Alkimos Seawater Desalination
Plant Project
Read a transcript of this video
Delivering WA’s next major water source
To meet growing demand and secure our water future, we’re working to deliver a climate-independent, sustainable drinking water source - the Alkimos Seawater Desalination Plant (ASDP).
On this page
What's happening?
What are we doing?
Project timeline
Protecting the environment
Protecting Aboriginal heritage
How to get involved and stay updated
What’s happening?
A decline in rainfall and increase in WA’s population means we need a new water source. Based on current trends, we will need an extra 75 to 125 billion litres of water per year by 2035.
To help make up this shortfall, a new desalination plant in Alkimos will provide a safe, reliable and economically-feasible water source.
What are we doing?
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Constructing a 50 billion litre per year desalination plant
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.
This will include the construction of two underground marine pipelines: an intake pipeline to take seawater into the plant, and an outflow pipeline to return the brine (concentrated salty water) back into the ocean.
With further investment and construction, stage 2 will increase the plant’s capacity to 100 billion litres per year.
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Building a new pipeline to transport water into our Integrated Water Supply Scheme
We’re building a 33.5-kilometre pipeline to connect the new plant to Wanneroo Reservoir, which feeds into the Integrated Water Supply Scheme (IWSS). Find out more about the Alkimos to Wanneroo desalination pipeline project.
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Incorporating a new groundwater source to turn desalinated water into drinking water
We’re building a groundwater treatment plant onsite that will mix naturally-mineralised groundwater with fresh desalinated water.
This reduces the amount of treatment required for this new water source, as well as the costs and environmental footprint of the ASDP. Find out more about the Eglinton Groundwater Scheme project.
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Upgrading the power supply to the Alkimos Water Precinct
To build and operate the plant, we’re working with Western Power to upgrade the power supply to the Alkimos Water Precinct. Find out more about the ASDP power supply upgrades.
In addition to this work, a number of smaller projects will be delivered across Perth 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.
Project timeline
- Public engagement around our next major water source
- 2017 - 2019
- Completion of enabling earthworks in the Alkimos Water Precinct
- Late 2024
- Completion of the Alkimos Water Precinct power supply upgrades
- Late 2025
- Drilling of a third bore and pipeline construction for the Eglinton Groundwater Treatment plant
- 2026
- Completion of the two marine tunnels for the plant’s intake and outflow pipelines
- Late 2026
- Completion of the Alkimos to Wanneroo desalination pipeline
- 2027
- Completion of the Alkimos Seawater Desalination Plant and first water production
- 2028
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 large map
Map showing the Alkimos Water Precinct and the location of the future desalination plant.
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. 
The pipelines will be tunnelled deep underneath the seabed to avoid impacting the reef and marine life.
Another important way we are reducing our impact on the environment is by minimising our construction footprint and revegetating areas within the Alkimos Water Precinct.
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.
We are committed to working collaboratively with the Traditional Owners of the land, the Whadjuk Noongar People, throughout this project.
How can I get involved and stay updated on this project?
You can find regular updates on the project’s construction in the Updates tab on this page. We will also provide direct updates to local Alkimos residents about work that directly affects them.
Here’s how else you can get involved and stay informed about this project:
Join our Community Reference Panel
To create a two-way conversation between us and the local community, a Community Reference Panel was established in 2023.
The panel meets quarterly and is open to local residents and key stakeholders in Alkimos who would like to share their views and any concerns about the project.
If you are interested in joining the Community Reference Panel, please contact Kate.Lee@watercorporation.com.au
Subscribe to our Community Newsletter
Want an inside look at how the ASDP is progressing?
To join our Community Newsletter, go to 'Subscribe for project updates' and enter your details for regular updates on key project and sustainability milestones, as well as opportunities for residents to help shape the future of the plant.
Tower Cranes
Two tower cranes are being installed within in the Alkimos Water Precinct to assist with moving equipment in and out of the tunnel access pit. The cranes will be 46m and 30m tall, with a 60m horizontal arm of the crane mounted on to the top of each mast.
They will be anchored to pre-built concrete foundations underground. Lights will be installed at the highest points of the cranes as a safety precaution, to ensure they are visible to passing aircraft. While the cranes may be visible, we don’t anticipate that they will be impactful to nearby residents.
