extra $15.5m for ailing swan river problems

Maybe dredging, maybe Phoslock but an extra $15.5M's been allocated for Swan River.

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The State Government may dredge the Swan River in a controversial bid to save the embattled State icon from being smothered to death by algal blooms.

Environment Minister Judy Edwards said dredging was one of the "innovative" methods under consideration to remove nutrient-rich sediment, which fuels algal blooms, from the river.

Dredging was last carried out in the Swan in the late 1960s to clear navigation channels. But it has been discredited as a solution to nutrient build-up because of the risks to natural ecosystems, the potential damage to the natural geography of the river bed and the cost.

The idea sparked a warning from Greens MLC Giz Watson, who called for more focus on preventing nutrients leaching into the river rather than simply using a "giant vacuum cleaner" that would also remove native organisms.

Dr Edwards' comments came after Nationals MLA Brendon Grylls accused the Government of complacency over the future of the river, pointing to a paragraph in the State Budget which said it would take "many years" to significantly improve the health of the river.

Mr Grylls said the Swan River Trust's annual budget of $8.9 million should be at least doubled.

"The alarm bells should be ringing," he said. "(The river) is the State's number one icon . . . in an economy growing at the rate of ours, there needs to be a serious injection of funds so that we can get a result for the Swan River."

In response to a question from South Perth MLA John McGrath, Dr Edwards said she had always been advised against dredging for fear it could do more harm than good.

But she had recently discussed the issue and believed in being open to different ideas.

"There comes a point in time that it's worth revisiting certain ideas to see whether the points against them are still valid," she said. "I believe dredging is an issue we should look at."

Details such as the locations, duration and cost of dredging were yet to be examined, with the idea only one of several options under consideration.

Ms Watson urged caution. "I think we still haven't done enough with catchment and run-off management," she said. "The trouble with dredging is it's a pretty big gamble and it isn't going to deal with the long-term need to reduce what is going into the Swan."

Dr Edwards said there had been progress in reducing nutrients running into the river.

But she said it was difficult to halt the flow of chemicals and fertilisers left in the water table from long-gone market gardens in suburbs like Dog Swamp, Inglewood and Balcatta, which were drained to make way for housing developments.

The increased use of the modified clay Phoslock, which acts to remove phosphorus from the water, was also an option, she said.

Brenda Conochie, from the Friends of the Maylands Peninsula Foreshore, said her group had an open mind on dredging.

The latest Budget allocated an extra $15.5 million over four years to fixing the Swan.

http://www.thewest.com.au/20050609/news/general/tw-news-general-home-sto131406.html