A short list of the detrimental effects of dams:
What difference does a dam make? By measuring the bug populations in the water before and after the removal of a dam on the Conestoga River in Lancaster County, Heather Calaman found that the dam was suppressing diversity. Before the dam was removed, she found 554 critters from 16 families. Afterward she found 3,783 from 30 families. Calaman believes the increase was due to the high amount of oxygen available in the faster flowing water.
-Elizabeth Monk (Research/Penn State September 2002, p 20)
Kyoto accord signals death knell for dinosaur era fish in Canada
Canada's effort to meet the Kyoto Treaty obligation is sparking an effort to build more than 100 new hydro-electric dams in central and western parts of the country.
Save Our Wild Salmon Coalition (Pacific Northwest US)
Glen Canyon Dam (Utah)
Dam Decomissioning in British Columbia, Canada
Opposition to Manitoba Hydro (Manitoba, Canada)