Installation of glass-reinforced pipes
GRP pipe lamination is the process of applying layers of fiberglass reinforced material, using a resin system to create a strong and durable pipe wall. The pipes are being installed below ground via open trench.
This process involves the intermittent use of angle grinders within the trenches and inside the dedicated workshop. Noise monitoring equipment has been installed to ensure the noise does not exceed acceptable levels.
Work is underway to build the Alkimos Seawater Desalination Plant within the Alkimos Water Precinct. We've begun electrical work and excavation to prepare for underground tunnelling towards the ocean. This has involved excavating, earthmoving, concreting, and crane operations. Rock breakers have also been used on hard limestone rock inside the tunnel access pit.
As approved by the City of Wanneroo, from Monday 6 January 2025 to the end of March 2025, we will complete some necessary construction activities outside of regular working hours.
What to expect:
- Continuous, 24-hour work including Sundays and public holidays.
- While we don't anticipate that nearby residents will be impacted, you may notice on-site light, noise, and activity.
- You may also notice additional truck movements accessing the site from Brindabella Drive.
We thank you for your ongoing patience while we complete this essential work.
Work is currently underway for the new Alkimos Seawater Desalination Plant.
We've been using piling machines to drill holes and fill them with concrete to act as in underground retaining wall. This work involves loud banging, as the machine moves back and forth to remove dug up soil.
This piling work was planned to be completed by the end of October, however due to ground conditions and weather, it will now be completed by late November 2024.
With the approval from the City of Wanneroo, we will continue piling from 7am Monday to 7pm Saturday, with a rest day Sunday until the piling work is complete. Extended working hours will help us to deliver the plant on time in 2028.
We understand that this work is noisy for some residents. We apologise for any inconvenience and thank you for your patience while we complete this essential work.
Additional overnight work and Sunday work
Additional overnight work and occasional Sunday work for lower impact construction activities, that will not include piling, has also been approved by the City of Wanneroo between now and Tuesday 24 December 2024. We'll keep you updated on out of hours work as the project progresses.
Our project team will continue to monitor noise and reduce impacts where possible.
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We're working with Western Power to supply electricity to the Alkimos Water Precinct. Western Power's authorised contractor, LS Cables, will construct a 5km underground transmission line from their Yanchep Substation near Wanneroo Road.
Start of work
Construction is planned to take place from around late October 2024 until late 2025 and will be completed in three stages.
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Stage 1 will take place along Romeo Road, between Wanneroo Rad and Marmion Avenue. This will involve installing conduit, which is a plastic sleeve underground, that the new transmission line will be installed into.
Work is underway for the new Alkimos Seawater Desalination Plant.
To keep to schedule, we will now be completing work outside of our regular working hours by adding overnight work. From Thursday 1 August 2024 work will occur continuously, with no work on Sundays. The new working hours will occur from 7am Monday to 7pm Saturday
Preparation work on the Alkimos Desalination Plant is progressing to the next phase, and portions of the site are now being handed over to the Alkimos SeaWater Alliance (ASWA). Our authorised contractor, Georgiou Group, will continue construction along the western berm, on a vegetated dune between the Alkimos Water Precinct and a future Development WA project.
For safety reasons, Georgiou will now be accessing the area via Graceful Boulevard, past the roundabout at Marginella Boulevard.
• To minimise traffic impacts, deliveries via heavy vehicles will occur outside of peak times via Route A (Brindabella Parkway and Pectoral Promenade) where possible.
• Route B (Graceful Boulevard, between Marmion Avenue and Pectoral Promenade) may be used as an alternate route, if required.
• You may notice increased activity along Graceful Boulevard between Marmion Avenue and Marginella Boulevard, consisting of Georgiou light vehicles, and 2 to 6 heavy vehicle deliveries per day.
• Access to the Alkimos Water Precinct via Graceful Boulevard will begin in mid July 2024 and continue through to early 2025.
• We will also access the Eglington bore area near Graceful Boulevard over the coming weeks to complete pump testing.
You may notice increased activity at this location during this time. A map of the work area can be seen above.
A new telecommunication tower will be constructed towards the Eastern boundary of the Alkimos Water Precinct in June 2024. This is to allow the currenttower to be decommissioned as it sits within the parcel of land where the plant will be constructed. The new tower is the same size as the current tower (60m) however it will sit on higher ground within the site so may appear slightly taller.
Over the next six months, works will be completed to upgrade the electrical supply to the new tower.
