Oil and gas giant Chevron and the Water Corporation have signalled they are unlikely to accept Andrew Forrest's ambitious plan to supply water to Onslow, filing environmental approval documents for a groundwater desalination plant instead.
Under its Wheatstone State Agreement, Chevron is required to find a way increase the potable water supply to Onslow, which is struggling to cope with the influx of oil and gas workers. The desalination plant, which will process water from deep groundwater bores sunk into the Birdrong aquifer 18 km from the Pilbara town, was a longstanding part of that commitment. Chevron would build the plant but would then hand it over to the Water Corporation to operate.
But Mr Forrest tried to derail that proposal late last year, floating plans to instead supply up to two megalitres of water a day from bores sunk alongside the Ashburton River on the Forrest family's Minderoo Station.
Under the scheme, which Mr Forrest argues would be more environmentally friendly and cheaper to operate than a desalination plant, a series of below-ground weirs would be built along the Ashburton River. They would recharge an alluvial aquifer from which H2Onslow, a Forrest-owned company created for the purpose, would draw bore water for processing to potable standards for use by Onslow. A similar weir was built at Minderoo three years ago as part of a station irrigation project, according to documents prepared by H2Onslow.
But it appears that Chevron and the Water Corporation are pushing on with the desalination plan, which includes a proposal to pump the residual saline stream, the byproduct of the desalination treatment, into Quick Mud Creek, which runs through the Minderoo Station pastoral lease.
It is unclear whether the environmental applications mean Chevron and the Water Corporation have completely ended negotiations over Mr Forrest's proposal. However, the documents say the Ashburton River aquifer was considered and then rejected as a water source, saying it was "poorly defined and significant investigation, testing and proving" would be required to determine whether it could provide a sustainable yield.
A spokesman for Chevron would not comment on the status of negotiations with Mr Forrest, saying only that the company "has engaged in discussions with Minderoo over its H2Onslow proposal".
A spokeswoman said Mr Forrest believed his proposal was the better option.
"H2Onslow maintains that its proposed water source is the most cost effective and sustainable option to supply the highest quality water to the Onslow community," she said.