The Anglesea River and estuary have a history of ongoing water quality challenges, including periods of high acidity caused by activated acid sulphate soils (ASS) which occur naturally in the Anglesea River catchment. Rainfall and runoff can carry acid from these soils into the river, increasing the water’s acidity and sometimes changing its colour.

Recent rainfall has increased flows into Marshy Creek – a known area of ASS – and has the potential to lead to an increase in acidic conditions in the Anglesea River and estuary.

Corangamite CMA and partner agencies will continue to monitor conditions and provide updates if significant changes in downstream water quality are observed.

In 2025, Corangamite CMA trialled an artificial estuary opening to see if any improvements in estuary water quality could be achieved, however it resulted in no discernible improvement.

Community members interested in learning more about the future of the Anglesea River can visit the Reimagining the Anglesea River & Estuary project on the Corangamite CMA website.

Information on current water conditions is publicly accessible. Instructions on how to access the data can be found here: Anglesea River Estuary Conditions - Corangamite Catchment Management Authority

• • pH throughout the Anglesea River estuary has remained around 4.5 over the past two weeks. The equipment at the Anglesea River monitoring station has recently been updated and the Corangamite CMA is currently undertaking planning work to install an additional monitoring station on the Anglesea River near Coalmine Road.

• • Corangamite CMA is leading the Reimagining the Anglesea River and Estuary project which aims to bring together agencies and community to determine immediate and future management options for the Anglesea River and estuary. The first Reimagining the Anglesea River and Estuary (RARE) Working Group is scheduled for 15^th April 2026.

• • If you want to chat further about the Reimagining the Anglesea River and Estuary project, please get in touch with Ryan Bath at ryan.bath@ccma.vic.gov.au. He is in the process of getting to know all the different stakeholders of the Anglesea River.

• • pH throughout the Anglesea River estuary has remained around 5 over the past two weeks. Corangamite CMA is undertaking planning work to upgrade the Anglesea River monitoring station, along with planning to install an additional monitoring station on the Anglesea River.

• • Corangamite CMA is leading the Reimagining the Anglesea River and Estuary project which aims to bring together agencies and community to determine immediate and future management options for the Anglesea River and estuary.

• • Corangamite CMA is running an expression of interest for representatives across the Anglesea community to join the Reimagining the Anglesea River and Estuary (RARE) Working Group. If you are interested in joining, please complete the Expression of Interest form and send to by 31 March 2026.

• • If you want to chat further about the Reimagining the Anglesea River and Estuary project, please get in touch with Ryan Bath at ryan.bath@ccma.vic.gov.au. He is in the process of getting to know all the different stakeholders of the Anglesea River.

• • pH throughout the Anglesea River estuary has improved slightly, although still below 5.   The data generated from the permanent monitoring station on Bingley Parade in Anglesea suggests that pH has increased over the last month. Corangamite CMA is undertaking planning work to upgrade this monitoring station, along with planning to install an additional monitoring station on the Anglesea River.

• • Corangamite CMA has been monitoring water levels in the Anglesea River closely and a request to Barwon Water to start pumping water into the Anglesea River was sent on Monday February 23. Pumping began that day and, other than a brief pause due to power outages, continued until Tuesday March 3.

• • The primary purpose of pumping water is to maintain water levels that minimise risks of further oxidising acid sulfate soils. Although the purpose is not to maintain a water level for recreation, Corangamite CMA acknowledge that managing the water level has provided important shared benefits to social and recreational values and activities.

• • Corangamite CMA is running an expression of interest for representatives across the Anglesea community to join the Reimagining the Anglesea River and Estuary (RARE) Working Group. If you are interested in joining, please complete the Expression of Interest form and send to by 31 March 2026.

• • If you want to chat further about the Reimagining the Anglesea River and Estuary project, please get in touch with Ryan Bath at ryan.bath@ccma.vic.gov.au. He is in the process of getting to know all the different stakeholders of the Anglesea River.

• • The permanent monitoring station within the estuary is showing that pH levels in the Anglesea River estuary have not improved, and water quality remains a concern. The Anglesea River EstuaryWatch group last monitored water quality in the river on the 18th of February, 2026. Their data and observations can be viewed here Anglesea River Estuary

• • The estuary is currently closed to the sea, a natural process where sand builds up at the river mouth, blocking exchange between river and ocean. This typically occurs when freshwater inflows are low.

