SA Water continues to power ahead on the Eyre Peninsula’s new desalination plant despite challenging geological conditions impacting tunnelling below the seafloor off Billy Lights Point.

This has slowed the construction of a 440m-long underground tunnel to house the plant’s marine infrastructure, with the 60-tonne tunnel boring machine (TBM) slowed by hard underground granite rock.

This obstacle hasn’t stopped the delivery of a new 7km-long drinking water transfer pipeline, which has now been constructed, tested and connected to the region’s existing drinking water network.

While 80 per cent of the tunnel is complete, SA Water chief executive David Ryan said the timeline to first water will now change.

“We completed comprehensive geotechnical analysis and borehole sampling as part of the project’s design, but the density of incredibly hard layers of granite rock below the seafloor is greater than expected and has significantly slowed our tunnelling progress,” he said.

“Based off the sequential nature of the marine construction activities, the project’s initially-forecast first water target of late 2026 will need to be revised.

“We recognise this is a critically important project to secure the Eyre Peninsula’s long-term drinking water security, and we assure the community we are working to complete the plant’s construction as quickly and safely as possible.”

Ryan said a decision on the revised schedule to first water would be determined in the coming weeks as SA Water closely monitors the TBM’s rate of progress through the remaining granite rock environment.

“We are also actively working with our marine contract partner to optimise the machine’s progress where we can, including adjusting the machine’s cutting disc used to drill through the surface,” he said.

Drinking water security in the Eyre Peninsula will not be impacted by the delayed schedule, with SA Water’s groundwater allocation for 2026–27 sufficient to meet current customer demands until the desalination plant is operational.

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