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
Steamboats of the Colorado River west side of the river sixty five miles above Fort Mohave near what was then considered the high water limit of navigation. George A. Johnson came up river and made a deal to supply the mines with his steamboats at $100 a ton, a lower price than the $240 a ton charged for overland freight across the Mojave Desert from Los Angeles. That fall news of the strikes brought a flood of miners to the canyon. Several camps were founded in the canyon. San Juan, or Upper Camp were at the top of the canyon, near modern Nelson, Nevada. Midway