The Los Angeles Aqueduct

The Los Angeles Aqueduct flows in its unlined channel on the east side of the Sierra Nevada range north of Lone Pine. (Los Angeles Times / September 4, 2013)

One hundred years after its opening, the Los Angeles Aqueduct continues to cast a long shadow over the rough and tumble of California water policy. The arrival of water from the Owens Valley made the modern city possible. But it also reshaped Los Angeles to suit its capabilities and changed water politics forever.

The aqueduct was not designed to bring water to Los Angeles but rather to the arid wasteland of the San Fernando Valley, which then lay outside the city limits. This would vastly enrich the lands owned by a small band of prominent industrialists who were promoting the aqueduct. To prevent this group from profiting from the public project, President Theodore Roosevelt prohibited Los Angeles from selling any of the Owens Valley water outside the city limits. Los Angeles promptly resolved that difficulty by annexing the San Fernando Valley, thereby cementing an often fractious relationship between the two communities.

Exclusive access to the aqueduct has given Los Angeles a much purer and less costly water supply than its neighbors, who must rely on supplies drawn from saltier sources that require much more expensive treatment. Through the creation of the Metropolitan Water District, Los Angeles today has access to much more water than it needs. But its continued reliance on the superior supplies from the Owens Valley means that the water Los Angeles hasn't used from the water district has been available to support the development of Orange County and San Diego.

The city originally frightened voters into supporting the aqueduct by fabricating a drought scare. But in the 1920s, a real drought descended that scared the city into two fateful decisions. First, worried that the aqueduct couldn't meet its needs, Los Angeles shouldered aside San Diego's plans to tap the Colorado River and took over that project for itself. That may help to explain San Diego's abiding resentment of all things Angeleno, its persistent opposition to water planning that might benefit the city and its often fruitless quest for an "independent" water supply of its own, no matter what the cost.

Second, to ensure that it was getting all the water the aqueduct could convey, Los Angeles determined to strangle agricultural water use in the Owens Valley. This prompted the valley's armed resistance. The aqueduct was repeatedly blown up, and at one point, it was seized by the embattled farmers, who shut it down entirely.

Los Angeles ultimately won that conflict. The Owens Valley economy was devastated and the city wound up owning most of the area, which it attempted to run as a virtual colony. For half a century, investments in valley business were actively discouraged. Agriculture was briefly revived to supply a federal internment camp for Japanese Americans during World War II. But Los Angeles ripped out the orchards and plowed up the vegetable patches as soon as the internees were released.

When a company set up a plant to extract valuable chemicals in the dry bed of Owens Lake, the city waited until the plant was ready to open and then flooded it out. And as recently as 35 years ago, a valley radio station that dared to criticize the city was forced to fire its reporters when Los Angeles threatened to shut down its broadcasting tower.

The suffering of the Owens Valley in Los Angeles' hands rewrote California's water law. State statutes now ensure that the areas of origin can never again be stripped of their water resources for the sake of development elsewhere. Without those guarantees — and the federal government's promise to respect them — approval could never have been secured for California's much larger modern water systems, the Central Valley Project and the State Water Project.

And the efforts of state and federal water planners today to ensure that these systems will continue to meet the needs of two-thirds of California's people through the implementation of the proposed Bay Delta Conservation Plan likewise rely on the assurance that the rights of Northern California water users will be protected.

Opponents of modern water planning often evoke the bad example of Owens Valley. But the Los Angeles Aqueduct has a much more relevant role to play in these debates. Los Angeles, after all, has withdrawn its heavy hand in recent years. Town properties have been returned to private ownership. Water withdrawals from Mono Lake have been reduced, and stretches of the Owens River have been restored. The city is even putting water back into Owens Lake to cut down on dust.

These concessions have drawn applause from some environmental advocates. But such kindness isn't cost-free. The less water Los Angeles takes from the Owens Valley, the more it needs from someplace else. This has inevitably increased pressure on the supplies the Metropolitan Water District draws from the Sacramento-San Joaquin River Delta, which is what the current water policy debate over the Bay Delta Conservation Plan is trying to resolve.

The opening of the aqueduct inspired water planners throughout the Western states as a demonstration of the public benefits that a healthful and reliable water supply can deliver. Its continuing operation today serves as a constant reminder that we live in a hydraulic society. Our water needs and our prosperity are linked. The old north-south rivalries that once divided Californians don't play so well to a more sophisticated society that better understands these interconnections, and that Oakland won't benefit from denying water to Glendale.

William Kahrl is the editor of "The California Water Atlas" and the author of "Water and Power," a history of the conflict over Los Angeles' water system.