History of California 1900–present conduit and siphons. Average annual throughput is . Davis Dam is located on the Colorado River about downstream from Hoover Dam. Davis Dam stretches across the border between Arizona and Nevada and impounds the Colorado River to form Lake Mohave. The United States Bureau of Reclamation owns and operates the dam, which was completed in 1951. Davis Dam is a zoned earth fill dam with a concrete spillway, in length at the crest, and high. The earth fill dam begins on the Nevada side, but it does not extend to the Arizona side. Instead, there is an inlet formed by
Geology of the Grand Canyon area the Rocky Mountains in early Miocene time terminated in landlocked basins in Utah, Arizona and Nevada but there is no evidence for a major river. Around 18 million years ago, tensional forces started to thin and drop the region to the west, creating the Basin and Range Province. Basins (grabens) dropped down and mountain ranges (horsts) rose up between old and new north–south–trending faults. However, for reasons poorly understood, the beds of the Colorado Plateaus remained mostly horizontal through both events even as they were uplifted about in two pulses. The extreme western part of the canyon ends at one