Why were the lower Snake River dams constructed? What services do they provide?
The four lower Snake River dams were primarily built for barge transportation and hydroelectric power production. These are “run-of-the-river” dams – providing very little flood control and no water storage for farms or cities. Currently, wheat, barley and other goods are barged downriver from Lewiston, ID and a small number other ports on the lower Snake River. Fewer goods, mostly fertilizer and fuel, travel upriver. Prior to 1975, when the last of the four lower Snake River dams was built, goods traveled by railroad 140 miles downstream to Pasco, WA for barge loading or were taken by rail or truck to coastal ports. The lower Snake River dams were also constructed with electricity-producing turbines. Together, the four Lower Snake River dams have a yearly output of just over 1,000 average megawatts, or about what a city of size of Seattle uses. In winter and late summer, when electricity is most needed and most valuable, these four dams are able to generate less than half that average
