THE Isa Rats (Running and Triathlon Club) are delighted not to have to hand-weed Lake Moondarra anymore.
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The Mount Isa Water Board's weed harvester is back in business after a major mechanical problem had it out of operation for just over six months, according to Water Board chief executive Greg Stevens.
However, president of Isa Rats, Kylie Baker, said it had been out of action for as long as she has been in Mount Isa, two and a half years.
The Isa Rats have had to hand weed the lake during the last few summers to create a safe path for swimmers, she said.
"For us to run the swim legs of our races we've had to pull the weed out by hand while floating with life vests.
"We put the weed onto a knee board and somebody with flippers swims with it in to shore, empties it into a pile and swims it back out again.
"We're so thrilled that the Mount Isa Water Board have finally got the harvester in the water," Mrs Baker said.
Mr Stevens said the weed harvester was designed to remove floating and underwater weed from the lake, collect it, then discharge it on shore for later collection and disposal.
"It sits on a large floating pontoon and is operated by one person, with support from another person on the shore.
"It has a cutter box at the front end with scissor-like cutting blades that cut and collect the weeds, a conveyor belt to collect, drain and store the weed and a discharge boom at the back to unload onto shore.
"To minimise the chance of fouling a propeller with weeds, the weed harvester is driven by two paddle wheels," Mr Stevens said.
The weeds had comparatively small nutrient value and were comprised mainly of water.
"Mount Isa Water Board has investigated the feasibility of using it as a composting material but this appeared largely unviable."
Even with the harvester, Mr Stevens said the weeds could never be completely eradicated from the lake.
"The weed is a part of the natural eco system.
"Weed harvesting can be likened to mowing your lawn - the grass will keep growing, but it is controlled," he said.
The weed harvesting process was slow and laborious, as it was driven by paddle wheels and travelled at under three knots.
"It will only be used in highly trafficked areas, such as Transport Bay and Blackrock.
"It has to unload the collected weed onto the shore in a place that is accessible for a vehicle to transport the harvested weed away," Mr Stevens said.
