The San Diego Aqueduct, or San Diego Project, is a system of four aqueducts in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sover ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, supplying about 70 percent of the water supply for the city of

San Diego San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the List of United States cities by population, eigh ...

. The system comprises the First and Second San Diego Aqueducts, carrying water from the

Colorado River The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid drainage basin, watershed that encompasses parts of ...

west to reservoirs on the outskirts of San Diego. The First Aqueduct consists of the pipelines 1 and 2, which run from the

Colorado River Aqueduct The Colorado River Aqueduct, or CRA, is a water conveyance in Southern California in the United States, operated by the Metropolitan Water District of Southern California (MWD). The aqueduct impounds water from the Colorado River at Lake Hav ...

near San Jacinto, California, to the

San Vicente Reservoir San Vicente Reservoir is a reservoir created by the San Vicente Dam in San Diego County, California. It is located in the Cuyamaca Mountains, approximately north of Lakeside off California State Route 67. Description The reservoir is formed by ...

, approximately northeast of the city. Pipelines 3 and 4 make up the Second Aqueduct. Together, these four pipelines have a capacity of . The smaller, Fallbrook-Ocean Branch branches from the First Aqueduct into Murray Reservoir. The La Mesa-Sweetwater Branch originates from the First Aqueduct, flowing into the

Sweetwater Reservoir Sweetwater Reservoir is a artificial lake in San Diego County, California, formed by the Sweetwater Dam on the Sweetwater River. Construction of the dam was completed in 1888. Environment The area surrounding the reservoir is home to several s ...

Construction

The First Aqueduct was designed by the

Bureau of Reclamation The Bureau of Reclamation, and formerly the United States Reclamation Service, is a federal agency under the U.S. Department of the Interior, which oversees water resource management, specifically as it applies to the oversight and opera ...

and constructed from 1945 to 1947 by the Navy Department. Pipeline 2, of the First Aqueduct, was built by the Bureau of Reclamation from 1952 and 1957, roughly paralleling Pipeline 1. In 1957, the construction of Pipeline 3 of the Second Aqueduct was begun by the

Metropolitan Water District The Metropolitan Water District of Southern California is a regional wholesaler and the largest supplier of treated water in the United States. The name is usually shortened to "Met," "Metropolitan," or "MWD." It is a cooperative of fourteen cit ...

(MWD), completing it in May 1960. In 1968, the construction of Pipeline 4, of the Second Aqueduct, began. Pipeline 4 was completed in 1971. In 2005, the San Diego County Water Authority began construction on the , San Vicente Pipeline, connecting the San Vicente Reservoir to the Second Aqueduct. Construction on the project was completed in 2010.

First Aqueduct

The First Aqueduct, built of two parallel precast concrete pipes, ranging in diameter from , branches from the Colorado River Aqueduct in

San Jacinto, California San Jacinto ( ; ; Spanish for " St. Hyacinth") is a city in Riverside County, California. It is located at the north end of the San Jacinto Valley, with Hemet to its south and Beaumont, California, to its north. The mountains associated with ...

just north of the San Jacinto River, continuing south to its terminus at

. There are seven tunnels on the First Aqueduct, which range in length from . The total capacity of the First Aqueduct is .

Second Aqueduct

The Second Aqueduct is long, beginning at the Colorado River Aqueduct, flowing into

Lake Skinner Skinner Reservoir, also known as Lake Skinner, is a reservoir in western Riverside County, California, located at the foot of Bachelor Mountain in the Auld Valley, approximately northeast of Temecula. It was created in 1973 by the construction o ...

and then into

Lower Otay Reservoir Lower Otay Reservoir is a reservoir in San Diego County, Southern California. It is flanked by Otay Mountain to the southeast, the Jamul Mountains to the east, Otay Lakes Road and Upper Otay Reservoir to the north, and the city of Chula Vista to ...

near San Diego. In the first from the Colorado River Aqueduct to Lake Skinner, Pipeline 3 consists of an open canal handling approximately . The remaining consist of pre-stressed diameter concrete pipe and steel pipe. Pipeline 4 consists of pre-stressed concrete pipe with a capacity of .

References

External links

Metropolitan Water District of Southern California official website

''Aquafornia'' California Water News Blog
{{Colorado River system Aqueducts in California Transportation buildings and structures in Riverside County, California Transportation buildings and structures in San Diego County, California Colorado River