Blue-green algae (cyanobacteria) are a natural part of Australia's river systems. When in balance they are not a problem, but increased nutrients and low flows have contributed to severe algal bloom outbreaks in many of our river systems and water storage areas. The conditions that favour algal blooms are now well understood. Algal growth depends on the availability and supply of the nutrients nitrogen (N) and phosphorus (P), light and warm water temperatures. These conditions result in blooms of blue-green algae often coinciding with long periods of warm, sunny weather, high nutrient levels and still water.
Recent research suggests that another factor that affects bloom formation is the management of flows in both rivers and water storage areas. Rivers rarely experience algal bloom outbreaks during periods of high flow. This means that new approaches to manipulating the flow of rivers and water reservoirs may hold the key to preventing algal blooms, saving millions of dollars in water treatment costs and environmental damage caused by algal bloom outbreaks.
The full fact sheet is available in Adobe Acrobat format:
Fact Sheet 10 - River flows and blue-green algae (facts10.pdf, 369Kb)
Topics covered
- Algae and river flow
- Why do low flows favour blue-green algae?
- Why does high flow favour other algal species?
- Algal growth and flow management
- Flow management in reservoirs
- Recommended management practices
- For further information
This Fact Sheet is the tenth in a series dealing with the management of riparian land.
