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
Mohale Dam a rock-fill concrete-face on the upstream side. The volumetric content of the dam structure is 7.5 million m³. The dam has a length of with a wide crest. The spillway, located on the left bank of the dam, is not gated and flood is routed over the crest of the ogee shaped spillway through a concrete lined chute with a flip bucket and a stilling basin at its terminus. The concrete spillway is designed for a flood discharge of per second. The total quantity of concrete contained in the dam is . During the construction phase of the dam, river