Anglesea River: Low water levels prompt ‘proactive’ response to prevent fish death event

The state government has announced plans to to prevent a potential fish death event. Here’s how.

Friends of Anglesea River member Dick O’Hanlon by the Anglesea River in 2022. Picture: Aaron Francis

The state government has announced plans to manage the health of the Anglesea River, in an effort to prevent “a potential fish death event” amid falling water levels.

Under the Department of Energy, Environment and Climate Action (DEECA)’s plan, Barwon Water on Wednesday began pumping stored water back into the river to reduce the “significant and irreversible” risk of activating acid sulfate soils in Coogoorah Park.

“We all understand the value the Anglesea River has to the local community, so we’ve taken proactive action to help manage the water quality,” a DEECA spokesperson said.

“Multiple agencies are working together to manage this complex issue and identify viable long-term options to ensure the river remains healthy and is an asset for the Surf Coast region”.

Fish killed in Anglesea River in 2016. Picture: Mitch Bear

DEECA acknowledged the stored water could increase the river’s acidity, but considered continued low water levels in the river a greater risk to native fish.

Barwon Water has a licence to harvest 126 megalitres over the winter months, which is then used to raise the river level each summer.

If the introduced water does not mitigate the risk and the acidity reaches a “trigger point” the state government could ask Surf Coast Shire to open an artificial estuary, connecting the river to the sea.

It’s a proposal that environmental group Friends of Anglesea River is supportive of.

Group member Dick O’Hanlon said the possibility of the artificial estuary was a step in the right direction.

“It would create the precedent for the river being opened for environmental reasons,” Mr O’Hanlon said.

“We think it’s a good option,” fellow member Keith Shipton said, noting the river had recently formed its own sea connection due to spring rainfall.

The Anglesea River has had issues with acidity in the past.

Seawater has naturally high pH levels, which neutralises acidic water.

Mr Shipton said fish were seen in the river for the first time in years in October, due to heavy rainfall.

“It was amazing to see the river go from far too acidic to being able to sustain fish life in 24 to 48 hours,” Mr Shipton said.

Mr Shipton said regular openings could be a way to reinvigorate the health of the troubled waterway, which has previously had issues with acidity and saw a fish death event in 2016.

“The seawater rejuvenated the river,” Mr Shipton said.

“It changed the whole situation... perhaps we should take our lead from nature.”

However, Corangamite CMA said the opening an artificial connection to the sea would be an option of last resort.

“The opening can only occur when conditions in the estuary trend towards being unfavourable as that will be the cue for fish to leave the estuary,” a CMA statement read.

“An artificial estuary opening like this has not been done before and will act as a trial.”

Originally published as Anglesea River: Low water levels prompt ‘proactive’ response to prevent fish death event