Blue-green Algae - December 2009
Cyanobacteria (blue-green algae) are a common seasonal occurrence in Victoria and a natural component of most aquatic systems, including streams, lakes, estuaries and the sea. Many factors trigger blue-green algae blooms including nutrient loads, low inflows, low storage volumes and higher than normal temperatures.
Blue-green algae blooms are monitored regularly by water corporations and local waterway managers. When sampling and testing have confirmed the existence of blue-green algae, appropriate action is taken based on the use of the water body and the density and nature of the bloom.
The table below is a summary report of significant blooms that have occurred across the state in December. The trend is taken from the last sample report sent to Department of Sustainability and Environment during the month and the action is a summary of what has occurred. For more up to date information on a bloom, refer to the relevant Water Corporation's website.
| Drainage Basin | Location | Use | Trend | Action |
|---|---|---|---|---|
| Corangamite | Lake Bullen Merri | Recreation | ↔ | Warning signs erected. Media release issued. Regular Monitoring. |
| Corangamite | Lake Cobden | Recreation | ↑ | Warning signs erected. Media release issued. |
| Glenelg | Lake Hamilton | Recreation | ↑ | Warning signs erected. Regular Monitoring. |
| Loddon | Gum Lagoon | Irrigation, Domestic & Stock | ↑ | Customers notified and warning signs erected. |
| Ovens | Diddah Diddah Reservoir | Drinking | ↔ | Carting water to Springhurst. |
| Otway Coast | Simpson Historical Park Waterbody | Recreation | ↑ | Warning Signs erected. |
| South Gippsland | Lance Creek Reservoir | Drinking | ↑ | Regular monitoring and water treatment. |
| Werribee | Pykes Creek Reservoir | Domestic & Stock, Drinking, Irrigation, Recreation | ↑ | Stakeholders notified. Routine monitoring. |
↔ = no change
↓ = blue-green algal cell counts and/or biovolumes decreasing
↑ = blue-green algal cell counts and/or biovolumes increasing