Course of the Colorado River into the Virgin River, which ran southward through what is now Overton Arm to join the Colorado River near the now-ghost town of St. Thomas, Nevada. At Hoover Dam, the Colorado turns due south through Black Canyon, a direction it will follow for the remainder of its course to the Gulf of California. It passes under the Mike O'Callaghan–Pat Tillman Memorial Bridge (Hoover Dam Bypass), the highest concrete arch bridge in the world, carrying U.S. Route 93 at a height of above the Colorado River. At the end of Black Canyon the Colorado widens into Lake Mohave, created by the
Boise River Diversion Dam Boise River Diversion Dam The Boise River Diversion Dam is a diversion dam on the Boise River in the U.S. state of Idaho, southeast and upstream of Boise in Ada County. Completed in 1909, it is operated by the U.S. Bureau of Reclamation. The diverted water fills the concrete New York Canal, the primary irrigation channel for Ada and Canyon counties. In March 1906, the Utah Fire Proofing Company began work on the Boise River Diversion Dam with the provision that the structure would be completed within one year. It soon became apparent that the dam would not be finished