• • Corangamite CMA sent a request to Barwon Water in the week of the 16th of February to initiate pumping of water from a nearby storage pond into the river to increase the water level in a bid to reduce the risk of activation of coastal acid sulphate soils in Coogoorah Park.  Pumping began on Monday the 23rd of February and since then Corangamite CMA has been closely monitoring water level and the weather forecast to determine how long pumping will continue.

• • The permanent monitoring station at the estuary indicates that pH levels in the Anglesea River estuary are slowly improving but water quality remains a concern.

• • Anglesea River EstuaryWatch completed water quality monitoring at five locations on the Anglesea River on January 21.  Their water quality data and river mouth observations can be viewed here https://ew-data.waterwatch.org.au/estuary/ccma/45

• • The estuary remains closed to the sea, a natural process where sand builds up at the river mouth, blocking exchange between river and ocean.

• • With warmer weather, evaporation will increase. If rainfall remains low, river water levels will continue to drop. To help maintain levels, Corangamite CMA will continue to work with Barwon Water to periodically pump water from a nearby storage pond into the river over summer and autumn.

• • Agencies intend to meet with the Anglesea River Working Group in the coming weeks. This meeting will provide an opportunity to update the community on the Reimagining the Anglesea River Project. Community will also be invited to participate in the Project through an upcoming ‘Expression of Interest’ process to join the Project Working Group.

• • An investigation into the August 2025 acid flush event is now published Corangamite CMA Knowledge Base - Anglesea River Acid Flush Event October 2025 – Part A – Estuary Op…

• • The permanent monitoring station with the estuary is showing that pH levels in the Anglesea River estuary have not improved, and water quality remains a concern. A monitoring station upstream of the estuary indicates that flows carrying acidic water from Marshy Creek into the Anglesea River have ceased.

• • The permanent monitoring station with the estuary is showing that pH levels in the Anglesea River estuary have not improved, and water quality remains a concern. A monitoring station upstream of the estuary indicates that flows carrying acidic water from Marshy Creek into the Anglesea River have ceased.

• • The estuary is currently closed to the sea, a natural process where sand builds up at the river mouth, blocking exchange between river and ocean. This typically occurs when freshwater inflows are low.

• • With warmer weather, evaporation will increase. If rainfall remains low, river water levels will continue to drop. To help maintain levels, Corangamite CMA will work with Barwon Water to periodically pump water from a nearby storage pond into the river over summer and autumn.  Pumping infrastructure is in place and Barwon Water operators are on standby to begin pumping of water from storage into the Anglesea River when needed.

• • We can report that people are not the only visitors to the coast this time of year.  The Latham's Snipe, Gallinago hardwickii, has been spotted in Coogoorah Park this January. Latham’s Snipe breeds in Japan and south-east Siberia during Australia's cooler months. Most of the population spends its non-breeding season in eastern Australia from August to February, with the largest concentrations occurring in south-eastern Australia. For more information about this secretive bird, visit Latham's Snipe

• • The permanent monitoring station with the estuary is showing that pH levels in the Anglesea River estuary have not improved, and water quality remains a concern. A monitoring station upstream of the estuary indicates that flows carrying acidic water from Marshy Creek into the Anglesea River have ceased.

• • The estuary is currently closed to the sea, a natural process where sand builds up at the river mouth, blocking exchange between river and ocean. This typically occurs when freshwater inflows are low.

• • With warmer weather, evaporation will increase. If rainfall remains low, river water levels will continue to drop. To help maintain levels, Corangamite CMA will work with Barwon Water to periodically pump water from a nearby storage pond into the river over summer and autumn.  Pumping infrastructure is in place and Barwon Water operators are on standby to begin pumping of water from storage into the Anglesea River when needed.

Monitoring water quality – public access

The Water Measurement Information System (WMIS) is a Victorian Government data portal that can help you to track water level and pH at the Anglesea River estuary from the comfort of your own home. Here are some instructions to help you access the data:

• • visit Anglesea River @ Great Ocean Road Bridge Site: 235278 https://data.water.vic.gov.au/WMIS/g/38dad4f4-363a-4cf5-8db1-04349474fe47

• • click on the “Show”  link on the left-hand side of the web page and the current water level and water quality recorded at the monitoring station on the Anglesea River estuary will be revealed.

• • click on any of the tiles under the “Data” heading and you will then be able to view the last 12 months of data in a graph. This is a great way to see how water level and water quality changes with the seasons.