During this time, the old tower will need to remain in place. In early 2025, the original tower will be decommissioned and removed from the site.
To inform detailed design of the Alkimos Seawater Desalination Plant, we are currently completing drilling investigations 500m - 3.5km offshore of Alkimos Beach until late-May.In addition to this, we are now planning to complete geophysical surveys including low volume seismic testing for a period of 6 days from 22 April.
During this survey you may notice a catamaran with equipment attached to the hull or being towed behind the vessel through the area. Streamers behind the vessel will range from 20-100m in length and will traverse the area typically adjacent to the coast. A 100m exclusion zone will remain in place throughout this work to ensure the safety of everyone.
As the scale and duration of the survey is small, no adverse impacts to the surrounding marine environment are expected. Equipment has been specifically selected to minimise any potential risks to marine life. While the underwater noise levels are low, these works have been bought forward as a precautionary measure to occur outside of whale migration season.
We have now awarded the contract for design, construction and operation of the Alkimos Seawater Desalination Plant to Acciona and Jacobs Group.
The two contractorswill form an alliance known as the Alkimos SeaWater Alliance, working in partnership with Water Corporation to deliver the first 50 billion litres per year plant.
To inform detailed design and support delivery of the ocean intake and discharge pipelines with minimal environmental impacts, we need to gather further detail regardingthe seabed conditions. A jack-up barge, marine drill rig and small support vessel will be visible around 500m-3.5km offshore of Alkimos Beach from around 2 April 2024. Work to collect seabed samples will occur during daylight hours for up to nine weeks. This factors in additional time for adverse weather conditions and a week to mobilise/demobilise either side of the works. A temporary marine exclusion zone will be set up to ensure everyone’s safety. A comprehensive marine management plan has been prepared, and no adverse impacts to the marine environment are expected during this work. Access to Alkimos Beach and the Alkimos and Eglinton wrecks will not be affected. Some noise may be heard at times during the drilling work.
To provide potable water to the plant, our authorised contractor Georgiou Group is constructing a water pipe to the Alkimos Water Precinct, connecting from theexisting network on Marmion Avenue.
The pipe will be constructed by tunnelling under Marmion Avenue, and open trench in the southbound lane and verge of Marmion for the final connection.
To complete the tie in connection safely, we will need to close around 120m of single southbound lane on Marmion Avenue between Modernism Avenue and Brindabella Parkway. Traffic management will be in place for approximately 5 weeks in mid-March / mid-April.
As a result of recent enquiries regarding kangaroo sightings around the Alkimos Water Precinct, we are making the following changes to the temporary fencingon Graceful Boulevard and Pectoral Promenade:
- A temporary access point has been installed along Pectoral Promenade.
- In the coming days, our authorised contractor Georgiou Group will relocate part of the temporary fence further within our site footprint. This will provide a vegetated space for wildlife outside the fence, away from the road and public interaction. This will also reduce visual impacts of the fence, for the local community.
- These works will occur between the hours of 7am and 7pm weekdays to minimise disturbance to residents nearby.
We have recently been contacted by members of the Alkimos community about kangaroo sightings in the area around Water Corporation’s Alkimos Water Precinct (the Precinct).It has been suggested that our temporary fencing along Graceful Boulevard and Pectoral Promenade, installed in November last year, is preventing kangaroos from entering and exiting the Precinct. The fencing is in place for the safety of the community and the security of the construction site.
We have since reached out to the relevant authority for more information about kangaroos in the area. We have been advised that it is normal to see an increase in kangaroo movements at this time of year as they forage for food and water during hot periods. There are existing access points for kangaroos to move in and out of the vegetated areas on the northern side of the Precinct.
It is recommended that members of the community do not approach kangaroos as this will cause distress. If the kangaroo is left alone, it is capable of making its own way back into the Precinct. In response to recent enquiries, we are reviewing options to change the alignment of the temporary fencing to provide a wider vegetated buffer from vehicles and public interaction. We are also arranging signage to be installed on the fence to indicate the contact details for Water Corporation’s contractor Georgiou Group, who have a qualified fauna handler available to assist as required.
If there are further concerns regarding kangaroos or other wildlife along the fence line, please contact them on 0408 036 578. Water Corporation completed extensive environmental investigations and works to support environmental approvals for the Alkimos Desalination Plant.
