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
Course of the Colorado River through the desert Lower Colorado River Valley (LCRV), where its character changes significantly from fast-flowing whitewater to a low gradient braided stream with a wide floodplain. Here, the Colorado River ranges in width from and from in depth. It becomes a losing stream, with a gradual reduction in volume both due to evaporation in the hot desert climate and massive diversions for irrigation, urban areas, industry and thermo-electric power generation. The average flow rate of at Davis Dam diminishes to just at the Mexican border. At Needles, California the Colorado is crossed by Interstate 40; shortly downstream it passes the