Southern California relies on most of its water coming from a long way away. Here’s a look at several of the aqueducts that keep our taps flowing year-round.
California receives 75% of its rain and snow in the watersheds north of Sacramento. However, 80% of water demand comes from the southern two-thirds of the state.
About 25% of the water used in Southern California comes from the Colorado River. Another 30% originates in the northern Sierra. The remaining 45% comes from a mix of what are considered local supplies, which include Los Angeles’ Eastern Sierra deliveries as well as recycling, desalination and groundwater supplies.
An acre-foot of water (325,851 gallons) typically serves three Southern California households for a year.
The Los Angeles Aqueduct
It was designed and built by the city’s water department under the supervision of Chief Engineer William Mulholland.
It only took five years (1908-1913) to build the 233-mile project from the Owens River to Los Angeles.
When completed, the aqueduct was considered an engineering triumph second only to the Panama Canal.
Some 3,900 workers signed on to work in camps along the route for its duration.
Impressive features
In the desert 120 miles north of Los Angeles, the aqueduct’s engineers designed an 8,095-foot steel pressure siphon across Jawbone Canyon.
The siphon varies from 7.5 feet to 10 feet in diameter and drops the water 850 feet to the canyon floor.
The most difficult and time-consuming parts of the project were the tunnels. In the first 11 months of work, 22 miles of tunnel were dug. The Elizabeth Tunnel set a record for hard rock tunnel driving at 604 feet in a month. At the aqueduct’s dedication ceremonies at the cascades in Sylmar on Nov. 5, 1913, more than 30,000 people attended. The population of Los Angeles was about 400,000 in 1913.
The roar of the water crashing down the hill was so loud, Mulholland’s speech to present the aqueduct to the mayor was simply, “There it is, take it.”
Washed away
Mulholland’s time in the limelight ended with the failure of a dam he designed. The March 12-13, 1928, St. Francis Dam disaster killed more than 385 people. Mulholland had inspected it just before it broke. Close to midnight on March 12, a 140-foot wall of water took about 5½ hours to travel from above Saugus all the way to Ventura. Mulholland retired the next year and the Legislature passed laws to regulate civil engineering and created the state Board of Registration for Civil Engineers.
The Colorado River Aqueduct
The 242-mile system includes open aqueduct, siphons, five pumping plants, reservoirs and 16-foot-wide tunnels that vary in length from338 feet to 18.3 miles.
It was built from 1933-41 by about 30,000 workers.
The California Aqueduct, seen here in the Antelope Valley. Water from Northern California will be a large source for Southern California water departments and cities, once the Sierra Nevada snowpack starts to melt. (File photo by David Crane/SCNG)
The California Aqueduct
The aqueduct carries water from the Sacramento-San Joaquin Delta to the San Joaquin Valley and Southern California.
Established as part of a $1.75 billion bond (about $13.57 billion today) passed by voters in 1960, the 444-mile aqueduct begins at the Harvey O. Banks Pumping Plant and parallels the 5 Freeway. It is 50-110 feet wide and up to 32 feet deep.
When it reaches the Tehachapi Mountains, a huge amount of water is lifted some 2,000 feet at the A.D. EdmonstonPumping Plant – it’s more water pumped higher than anywhere else in the world.
Fourteen pumps drive the water over the mountains.
The aqueduct was constructed from 1963 to 1971 at a cost of $20 billion.
By comparison, the section of high speed rail from Bakersfield to Merced was estimated to cost $89 billion-$128 billion earlier this year.
Construction contracts were awarded in 2013, and the 119-mile track is projected to have trains running by 2028.
Recent news
A 2021 study published in Nature Sustain-ability estimated that the installation of solar panels over California’s canals and aqueducts could potentially reduce annual evaporation by 11 million to 22 million gallons per mile. The electricity produced could power pumping stations.
A team from UC Merced is studying the feasibility on the Delta-Mendota Canal. The solar project received $15 million in funding this year from the federal Inflation Reduction Act.
Sources: Los Angeles Department of Water and Power, waterandpower.org, Filmore Historical Museum, Water Education Foundation, National Geographic, California Department of Water Resources, Metropolitan Water District, UC Merced
