Please be informed that a decision has been made by the Glenelg Hopkins CMA and Parks Victoria to attempt an artificial river mouth opening (ARMO) on the Glenelg River estuary at Nelson tomorrow, Friday 30th May 2025.

This decision has not been made lightly, as natural openings are our preferred management outcome.  In this instance however, the significant coastal storm event which hit our coastline earlier this week has significantly increased the height of the sand bar at the mouth to a record high level, and no longer allows for a natural opening at the current rate of freshwater inflow.

Significant future flooding impact and public safety risk subsequently exists.  Prolonged flooding at current or higher levels could also have a detrimental effect on estuarine wetland vegetation, particularly low-lying Coastal Saltmarsh.

Recent rainfall has been important, and water quality testing this week has found that sufficient and safe levels of dissolved oxygen are present in the estuary.  Favourable swell and tidal conditions are also predicted over the coming week.  Together, these factors indicate a current ARMO is safe, appropriate and effective.

The community is reminded that regardless of how an opening is undertaken, if dry conditions persist, there is a very high chance the estuary mouth will naturally re-close again.  Ocean swell, tides, and wind patterns will also play a critical role – all of which are outside of human control.

As always, the CMA will continue to monitor conditions closely and apply the established protocols for consideration of the need for artificial river mouth openings.  Further artificial openings this season may or may not be possible depending on how the season progresses.  Unfortunately, the lack of freshwater inflow to the estuary due to drought conditions increases the challenges in taking care of the natural values of the estuary, whilst minimising the negative impacts of flooding.   

The public are requested to stay well clear of the opening activities to ensure their safety.  If the opening can be completed successfully, water levels around jetties etc are expected to drop Friday night and into the weekend.  Boat owners are advised to take any action required around mooring of vessels to avoid damage with this water level drop. 

This decision is being made under our statutory obligations to balance the environmental, socio-economic and cultural values of the system.