A plan to use recycled water, which currently runs out to sea, could double the production of food in Australia's salad bowl, avoiding future vegetable imports by shoring up domestic supply.
The Lockyer Valley Somerset Water Collaborative, west of Brisbane, said the region was among the most fertile in the world, but much of the land remained under-used because there was not enough water to produce food crops.
The collaborative was made up of representatives from local government, farming and business communities, and under its plan, recycled water currently running out to Moreton Bay would come from Wivenhoe Dam via a pipe scheme, costing $200 million to build.
"We see more and more foodstuffs coming from overseas when we have the capacity to grow so much more here locally, and indeed develop our own earnings through further export to those countries looking for clean and healthy food," the collaborative's chairman Graham Quirk said.
The collaborative had developed a business case, which it said proved it could create 2,600 new full-time jobs and generate export earnings of more than $300 million in economic benefit to Queensland and Australia.
"During the time of the drought, this region, despite having one of the most fertile lands in the world, saw only $200 million in production," Mr Quirk, who was also Brisbane's former Lord Mayor, said.
"Yet after the floods came, [and] water was available, that production level grew to $800 million a year.
"Even today, with a plentiful supply of water we're still about 60 to 70 per cent utilisation of land."
Does recycled water have an image problem?
Purified recycled water could be treated to drinking water standards.
"It's very safe and it's widely used in more than 35 places around the world now, including Perth in Western Australia, also Singapore, London and Orange County in California," Urban Utilities spokesperson Michelle Cull said.
Brock Sutton, manager of Sutton Farms, said it would be a missed opportunity not to use purified recycled water to grow food, with all growers of fruit and vegetables held to Australian recognised standards.
"I think everyone knows that there are plenty of cities that use recycled water for their own urban use, so the safety factor shouldn't be really questioned," he said.
Somerset Regional Council Mayor Graeme Lehman described the scheme as a no-brainer but said getting people to accept recycled water had been one of the biggest hold-ups.
"We need water. Have a look at the number of people who are going to be moving into our region over the next couple of years," he said.
"We've got to be able to feed those people."
Lockyer Valley Regional Council Mayor Tanya Milligan said memories of the toll of the recent drought were still front of mind, despite recent flooding.
"People were having to put down their livestock," she said.
"Do we want to live like we're in drought when we have this untapped resource, purified recycled water?"
State investment needed
The collaborative said the "homework was done", but the plan needed state government investment.
Queensland's Water Minister Glenn Butcher said the government would invest in water infrastructure projects where they stacked up and delivered the best possible outcomes.
"The Queensland government has met with members of the Lockyer Valley and Somerset Collaborative — including chair Graham Quirk, local mayors and irrigators in the Lockyer Valley — on several occasions, including earlier this year, to discuss the proposal," he said.
"The Department of Regional Development, Manufacturing and Water, the Collaborative and Seqwater are working together to understand the implications of the proposal and the requirement for no negative impact on south-east Queensland residents and businesses from the proposed project, including in relation to cost impacts and water security."
Why does water security matter?
Urban Utilities spokeswoman Michelle Cull said, with climate change and a growing population in south-east Queensland, it was important to plan for water security before the next drought.
She said unlocking purified recycled water as a potential water source for agriculture played an important role in those preparations.
"Right now, around 3.8 million people call south-east Queensland home and our population is expected to grow by 2 million people over the next 25 years," she said.
"It's vital that we have access to climate-independent water sources such as desalination and purified recycled water."
Recycled water is produced by the western corridor recycled water scheme in south-east Queensland, which consists of three advanced water treatment plants.
Purified recycled water is currently supplied to industry and power stations and under the region's water security plan, it could even be used in future if needed to top up water storages in Wivenhoe dam.
While that is not currently in place, the plan does allow for it to be blended with water in the dam and then retreated again at Seqwater's Mount Crosby treatment plants.
