The SA Water documents I have obtained, reveal an advanced stage of preparation with detailed maps and water quality analysis. Th is was not done on the back of an envelope. SA Water spent a lot of time and energy ensuring this idea was viable.

Currently, about 90 Gigalitres (a gigalitre is a thousand million litres – enough to cover Adelaide oval to a depth of 50 metres) of treated effluent is produced in Adelaide every year. While some is sent to Virginia to be used on market gardens during the summer months, the vast majority gets pumped directly off Adelaide's beaches into Gulf St Vincent. This release of effluent has long been implicated in the decline in coastal water quality, as well as the loss of more than 4000 hectares of shallow sub tidal sea grass along the metropolitan coast since the late 1940's.

Since 1991, an Adelaide Coastal Waters Study has been underway to try and reverse this damage. Th eir final report will be released soon, and is set to recommend that SA Water reduce its nutrient load in the effl uent it discharges by up to 60%. To achieve this, I have been reliably informed, SA Water faces a potential $500 million upgrade to its Christies Beach, Glenelg and Bolivar treatment works.

So instead of dumping it, SA Water quite rightly see an opportunity to harvest the recycled water as a resource. Their plan involves a new pipeline from Bolivar to Roxby Downs, using the Bundaleer, Beetaloo and/or Baroota reservoirs as a half way storage point. The reservoirs will hold up to 200 days storage, balancing the diff erent availability of recycled water in summer and winter.

In comparison, the desalination option, according to BHP Billiton, has a maximum storage of only 7 days at the mine site. According to the documents, negotiations have taken place between SA Water and BHP Billiton, with the company indicating the quality of the water is fine for their needs. Seven pages of costings comparing the recycled water option with the desalination option are blacked out, but the FoI documents frequently state the two competing options cost the same.

Since 1991, an Adelaide Coastal Waters Study has been underway to try and reverse this damage. Th eir final report will be released soon, and is set to recommend that SA Water reduce its nutrient load in the effluent it discharges by up to 60%. To achieve this, I have been reliably informed, SA Water faces a potential $500 million upgrade to its Christies Beach, Glenelg and Bolivar treatment works.

So instead of dumping it, SA Water quite rightly see an opportunity to harvest the recycled water as a resource. Their plan involves a new pipeline from Bolivar to Roxby Downs, using the Bundaleer, Beetaloo and/or Baroota reservoirs as a half way storage point. The reservoirs will hold up to 200 days storage, balancing the different demand requirements.It requires no hyper-saline discharge intothe delicate Upper Spencer Gulf- the ecology of both Gulfs is better off. Next article here.

SA Water proposal

Mark Parnell. Greens Upper House MP.