Hydroelectric energy, a renewable energy, makes up 7% of total energy production in the United State as of 2012 according to eia.gov. Hydro power has had a long history in the US, with the first Edison hydroelectric power station (the Vulcan Street Plant) built in 1882 in Appleton, WI.
Hydroelectric power has had a long history in this country and around the world. Along with coal, hydro energy helped to fuel the industrial revolution in the United States. While hydro power is widely seen as a benign and long-term source of renewable energy, most scientists agree that there are severe repercussions to installing and using hydro power.
(CC Image (right) of Three Gorges Dam in China, the world's largest dam. By Le Grand Portage [CC-BY-2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons) (Click to enlarge)
Hydroelectric power can, and often does, destroy ecosystems, flood plains, wildlife, and their habitat. By damming a river, the ecosystem in that watershed is forced to rapidly adapt, or die. In many instances, the wildlife is unable to adapt. For instance, salmon (and other migratory fish) that migrate up stream to find suitable spawning areas are unable to access those areas, often times due to the existence or style of the dam. Furthermore, the churning of water, and restricted flow alters the aquatic habitat in ways that can increase/decrease the turbidity of the water. Such action can also have a deleterious effect on the habitat and wildlife in the watershed.
While examining hydroelectric power through the sustainability lens, it is important to remain critical and skeptical of all purported renewable or safer energy sources. Hydro power, along with all other forms of energy production have inherent pluses, minus, and flaws. Fossil fuels are having by far the greatest negative effect on our health and planetary boundaries. However, renewable energies have their own problems that must be acknowledged as well.
(Image of dam in Appleton, WI)