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
The Exploration of the Colorado River and Its Canyons The Exploration of the Colorado River and Its Canyons The Exploration of the Colorado River and Its Canyons by John Wesley Powell is a classic of American exploration literature. It is about the Powell Geographic Expedition of 1869 which was the first trip down the Colorado River by boat, including the first trip through the Grand Canyon. Powell's first written accounts of his exploration appeared in the January, February and March 1875 editions of "Scribner’s Monthly" as "The Canons of the Colorado". The Smithsonian published it in book form in 1875 under title "Report of the Exploration of the Colorado