The 70 metre by 10 metre collapse signalled the start of what many environmental experts had predicted and many local residents feared.

The event, which happened without warning, prompted the Department of Water, Land and Biodiversity Conservation (DWLBC) to close a further five areas between Lock One and Wellington deemed at high risk of collapse.

Long Island Marina manager and part-owner Bob Hall said the collapsed area had been roped off and there was signage, but little else had been done.

“(The Government) needs to acknowledge the fact we need a certain level of water (in the river) to protect the banks,” Mr Hall said.

“Nothing has happened...the issues are still there.”

DWLBC River Murray bank collapse hazard project leader Richard Brown said the department was working with the Long Island Marina operators in regard to the collapsed area.

“It is privately owned land which has been cordoned off with signage,” he said.

“Work has been done in the channel (adjacent to the collapsed bank) to remove trees that pose a hazard.

“We will continue to monitor all high risk sites.”

Mr Brown said the region was currently in a high risk period.

“Low water levels are currently being experienced,” he said.

“There has been no sustained rise in the water level below Lock One this year.

“The increased flows have not shown an appreciable rise and irrigator usage is relatively high given the weather conditions.”

Mr Brown said DWLBC used mitigation and prevention measures when a site was at risk.

“Prevention work (seen on sites such as the old Murray bridge and Swanport bridge) has been done on areas which cannot tolerate collapse activity and that would come at a high consequence,” Mr Brown said.