The Colorado River Aqueduct

Historical Background

The Colorado River Aqueduct begins at the Parker Dam southeast of Lake Havasu City, Arizona, and terminates at Lake Mathews in western Riverside County, Calif. It was constructed between 1933-1941 by the Metropolitan Water District of Southern California. Conceived by William Mulholland and designed by Frank E. Weymouth, it was the largest public works project in southern California during the Great Depression. The project employed 30,000 people over an eight-year period and as many as 10,000 at one time.*


(1931) - Three leaders in community planning that brought Colorado River water to Southern California. On a desert survey trip at the start of the huge aqueduct project in 1931 were (left to right) F. E. Weymouth, who built the aqueduct; William Mulholland, who conceived it; and W. P. Whitsett, first chairman of the Metropolitan Water District of Southern California. Photo courtesy of the Metropolitan Water District of Southern California.  


The Colorado River: A Regional Solution**

William Mulholland turned east to the Colorado River as a new source of water. He began a four-year series of surveys in 1923 to find an alignment that would bring the water of the Colorado River to Los Angeles.
In 1925 the Department of Water and Power (DWP) was established and the voters of Los Angeles approved a $2 million bond issue to perform the engineering for the Colorado River Aqueduct. The DWP brought the cities of the region together with Description: Los Angeles in 1928 to form a state special district. An act of the State Legislature created the Metropolitan Water District of Southern California (MWD). Its original purpose was to construct the Colorado River Aqueduct to supply supplemental water to Southern California. In 1931, voters approved a $220 million bond issue for construction, and work began on the ten-year project that would bring the water 300 miles to the coast.

Part of the success of the project was the spectacular Boulder Canyon project, now known as Hoover Dam. The DWP, manager of its own hydroelectric power facilities along the Los Angeles Aqueduct, was instrumental in the struggle to gain federal approval for the project which combined flood control, water supply, and energy production for the three states that form the lower Colorado River basin.

Los Angeles, as primary consumer of the power, guaranteed its power purchases against the federal government’s costs for the dam. Completed in 1935, the dam began furnishing power to the city the following year over a 226-mile transmission line built by the DWP.

Upon the completion of the Colorado River Aqueduct in 1941, MWD began to wholesale Colorado River water to its member agencies. Today those agencies include 14 cities, 12 municipal water districts, and a county water authority. More than 130 municipalities and many unincorporated areas are served by this project of the DWP’s and Mulholland’s vision.

Before his death on July 22, 1935, Mulholland lived to see the beginnings of the Colorado River Aqueduct and Hoover Dam, constructed in the spirit of greatness he had always envisioned for Los Angeles.




(1931)*# – Map showing routing of the Colorado River Aqueduct.  


Historical Notes

The MWD considered eight routes for the aqueduct. In 1931, the MWD board of directors chose the Parker route which would require the building of the Parker Dam. The Parker route was chosen because it was seen as the safest and most economical.  A $220 million bond was approved on September 29, 1931. Work began in January 1933 near Thousand Palms, and in 1934 the United States Bureau of Reclamation began work on the Parker Dam. Construction of the aqueduct was finished in 1935. Water first flowed in the aqueduct on January 7, 1939.

The Colorado River Aqueduct (CRA) begins near Parker Dam on the Colorado River. There, the water is pumped up the Whipple Mountains where the water emerges and begins flowing through 60 mi f siphons and open canals on the southern Mojave Desert. At Iron Mountain, the water is again lifted, 144 ft. The aqueduct then turns southwest towards the Eagle Mountains. There the water is lifted two more times, first by 438 ft to an elevation of more than 1,400 ft, then by 441 ft to an elevation of 1,800 ft above sea level. The CRA then runs through the deserts of the Coachella Valley and through the San Gorgonio Pass. Near Cabazon, the aqueduct begins to run underground until it enters the San Jacinto Tunnel at the base of the San Jacinto Mountains. On the other side of the mountains the aqueduct continues to run underground until it reaches the terminus at Lake Mathews. From there, 156 mi of distribution lines, along with eight more tunnels, delivers water to member cities. Some of the water is siphoned off in San Jacinto via the San Diego canal, part of the San Diego Aqueduct that delivers water to San Diego County.*^





(ca. 1933)* - Empty reservoir on the Colorado Aqueduct. An aerial view of an empty Colorado River Aqueduct reservoir under construction in the 1930s.





(ca. 1938)* - Colorado Aqueduct construction - The Colorado River Aqueduct, built 1935-1941 by the Metropolitan Water District (MWD).




(1930s)* - Colorado River Aqueduct Engineering Team  




(June, 1941)* - Ellis Davey (MWD) and B. W. Weaver (DWP) turn 30" valve that lets the first Colorado River water into the city system - Ascot Reservoir.  




(1977)* - Caption Reads: "The MWD Colorado River Aqueduct is brimful now that it is operating at 20 per cent above design capacity". Photograph dated: June 23, 1977.




(1977)* - Photograph caption reads: "Like huge arms, giant pipes carry Colorado River water to Southern California from the Gene Pumping Plant on the Colorado River Aqueduct. The plant, second of five on the system, is located 3 miles east of the Colorado River". The Gene Pumping Plant is just south of Parker Dam and lifts the water 303 feet.  


Historical Notes

In 1955, the Colorado River Aqueduct was recognized by the American Society of Civil Engineers (ASCE) as one of the "Seven Engineering Wonders of American Engineering".





Construction of the Colorado Aqueduct

Click HERE for a short video.^



Click HERE to read 'Mulholland and the Colorado River Aqueduct' from LADWP's Historic Archive.


* * * * *




History of Water and Electricity in Los Angeles




More Historical Early Views



Newest Additions



Early LA Buildings and City Views


* * * * *




References and Credits

* DWP - LA Public Library Image Archive

**LADWP: History of the Colorado River Aqueduct

*#Claremont Colleges Digital Library

^ YouTube - Construction of the Colorado Aqueduct to Southern California



< Back