Opinion

Opinion

LOS ANGELES is the nation’s water archvillain, according to public perception, notorious for its usurpation of water hundreds of miles away to slake the thirst of its ever-expanding population. As a character in “Chinatown,” the noirish 1974 film starring Jack Nicholson that churns through the city’s water history, puts it, “Either you bring the water to L.A., or you bring L.A. to the water.”

Recently, however, Los Angeles has reduced its reliance on outside sources of water. It has become, of all things, a leader in sustainable water management, a pioneer in big-city use of cost-effective, environmentally beneficial water conservation, collection and reuse technologies. Some combination of these techniques is the most plausible path to survival for all the cities of the water-depleted West.

One sign of Los Angeles’s earnestness is its success in conservation: The city now consumes less water than it did in 1970, while its population has grown by more than a third, to 3.9 million people from 2.8 million. Two projects — a nine-acre water-treating wetland constructed in a former bus maintenance yard and a water management plan devised for a flood-prone district of 80,000 people — won awards this year from the Institute for Sustainable Infrastructure. The city itself won one of the first water sustainability awards given by the U.S. Water Alliance, in 2011.

Los Angeles’s shift occurred out of necessity, after legal decisions in the 1990s forced it to give up some of its imported water. More and more cities now face water constraints. In the West, where most climate scientists expect droughts to lengthen and deepen, the techniques being introduced in Los Angeles ought to be viewed not just as smart choices, but as requirements.

Though most projects will start too late to address the severe drought now plaguing much of the West, they show how to cope with future ones. Together, these projects will treat polluted and even sewage water, capture rainwater, store water in aquifers, and use (or reuse) all of it, often while mimicking or supporting natural processes. The area’s water administrators who, until recently, thought of watersheds as merely rural concerns now recognize that even in Los Angeles, all living things are linked by their common water course and that its proper management is essential to the administrators’ success.

In the last decade the tenets of sustainable watershed management have spread across the country. The city of Los Angeles still imports 89 percent of its water, a proportion that underlines the severity of its water needs, but dozens of other cities (including some Eastern ones) are embracing pieces of Los Angeles’s water sustainability approach.

San Francisco has become a leader in using recycled wastewater for nonpotable purposes like toilet flushing and gardening while reducing its per capita water use to 46 gallons a day, one of the lowest rates in the nation. San Antonio has developed a multifaceted conservation program that has cut the city’s per capita water use by nearly half over the last two decades. Even Philadelphia, which usually has ample water, committed itself in 2011 to a $1.2 billion green infrastructure program that uses storm water capture to prevent environmental degradation. These efforts share the basic tenet that all the water in any watershed — whether tap water, groundwater or toilet water — must be considered part of a constantly circulating hydrological whole.

Los Angeles gets little rain, and what it does get occasionally arrives in the form of harsh, flood-generating storms, like the ones last week. After numerous destructive floods in the first third of the 20th century, the Army Corps of Engineers and the city’s public works department began building a flood-control infrastructure. It was designed to move storm water quickly off city streets and into the Pacific Ocean. All but seven miles of the 51-mile-long Los Angeles River was turned into an ugly concrete conduit that is usually empty.

Flooding stopped, but at a cost. As the region grew, agriculture gave way to urban development, and more and more land was covered with an impermeable layer of pavement and buildings. This meant that even if a storm produced no more rainfall than one a decade earlier, it generated far more runoff. As the water flowed over the city’s hard surfaces, it collected more and more pollutants — animal waste, car oil, toxic chemicals and metals — and deposited them on the beaches and in the sea. Of course, Los Angeles was also importing huge amounts of water, drying out previously pristine areas far to the city’s north. The water-supply infrastructure imported water while the flood-control system exported it, and both processes ravaged the environment.

By the late 1980s, storm water quantities were getting so high that the flood-control channels could no longer contain them. The authorities assumed their only alternative was to raise the cement walls still higher, which they did in the 1990s at a cost of $180 million.

Meanwhile, two environmental campaigners, Dorothy Green of Heal the Bay and Andy Lipkis of TreePeople, were telling anyone who would listen that the flood-control infrastructure should be reorganized to capture water, not cast it into the sea. If storm water is harvested and directed into aquifers, they argued, floods can be prevented. Then the stored water can be pumped when needed, treated and consumed.

