The future water supply of South Australia’s Eyre Peninsula remains contentious as scientists dispute research supporting a proposed desalination site at Billy Lights Point in Port Lincoln.
Key points:
- A scientific report finding a desalination plant at Billy Lights Point will not impact the marine environment is being disputed
- There are concerns about modelling and the plant’s impact on mussel larvae
- SA Water says the research has been reviewed by six independent scientists
The South Australian Research and Development Institute (SARDI) has produced a report for SA Water, which found Billy Lights Point to be the best location for a desalination plant, and that it would not impact the marine environment.
While the South Australian government continues to stand by the findings of the report, there has been significant industry pushback.
SA Water first identified three sites in the Sleaford Bay area for a desalination plant for Eyre Peninsula in 2009.
When the Billy Lights Point site was announced it sparked community protest in November 2021, with a rally of about 350 people and a flotilla of fishing vessels.
Eyre Peninsula’s 35,000 water customers currently use the Uley Basin water supply and 1.7 gigalitres annually from the Murray River, but its potable water is expected to be depleted by 2025.
Concerns about aquaculture industry
Marine biologist Paul McShane, a researcher who has worked with EP Seafoods, said Billy Lights Point was “one of the worst possible locations for a desalination plant” and claimed SARDI’s modelling was flawed.
Dr McShane raised concerns about the report’s data relating to wind-driven water currents, which would determine where seawater was collected and where effluent brine would be deposited.
Effluent brine is a by-product of the desalination process and contains a high concentration of salt.
It can have negative effects on the surrounding marine environment and its biodiversity by increasing salinity and temperature.
“The obvious issue is that you have an industrial scale desalination plant right next to a designated aquaculture zone, which relies on clean, unpolluted sea water,” Dr McShane said.
“[SA Water] really need to go back to the drawing board and measure currents that are more reflective of the waters where they are going to take the seawater out and put brine effluent back, and so the model doesn’t accurately reproduce water currents.”
Concerns for mussel farming
Dr McShane also has concerns about the aquaculture industries that operate out of Port Lincoln’s Proper Bay.
He said every hour, the desalination plant would take in “two Olympic-sized swimming pools” of seawater.
“That will certainly trap mussel larvae, and those mussel larvae would otherwise have been able to settle on the mussel ropes,” Dr McShane said.
Eyre Peninsula Seafoods chief executive Mark Andrews has been farming mussels out of Proper Bay for 17 years, with his business responsible for turning over 2,000 tonnes of mussels every year.
Mr Andrews was not convinced by the SARDI report, saying it did not guarantee he would not lose out on the natural mussel spat his business relied on.
“Why would you want to put a business at risk?” he said.
“If they can prove to me that there is no risk then that’s fine, but they haven’t been able to prove to me that there is no risk.
“I’m not putting my investment, my time over here, with all the 76 staff that I employ at risk.
“There’s locations where they can put a desalination plant with no risk to aquaculture or fisheries.”
Standing by the science
According to the SARDI research and SA Water, fewer than 0.1 per cent of the particles in the seawater, such as larvae, are at risk of coming within a 25-metre zone of the intake piping.
SA Water general manager of sustainable infrastructure Amanda Lewry said the SARDI research had been reviewed by six independent scientists.
“We are very comfortable with the science and the reviews we have done on the science,” she said.
SA Water was confident the engineering criteria could be met, ensuring the 5.3 gigalitre per annum plant operated safely within the marine environment.
The state government has confidence in the SARDI science, having the backing of SA Deputy Premier and Minister for Climate, Environment and Water, Susan Close.
The Labor MP was confident the plant would not harm the marine environment or the fisheries industry.
“At present the advice we have from the SARDI scientist and from the peer review of that science, is that Billy Lights Point is an appropriate place to have a desalination plant,” she said.
“It won’t have an impact on the average salinity of the water and won’t therefore have harmful effects on the aquaculture industry.”
What is next for desalination?
Plans to build a desalination plant at Billy Lights Point still need to go through the developmental approval process, during which the South Australian Protection Authority and other governing agencies will review the evidence.
Ms Close said the authority would scrutinise the science behind the government decision.
“It is designed to assess the impact and the way the desalination plant is regulated and will be managed, that process needs to be allowed to go through because all of the science will be scrutinised, and then a decision will be made,” she said.
“It’s yet to be made but right now SA Water and SARDI express confidence that it is the right location.”
A marine science forum will be held in Adelaide on September 14 to give scientists and stakeholders a chance to discuss the research.
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