Colorado River Aqueduct, Historic American Engineering Record

The Colorado River Aqueduct pumps water from the Colorado River through, over, and across mountains and desert in a 242- mile-longmarchtothecoastalplainofSouthernCalifornia. When completed,itwasoneofthelongestwater-conveyancefacilitiesin the world. The aqueduct includes power lines, tunnels, siphons, covered conduits, open canals, dams, reservoirs, and five pumping plants, involving ingenious engineering solutions and newly- introduced construction equipment. The project also employed over 35,000 people during its eight-year span and as many as 10,000 at one time, making it southern California’s single-largest work opportunity during the Great Depression. In 1995, the Colorado River Aqueduct was named a National Historic Civil Engineering Landmark by the American Society of Civil Engineers. Today, it is the major water supply for urban and suburban southern California.