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
Glen Canyon Dam from Lee's Ferry. Because of the cold, clear water released from Lake Powell, the stretch of the Colorado River between Glen Canyon Dam and Lee's Ferry has become an excellent rainbow trout fishery. Trout are not native to the Colorado River system; they were stocked in the river below Glen Canyon Dam after the dam was built. Other non-native fish such as smallmouth bass, striped bass, largemouth bass and black crappie were planted in Lake Powell to provide sport fishing opportunities. Like many U.S. lakes and reservoirs, Lake Powell has an active problem with zebra and quagga mussels, invasive bivalve