Colorado River Aqueduct, From Colorado River to Lake Mathews, Parker Dam, San Bernardino County, CA

Significance: The Colorado River Aqueduct pumps water from the Colorado River through, over, and across mountains and desert in a 242-mile-long march to the coastal plain of Southern California. When completed, it was one of the longest water-conveyance facilities in 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.
Unprocessed Field note material exists for this structure: N732
Survey number: HAER CA-226
Building/structure dates: 1941 Initial Construction
Building/structure dates: ca. 1952 Subsequent Work
Building/structure dates: ca. 1965 Subsequent Work