Los Angeles Aqueduct : Bringing water to a parched region

For thirsty Angelenos, water is never further away than the tap, hose or shower. During droughts we conserve, but most of the time we tend to take our water for granted. Where it comes from and how it gets here is somewhat of a mystery. Through the movie Chinatown we have become familiar with the 80-year water wars between Los Angeles and the Owens Valley.

As hard as it is to imagine, before the Los Angeles-Owens Valley Aqueduct was built, Angelenos got their water from the Los Angeles River. Ditchtenders, or zanjeros, carried water from the river to water wheels which lifted the water for gravity flow into homes and fields. Future water engineer William Mulholland got his start as a zanjero.

Many doubted the plan to bring Sierra Nevada mountain snowmelt hundreds of miles through the mountains and desert to Los Angeles. But Mulholland knew that since the Owens River sat at an elevation of 4,000 feet and Los Angeles was only a few feet above sea level, gravity alone could propel the water. Mulholland masterminded the 223-mile water system of pipes, channels, tunnels and reservoirs and the resulting deluge brought prosperity to the area, while draining the agriculturallyrich valley to the north.

First Los Angeles Aqueduct Facts

Construction: 1908 to 1913

Capacity: 485 cubic feet per second

Length: 223 miles

Concrete conduit: 98 miles

Tunnel: 52 miles

Concrete-lined open channel: 37 miles

Unlined open channel: 24 miles

Steel and concrete pipeline: 12 miles

Cost: $23 million

Second Los Angeles Aqueduct Facts

Construction: 1965-1970

Capacity: 290 cubic feet per second

Length: 137 miles

Steel pipeline: 69 miles

Concrete conduit: 64 miles

Other: 4 miles

Tunnel: 0

Open channel: 0

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- Bouquet Reservoir, located just downstream from the San Andreas Fault, serves as emergency water storage if a large earthquake damages the aqueduct. Elizabeth tunnel--at 26,870 feet the longest in the aqueduct system--goes directly through the San Andreas Fault.

- Concrete used for the conduits was manufactured at the site. Rock was extracted from the Techachapi Mountains and made into concrete at three mills built at the aqueduct site.

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Steel siphon was used sparingly due to the expense of transporting it. Because the Panama Canal wasn’t yet completed, ships carrying the steel pipes had to round Cape Horn to get to San Pedro. Trains carried pipes from the harbor to the Valley, and mule teams then hauled the huge pipe sections to the aqueduct site.

Timeline

1902-1903: Los Angeles’ population grows from 85,000 to 175,000.

1905: Water engineer Fred Eaton begins acquiring land and water rights in the Owens Valley.

Oct. 1908: Digging of the aqueduct begins. During construction, the maximum number of aqueduct workers at any one time was 3,900.

Nov. 5, 1913: Construction is completed and water is released into the aqueduct for the first time. A crowd of 30,000 gathered on hillsides just north of San Fernando to watch the first mountain waters from the Owens Valley plunging down the open channel into the San Fernando Valley.

1915: The San Fernando Valley is annexed by Los Angeles. The Valley’s irrigated acreage increased from 3,000 acres in 1914 to 75,000 in 1917.

1921-1929: Five reservoirs were constructed: Tinemaha on the Owens River, Upper San Fernando (Van Norman), Stone Canyon, Encino and Hollywood.

1924-1927: Aqueduct was dynamited many times by angry farmers in an attempt to force Los Angeles to share aqueduct water.

May 1926: Construction of the St. Francis Dam is completed. St. Francis Reservoir, the water pool caused by the dam, was used to regulate the flow of the aqueduct.

March 12, 1928: The St. Francis Dam, located 50 miles north of Los Angeles, collapses at midnight, flooding the valley below with 12 billion gallons of water and leaving 450 people dead.

1970: The Second Los Angeles Aqueduct is completed at a cost of $89 million, adding another 50% capacity to the water system. The project is shorter and half as wide as the original aqueduct.

1986: Construction of the Los Angeles Filtration Plant in Sylmar is completed. Because part of the aqueduct consists of unlined channels, water can become turbid, or cloudy. Aqueduct water is treated at the filtration plant using ozone and rapid rate deep bed filters.

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* Sources: Los Angeles Dept. of Water and Power; “Rivers in the Desert: William Mulholland and the Inventing of Los Angeles”; Researched by JULIE SHEER / Los Angeles Times.