Cairns Post article - March 19 2009

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Pressure on water supply

Thomas Chamberlin

Thursday, March 19, 2009

© The Cairns Post

CAIRNS is running out of drinkable water, but where to find a secure future supply remains in doubt.

Cairns Regional Council met yesterday to review six options ranging from drilling wells to building a desalination plant with costs forecast between $161 million and $402 million.

Reports show the region’s water supply coming under increasing pressure as population and demand increases – but a solution will have to wait at least another month with councillors opting to seek more advice before making a
decision.

The city’s water supply is taken from Copperlode Falls Dam and Behana Creek, which in recent times of high demand have reached 40 per cent safe yield capacity – a trigger compelling authorities to find another freshwater source.

Options include drilling into the Mulgrave River aquifer, purifying water from the Barron River – with an intake at Lake Placid – and building a desalination plant.

Several of the plans seek to combine these options in stages across the next two decades.

Council general manager of waste and water Bruce Gardiner told the meeting a decision was needed soon.

"There really is a need to shore up our next water supply as soon as we possibly can so that safety yield isn’t exceeded again," he said.

Councillors leaned towards the cheapest option – drilling the aquifer – but requested more information, agreeing a hasty decision could affect farmers, the environment and the council’s budget.

Investigations into future water supplies have been under way since 1988.

The option drawing most council support involves drilling 90m borefields at Aloomba this year, which has the potential to supply 15 megalitres a day.

But the next step, proposed for 2013, is under debate. Plans for a second stage involving the aquifer, providing 40 megalitres a day, raised environmental concerns from Cr Paul Gregory.

"I really think we need to test that aquifer and that is by using it in a limited way over a long time," he said.

He preferred tapping the aquifer and then taking water from Lake Placid.

Mayor Val Schier strongly opposed the idea, saying Tableland farmers may need more water from Lake Placid in the future.

The council’s background report showed the city exceeded safe yield limits in 2002 and 2005 and was near its limit in 2003, 2004, 2006 and 2007.

Building a desalination plant was the most expensive option, projected at $402 million, and increasing the Behana Creek and Copperlode Falls Dam capacity have been all but ruled out.

The State Government is expected to fund 40 per cent of the chosen project.

After choosing an option, the council will need to do a feasibility study, planning report and require statutory approvals, design and documentation.