Black Canyon of the Colorado the Nevada side of the canyon is the Sauna Cave. This cave was drilled by miners working on Hoover Dam while it was being constructed. It is a deep cave with calcium carbonate crystals on the walls. At the end of the cave is a hot spring, which causes temperatures in the cave to reach . One prominent canyon that splits from this canyon south of the Hoover Dam is Boy Scout Canyon. Boy Scout Canyon has water running through it that is warmed from a geothermal source. On the Arizona side of the river, there are several large hot
Course of the Colorado River into the Salton Sink flooding farmland and creating the Salton Sea, which still exists today as the largest inland body of water in California. The river was finally diverted back to its present course in 1907. Geological evidence suggests that this has happened naturally many times in the past, filling Lake Cahuilla, with the floodwaters slowly evaporating over spans of decades before being re-flooded by the Colorado. The Colorado River meets the Mexico–United States border at the Northern International Boundary (NIB), where the Morelos Dam diverts nearly the entire remaining flow into the Reforma Canal and the Tijuana Aqueduct. Most