http://en.wikipedia.org/wiki/Hydroelectricity

http://en.wikipedia.org/wiki/Hydroelectric_dams_on_the_Columbia_River

http://www.answers.com/topic/hydroelectricity

http://www.enviroliteracy.org/article.php/59.html

http://waterpower.hypermart.net/hdams.html

http://www.lcra.org/energy/power/renewable_energy/hydroelectric.html

http://www.tva.gov/power/hydro.htm

http://ga.water.usgs.gov/edu/hyhowworks.html

http://wiki.idebate.org/index.php/Debate:Hydroelectric_dams

http://www.mbgnet.net/fresh/rivers/dams.htm