GBCMA update on Lake Benalla

Published on 29 March 2021

Lake Benalla is slowly refilling as increased flows from Hollands Creek start making their way downstream after recent rain.

The lake has been drawn down since mid-February to try to manage the aquatic weed cabomba.

Goulburn Broken Catchment Management Authority’s Jo Deretic said it would have been preferable to leave the lake level down for a few more weeks to maximise weed exposure and drying.

“Exposing and drying the weed has proved to be the most effective control method in the past,” she said.

“We had hoped to keep the lake level down until early April, but the recent rain has changed the situation.

“Fortunately, we did have about five weeks of good drying time. Benalla Rural City Council has also carried out some mechanical weed removal, which means we’ve controlled the cabomba population and spread to some extent. We will carry out follow-up monitoring to assess how effective the drawdown was in controlling cabomba and when further drawdowns will be required.”

Cabomba is classed as a Weed of National significance. It smothers native aquatic vegetation that provides valuable habitat for animals, fish and water bugs, clogs pumps and filters, compromises the aesthetic and recreational value of waterways and poses a real water quality hazard to people and animals.

Cabomba is an introduced plant that is often used in aquariums. It has fan-shaped, brownish ferny leaves that sit mostly underwater, with a white flower floating on the surface. To prevent further infestations, it is essential that aquarium plants be composted and not disposed of in or near waterways.

Goulburn Broken CMA works with Benalla Rural City Council and Goulburn-Murray Water to manage cabomba in the lake.

For more information visit gbcma.vic.gov.au or phone 5822 7700.