The Powlett River/Kugerungmome estuary on Bunurong Country near Kilcunda is a significant and ever-changing wetland that provides essential habitat for wildlife. In late August 2024, the river mouth closed to Bass Strait naturally and West Gippsland Catchment Management Authority (CMA) is monitoring the event. 

The closure is a result of sustained large swells over the past weeks which deposited sand into the estuary entrance.  Large ocean swells and low river flows allow the ocean to develop a sandbar at the mouth of an estuary eventually closing its connection to the ocean. 

 “Estuary closures provide critical habitat for many threatened species,” said West Gippsland CMA CEO, Martin Fuller. 

“The Powlett River Estuary is one of many estuaries across the state that has recently closed its connection to the ocean”. 

“Over the coming weeks, if the river mouth remains closed, we can expect to see water continue to nourish the wetlands,” explained Mr Fuller. 

“This helps maintain the health of the wetland that surrounds the estuary”.

“The wetland provides important habitat and an abundance of food for many species of fish, birds and invertebrates that seek food and shelter, some of which are endangered.” 

Mr Fuller explained that it is very important to support this natural process, otherwise the integrity of the surrounding wetland and the species it supports maybe jeopardised. 

“There is a flow on effect when the river mouth closes,” continued Mr Fuller.  

“Algae begins to grow which provides food for insects and fish. The calm waters then turn into a fish nursery and with the increase in fish and insects – birds flock to the wetlands to feed”. 

“The environmental benefits of the estuary mouth closing cannot be overstated and if the mouth does open naturally, particularly as a result of increased water level height and freshwater river flows, it will trigger fish migration upstream and out to sea,” explained Mr Fuller. 

West Gippsland CMA will monitor conditions and if required, the river mouth may need to be artificially opened. Decisions to open the estuary mouth are informed by the Estuary Entrance Management Support System (EEMSS) and additional data and information connected through onsite monitoring and stakeholder consultation.

“If it is decided that an artificial opening is required, it will only take place if it is deemed safe and sustainable. This requires a number of things to line up,” Mr Fuller explained. 

In an effort to look for a long-term solution to address this issue, and alleviate the need for artificial estuary openings, West Gippsland CMA continues to work with landholders and other agency staff to explore options for the management of this land moving forward.