Will California Run Out of Water?

By Bill Weber

Thousands of years ago, the Sahara was humid, lush and green. Thanks to gravity, earth wobbles periodically increased the area’s exposure to the sun, making it the desert we know today.

In the 1500s, native populations of Arizona and Nevada abandoned 36 of their 47 villages because they ran out of water. Even with their skillful use of canals and drawing water from the Colorado River, they had to move on because they were unable to tap below-ground sources.

The dust bowl of the 1930s, caused by a drought and man-made destruction of land, created a migration of people from the Midwest to the Los Angeles and Central valleys of California, a movement comparable to that of the California gold rush. The water requirements of the booming urban areas, as well as increased agricultural demands for irrigation, put a new strain on both surface and ground water in the state.

In 1913, the Los Angeles aqueduct was created to supply water to the region via a canal through the Owens Valley from Mono Lake. In 1919, the California Water Resources Board was created to manage the water supplies to urban and agricultural parts of the state. From its inception, a series of water rights agreements were created and subsequently contested as supplies dwindled from the stress of urban growth, along with climate change.

Climatologists tell us the western United States is in the midst of a 1200-year drought, and that the year 2002 was the driest in the region’s history — quite possibly as dry as it had been during the 1500s period of the native populations’ migrations in Arizona, when they could not access ground water and suffered from deficits in the Colorado river. (See the essay on our website of 9/15/24 by Jim Wechsler and Gary Richardson). And the 2002 drought was quite possibly the worst in the current drought period so far. Depleted aquifers, climate change and population increases, as well as declining flows in the Colorado River, are the main causes of concern for the future of the water supply in California.

Even though there have been atmospheric rivers (the pineapple express) recently refilling reservoirs, the forecast is for 80% less snow pack by 2100. With water conservation reducing demand by 15%, the still uncertain future of the water supply in California is discussed in the balance of this essay.

The fundamental fact about water availability — either surface water or ground water — is that it originates from precipitation in the form of rain or snow. As the drought progresses, the scarcity of precipitation increases and, as of this writing, the only sources immune from the western drought are the Pacific Ocean and possibly the Columbia River Basin.

The use of ocean water requires desalinization (discussed below), and the potential transfer of water over long distances, mountains, and native lands pose political obstacles. Power requirements do not provide a solution to ease or solve the unmet need for water in the west.

California has a population of about 39 million (1.4 million households in Los Angeles alone), consuming 360 gallons per day per household. The state’s main sources of domestic water (as opposed to agricultural water) are three aqueducts:

1. The Los Angeles aqueduct running from Mono Lake to L.A.
2. The Lake Havasu aqueduct running from the Colorado River to a lake in Riverside, and
3. The Great California Canal aqueduct bringing water from northern to southern California at the rate of 650 million gallons per day.

The California Water Resources Board controls the distribution of water for domestic and agricultural use, subject to a variety of water agreements, jurisdictional issues and water availability. Today, 40% of all California water (80% of the water under control) is used for agriculture. Water not controlled by dams or aqueducts can end up being used to benefit wildlife, or is simply allowed to run into the ocean.

There are more than 1,000 dams in California; nearly every river has at least one dam. The 386 hydropower plants at those dams generate 10.9 million megawatt hours of electricity. For example, the Oroville Dam hydro station generates over 800 megawatts of power, which decreases the need to burn fossil fuels for electricity elsewhere in the state. BUT as the drought continues, hydro stations will have less ability to generate power because of lower water levels. Other dams in the state are in danger of silt formation reducing their capacity. The Hetch Hetchy dam in Yosemite National Park feeding the San Francisco area is relatively free of silt formation, but there are groups wanting to shut it down and return the area to its original state. If that happens, where will this area get its water?

Ground water depletion has become a serious issue as the drought continues and aquifers are not being replenished. In fact, they are over-pumped to the extent of lowering the available water at any depth. There are now reports that communities dependent upon ground water for domestic use are seeing their sources running dry, and agriculture is suffering as well. In response, the water authorities in California and other western states are recognizing the ground water scarcity issue by creating standards for pumping and more economical use of water for agriculture, resulting in preserving and restoring ground water to some degree.

Looking at the question of supplying water for domestic use (and leaving out agriculture for the moment), desalinization of the Pacific Ocean is technically possible. As an example, if the San Onofre Nuclear Generating Station were still in operation, the 2.2-gigawatt production of all three units could supply more than 97 million gallons of water per hour. (Sadly, it is not, having been shut down in the 1990s.) That station could have provided nearly 6 million households with domestic water. Since Los Angeles has only about 1.4 million households, the extra water could have been used for other purposes, including agriculture.

But this concept must be considered in light of its costs (the capital cost of the desalinization plant, infrastructure, brine disposal and delivery systems), as well as issues such as nuclear vs. fossil fuel or hydroelectric sources, how it affects the ultimate objective of reducing carbon emissions, and the public’s fear of nuclear plants. Although the City of San Diego and Alameda County currently have desalinization plants delivering domestic water to fill a fraction of their needs, as we think about the impending water crisis, the possibilities of hydropower being used for desalinization are questionable, to say the least, given the water levels required for the dams and its cost weighed against those for other sources of drinking water.

So will California run out of water? Probably not, but with conservation and technology, it still will be a tough call for the future of the state — both for agriculture, power production and domestic use of this dwindling supply.

 

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