A wetland designed to filter pollutants underwater is being considered for Belconnen Oval, one of several waterway projects expected to get underway in the next 12 months.
Designed to remove pollution for the Emu Creek Catchment and improve the quality of stormwater flowing downstream, the Belconnen wetland is expected to help control blue-green algae in Lake Ginninderra.
The subsurface wetland, a first for the ACT, will rely on rocks, gravel, sand and soil to filter out pollutants below the surface of the pond.
Water Minister Shane Rattenbury said water quality modelling had determined around 30 per cent of suspended soils, nitrogen and phosphorus could be filtered through the new pond.
Mr Rattenbury said the proposal would provide an innovative and attractive solution for improving water quality, while also improving amenity for the area.
Thirteen new waterway assets are planned across the territory as part of the Healthy Waterways Program, a joint Commonwealth and ACT government initiative designed to protect suburban water and water downstream in the Murrumbidgee River system.
Two of the infrastructure projects are near completion, including a floating wetland at Yerrabi Pond scheduled to wrap up later this month.
Another 11 assets have been proposed over the next year, including projects to capture, filter and reuse stormwater on playing fields, after runoff was identified as a potential contributor to high-nutrients levels.
Mr Rattenbury said the Belconnen project was part of a holistic approach to improving water quality through new infrastructure and improvements to existing services, including street sweeping and litter trap cleaning.
The ACT government announced it would invest $14 million into this stage of the waterways program in April, which included funding for research through the University of Canberra to ensure best practice.
Waterways feeding into Lake Tuggeranong and Lake Ginninderra will be given special attention as urban runoff, in addition to higher inflows of nutrients from increased rainfall, had put pressure on water quality.
Ralph Ogden, Healthy Waterways Program manager, said pollutants in the Lake Tuggeranong catchment had been flowing from a wide range of suburbs, with leaves, grass and fertilisers identified as potentially harmful,
"One of the ways that we can deal with that is to build large water quality assets like we have over the last three or four years, but it's hard for them to filter all of the pollution out.
"It's a much sounder approach to try and prevent the pollution from occurring in the first place."
Mr Ogden said, in addition to new designs they were using existing assets in new ways, with water gardens moved to the top of catchments to filter water before it entered the system.
"When rain falls on a rural catchment it gets filtered through the plants and to the soils and comes out cleaner," he said.
"In an urban area the water falls onto urban surfaces and picks up whatever pollutants are there has no filtering before basically going straight down into our ponds and lakes.
"We're trying to reconnect the urban runoff with its catchment."
Information sessions will be held at Belconnen Library on October 11 and 15 for people wanting to learn more about the oval proposal.
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