$2.8bn Alkimos Seawater Desalination Plant project reaches major milestone

The $2.8 billion Alkimos Seawater Desalination Plant project in Western Australia has marked a major milestone with half of the locally made water pipelines already laid.

More than 17 kilometres – about the same distance between Perth’s CBD and Rottnest Island – of the 33.5-kilometre underground trunk main has now been built and will link to Water Corporation’s Wanneroo Reservoir.

The water pipeline has an internal diameter of 1.6 metres, and it is one of the largest to be built in the State. The pipeline has also been designed to accommodate future expansion of the Alkimos plant.

“This pipeline is the perfect example of my government’s Made in WA plan.

“Not only will it be built with products and materials sourced from local businesses, it will also be a key part of our Alkimos desalination plant, which when built will support hundreds of jobs while supplying households and businesses a year with water that is Made in WA.

“It’s part of my government’s continuing delivery of quality infrastructure to support all Western Australians,” Premier Roger Cook said.

The pipeline’s large diameter will help reduce the energy required to pump water, ultimately lowering greenhouse gas emissions by 21 per cent compared to a smaller pipeline.

The cement-lined steel pipe was manufactured locally by Steel Mains in Kwinana, using Pilbara iron ore and Cockburn cement. The pipe has an expected operational lifespan of about 120 years.

To date, close to 1,600 pipe sections that range between 6 to 12 metres in length have already been installed – with each of the 12-metre sections weighing nearly nine tonnes.

“This milestone marks the halfway point in delivering one of the largest water pipelines built in WA and is a critical step in securing our State’s water future.

“It is a critical part of the $2.8 billion Alkimos Seawater Desalination Plant project that will strengthen the resilience of our water network as demand grows and our climate continues to change.

“Built using WA materials, this project is supporting local manufacturing, creating hundreds of jobs, and contributing to our Made in WA agenda.

“The Cook Labor Government is investing $2.7 billion next financial year to ensure Western Australians continue to have access to safe, reliable and sustainable water supplies for the long term,” Water Minister Don Punch said.

Once completed, the trunk main will connect the Alkimos Seawater Desalination Plant to the Integrated Water Supply Scheme via Carabooda Tank, the future Nowergup Tank and Wanneroo Reservoir.

The pipeline route has been carefully planned in consultation with local stakeholders to minimise environmental and community impacts.

The trunk main, which is expected to be completed next year, is being built by the Alkimos Pipeline Alliance – comprised of Water Corporation, Georgiou Group and DM Civil.

“This pipeline is helping to create more local jobs across Alkimos, Eglinton and Yanchep while supporting WA manufacturing and strengthening our workforce for the future.

“By backing local jobs and delivering critical water infrastructure from Alkimos to the Upper Greater Southern, this project is helping secure supply and economic growth across the State,” Butler MLA Lorna Clarke said.

Overall completion of the Alkimos Seawater Desalination Plant as well as first water production is expected in 2028.

The new plant will supply up to 50 million litres of clean, safe drinking water to millions of Western Australians annually once Stage 1 is completed. The project includes the construction of two underground marine pipelines, one taking seawater into the plant (inflow pipeline) and another returning the brine or concentrated salty water back into the ocean (outflow pipeline).

Further investment and construction of Stage 2 will increase the plant’s capacity to 100 million litres per year.

“Spanning the City of Wanneroo, this is a flagship project for the northern suburbs and for Western Australia. It will deliver lasting benefits for our growing community.

“I thank local residents and businesses for their patience and support as these important works continue,” Wanneroo MLA Sabine Winton said.

Source: Government of Western Australia – Media Statements; Water Corporation (1, 2)