Supporting the health of the Angelsea River Estuary

January 2023

What is happening:

Agencies and partners are working together to support the health of Anglesea River, which is enjoyed by the Surf Coast communities and remains a popular holiday destination for many Victorians.

In late 2022 with the persistent heavy rain, the Anglesea River reconnected with the ocean. This provided an opportunity for fish migration into the river and improved water quality, which has been welcomed by local residents and anglers.

In early January the river mouth closed, with reduced flows from the upper catchment tributaries of Salt Creek and Marshy Creek. This is likely to result in increasing acidity over the coming weeks, especially if rainfall mobilizes acid sulfate soils in the upper catchment wetlands.

The river level has also dropped, creating a significant risk of activating acid sulfate soils at Coogoorah Park and releasing metals and acids into the river system. The Anglesea River remains safe for local and visitor communities to enjoy water-based recreation.

Planning for an Artificial Estuary Opening:

Corangamite Catchment Management Authority (CMA) is working closely with the Wadawurrung Traditional Owners Aboriginal Corporation, the Department of Energy, Environment and Climate Action (DEECA, previously DELWP), Barwon Water, Surf Coast Shire Council, Great Ocean Road Coast and Parks Authority, and Environment Protection Authority (EPA) Victoria, to proactively manage the risks of a potential fish death event.

If the pH or dissolved oxygen in the Anglesea River reaches a trigger point which is harmful to fish, the Surf Coast Shire Council, at DEECA’s request will undertake an artificial estuary opening to allow the fish to escape and reduce the likelihood of a fish death event occurring.

An artificial estuary opening like this has not been done before and will act as a trial. Corangamite CMA has received independent expert advice that 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. DEECA and Corangamite CMA may also coordinate manual fish rescue to remove the fish if required.

Releasing stored water into the Anglesea River:

Since 2016, DEECA, Corangamite CMA, Surf Coast Shire Council and Barwon Water have worked together to collect and store water from the Anglesea River during the winter-spring period and pump it back in over the drier summer months.

These supplemental flows maintain water levels in the estuary and deliver social, cultural, economic and environmental benefits to the local community.

To prevent a significant environmental impact on Anglesea's aquatic ecosystem, DEECA has requested Barwon Water to start releasing stored water into the Anglesea River to reduce the risk of activating acid sulfate soils in Coogoorah Park. The stored water having been harvested from the Anglesea River during winter is acidic, and may contribute to increasing the acidity of the river.  However, the risk of continued low water levels in the estuary activating additional areas of acid sulphate soils has been identified as a more significant and irreversible overall risk to the Anglesea River.

Looking at the longer-term management of the Anglesea River:

Work on the Anglesea River Options Identification project is also underway. The project is being undertaken by consultants CDM Smith, using an independent expert panel (consisting of acid sulfate soil, estuary, and water pollution specialists). The project aims to identify and assess management options to address acidity issues in the Anglesea River. Community participation in the project is being coordinated through the Community and Stakeholder Reference Group.

Agencies and partners are continuing to work together to monitor the health of the Anglesea River and respond as appropriate. Corangamite CMA will continue to monitor water quality conditions in the river/estuary and look for opportunities to expand the monitoring network through Citizen Science programs. Agencies and partners will keep the community updated about actions underway in the Anglesea River estuary.