This incorporated careful consideration towards minimising the plant footprint to preserve environmental conservation areas and native vegetation. These areas will continue to be managed during and after construction providing valuable ecological habitat for native wildlife. We expect this will become increasingly important as further development occurs outside the Water Corporation site.
A preferred proponent has been selected for the design, construction and operation of the future Alkimos Seawater Desalination Plant.
Pending successful negotiations, Acciona and Jacobs Groupwill form an alliance which will be known as the Northern Water Partnership.
• Acciona brings considerable experience in delivery and operation of drinking water infrastructure, having previously built and now operating the Adelaide Seawater Desalination Plant.
• Jacobs has similar expertise, having partnered with Water Corporation to deliver vital water supply and wastewater projects across Western Australia.
Award of the contract is due to occur in March, with construction of the plant to commence mid-2024.
07 Dec 2023
Water Corporation has commenced works to prepare the site for the future Alkimos Seawater Desalination Plant.
The following activities will be completed ahead of plantconstruction which is scheduled to start mid-2024:
• Earthworks to reduce the ground level to lower the site into the landscape.
• Construction of a retaining wall and sand dune to shield the plant from the coast.
• Installation of temporary perimeter fencing, demountable offices, and connection to water for construction activities.
These works will occur within Water Corporation’s site at the Alkimos Water Precinct. As there is a buffer area separating the site from residential areas, it’s expected that construction impacts including noise and dust will be minimised as much as possible.
10 Nov 2023
Following a rigorous assessment, Water Corporation has received State and Commonwealth environmental approval for the Alkimos Desalination Plant.
The approvals is subject to Ministerial conditions whichstipulate how Water Corporation will deliver and operate the plant and associated infrastructure with appropriate management of terrestrial and marine environments.
The project was granted development approval in September by an independent Development Assessment Panel, and enabling works, including earthworks are expected to start on site in the coming weeks. Construction of the major infrastructure is expected to commence in 2024, with completion in 2028.
10 Aug 2023
The Western Australian Minister for Environment (Hon. Reece Whitby MLA) has decided that the Alkimos Seawater Desalination Plant (ASDP) proposal can be implemented subject tothe conditions outlined in Ministerial Statement 1207. The conditions are consistent with those recommended by the Environmental Protection Authority (EPA) in Report 1739.
You can find the EPA Assessment Report and Ministerial Statement on the EPA’s website
The ASDP proposal is awaiting approval under the Commonwealth Environmental Protection and Biodiversity Conservation (EPBC) Act 1999. A separate approval decision will be issued by the Commonwealth.
24 May 2023
The Environmental Protection Authority (EPA) today released its assessment report on Water Corporation's Alkimos Seawater Desalination Plant proposal.
The assessment report has been prepared by the Environmental Protection Authority (EPA) under s.44 of the Environmental Protection Act 1986 (WA). It describes the outcomes of the EPA's assessments of the proposal. The EPA has recommended that the proposal may be implemented subject to conditions recommended in Appendix A of the assessment report.
You can read the Assessment Report 1739 on the EPA's website via https://www.epa.wa.gov.au/epa-assessment-reports.
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.
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.
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 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.
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.
Environmental management plans
- Terrestrial construction environmental management plan PDF 7.44MB
- Alkimos Water Precinct environmental management plan PDF 1.57MB
- Commissioning and operations marine environmental management plan PDF 1.3MB
- Compliance assessment plan PDF 757KB
- Construction marine environmental management plan PDF 951KB
- Weed and dieback weed management plan PDF 6.84MB
- Greenhouse gas management plan PDF 864KB
- Landforms environmental management plan PDF 4.12MB
- Environmental offsets strategy PDF 8.89MB
Annual Compliance Assessment Reports
Sustainability
Marine Stakeholders
- Information for Alkimos SDP Marine stakeholders March 2023 DOC 3.33MB
- Information for Alkimos SDP Marine stakeholders January 2023 PDF 292KB
- Information Sheet for Alkimos SDP Marine stakeholders November 2022 PDF 291KB
- Information Sheet for Alkimos SDP Marine stakeholders August 2022 PDF 188KB
- Information for Alkimos SDP Marine stakeholders January 2019 PDF 258KB
- Information for Alkimos SDP Marine stakeholders November 2018 PDF 284KB
Notifications to impacted residents
Community consultation & Community Reference Panel
Notices of Proposal
Notices of Proposal
Kate Lee - Community Engagement Specialist