UPPER Ovens Valley residents will once again turn to giant booms to clear the native weed choking their heritage-listed swimming hole.
The water weed had covered the entire Tronoh dredge hole earlier in the summer before a community campaign was able to push back the red bloom of Azolla, restricting it to a small part of the popular swimming and fishing hole.
But John Atkins, a member of the reserve committee fighting the infestation, says a more permanent solution must be found.
“We are investigating other options — perhaps a spray that is not harmful to people or fish,” he said.
“In a couple of weeks we will look at again using the booms to push the weed back on itself, killing off some of the Azolla trapped without sunlight.
“We need the younger blokes for that and at the moment they are caught up with the fires.”
Mr Atkins said the North East Catchment Management Authority would also visit the dredge hole in the coming weeks.
Testing had revealed a source of nutrients, containing traces of E. Coli, feeding the blooms.
“But we are still at a loss to explain what the source is,” he said.
“In early January the water was crystal clear but now it looks a little muddy — it may be the Azolla that has died breaking down but we can’t really explain that either.”