There are more than 9,800 regulated dams in the Mountain States and 69 percent are in Colorado and Montana. This does not include a large number of dams that are not regulated under dam safety codes, in particular the large number of water withdrawal structures. Dams and irrigation diversion structures provide power and flood control along the rivers of the mountain states, as well as supply water to the farms, ranches, and cities in these states. The reduced flows from water diversions result in less water in the streams for fish, and these altered flows change river habitat by changing sediment and woody debris recruitment and transport, a key factors that control fish habitat that could only be partly examined using existing datasets [...]
