History of the Grand Canyon area stretched along a 278-mile (447 km) segment of the Colorado River from the southern border of Glen Canyon National Recreation Area to the eastern boundary of Lake Mead National Recreation Area. Grand Canyon National Park was designated a World Heritage Site on October 24, 1979. In 1935, Hoover Dam started to impound Lake Mead south of the canyon. Conservationists lost a battle to save upstream Glen Canyon from becoming a reservoir. The Glen Canyon Dam was completed in 1966 to control flooding and to provide water and hydroelectric power. Seasonal variations of high flow and flooding in the spring and
Black Canyon Diversion Dam by the Bureau. The riverine reservoir it creates, the Black Canyon Reservoir, has a normal water surface of 1.7 square miles, about twelve miles of shoreline, and an original maximum capacity of 44,700 acre-feet, reduced by siltation to about 31,200 acre-feet. Recreation includes boating and fishing. The installation of a third hydropower generating unit has been funded by Bonneville Power Administration for completion in 2013. Black Canyon Diversion Dam Black Canyon Diversion Dam (National ID # ID00282) is a dam in Gem County, Idaho. The concrete dam was originally completed in 1924, then re-constructed between 1951 and 1955, by the