"...The Imperial Dam and Desilting Works are situated on the Colorado River 18 miles northeast of Yuma, Arizona. The purpose of the dam is to raise the water surface 25 feet and provide diversion of Colorado River water to the All-American Canal, the Coachella Canal, the Yuma Project and the Gila Gravity Canal. The desilting works remove most the sediment carried by the Colorado River. This sediment removal prevents clogging of the canals and subsequent, expensive, difficult maintenance...."
Dating back into the 1850's early settlers began trying to divert Colorado River water into the Imperial Valley.
The dam was constructed from 1935-1938 and it straddles the California-Arizona border.