PLANS for a mega-dam that would dramatically drain water from Wivenhoe Dam need much more consideration, Mayor Paul Pisasale believes.
Advocates of expanding the dam at Borumba, 60km south-west of Gympie, met this week with Water Supply Minister Mark McArdle.
Ron McMah, John Hodgkinson and Trevor Herse want the dam in the Mary Valley to hold enough water to drought-proof south-east Queensland.
They also believe water could be pumped from Wivenhoe and Somerset dams via new pipeline before a La Nina wet season to lesson the threat of another major flood in Ipswich and Brisbane.
Mr Hodgkinson said the idea was given a good hearing at Thursday's meeting with Mr McArdle, department director-general Jon Black and new Seqwater CEO Terri Benson. He said the project would take three years to complete and cost about $1.9 billion - $1.4 billion for a 85m-high dam wall extension and $500 million for pipeline.
The dam existed so there would be no displacement of people and the state owned some of the land with the rest national park, he said.
Mayor Pisasale said the proposal should be considered further as part of strategies for drought and flood prevention and water supply.
"While I cautiously welcome the idea, any proposal must be considered by an expert panel," he said. "It may be that the idea stacks up as more of a drought prevention measure with the by-product being a reduction in the impact of a major flood event in the future.
"One thing is certain. We need to plan well ahead to secure a reliable water supply for an expanding population."
One thing is certain. We need to plan well ahead to secure a reliable water supply for an expanding population.
Ian Chalmers, the engineer who supervised construction of Wivenhoe in the 1980s, said such a plan wasn't viable.
But Mr McArdle said the government was open to all ideas in planning for south-east Queensland's water future.
"We've learned from the 'super storm' that hit New York and the floods that devastated south-west England last year, that it is impossible to 100% flood proof south-east Queensland," he said. "However, we can never stop learning and I am keen to hear more about their proposal and suggestions concerning flood mitigation.
"If the proposal was to be considered, it would be up to Seqwater to thoroughly assess its viability against a number of criteria including future water security, infrastructure costs and environment and financial considerations."