A MILLION dollar plan is in the works to help rid the trio of sickly lakes on Maylands Peninsula of their plague-like midges.
Brearley, Bungana and the Brickworks lakes have abysmal water quality. Low oxygen levels and high phosphorous contamination from storm water runoff, fertilisers and bird poo have led to persistent algal blooms.
Bayswater council has deployed anti-midge measures including solar-powered midge traps, but there’s so many bugs they’ve starting jamming up their fans.
After receiving a consultant report on the state of the lakes Bayswater council will now install mechanical mixers to de-stratify lakes Brearley and Bungana. The lakes are human-made and their design means the deep and shallow waters don’t mix, so the lower levels don’t get oxygenated and the sediment releases even more nutrients for algae to feast on.
The expert report recommended the council hold off on more dredging until the benefits can be proven, as it hasn’t conclusively helped the water quality so far. But council decided Brearley will get “selective dredging” soon to scrape out the prime midge breeding zone.
Friends of Maylands Lakes chair Geoff Trott told Bayswater council the group supports the overall plan, and they reckon the Bungana dredging had helped with midges there.
“After a brief winter respite we are already in the grip of plague levels of midges despite the City of Bayswater’s best efforts to alleviate the problem,” Mr Trott said at October’s council briefing.
“Lake Bungana residents were also plagued by midges the summer before last but have been virtually midge free since the dredging of that lake. It’s not done any harm to the lake as some were concerned it may.”
The dredging has to go out to tender and might take a few months to get started.
As the measures are rolled out, a fauna study will keep an eye on the health of turtles, frogs and bird life, and continual water sampling will be conducted. It’ll cost $990,000 for the mixers, dredging, water and wildlife monitoring.
Long-term measures include replacing surrounding non-native trees with lake-friendly local ones, replacing grass with sedges, creating rain gardens and “living streams” in the upstream tributaries to filter out nutrients, and continuing the campaign to reduce nearby fertiliser use.
by DAVID BELL