Risks to the Glen Canyon Dam that the resulting flood would scour the bottom few hundred feet of the Grand Canyon, overtop Hoover Dam, and cause severe damage all along the lower Colorado River. In the event of a complete dam failure with Lake Powell at high pool, about of water would surge out of Lake Powell at an initial depth of over . Downstream communities and perhaps every dam along the river, excluding possibly Hoover Dam, as well as riverside lowlands, would be inundated or severely damaged. Located downstream from Glen Canyon Dam are Hoover Dam forming Lake Mead, Davis Dam forming Lake Mohave, Parker
Risks to the Glen Canyon Dam Risks to the Glen Canyon Dam Glen Canyon Dam, a concrete arch dam on the Colorado River in the American state of Arizona, has been associated with a large amount of risk, most notably the risk of its siltation and failure. Because of high silt content carried in by the Colorado and San Juan rivers, Lake Powell is gradually filling with sediment, decreasing its capacity; eventually the sediment will build up against the dam and affect its safe operation. The dam, anchored in unstable Navajo sandstone (sometimes said to be "solidified sand dunes"), nearly failed in 1983 as the result