Los Angeles has two major water problems. The first is too little water. The second is too much water.
California's imminent water shortage by now is well known. Because the state is facing its fourth consecutive year of drought, residents are bracing for some strict water-saving measures--bans on using water to hose down driveways or sprinkle lawns and gardens, moratoriums on new connections and household rationing.
Then how can Los Angeles have too much water? Each year the city and county produce billions of gallons of sewage waste-water, most of which is partially treated then dumped into the Pacific. This effluent is a major source of coastal water pollution. Equally important, it is lost forever as a valuable source of recycled water.
The real problem, then, is finding a way to resolve this hydrologic paradox. Can the billions of gallons of sewage dumped into Southern California coastal waters be redirected to profitable use? And if this water is so polluted, is it safe to do so?
To answer these questions, some background is needed on water use in the region and methods of waste-water reclamation.
The serious water shortages facing Southern California should come as no surprise. After all, America's second-largest city sits in the middle of what is essentially a desert. What is surprising is that the problem has been postponed for so long.
For many years Southern Californians have been spoiled by ample water deliveries, despite rapid population growth and sparse local supplies. In 1952 the Metropolitan Water District issued the Laguna Declaration, which promised to supply Southern California with sufficient water to spur postwar economic growth. And it did so with a vengeance--water from the Colorado River, the Mono Lake basin, the High Sierra and the Owens Valley bathed Los Angeles despite steady population growth over the past half-century.
But now, many of Southern California's traditional outside water sources are drying up. Because of a court decision a quarter-century ago, California's share of the Colorado River is being reduced. Other litigation has cut water supplies from Mono Lake and the Owens Valley. Combined with four years of below-average precipitation, the region now faces a severe shortage.
More important, the steady stream of low-priced water has given Southern Californians little incentive to use it efficiently. Americans in general treat water as a virtually unlimited resource, using almost 50% more water per capita than the nearest runner-up nation, and almost five times as much as some industrialized countries. But Southern California, because the area is hotter and drier than other regions, uses about twice as much water per person than is the case in New York or other Eastern states. And California is almost entirely dependent on irrigation to grow more than 200 crops.
Part of the solution to this problem lies in more efficient use of water. While conservation--such as installing toilets that use only 1.5 gallons per flush, as Los Angeles has mandated, and water-saving showerheads and faucets--can and should make a big difference, an equally valid aspect is why water rationing is imminent when billions of gallons of water are being dumped into the Pacific each year. Sixteen sewage-treatment plants from Santa Barbara to San Diego dump 1.3 billion gallons of waste-water every day into Southern California coastal waters.
Why can't this water be reused to help meet the region's fresh-water needs? One reason is that this sewage--much of which receives only advanced primary treatment--carries with it massive amounts of pollution.
Many of these pollutants can be removed with better treatment. While not clean enough to drink or use for other human-contact uses, adequately treated sewage water can be reused as irrigation water for crops, forests and parks and to recharge ground-water deposits. In some cases, pollutants that interfere with water reuse--especially metals and other toxics--come from industries that discharge their wastes into public sewage-treatment plants. These industries are legally required to "pretreat" their wastes before they reach sewage plants; better pre-treatment and enforcement of existing standards would allow cleaner, reusable sewage effluent.
Some of the chemicals--such as nitrogen and phosphorus--seen as "contaminants" in sewage effluent are actually beneficial nutrients in irrigation water. Sewage reuse can improve agriculture, because nutrients are released slowly, rather than in a single large dose, as is the case with chemical fertilizers.