SA Health’s Principal Water Quality Adviser, Dr David Cunliffe, said blue green algae levels had significantly increased at the Barmera foreshore since Saturday, despite mitigation efforts including the use of aerators and pumps.

“Direct contact with the water may cause local irritation to the skin, eyes, ears, nose and mouth and accidentally swallowing algae-affected water can lead to illness,” Cunliffe said.

“Anyone who has been swimming at Lake Bonney should closely monitor for symptoms – especially in children and pets, these symptoms can include nausea, diarrhoea, vomiting and abdominal cramps.

“About one in 10 people may also develop a rash or skin irritation, which usually goes away after washing the affected area.

“If you have been in the water at Lake Bonney and you start feeling unwell, seek help. Consult with your GP and say you may have been exposed to blue green algae.

“We will continue to closely monitor algae levels at Lake Bonney and will advise the community regularly of updates including when it safe to swim and dive again at the jetty and foreshore.

“Pets are particularly vulnerable and should be kept out of the water because algae may stick to their fur, giving them a higher exposure.”

Fishermen are being warned to thoroughly clean and gut any fish caught in the lake before consumption.

“Algal blooms are naturally occurring, and appear during low rainfall, low water flows, and ongoing warm weather conditions,” he said.

“We expect that as Lake Bonney is reopened to the River Murray that algae levels will quickly reduce.”

SA Health’s latest testing results show other parts of Lake Bonney are not impacted by elevated algae levels and remain safe for water activities.

However, a statement from SA Health said algal blooms could move across the lake with changing weather conditions and swimming and diving should be avoided wherever there are areas of water with visible blue-green discolouration.

Water testing frequency has been increased and regular updates will be provided to the community.

Member for Chaffey Tim Whetstone told ABC Radio that the closure of Lake Bonney to the wider river system during recent flooding along the River Murray has contributed to the current algal bloom.

“Lake Bonney has missed out on a natural flow and it was done to mitigate flood and storm water damage in the town,” Whetstone said.

“It’s something that I’ve not been in favour of, but it was done for different reasons and I’m very hopeful that we’ll have that levee breached later this week and we’ll see water go into the lake before we see some of those river levels recede to a point where we’ll see water exit Lake Bonney.

“It has missed out on a natural flow.

“History will tell us that we have seen quite significant algal blooms come along after high flow events, particularly in 1956 and 1974 and if that is coming our way we need to be very much ready for it.”

It comes as the Department for Infrastructure and Transport announced the Tailem Bend Ferry will be temporarily closed between 10am-2pm on Thursday to move landing infrastructure for rising water levels.

An alternative river crossing is available upstream at the Swanport Bridge, however, this ferry also continues to be at risk of flood-related closure in the coming days due to the potential for the road access to the ferry to close as rising water levels reach the area.