Hydropower on the Colorado River

The Colorado River falls 14,000 feet from the Rocky Mountains to sea level in the Gulf of California and carries more silt than any other river in the world, including the “muddy” Mississippi.  The original time estimate for Lake Powell, the reservoir in back of Glen Canyon Dam, to fill up with silt was 400 years, but this was subsequently revised to 1,000 years by later estimates of the silt-capturing capacity of other dams upstream of where the Colorado River enters Lake Powell. 

The primary advantages of the Colorado River from the point of view of dam building are that the river flows through a canyon whose geology is ideal for damming and through a region desperate for water.  The disadvantage of the Colorado is its relatively low average water flow, which varies from a summer trickle to a springtide flood that carries away the snowmelt of a large area of the Rocky Mountains.

Source: ("Energy for the 21st Century," Nersesian)