To prove his point, in 1998 Mr. Lipkis’s nonprofit retrofitted a house in South Central Los Angeles, then staged a mock flood. The house’s roof was lined with gutters that fed rainwater into two 1,800-gallon cisterns, and the lawns in the front yards and backyards were lowered six inches to form a wetland. On the big day, local officials watched from beneath umbrellas as a 4,000-gallon water truck dumped around 15 tons of water on the roof, yet none of it left the premises.

The property functioned instead as a miniature watershed, storing water for outdoor use or absorbing it and redirecting it to an aquifer below. Flood-control officials were so impressed that they dropped a $42 million proposal they had been considering for a storm drain in a highly flood-prone section of the San Fernando Valley called Sun Valley and instead introduced a plan to test storm water capture there.

Under the stewardship of the Council for Watershed Health, a local nonprofit, six local government agencies responsible for water supply, water quality, floods and groundwater worked with academic researchers and the United States Bureau of Reclamation, the federal agency once known as the West’s leading dam builder, to retrofit an entire Sun Valley city block. The officials chose Elmer Avenue, a street so flood-prone that routine storms turned it into a river.

Completed in 2010, the $2.7 million project enables residents to collect rainwater on their rooftops and divert it to rain barrels for later use. Water that overflows the rain barrels spills into spongelike rain gardens that replaced grass lawns. Further overflow seeps through permeable driveways or is conveyed by drain to a swale of rocks, soil, plants and mulch running the length of the sidewalks.

The street itself was excavated, filled with a six-foot-deep layer of gravel fed with rainwater through large perforated pipes and topped with pavement; in an average rain year, that expanse should collect enough water for 80 houses, not just the 24 retrofitted ones. As the water slowly drips into the aquifer below, it is cleansed of pollutants it collected on the street. By encouraging natural processes that perform ecological services, the project simultaneously mitigates flooding, pollution and water scarcity.

Production of water like that captured on Elmer Avenue costs $300 an acre-foot, while Los Angeles now pays $800 to $1,000 an acre-foot for imported water. According to a study conducted by the Pacific Institute and the Natural Resources Defense Council, a fully developed storm-water capture system in greater Los Angeles could add 309,000 acre-feet per year to water supplies, more than half of Los Angeles city’s annual current consumption of 587,000 acre-feet per year.

The demonstration projects persuaded Los Angeles officials last year to adopt an ambitious 20-year plan that treats the Los Angeles basin as a single watershed, integrating water quality, water supply, flood control, wastewater, parks and habitat programs. However, given the huge retrofit the plan requires, the program is still in its infancy. It enjoys backing from the state, which as early as 2002 enacted legislation embracing integrated watershed management, and last month Eric Garcetti, the mayor of Los Angeles, underlined the city’s shift to local water by issuing a directive to cut purchases of imported water by half within a decade. Even so, implementation is far from assured.

“Governance is probably the biggest obstacle to a sustainable water supply,” Mark Pestrella, who heads flood control for the Los Angeles County Public Works Department, told me.

A 2014 study by the geographers Miriam A. Cope and Stephanie S. Pincetl at the University of California, Los Angeles, found that more than 100 entities in Los Angeles County — private utilities, nonprofit water companies, cities and an assortment of “special districts” — conveyed water; simply identifying and classifying them took the researchers more than a year. Some are tiny and will face pressure to consolidate. And some — agencies with a designated mission like sanitation or flood control — may be impeded by the Los Angeles city charter from participating in multipurpose projects. Even if they can, they will undoubtedly find it hard to cede some of their authority to carry out multipurpose, multiagency projects. So far most money for the projects has come from government grants and voter-approved bond measures, but new sources must be found for the vastly larger sums the projects require.

Even so, what has already happened in Los Angeles is something rare: a straightforward environmental victory. Environmentalists diagnosed a major problem and outlined its solution, and government officials eventually accepted their approach.

Strangely, many, if not most, Angelenos are oblivious to the region’s pathbreaking role. Like everyone else, they think of Los Angeles as a water extorter, and don’t realize that its current path is the sincerest form of atonement.

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Jacques Leslie

Los Angeles, City of Water