It looks like a departure from their initial plan. In the EIS...

It looks like a departure from their initial plan. In the EIS Project Alternatives: https://plan.sa.gov.au/__data/assets/pdf_file/0003/574329/EIS-Chapter-03-Project-Alternatives.pdf three options including a desalination plant were evaluated, with a borefield at Kielpa being the preferred option at the time. It was noted with the desalination option that it would involve higher construction and operating costs.

Clearly something has changed recently - in the AGM presentation Page 8, “Desalination plants at Cape Hardy and Kielpa (the latter allowing reinjection of brine back into an enormous hypersaline aquifer) having the potential to revolutionise water reticulation on the EP and remove all dependence on stressed aquifers or the river Murray. Essentially water will flow to Port Lincoln and not from groundwater aquifers around Port Lincoln. Similarly water will flow to Whyalla and not from Whyalla, sourced from Murray River. This complementary infrastructure is capable of delivering sustainable water required for industry, underpinning economic development of the EP. Distances are modest- Kielpa to Kimba 53km and to Lock 43km; Cape Hardy to Cummins 55km. Water is a strategic asset for any development and noting that this is ‘green’ water.“

There appears to be quite a bit of activity around the EP and building a desalination plant - there’s even a dedicated website for it: https://watertalks.sawater.com.au/Desalination-Eyre-Peninsula

The desalination plant is required by 2025 to prevent permanent damage to Uley South Basin and the flow-on impacts to water availability across the Eyre Peninsula. The most recent presentation regarding a desalination plant on the EP ruled out Cape Hardy quite overwhelming against a group of 20 potential sites

https://ehq-production-australia.s3.ap-southeast-2.amazonaws.com/243caee3e6b6b8b94701ee55c33a3242e815b195/original/1635133693/2baa8547fec73ca759181264fca34f3d_Industry_Reference_Group_-_PowerPoint_presentation_%2819_Oct_2021%29.pdf?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIBJCUKKD4ZO4WUUA%2F20211127%2Fap-southeast-2%2Fs3%2Faws4_request&X-Amz-Date=20211127T021903Z&X-Amz-Expires=300&X-Amz-SignedHeaders=host&X-Amz-Signature=6b85ee8db804157ad226046a830b6c12b8940a9c7ec5318cbef6fd0ad6b05313

However, in the meeting minutes for this most recent meeting, it was noted:

Industry members asked if there is an opportunity to pursue a joint venture to build the desalination plant in Arno Bay?- SA Water replied that the way the water supply network operates is that water flows from Port Lincoln north. Therefore any desalination sites north of port Lincoln will need a pipeline to bring the water back to connect into the distribution system so the water can be distributed across the whole Eyre Peninsula, and achieve water security and quality outcomes for Port Lincoln

https://ehq-production-australia.s3.ap-southeast-2.amazonaws.com/4a302d351b731760f32fcd675ec57c9f785d27bd/original/1637565518/608233604cb2f32b2f3cb4248011ce7e_191021_Industry_Reference_Group_-_Meeting_minutes_%28Final%29.pdf?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIBJCUKKD4ZO4WUUA%2F20211127%2Fap-southeast-2%2Fs3%2Faws4_request&X-Amz-Date=20211127T022108Z&X-Amz-Expires=300&X-Amz-SignedHeaders=host&X-Amz-Signature=7c36380d47212b52751d2eed609e6c45f4d3fa320547eee48c09e66d32c2136a

My read on all of this is that SA Water wants the desalination plant in a certain area, but the fisheries-dominated industry group has concerns and there’s discussions about potential JV’s to do the desalination plant elsewhere that won’t impact the mussel industry etc. Arno Bay is only 50km from Cape Hardy so it was interesting that this question was asked - perhaps IRD is also thinking about a joint venture for the desalination plant, maybe another Portalis-style arrangement?