A RIVER Murray management board has advised blackwater events in South Australia are unavoidable due to ongoing high flows. 

The Murray-Darling Basin Authority (MDBA) recently warned high river flows and flooding events would result in “an increased risk of water quality issues like low-oxygen blackwater” throughout the Murray-Darling system. 

MDBA senior director of environmental management Dr Janet Pritchard said “given the scale of natural flooding, prevention is not possible and mitigation options are very limited”. 

“Hypoxic blackwater events occur as leaf litter and other carbon-based debris is swept into waterways,” Janet said.  

“As this material is consumed and broken down by bacteria, oxygen can be sucked out of the water, making it difficult for fish and other aquatic animals to survive. 

“There are already isolated reports of crayfish exiting floodwaters to escape poor water quality.

“With the onset of warmer weather… water temperatures will start to climb and the possibility of hypoxic blackwater will increase and unfortunately we could see fish deaths.” 

Janet said “high flows and widespread flooding will also add nutrients to waterways, which will favour the growth of blue-green algae with warmer conditions”. 

Further information regarding blackwater events can be found by visiting the MDBA website.

Rain Levels

Renmark 
August to October 27, 2022: 278mm 
Rainfall to November 2021: 110.8mm
Rainfall to November average: 191.7mm

Loxton
August to October 27, 2022: 237.2mm
Rainfall to November 2021: 142.6mm
Rainfall to November average: 218mm

Waikerie 
August to October 27, 2022: 186.4mm
Rainfall to November 2021: 145.3mm
Rainfall to November average: 199.2mm 

Lameroo
August to October 27, 2022: 220.4mm
Rainfall to November 2021: 196.6mm
Rainfall to November average: 257.9mm

Gawler
August to October 27, 2022: 200.6mm
Rainfall to November 2021: 321.8mm 
Rainfall to November average: 335.9mm