EP desal tunnelling complete as revised delivery date confirmed

A major milestone has been reached in construction of the Eyre Peninsula’s new desalination plant, with a large, 440-metre-long marine tunnel safely installed below the seafloor.

This comes as SA Water advises the plant’s first water is now expected to flow by the end of June 2027, with the region’s hard underground granite rock delaying the tunnel’s construction timeframe.

Constructed using a 60-tonne tunnel boring machine named ‘Janette’, the concrete tunnel will soon contain the large marine intake and outfall pipelines tasked with transferring water to and from the new plant.

As announced by SA Water earlier this year, challenges with the region’s underground granite had slowed Janette’s tunneling progress, with the sequential nature of marine construction meaning the initially-forecast first water milestone of the end of 2026 would need to be adjusted.

SA Water’s General Manager of Sustainable Infrastructure Peter Seltsikas said with the tunnel complete, the project was now progressing towards the revised delivery timeframe.

“Delivering the marine tunnel is an important milestone towards delivering the Eyre Peninsula’s long-term drinking water security, and our full focus is on getting the project completed,” Peter said.

“Constructing a large tunnel underneath the seafloor is a complex task, with crews working around the clock over recent months to safely and carefully connect more than 150 individual segments of concrete pipe underneath the shoreline of Billy Lights Point.

“The added challenges presented by the harder-than-expected Eyre Peninsula granite has had a clear impact to our progress, and this has underpinned the need to revise the estimated project first water timeframe to be delivered by the end of June 2027.

“Importantly, we do not foresee the need to introduce water restrictions due to this revised timeframe, with our groundwater allocation for 2026-27, together with supply from the River Murray, sufficient to meet customer demands through to the plant’s commissioning.

“Having safely made it through the other side of the granite, we are now in a great position to ramp-up construction of the next stage of marine works, including installing the 450-meter-long marine intake pipeline used to draw seawater in, and the 1040-meter-long outfall pipeline to return saline brine back to the ocean.

“In parallel, crews are making significant progress on constructing the reverse osmosis plant infrastructure, with more than 140 people currently working on-site to build this vital water treatment infrastructure.

“We look forward to continuing this progress into the warmer months to deliver the region’s new desalinated drinking water supply as quickly and safely as possible.”

The complexities in tunnelling and external factors will result in higher costs, with the revised budget to be detailed once contractual processes with delivery partners are complete.

To help the region continue to save water, SA Water is extending the availability of rebates on select water-efficient appliances and household fixtures for SA Water customers on the Eyre Peninsula through until the end of the 2026-27 financial year.

Introduced in late 2024, eligible customers can access rebates on new showerheads, dual flush toilets and washing machines with 4-star Water Efficiency Labelling and Standards (WELS) ratings or higher, as well as pool covers and irrigation timers carrying a Smart Approved Watermark certification.

“Simple steps like replacing old household fixtures and appliances are an easy way to make a positive impact on reducing water use in the home or garden, and we encourage all of our local customers to visit our website and check their eligibility,” Peter said.

When constructed, the new desalination plant will produce up to 5.3 billion litres of safe and clean drinking water to supply an estimated 35,000 people on the Eyre Peninsula.

For more information on the Eyre Peninsula desalination project, visit watertalks.sawater.com.au.