Onslow Desalination Plant

What's happening?

To secure Onslow's long-term water future, Water Corporation plans to construct a seawater desalination plant in Onslow. The plant will include:

• Reverse osmosis seawater desalination plant
• Intake and outfall pipeline(s) at Beadon Bay
• Water tank and pumping station
• A 2.5 kilometres-long belowground pipeline to the existing Onslow tanks, where the water will be connected to the town’s water supply.

_{Artist’s impression of the future plant based on the engineering design at 60 per cent complete. The appearance of the plant will change as further progress is made on the design. Water Corporation awarded a contract to design and construct the desalination plant to Guidera O’Connor in August 2023.}

Where is this happening?

The facility will be built on the coastal side of Beadon Creek Road, between Bindi Bindi Aboriginal Community and Discovery Parks Onslow.  

Why is this work taking place?

The desalination plant will provide a reliable drinking water source for Onslow, which is currently supplied by the Cane River Borefield. The borefield requires rainfall to recharge and there is a trend towards a drying climate. A further 1.5 million litres per day of drinking water is needed to meet demand for the next 20 years. The desalination plant will supply an additional, rainfall-independent drinking water source for Onslow.

When is this happening?

Construction is expected to start in July 2024 (subject to approvals) and will take approximately 18 months to complete.

What consultation has occurred?

Public consultation occurred in 2019 and 2020. In October 2020, a project fact sheet was provided to every post office box in Onslow requesting feedback on the proposal. We held meetings with stakeholders and members of the community to obtain further feedback.

Consultation has informed aspects of the plant, such as its location and the method of pigging (removal of build-up in the marine pipelines).

Water Corporation referred the desalination plant proposal to the Environmental Protection Authority in January 2021. A public comment period occurred between 29 March and 7 April 2021. The regulator decided that the proposal would not be assessed under Part IV of the EP Act. See the referral here.

How will this project affect the community?

• The desalination plant will be new infrastructure on the coast of Onslow. It will be minor compared with similar proposed desalination plants and is being designed to minimise environmental impacts.
• Construction work can have local impacts, including noise, dust, traffic management and vibration. Before we start work in an area, we notify the surrounding community.
• The marine pipelines will be constructed below ground, and the community can access the beach area as normal when construction is complete. The location of the marine pipeline will be added to navigational charts for mariners.
• Vegetated dunes will be constructed on the Beadon Creek Road and Bindi Bindi Aboriginal Community sides of the plant to provide a visual buffer for the community.

_{Image from an engineering model of the future plant from the perspective of Bindi Bindi Aboriginal Community. The plant will be partially visually obscured by vegetated sand dunes.}

Has Water Corporation investigated alternatives to the desalination plant?

We have considered various alternatives to the desalination plant. We investigated a Water Treatment Plant involving water from Birdrong Aquifer and deferred this option due to concerns about the source’s complexity and water quality. Plans for a desalination plant with water sourced from Beadon Creek were also discontinued due to proximity to mangroves and salt production operations. We have also explored sourcing water from coastal bores, however the yield and water quality were inadequate. Ultimately, the Onslow Desalination Plant is the best option.

 How is this project funded?

The project is funded by Chevron Australia.