- Major milestone with completion of tunnelling and marine works at Alkimos plant
- Tunnel boring machines complete 15-month journey below the seabed
- More than 6km of tunnel, lined with 32,000 WA-made concrete segments
- Intake and outfall structures installed by Australia's largest registered jack-up barge
- Recent dry winter highlights importance of desalination investment
- Cook Labor Government delivering projects Made in WA and creating local jobs
Two of the longest undersea tunnels in Australia have been completed, marking another major construction milestone for the Cook Labor Government's $2.8 billion Alkimos Seawater Desalination Plant (ASDP).
The separate 2.5km-intake and 4km-outfall tunnels, extending 1.6km and 3km offshore respectively, will draw seawater into the plant and return the brine to the ocean. They are the longest desalination intake and outfall tunnels in Australia.
Over the last 15 months, tunnel boring machines, Mary and Karli, have excavated up to 50m each day, 20m below the seabed, installing around 32,000 locally made concrete segments.
Delivered by the Alkimos Seawater Alliance, the machines are now being demobilised before work commences to connect the tunnels to the undersea intake and outfall structures, installed by Australia's largest registered jack-up barge, Beverley.
Marine exclusion zones around offshore work areas have been removed, although some vessel activity will continue for final inspections, surveys and commissioning checks.
Each tunnel is sized to allow for future expansion beyond the plant's first stage capacity of 50 billion litres of drinking water, which will help supply more than 2.5 million people in WA and reduce reliance on climate-impacted groundwater sources.
The wider project's focus now shifts to the fit-out of the plant's buildings and the start of electrical and mechanical works within the 29-hectare work site.
The ASDP project is supporting more than 1,500 local jobs and has been funded utilising the State's strong budget position. With the tunnelling and marine works complete, and pipeline and site work well advanced, the plant remains on track to be fully operational in 2028.
For more information on the project, visit the Water Corporation website: www.watercorporation.com.au/asdp
As stated by Premier Roger Cook:
"The culmination of 15 months' work, these tunnels are an amazing feat of engineering - two of the longest undersea tunnels in Australia - and proudly built using Made in WA materials.
"They establish the critical connection between the future Alkimos Seawater Desalination Plant and the ocean, bringing in the seawater and safely returning the brine.
"As WA's next major water source, this vital Cook Labor Government project will help meet the needs of our growing population and reduce the pressure on our precious groundwater, while delivering strong economic benefits for the State."
As stated by Water Minister Daniel Pastorelli:
"Completing these highly specialised works safely and successfully is a credit to the hundreds of workers, engineers and contractors delivering this critical project - one of the most significant infrastructure projects in WA.
"With tunnelling and marine works complete, the plant remains on track to begin operation in 2028, supplying an initial 50 billion litres of drinking water every year.
"But while desalination will form the bedrock of our future water supply, off the back of a dry winter, it's more important than ever to use water - our most valuable resource - wisely for our collective water security."
As stated by Butler MLA Lorna Clarke:
"The Alkimos Desalination Plant is creating more than 1,500 jobs - many of them here locally in Alkimos, Eglinton, Yanchep and Two Rocks.
"I'm so proud of these workers and the future water security that they are building.
"It's another example of how we are delivering projects that are Made in WA.
"It's also why we are investing in free TAFE, skilling up the next generation - our kids and grandkids - for the jobs of the future, and so we can make more things here in WA."