For more information about surface water, ground water and rainfall/weather data available to the public, visit https://data.water.vic.gov.au/

Corangamite CMA will resume posting regular updates on our website about the current condition of the Anglesea River estuary in early 2026.

• • Permanent monitoring stations show that pH levels in the Anglesea River estuary have not improved, and water quality remains a concern.

• • The estuary is currently closed to the sea, a natural process where sand builds up at the river mouth, blocking exchange between river and ocean. This typically occurs when freshwater inflows are low.

• • With warmer weather, evaporation will increase. If rainfall remains low, river water levels may drop. To help maintain levels, Corangamite CMA will work with Barwon Water to periodically pump water from a nearby storage pond into the river over summer and autumn.

• • Permanent monitoring stations on the river and monitoring by Anglesea River EstuaryWatch indicate the current state of the Anglesea River estuary is showing no improvement in pH levels and water quality continues to be a concern.

• • Anglesea River EstuaryWatch completed water quality monitoring at five locations on the Anglesea River on November 19.  Their water quality data and river mouth observations can be viewed here https://ew-data.waterwatch.org.au/estuary/ccma/45

• • Following the brief low flow artificial estuary opening trialled in August 2025 (see more info in the September update below), Corangamite CMA, GORCAPA and Surf Coast Shire commissioned an investigation to analyse monitoring conducted during the acid flush event and assess the impacts of the trial opening.

• • The investigation showed the artificial estuary opening revealed no discernible improvement in water quality. The pH remained below 4.5 throughout the lower estuary, and no reductions in metal levels were observed.

• • Corangamite CMA and DEECA commissioned an investigation into Acid Sulphate Soils at Coogoorah Park. The report is currently being finalised.

• • Corangamite CMA is committed to undertaking a berm grooming trial as soon as conditions allow, to assess if it is an effective management option to increase water levels in the estuary.

Further update on Anglesea River Pumping:

• • Barwon Water has confirmed that pumping from the river into the storage pond has now ceased.

• • The storage pond is now at its capacity volume of 100ML. This water will be periodically pumped back into the river over summer and autumn to top up water levels.

• • Permanent monitoring stations on the river and monitoring by Anglesea River EstuaryWatch indicate the current state of the Anglesea River estuary is showing no improvement in pH levels and water quality continues to be a concern.

• • Following the brief low flow artificial estuary opening trialled in August 2025 (see more info in the September update below), Corangamite CMA, GORCAPA and Surf Coast Shire commissioned a report to analyse monitoring conducted during the acid flush event and assess the impacts of the trial opening. The estuary mouth remained open for approximately nine days before closing.

• • Corangamite CMA and DEECA commissioned an investigation into Acid Sulphate Soils at Coogoorah Park. The report is currently being finalised.

• • Both reports will be shared with the community once completed, and findings will be presented to the next Anglesea River Advisory Group.

• • Corangamite CMA is committed to undertaking a berm grooming trial as soon as conditions allow, to assess if it is an effective management option to increase water levels in the estuary.

Further update on Anglesea River Pumping:

• • Barwon Water has confirmed that pumping from the river into the storage pond is now underway.

• • Barwon Water has been granted an extension by Southern Rural Water to continue pumping for an additional month (to the end of November 2025).

• • Barwon Water is currently pumping approx. 2-3 ML per day. There are currently approx. 30 ML in the storage basin, and storage levels should increase significantly by the end of the month with the extended pumping timeframe. The capacity of the storage pond is approx. 100 ML.

• • The Anglesea River estuary currently has low pH (acidity) due to acidic inflows coming from Marshy Creek (this acidity is caused by naturally occurring acid in soils).

• • The estuary is experiencing flocculation, which is a physical-chemical process of suspended particles clumping together, often resulting in altered clarity and colour (this can be observed as a milky blue appearance). This reaction is a result of acidic river flows meeting the salty water in the estuary.

• • Fish deaths have been observed at Anglesea River estuary since Tuesday 5 August.

• • Several water quality factors (not just pH) can impact fish populations including:

    • • Low pH can damage fish skin and gills, leaving them susceptible to disease and infection.
    • • Direct aluminium toxicity can occur from dissolved aluminium and potentially other metals
    • • Fish can suffocate as the aluminium precipitate (solids) clog their gills
    • • The process of metal oxidation to form precipitates can use up oxygen, which fish need to survive.

