A much-loved Riverland lake has been closed off from the River Murray to protect community infrastructure and try and reduce the number of residents who may need to evacuate as South Australia grapples with ongoing flooding.
Lake Bonney in Barmera joins the Murray via Chambers Creek and through Nappers inlet, but it does not have an outlet.
It's a place with special meaning to many, including the local First Nations peoples, Barmera residents, community clubs, students and visitors who make the trek to the lake for a holiday.
Berri Barmera Council chief executive Dylan Strong said the decision to close the inlet was made by the SA State Emergency Service (SA SES) who are the lead agency in the ongoing River Murray flood event.
He said it was primarily done to protect community infrastructure on the shores of the lake and reduce the number of residents who would need to evacuate if wastewater services were cut off.
"The critical nature of the wastewater network is that it supports the Barmera, Cobdogla and Loveday townships so there's about 4,000 residents there connected to that network," he said.
Mr Strong explained inundation of the network could occur through groundwater seeping up from the lake or water potentially overtopping the road and inundating pumps and sumps located nearby.
"In that event ... it would effectively knock out the network," he said.
"There's no alternate route or bypass available which means people may not be able to remain in their homes because they would be effectively disconnected from any wastewater network."
SA SES chief of staff Derren Halleday said they consulted with a number of organisations before ordering a levee to be built at Lake Bonney, which has now been completed.
"[Lake Bonney] will be closed off until it's safe and the water levels drop on the river side of the levee [so we can] open it back up at normal levels," he said.
"As soon as the levee can be removed safely, we'll certainly make sure everything is done to remediate it and create normal flows back to that part of Murray and the lake itself."
Authorities had initially warned of a peak in Renmark about December 14, and another peak later in the month because of flows coming from the Victorian catchments and Hume releases, but this was today revised to suggest one higher peak would hit the region towards the end of December.
Lake closure could stop blackwater
Local fisherman Kym Manning was not overly concerned about the closure and said it could help with water quality issues as the flood event continued.
"It's closed for a short period, the salinity won't change much in that time. We've just had a massive flush of nice fresh water," he said.
"It's not what I would've liked to see, but at short notice, the council didn't have a lot of time to work on some of these projections with the flood predictions being [much lower] only a couple of months ago.
"It does block a bit of a fish passage but the fish that are in there will be fine."
Mr Manning said closing off the lake also reduced the risk of blackwater from entering it if it were to develop in the river.
"The lake will probably be one of the only freshwater bodies in the state that's going to be open for activity so I see that as a positive," he said.
"Barmera will hopefully be booming and you'll be able to put your boats in and go hell for leather as there's plenty of room out there."
