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Slowing the flow can improve catchment health

Slowing the flow of water through catchments and river systems could help resolve some of Australia's most pressing environmental concerns, according to one water quality expert.

Exploring his mantra ‘slow the flow’ in the CQUniversity IMPACT podcast series, researcher Dr Adam Rose is advocating for a new approach to catchment health in Australia, one which works to retain water within water systems longer via catchment-specific solutions.

“The idea behind ‘slow the flow’ is to simplify the messaging around catchment water management in order to create a new narrative around what we are doing,” he said.

“We've got farmers already practicing water retention in , but for it to work we really need everybody to take it up at a catchment level. We've got over 200 catchments in Australia and every catchment behaves differently.

“They’ve got different rainfall patterns, different geology and different development. When we talk about slowing down the flow, how that’s achieved and the solutions applied will need to be tailored to each catchment.”

Taking Queensland’s Fitzroy River catchment as an example, Rose said slowing the flow in our catchments has the potential to produce many benefits, social, economic and environmental.

“In central Queensland, we've got lots of cattle grazing, we've got regional centers for water supplies, but we've also got the reef. In 2011, 7600 Sydney Harbours worth of fresh water went out of the Fitzroy catchment alone, as well as a billion kilograms of soil,” he said.

“Traditionally, rainfall penetrated into the soil profile, filtering through to our creeks and river. In that scenario, far less sediment and far less water reached the ocean.

“By retaining more water in the catchment, natural habitats are better off, including the Great Barrier Reef, native species are more comfortable, the farms could benefit from additional water as well. Insurance companies doing flood plans will have to pay out less on insurance claims, too.

“Furthermore, if we retain more water we can actually change the climates of the catchment. Taking central Queensland as an example, if we've got more water out west, when that water is evaporating and transpiring from the soil and the trees, resulting in more rain for Rockhampton.”

Rose said investing in catchment works is also a great way to bounce back after COVID-19 in regional Queensland.

“If everybody looks after their catchment’s specific needs, we'll get more jobs in the regions. But also, by involving the people that live there, the decisions made about catchment water bodies will more likely be accepted by the community,” he said.

In terms of solutions, Rose said contouring, habitat rehabilitation and catchment-sensitive damming are a few of the ways to help retain water within the system.

“Slowing the flow would involve a series of solutions involving contouring. Planning ecologically relevant species on those contours helps build and give back habitat to the native animals,” he said.

“Dams are also a viable solution. While they’ve received a bit of a bad rap, it’s important to consider them as more than simple water storage.

“The reality is that our river systems here in the Fitzroy catchment do not reflect what they would have been 200 years ago. They've changed so dramatically. Stopping dams for the sake of restoring the rivers to what they once were is not a possibility. We need to work towards helping those water bodies become as healthy as possible now, and dams aren’t always a bad thing.

“Instead of thinking of them as a giant chunk of cement that's being thrown down to stop the water, I'm envisaging bespoke dams that have fish ladders, that are also equipped with the technology required to treat the water sufficiently. It's a really simple solution. There's no tricks to it.”

Rose said contouring is an excellent way to cover many environmental issues currently plaguing catchment waterways, including stress on biodiversity, agriculture and water quality.

“By planting in contours, we're going to increase the biodiversity of the catchment. It also increases the productivity of the farm. By retaining more water in the soil profile for longer. So after floods, we’ll have a longer period of good times and we can reduce the bad times e.g. drought,” he said.

“By slowing the flow and letting the soil profile act as a filter, like it always has been, it makes the water quality better, which means we have less toxic algae in our water supplies as well.

“This then has a positive effect on estuaries downstream, including the health of the fish species that rely on those aquatic environments.

“The biggest weapon that we have in climate change is water. Unless we get our water sorted, we're going to be fighting a losing battle for the next few decades.

“It's a really important conversation, not just for environmental health, but also for our capacity to farm and to keep safe drinking water supplies. It all rests on water.”