Stream flow regulation
Management Activity
Rivers and other natural waterways are mainly regulated to provide water storage and flood mitigation. Stream flow regulation is typically in the form of weirs, dams (private and public) and barrages. Stream flow regulation may impact biodiversity and aquatic ecosystem function by decreasing flow volume, velocity and variation, which influence water quality, the type of aquatic habitat present and the transportation of food, nutrients, eggs and larvae. The impacts of stream flow regulation occur upstream, downstream and at the site of obstruction.
The direct upstream impacts of stream flow regulation may include:
- Pooling and stratification (layering) of water
- Reduced water sediment load
- Accumulation of water contaminants
- Barriers to fish passage
The direct site impacts of stream flow regulation may include:
- Alteration of a running-water environment to a still-water environment
- Submersion of important terrestrial habitats
The direct downstream impacts of stream flow regulation may include:
- Reduced stream flow
- Impacts associated with controlled dam release and sediment discharge
- Altered river channels
- Altered seasonal stream flows
- Altered water temperature (release of cold water from deeper layers in dams and weirs)
- Rapid rise and fall in water level leading to:
Last updated 7 September 2010
