General News
17 May, 2023
River mouth opening a success
IN welcome news for Peterborough residents an artificial opening of the Curdies River estuary was completed earlier this month.
IN welcome news for Peterborough residents an artificial opening of the Curdies River estuary was completed earlier this month.
Corangamite Catchment Management Authority (CMA) estuaries and environmental water manager Jayden Woolley said Parks Victoria completed the artificial opening.
“When the river mouth is closed (which is a natural occurrence for the Curdies River estuary), water levels in the estuary slowly rise,” he said.
“The decision to artificially open the estuary was made to minimise the threat of inundation to human assets (e.g. jetties, boardwalks, roads, private property) and productive use of surrounding land.
“There are risks associated with artificially opening the Curdies estuary. This can include fish strandings, and on occasion fish deaths resulting from a decline in dissolved oxygen levels.”
Mr Woolley said artificial estuary openings were timed to minimise these risks.
In this situation we are not aware of any impacts to fish populations, and recent rainfall is expected to reduce the overall risk,” he said.
“There are no benefits to marine life by artificially opening the estuary, and while there are amenity benefits to the local community by the flushing away of decomposing cyanobacteria material (commonly referred to as Blue-green algae) it is unlikely to result in improved water quality conditions or to reduce the ongoing impacts from cyanobacteria blooms.”
“It is very difficult to predict how long the estuary will remain open.”
Mr Wooley said the conditions which influence whether an artificial opening is successful or immediately returns to its previous closed state include:
• Flows from the catchment;
• Wave height;
• Wave and wind direction (so the sand is not deposited directly back into the estuary mouth); and
• Estuary water level.