Another important milestone was reached at the Alkimos Seawater Desalination Plant earlier this year, when the team completed the Southern Shaft topping slab for the plant’s seawater intake system.

This work brings Perth one step closer to securing a new, climate independent water source.

Southern Shaft Topping Slab: A Key Structural Milestone for Perth's Water Future

The Southern Shaft forms part of the Seawater Intake Pumping Station (SWIPS), which draws seawater from offshore and feeds it into the desalination process. Finishing the topping slab was a key structural stage and signals the completion of one of the most complex concrete packages on the project.

13-Hour Continuous Pour Places 600 Cubic Metres of Concrete

To complete the slab, crews carried out a 13-hour continuous concrete pour that placed 600 cubic metres of concrete across a 30 metre by 30 metre footprint. 

While not the largest pour on the site, it was among the biggest undertaken across the broader project and represents months of planning and preparation.

Work began early in the morning, with pumps on site from 4.00 am and the first concrete placed at 5.00 am.

The team used two boom pumps and maintained a steady supply of 90 cubic metres per hour from the Alkimos Seawater Alliance and Wanneroo batch plants. Ahead of the pour, crews installed 260 tonnes of reinforcement to support the slab structure.

35-Strong Crew Delivers Complex Operation Under Environmental Controls

Around 35 workers carried out the operation, supported by strong environmental controls to meet the standards required for a water retaining structure.

Finishing teams completed the slab by late evening under favourable weather conditions.

What Comes Next: Mechanical Installation and Structural Assembly

With the topping slab in place, the Alkimos Seawater Alliance has moved into the next stage of the build. This includes mechanical pump installation, instrumentation and monitoring services, and structural steel and precast assembly.

Each step progresses the future desalination plant toward delivering safe, reliable drinking water to Perth.

Alkimos Seawater Alliance: ACCIONA, Water Corporation and Jacobs

The milestone adds to the growing momentum at Alkimos and reflects the teamwork and technical skill driving the project forward by the Alkimos Seawater Alliance, led by ACCIONA, Water Corporation and Jacobs.

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