The Hopkins River has returned to a stable level in Warrnambool after “highly problematic” ocean conditions caused the river mouth to close, resulting in a flood that put a waterfront restaurant in the danger zone.

As of 2pm Tuesday, the estuary water level sat at 0.75 metres Australian Height Datum, the Glenelg Hopkins Catchment Management Authority (GHCMA) told the Brolga. This represents the height of a point above average sea levels.  

Proudfoots by the River restaurant shared on social media on Monday that the water from the river had flooded the building’s deck.

The mouth was opened on Monday night and into Tuesday, decreasing water levels and alleviating flooding impacts.  

By Tuesday morning Warrnambool City Council had successfully opened the river mouth manually, allowing the river to flow back into the sea. 

Warnings about increased flooding in Warrnambool, including along the Hopkins River, continue to spark debate in the community.

As the Brolga previously reported, Warrnambool City Council voted recently to reject recommendations from a peer-reviewed, state-funded flood study that identified worsening flood risks across the city.

The study, conducted by independent experts and incorporating the latest climate modelling, found that increased rainfall intensity and sea level rise were expected to significantly raise flood levels in local waterways - including estuaries like the Hopkins.

Despite this, some councillors dismissed the findings as “supposed science” and raised concerns about the impact on property values.

Why did the river flood?

Initial works to open the river mouth manually started on Friday, following a “very large swell and storm tide event” earlier in the week, which resulted in very high water levels and flooding impacts on the estuary.  

A spokesperson for the GHCMA said it had approved the river mouth opening, with physical works undertaken by Warrnambool City Council.

Further excavation works were also required by the council to maintain river flow throughout the weekend and Monday, due to “highly problematic and challenging ocean swell and sea state conditions”, which saw persistent swell backfilling the flow channel. 

The GHCMA said the Hopkins River is classified as an intermittently closed system, with natural seasonal closure and associated flooding “a critical component of the ecosystem”.  

“Natural estuary openings are our preferred outcome, however when this is not a feasible management option, the CMA as waterway managers coordinate the decision process to either open or not open the estuary, in balance with the environmental, socio-economic and cultural values of the system,” the spokesperson said.