• • A fish survey and water quality monitoring was carried out by Arthur Rylah Institute on 13 August 2025 at six sites across the Anglesea Estuary to help inform management decisions.

• • The results indicated that remaining refuge areas for fish were very limited with poor quality water extensive throughout the estuary except for a very thin layer of oxygenated water near the surface. There were also very few invertebrates reported and hence an additional risk of fish not having a food source. Based on this, Corangamite CMA trialled an artificial opening in low inflow conditions on Wednesday 20 August to test if any environmental benefits could be achieved.

• • Over the following week, the estuary mouth remained open and water was still flowing steadily out to sea and had scoured sand to form a deeper channel than what was seen on the day of the opening. There weren't any significant changes to observed water quality parameters or fish deaths after the artificial opening was conducted.

• • Initial results of independent water quality testing by ALS provided further evidence that the Anglesea River and estuary are experiencing severe acid sulfate soil stress and extreme risks for fish and biodiversity including:

    • • Very acidic, poorly buffered water (pH 3.7–4.8, alkalinity <2)
    • • Heavy metals (aluminium up to 55 mg/L, iron up to 3.9 mg/L, zinc up to 1.2 mg/L).
    • • Worst water quality near Coalmine Road and Bingley Parade, improving slightly at the estuary mouth.
    • • A formal analysis of these results is currently underway and will be summarised on this webpage once complete.

• • On Friday 29 August, the Anglesea River EstuaryWatch group confirmed the river was no longer flowing out to sea. Although the estuary appears closed at low tide, there may still be some seawater that overtops the sand and into the river at high tide.  Estuaries are dynamic in nature so Corangamite CMA and Anglesea River EstuaryWatch will continue to monitor the river mouth.

• • Expert analysis of the water quality results is underway and updated information will be posted here once complete.

The Anglesea River estuary currently has high acidity (low pH) caused by naturally occurring acid in soils in the upper catchment above Coogoorah Park.

The estuary is experiencing flocculation, which is a physical-chemical process of suspended particles clumping together, often resulting in altered clarity and colour (this can be observed as a milky blue appearance). This reaction is a result of acidic river flows meeting the salty water in the estuary. Fish deaths have been observed since Tuesday 5 August.

Independent water quality and fish monitoring on 13 August indicated that poor water quality was extensive, with limited refuge areas and food sources remaining for fish.

An artificial estuary opening was conducted on 20 August, despite the low river flows, to trial if any environmental benefits could be achieved. No significant changes to observed water quality parameters or fish deaths have since been reported. Independent analysis of water quality date pre and post the opening is currently being completed.

The acidity is caused by naturally occurring acid in soils in the upper catchment.

The Anglesea River experiences periods of acidic conditions as a result of acid sulfate soils that are naturally present in the catchment above Coogoorah Park. Prolonged dry spells followed by heavy rain often trigger these events, as the rain mobilises acid from these soils downstream into the estuary. Several fish death events have occurred during periods of acidic conditions over the past few years.

Management of acidity in the estuary is a complex issue and there have been several detailed studies completed to understand the issues in the Anglesea River. These studies have shown that there is no certainty the issues can be successfully addressed, and all options will take time and require a sustained, long-term effort.

Corangamite CMA continues to work with partner agencies to monitor and review the current conditions in the estuary. Community members can find out more and stay informed by visiting this page.

Corangamite CMA trialled an artificial estuary opening on 20 August to determine if water quality conditions could be improved and provide an opportunity for fish to move out to sea.

This followed independent monitoring of water quality conditions and fish populations on 13 August which revealed fish refuge areas were very limited with poor quality water extensive throughout the estuary except for a very thin layer of oxygenated water near the surface. There were also very few invertebrates reported, posing an additional risk of fish not having a sufficient food source.

Corangamite CMA continues to conduct regular water quality testing and meet with agency partners including GORCAPA and Surf Coast Shire to understand the situation. This is an evolving and complex issue and we acknowledge there is uncertainty.

The Anglesea River Advisory Group, supported by Corangamite CMA, DEECA, Barwon Water and Surf Coast Shire, has been exploring options to improve the health of the Anglesea River since 2014.  These studies have shown that there is no certainty the issues can be successfully addressed, and all options would require a sustained, long-term effort and significant investment. Corangamite CMA will continue to update this web page . If you would like to discuss any of this information on the phone, by email or in person, please contact us at info@ccma.vic.gov.au.

