas within the Alkimos Water Precinct. See the planned before and after graphic below.

We will also compensate for the unavoidable impacts of clearing vegetation by purchasing land outside the project area. For example, under the conditions of our State environmental approval, Water Corporation must acquire land that has at least twice the environmental value of land the proposal will impact.

Protecting Aboriginal heritage

An Aboriginal heritage survey has been completed over the development area footprint of the proposed plant and pipeline route to Wanneroo Reservoir.

An Aboriginal Cultural Heritage Management Plan for the project has been developed between Water Corporation and Whadjuk Aboriginal Corporation in preparation for works commencing. This strategy will set the framework for engagement with Aboriginal stakeholders and identify opportunities for Traditional Owner participation in project planning, procurement, employment and heritage.

 

Powering the Alkimos Seawater Desalination Plant

We are upgrading the power supply to the Alkimos Water Precinct - click here to learn more.

10 March 2023

Water Corporations authorised consultants are undertaking marine investigations offshore of Alkimos between March 10 and 20, 2023. A large vessel will be in the area and lobster pots are a snagging risk. We respectfully request that lobster pots are removed from the area before work starts on the March 10. Lobster pots can be replaced from March 20, 2023 (which is when the vessel is expected to have left the area). We apologise for the inconvenience and thank you for your cooperation.

28 February 2023

Water Corporation invites organisations with suitable experience, capability, and capacity to submit a Registration of Interest for the ASDP Enabling Earthworks Project.

Bid Invitation Number - 70000013699

6 February 2023

Late last year, Water Corporation's authorised consultants Advisian and its contractor MES carried out investigations off the coast of Alkimos. Our consultants will return to the area to complete a small section of work that they were unable to complete during the previous campaign. Work will take place for approximately three days between February 20 and 27, 2023 during daylight hours.

30 January 2023

Come down to Oceans 27 927 Portside Promenade, Alkimos) on Thursday 9 February from 10 AM to 12 PM. Say hello to us and you may receive a coffee voucher (numbers limited)!

17 November 2022

Water Corporation's authorised consultants Advisian and its contractor MES will undertake geophysical investigations off the coast of Alkimos from 21 November 2022 for approximately one week.

The information is critical to inform the location and construction of the intake and outfall pipelines. Please refer to the information sheet for more information.

1 September 2022

Drinking water produced by the proposed Alkimos Seawater Desalination Plant will be transferred via a 33-kilometre below-ground pipeline to Wanneroo Reservoir where it will join Perth’s water supply.

Water Corporation and its contractors will undertake feature surveys and service location works along the pipeline alignment. The service identification will involve a vacuum excavation truck and you may notice PVC pipe left in place. The surveys will be in the road reserve and public open space and we will not need to enter private property. The surveys will be completed by mid-November 2022.

15 September 2022

Water Corporation referred the proposal for the Alkimos Seawater Desalination Plant to the Commonwealth Department of Climate Change, Energy, the Environment and Water and the Western Australian Environmental Protection Authority (EPA) in 2019. A detailed Environmental Review Document (ERD) is being assessed by the EPA. The EPA will consider submissions as part of its assessment process. The four-week public comment period starts on 28 September and will close on October 25, 2022. Copies of the ERD may be downloaded from www.epa.wa.gov.au (scroll down, click on 3. Assessment and then Environmental Review).

Hard copies are available for examination at the Wanneroo, Clarkson and Yanchep/Two Rocks Public Libraries. A limited number of hard copies are available on a first-come, first-served basis from Water Corporation Reception at 629 Newcastle Street, Leederville. Please telephone (08) 9420 2479 to ensure availability.

If you have more questions, we've got you covered. Please refer to the frequently asked questions below for more information.

The impacts of climate change on rainfall and groundwater recharge, together with a growing population, means we will soon need a new major drinking water source. 

Even by meeting our water reduction and recycling targets, Perth could need up to an additional 125 billion litres of water per year by 2035.

A new desalination plant north of Perth has long been considered as an option to provide safe, secure drinking water to our growing city.

Other locations were investigated, however, Alkimos was selected due to the site’s suitability to accommodate a new desalination plant with minimal impact. The site already has a wastewater treatment plant on what will become known as the future Alkimos Water Precinct.

To support a healthy groundwater system, we will also draw less groundwater from Perth’s north. It makes sense economically and practically to deliver a replacement source in the same area. 

A potential desalination plant in Alkimos would include:

- A  50 billion per year desalination plant within the Alkimos Water Precinct, with the possibility of a future 50 billion litre per year expansion

- An ocean intake pipeline below the seabed that brings seawater into the plant

- An ocean discharge pipeline below the seabed that safely takes brine (salty water) away from the plant

- A 33.5-kilometre pipeline to convey drinking water produced by the plant to Wanneroo Reservoir for supply into Perth’s Integrated Water Supply Scheme

- Built-up, vegetated sand dunes on the western side of Alkimos Water Precinct. We will incorporate this into the existing natural dune system to minimise potential visual and noise impacts from the plant

- Provision for a 4.9 billion litre per year groundwater treatment plant and local bores

Desalination is safe, reliable and rainfall independent. Nearly half the water supplied through WA’s largest drinking water scheme comes from existing desalination plants in Kwinana and Binningup.

A range of other water source options were investigated. Ultimately, a new desalination plant represented the most effective, economical and feasible option to meet growing demand and provide future water security.

The first 50 billion litre per year stage is required in 2028.

A seawater desalination plant is a vital state asset and requires significant investment.

In 2021, the WA Government announced it had included $1.4 billion in the State Budget towards Perth’s next desalination plant.

We already operate two advanced desalination plants. Over the past five years on average, these provided around half the drinking water to homes and businesses across Perth.

Today, there are six large-scale drinking water desalination plants in Australia. Two are right here in WA, and one in Queensland, New South Wales, South Australia, and Victoria. Desalination is used in 120 countries around the world due to its efficiency and sustainability as a safe water source.

The plant will be built on Water Corporation land and have a buffer zone around it. Based on community feedback, the plant will be sunk into the site. Large, vegetated sand dunes will be built to shield it from view and reduce potential noise.

Other noise reduction measures such as cladding and acoustic louvres will be used.

A previous study found background noise from traffic on nearby Marmion Avenue was louder than what is expected from the plant.

Perth’s northern suburbs are mostly supplied with treated groundwater. A greater mix of desalinated water may mean some people notice a subtle aesthetic change.

Energy use at ASDP will be mitigated primarily through design efficiencies and energy recovery technologies. The expected plant performance will match or exceed industry benchmarks for energy efficiency.

Find out more

We began consultation with the local community in 2018.

We’ll continue to update the community as the project progresses. Please subscribe for email updates.

A groundwater treatment plant will be built at the Alkimos Water Precinct to treat water from up to three local bores. Treated water from the local bores will be combined with the desalinated water. During the desalination process, minerals are taken out of the water and the water is not drinkable. Adding the groundwater to the desalinated water will add minerals back into the water. This means that we will not need to add in chemicals, reducing costs and our environmental footprint.

Rachael Cutler - Community Engagement Specialist

Subscribe for project updates