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
Tsukabaru Dam area drained at the dam site is and is highly forested to the extent of 95%, whereas the agricultural area is only 1%. The river catchment lies in a temperate climatic zone. There is cascade of six dams built on the river with two dams in the upstream basin of the Tsukabaru Dam and three dams (Yamasubaru Dam, Saigo Dam, and Ouchibaro Dam) downstream of it. The uppermost dam is the Kamishiba Dam, the first arch dam in Japan which is the largest on the river followed by the Iwayado Dam. Tsukabaru Dam, a concrete masonry gravity dam is in