2016 Feb/March – Murray River Blue Green Algae
GWMWater did experience a Blue-Green Algae (BGA) event at the Murray River which lasted for approximately 17 weeks. Six water agencies across Victoria were involved. GWMWater was made aware of upstream non-toxigenic BGA bloom on 23 February 2016 when NSW DPI released a red alert for the Cobram Barmah Section of the Murray River.
GWMWater commenced BGA sampling at river offtakes on 29 February 2016. DELWP Secretary declared a Class 2 Emergency on 11 March 2016 along the Murray River and Loddon River.
The bloom behaviour was unpredictable. Chrysosporum ovalisporum was the dominant species during the bloom and is potentially toxic.
Pumps were switched off when the concentration of BGA was above the trigger threshold.
Customers in the affected area were notified. Water carting was undertaken to domestic customers as required. GW MWater conducted daily water quality testing, managed storages and offtakes, and made modifications to the water supply systems to allow alternate pumping options and cross- connection to other supply sources to supply customers with fit-for purpose water at a total cost of approximately $1.5M. As BGA concentrations were found at a high concentration, a risk assessment was done to evaluate when BGA Water is acceptable for crop spraying….