If community members and anglers have any information about current populations of fish in the Anglesea River (species of fish that have been caught or observed recently, numbers etc) please let us know- you can email info@ccma.vic.gov.au

Surf Coast Shire is actively monitoring water levels in the estuary and flood risks.

The fish deaths have been reported to the EPA, who advise the public not to handle dead or dying fish.

The important information provided in this update reflects environmental conditions in the Anglesea River estuary and the potential impacts on aquatic ecosystems, particularly fish. It has been prepared from an environmental management perspective.

Independent monitoring of water quality conditions and fish populations conducted on Wednesday 13 August by Arthur Rylah Institute revealed fish refuge areas were very limited with poor quality water extensive throughout the estuary except for a very thin layer of oxygenated water near the surface. There were also very few invertebrates reported, posing an additional risk of fish not having a sufficient food source.

Given the likelihood that fish deaths would continue due to limited fish refuge areas and extensive poor water quality, there was an opportunity to trial an artificial estuary opening during low catchment inflow conditions on Wednesday 20 August.

The purpose was to understand if an estuary mouth opening could be successful and sustained long enough to allow sufficient tidal exchange of sea water into the estuary to improve conditions. The estuary would need multiple tidal cycles to improve water quality. An artificial opening also provides a possibility for some of the remaining fish to move out to sea, noting this may only be a relatively small number of fish.

Artificial estuary openings come with known risks to the environment including draining the oxygenated top layer of water in the estuary and leaving the lower layer of water that is less oxygenated, therefore reducing overall water quality.

As water quality throughout the estuary was already very poor and fish deaths were likely to continue even with the estuary mouth closed, Corangamite CMA decided to conduct an artificial estuary opening to determine if any benefits could be achieved by allowing tidal exchange to bring seawater into the estuary.

Under the low flow conditions at the time of the opening there was a very high risk that both a shallow or deep opening would close too quickly for any benefit to be realised. This is why we would usually not recommend or support an artificial estuary opening during low flow conditions.

Deep openings in particular carry additional risks, including the potential to change sand deposition patterns at the estuary entrance, and increased risk to cultural heritage due to the depth of the excavated channel.

In addition, a deep opening increases the risk that the estuary is left with very low water levels for an extended period and there is less knowledge and experience about conducting deep openings compared to shallow openings.

With the conditions deteriorating quickly agencies did not support a deep opening given the limited time to adequately consider and prepare for potential risks of a deep opening.

Water samples from ten locations were collected on 15, 22 and 29 August. These samples were analysed in a lab to measure acidity and the presence and concentration of heavy metals that are known to occur in the Anglesea River catchment that increase in concentration when there is an acid flush event (aluminium, arsenic, chromium, copper, iron, manganese, nickel, zinc, mercury and boron).

On Wednesday 20 August and Friday August 29, the Anglesea River EstuaryWatch group conducted water quality monitoring at five locations, measuring dissolved oxygen, salinity, temperature, turbidity and pH at depth.  They also took photos at photo-point sites located at the river mouth and recorded water level, tide, swell and weather conditions.

Corangamite CMA staff repeated the monitoring completed by the EstuaryWatch group on Friday 22 August, Wednesday 27 August and Friday 5 September .  Corangamite CMA and partner agencies will also be recording daily observations from the river mouth. The data collected by Corangamite CMA staff and the Anglesea EstuaryWatch group can be viewed at https://ew-data.waterwatch.org.au/estuary/ccma/45.

An independent researcher who specialises in the impact that poor water quality has on the ecology of waterways has been contracted to analyse all the data collected during the acid flush event.  This will help us to better understand the current condition of the estuary and if the artificial estuary opening has had an any impact on water quality.

Corangamite CMA is still planning to conduct a berm grooming trial when water levels and tide conditions are favourable (water levels in the estuary need to be low and tides high).

The Anglesea River Advisory Group, supported by Corangamite Catchment Management Authority, DEECA, Barwon Water and Surf Coast Shire, has been exploring options to improve the health of the Anglesea River since 2014.

These studies have shown that there is no certainty the issues can be successfully addressed, and all options would require a sustained, long-term effort and significant investment.

Read more by clicking the links below:

Anglesea River Management Options Investigation

Anglesea River Management Options
Investigation – Summary Report