Two TBMs – Karli, named after the Whadjuk Noongar word for boomerang, and Mary, named after a pioneering alchemist, are excavating a 2.5km intake tunnel and a 4km outfall tunnel beneath the seabed.
The project near Perth is being delivered by Alkimos SeaWater Alliance, an alliance of Water Corporation, Acciona and Jacobs Group Australia which is responsible for the design, build and operation of the plant.
Construction began in mid-2024. The tunnel drives are expected to be completed late next year and the plant is due to be commissioned in 2028.
Alkimos is part of Water Corporation programme of works valued at AU$2.8bn to secure drinking water to millions of western Australians.
