Initial stages of a trial aimed at controlling algal growth in the Lower Vasse River has demonstrated improved visual amenity and reduced phosphorus build-up associated with algal blooms.
High nutrient concentrations and low flows in the river over summer can lead to bluegreen algal blooms and nuisance odours.
In November last year, 15 tanks were immersed in the river near the Lower Vasse traffic bridge by Department of Water scientists.
The scientists tested whether an innovative new clay product, which was applied to the tanks at different doses, would strip phosphorous from the water column and prevent phosphorous release from the sediments.
Department of Water senior environmental officer Linda Kalnejais told the Mail that too many nutrients were carried through the rivers and ground water.
Ms Kalnejais said there had been a lot of work done in the catchments to minimise nutrients coming in but there were still a lot of nutrients stored in the sediments.
The clay being used in the trial was experimental and Ms Kalnejais said it should grab the phosphate, which was an essential nutrient for the phytoplankton.
“If they do not have phosphate then they cannot grow so that should help minimise the blue-green algal growth,” she said.
Department of Water environmental chemist Svenja Tulipia said they were pleased with the visual improvement in water quality in the tanks with the clay compared to those with no clay.
Ms Tulipani said they would look at the water quality data collected over the trial to assess if they would extend the trial over larger areas of the river next summer.
The trial was part of a series of experiments to explore unique ways to improve water quality in the Lower Vasse River and other regional estuaries.
It is part of the Revitalising Geographe Waterways Initiative, which aims to improve water quality and waterway health in Geographe waterways.
Results will inform the long-term management of the Lower Vasse River.
Comprehensive results will be shared with the community on Friday at a Community Science forum, for more details visit here geocatch.asn.au/event/community-scienceforum/.
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