Another algal bloom is unlikely: CSIRO

Another algal bloom is unlikely: CSIRO

Swimmers and water sport lovers rejoice: the likelihood of another blue-green algal bloom along the Murray River is unlikely this summer.

Wodonga-based CSIRO scientist Darren Baldwin said given Lake Hume was almost full, the chance of another bloom was negligible. 

During summer, cool water at the bottom of the dam mixes with warm water near the surface. 

But if the dam is low, storms or big inflows can cause the nutrient-rich cold water to rise up to the top, which blue-green algae thrives on. 

Fortunately for holidaymakers and retailers, the dam is now at 99.5 per cent capacity, and cold water will remain at the bottom of the lake, according to Dr Baldwin.

“The last periods where we’ve had Lake Hume at 100 per cent to 70 per cent, we haven’t had blue-green algal blooms,” he said.

However, Mr Baldwin stressed climate change brought with it a level of unpredictability.

He said blooms could still occur in billabongs and remaining floodwaters downstream of the wall.

“We’re seeing parts of the floodplain between Wodonga and Yarrawonga that hasn’t really been flooded since 1996,” Dr Baldwin said. 

“There is a potential you could get algal blooms in them, but they’ll be isolated, so it’d just be something to keep an eye out with respect to stock and the like.”

At its peak, this year’s blue-green algal bloom, which began in February, stretched for more than 1600 kilometres from Lake Hume to downstream of Wentworth. 

Widespread rainfall and cooler weather in May saw a red alert between the weir and Yarrawonga lifted.

But tourist operators along the Murray suffered a slump in late-summer trading during the outbreak.