Pollution pressure on our rivers
THE Swan River Trust hosted Community Newspaper Group reporter Jon Bassett on the river recently after the State Government absorbed the agency into the Department of Parks and Wildlife and before the estuary becomes one of three top policy areas this year. THE Swan River is in a better condition than many assume but there is still work to be done, Swan River Trust (SRT) acting general manager Mark Cugley says.
“Overall, it’s in good condition, based on the fact that people can continue to swim along it, the amount of fish and it supporting a vibrant dolphin population,” Mr Cugley said.
The SRT works to control excess nutrients reaching the river, including a $3 million project at the Bayswater Brook main drain where 150,000 riverbank plants may stop 1.3 tonnes of nitrogen reaching the river each year.
Nitrogen and phosphates from fertilisers can create toxic algae blooms in hot weather, so the Trust’s Midland and Wilson plants pump oxygen into the water to provide refuges from the blooms for fish in the rivers’ upper reaches.
However, it has been revealed that Ellenbrook is the worst tributary for the pollution, breaching short- and long-term reduction targets in the past four years.
Mr Cugley said 14 other Swan River catchments were meeting 20-year targets and work would continue with the catchments’ councils, farmers, golf courses and landscapers to reduce fertilisers, while other Government agencies would enforce the Swan and Canning Rivers Management Act.
He said the rivers would continue to be affected by a growing population and a drying climate, so the SRT would continue to educate the public about the threats.
Downstream, three screens will block any plumes during digging of a boating basin soon to start at Elizabeth Quay in the Perth CBD and the SRT continues to prioritise funds for riverbank restoration and riverwall repairs
SRT statutory assessment manager Jennifer Stritzke said monitoring had not indicated any inflow of contamination from historic dumps near the quay works. Ms Stritzke said much of what came out of the large main drain adjacent to the Quay and into the Swan would have flowed from Lake Monger, which was fed by smaller drains taking road run-off from places as far away as Shenton Park.
Acting riverpark manager Roland Mau said the river had been divided into 350 sections to decide which river wall repairs got funded, with council contributions depending on the frequency and type of public use at that part of the river.
Swan River Trust’s Mark Cugley.