2011 – April/May – Woodglen Storage Reservoir (Victoria) – Cyanobacteria Bloom

2011 – April/May – Woodglen Storage Reservoir
High algal numbers were detected in Woodglen (raw water) storage reservoir No. 1 between
13/04/2011 and 17/05/2011, with cyanobacterial biovolumes peaking at 0.58 mm3/L on
27/04/2011. Although algal identification analysis classified this bloom as nonBtoxigenic, with
low potential to impact water quality, East Gippsland Water’s Algal Management Plan (as
documented in the Drinking Water Quality Risk Management Plan) initiated the following action:
•Increased algal monitoring and surveillance of raw water (noteB due to the absence of any toxigenic algal species, no algal toxin monitoring could be performed);
•Increased algal sampling of treated (clear) water storage tank;
•Temporary switch to alternate raw water source. Monitoring of the clear water tank clearly demonstrated that the Woodglen water treatment plant (dissolved air flotation and filtration syste m) was capable of eliminating algae from the raw water prior to distribution to customer supply, prior to the switch to an alternate raw watersupply. Accordingly, there was no impact on the treated water supply during this incident.