Dictionary of Ichthyology  

dam = a barrier controlling the flow of water and backing up water. Forms a lacustrine habitat (the reservoir) for fish where one did not exist before.
Initially fish production is very high when stocked but declines as nutrients from flooded terrestrial ecosystems are used up. Release of water from
reservoirs may radically affect fish downstream by changes in temperature regimes, flushing of habitats, and changes in silt loads. Storage dams store water and diversion dams divert water.  

Symbol after the Federal Energy Regulatory Commission, Washington, D.C. (www.ferc.gov).

Canadian Museum of Nature www.briancoad.com