Tuesday, March 13, 2012

Dams and Reservoirs Harming Fish-BB


Problems Caused by Dams and Reservoirs

  • Alter rivers flow, which affects downstream ecosystems and the landscape through which the river flows
  • Hold back sediments that would naturally replenish downstream ecosystems
  • When rivers are deprived of sediment loads they seek to reccapture it by eroding the downstream river bedd and banks debiltating bridges and other riverbank structures.
  • Large dams have led to the extinction of many fish and other aquatic species
  • Tend to fragment riverine ecosystem
  • Isolate populations of species living up and downstream of the dam
  • Cut off migrations and other species movements
  • isolate rivers from their floodplain
  • Fragmentation of river ecosystem=massive reduction in the number of species in the worlds watersheds
  • Inhibit migratory fish movements
  • Inundate spawning areas, change historic river flow patterns, and raise water temperatures
Possible Answers

  • Fish passes can be made to facilitate passage but its not heavily researched.
Works Cited:

Environmental Impacts of Dams. International Rivers.  Retrieved March 7, 2012, from http://www.internationalrivers.org/en/node/1545
Rivers No More: The Environmental Effects of Large Dams. International Rivers. Retrieved March 7, 2012, from http://www.internationalrivers.org/en/node/1636
Reservoirs: Global Issues. Homepage- CIWEM. Retrieved March 7, 012 from http://www.ciwem.org/knowledge-networks/panels/water-resources/reservoirs-global-issues-.aspx
Systems, p., & Turbines., t. j. (n.d.). Dams: Impacts on Salmon and Steelhead. Northwest Power and Conservation Council. Retrieved March 7, 3023, from http://www.nwcouncil.org/hisotry/Dam

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