By rosebell
The tunnel was excavated using a 60-tonne tunnel boring machine (TBM) and will accommodate the marine intake and outfall pipelines required to transfer seawater to the desalination plant and discharge brine back into the ocean.
According to SA Water, granite conditions along the alignment slowed excavation, affecting the overall project schedule. The first water delivery, previously expected by the end of 2026, has been revised to the end of June 2027.
Marine Tunnel Completed Despite Difficult Ground Conditions
SA Water general manager of sustainable infrastructure Peter Seltsikas said completing the marine tunnel was an important milestone towards improving long-term drinking water security on the Eyre Peninsula.
Construction crews worked around the clock in recent months to connect more than 150 individual concrete pipe segments beneath the shoreline at Billy Lights Point.
Seltsikas noted that the harder-than-expected granite created additional challenges for the tunnelling operation, contributing to the revised delivery timeframe.
With tunnelling complete, the project is moving into the next phase of marine construction.
Intake and Outfall Pipeline Installation Next
The next stage includes installing two major pipelines:
- Marine intake pipeline: Approximately 450m long, designed to draw seawater into the desalination plant.
- Marine outfall pipeline: Approximately 1,040m long, designed to return brine from the treatment process to the ocean.
These marine works are essential to connecting the desalination facility to its seawater source and discharge system ahead of commissioning.
Desalination Plant to Supply 35,000 People
Once commissioned, the Eyre Peninsula desalination plant is expected to produce up to 5.3 billion litres of drinking water annually, supplying an estimated 35,000 people across the region.
The project is intended to strengthen long-term water security for the Eyre Peninsula. Completion of the marine tunnel brings the project closer to the next stages of pipeline installation, commissioning and the planned first water delivery by the end of June 2027.
