Nonetheless, Hoover Dam, aka Boulder Dam, on the Colorado River is a good starting point for positive features of dams. The creation of recreational reservoirs, like Lake Mead, is viewed as positive. Downstream flood control of agricultural areas has also been given as a reason for building dams, as with the development of the Imperial Valley below Hoover Dam. However, not every citizen views even Hoover Dam as in the best interest of the natural environment. Some dam critics question whether the benefits, not only of building dams but also of keeping all the ones we have, warrant the environmental costs.
Many ecologists feel that dams on big rivers have put numerous animal species in peril.
In the spirit of challenging an ecoparadigm, consider the recreational opportunities created by dams. Some people, including hunters, hikers, and bird-watchers, would get far more recreation from 50,000 acres of woodlands and small wetlands than from the same amount of boring open water. I do not suggest the elimination of all artificial lakes and reservoirs, only that we consider what would serve us best. One line of political illogic that does little to support dam building is that not building a dam can cost jobs. The argument was used at Tellico Dam where construction was delayed by the presence of the snail darter, a little fish thought to be endangered.