Little Colorado River - River Modifications

River Modifications

Because of its arid location and sparsely populated surroundings, most of the Little Colorado has not been affected much by human intervention. However, near its headwaters, the river is dammed twice, first in River Reservoir, then in Lyman Lake, where its water is diverted for irrigation. Another reservoir downstream of Springerville, where Mormon colonists dammed the river in 1905 to form Zion Reservoir, is now completely silted in. Many earthen and masonry dams were originally built along the river by the Mormons, but most of them no longer exist. At very few points in its course, is the river confined by levees, except for a 2,300-foot (700 m) floodwall near Holbrook. The river is also rarely crossed by bridges.

In one of the worst radioactive spills in the U.S. history, on July 16, 1979 100 million gallons of radioactive water containing uranium tailings breached into the North Fork of the Puerco River from a tailing pond of a uranium mine owned by Kerr-McGee Company and United Nuclear Corporation. Approximately 1,100 tons of uranium mine waste contaminated 250 acres (1.0 km2) of land and up to 50 miles (80 km) of the Puerco River, traveling into the Little Colorado River as far as the Navajo Indian Reservation. Traces of the spill can still be found today.