Illegal estuary openings lead to poor water quality

THE water quality at Lorne’s Erskine River estuary has taken a hit over the past month, following two illegal openings of the estuary to the ocean within two weeks.

The first illegal opening occurred on March 8, and water testing at the site on March 11 confirmed the water quality of the estuary was poor, with low oxygen levels and high water temperatures recorded.

Strong swells and rainfall following the opening had begun to assist the natural closing of the estuary again, but a second illegal opening on March 21 has placed the health of the waterway, which was already under stress, at greater risk.

“There is a misconception that artificially opening an estuary to the sea can help improve water quality of the river and estuary,” a Corangamite Catchment Management Authority (CMA) spokesperson said.

“It can in fact be detrimental to water quality and harmful to fish populations, bird habitats, vegetation and can lead to fish deaths.”

It is a serious offence to undertake artificial estuary openings without a permit, and Corangamite CMA is continuing to monitor the situation and work to educate the community that artificial openings of the estuary when river levels are low do not promote a water exchange with the ocean.

The management authority shared more information with the community on Facebook following the first illegal opening, noting the Erskine River estuary is one of many in Victoria that naturally alternates between being open and closed to the sea.

“When an estuary closes over summer and autumn, the higher water levels keep fringing vegetation wet and can act as an important refuge for birds, fish and frogs,” the post stated.

“When an estuary is opened to the sea, it is usually the oxygenated layer [of water] that flows into the sea first, leaving poor water quality behind.”

Community members with information about illegal artificial estuary openings in the area are encouraged to phone Corangamite CMA on 1800 002 262 or [email protected]