Water policy issues are very important, but we haven’t discussed them much on this blog yet. Much of my information here comes from Ellen Hanak and other analysts of the Public Policy Institute of California (PPIC), analysts from the Union of Concerned Scientists (UCS), a recent article by Christopher Ketchum in Harper’s, a book by Robert Glennon (Unquenchable), and other sources. I’m not an expert on water policy, and any errors are my own. As usual, please let me know if you notice any errors, and I’m happy to hear any comments. I’ll focus on the southwestern US (mainly because I grew up in Colorado and now live in California), but many of these issues apply elsewhere as well. And while the Southwest is dealing with drought and water scarcity, other places, such as the UK and the Midwest US, are dealing with flooding.

According to the Worldwatch Institute, already some 1.2 billion people live in areas of physical water scarcity, while another 1.6 billion face “economic water shortage”. By 2025, almost half of the world will be living in conditions of water stress. Some analysts predict that water wars (see Vandana Shiva’s book) and conflicts will increase in the future. Considering that we need water to live, it’s not surprising that the United Nations General Assembly voted in a resolution declaring that access to clean water and sanitation is a fundamental human right.

At least conditions on Earth are not as bad as Mars, which has experienced 600 million years of drought and which probably hasn’t supported life, at least on its surface. But water scarcity is an extremely important problem that we’re probably not taking seriously enough; as Stephen Colbert put it, “if the human body is 60 percent water, why am I only two percent interested?”

The Southwest and California in particular are experiencing their worst recorded drought (for example, see the NASA satellite images below). In response, the California state legislature and Gov. Brown passed a drought relief package last month, while Sen. Feinstein and others are seeking to pass a bill in Congress to aid drought-stricken states.

Now here’s some historical and legal context. The Colorado River Compact of 1922 was negotiated by members of the upper-basin states (Colorado, New Mexico, Utah, Wyoming) and the lower-basin states (Arizona, California, Nevada), and it was an agreement for hydraulic management of the Southwest. According to the US system of water rights, however, the person who first made “beneficial use” of a stream or river had first right to it. Under this doctrine, the earliest users of the Colorado River (California) could legally establish a monopoly over regional water supply, even though most of that water came from another state (Colorado). A major problem was that because 1922 happened to occur during an unusually wet period, people assumed that the Colorado held more water than it really did: its annual water flow as estimated to be 17-18 million acre feet, though it was later more accurately estimated at 14 million acre-feet (17 billion cubic-meters) on average. It was therefore already overallocated from the start. The lower basin (including southern CA) is now overusing its share of the Colorado River, and it’s not a sustainable situation. A court case (Arizona v. California) that was decided by the Supreme Court in 1963 affirmed that Arizona was owed 2.8 million acre feet of water annually, but under the doctrine of prior appropriation, Arizona’s rights would remain secondary to California’s.

For water use, it’s useful to distinguish between water withdrawal (from surface or ground sources) and the consumption of water already withdrawn. Consequently, as argued by Ellen Hanak at a recent PPIC event in Sacramento, we need to consider not just water supplies but also water management and (in)efficient water consumption. Although one usually thinks of water for drinking, washing, cleaning, and other residential uses, much more water is used for irrigation (agriculture), industry, and power plants; according to the UCS, power plants account for 41% of freshwater withdrawals in the US. It’s also useful to distinguish between direct and indirect water use, and I’ll get into that more below.

Water shortages, already a critical issue in the Southwest, are likely to become far worse with climate change (although the extent to which it’s due to climate change is still debated). Rivers such as the Colorado, which is primarily supplied by snowmelt and is already overallocated, are particularly vulnerable. For the past fourteen years, the Colorado River has been at its lowest level since the ninth century. According to Tim Barnett from UC San Diego’s Scripps Institution of Oceanography (SIO), with climate change, currently scheduled water deliveries from the Colorado River are unlikely to be met by mid-century. Rising air temperatures due to global warming will result in reduced snowfall: by the end of this century, California’s ski season could disappear with a 80% loss of Sierra snowpack, and Washington and Oregon would experience reduced snowfall as well. In addition, although per capita water use has been gradually decreasing, population growth in the Southwest is likely to increase urban water demand in some regions. In a high carbon emissions scenario, annual losses to agriculture, forestry, and fisheries could reach $4.3B in California alone, and the prices of fresh fruit, vegetables, dairy, and fish, will rise. There will be more competition between human water use and water needed to support fish and other wildlife, and potential solutions will involve difficult trade-offs. (The following figure from the EPA summarizes climate impacts on the hydrologic cycle.)

In the studies mentioned above by SIO scientists, the Colorado River’s average annual flow could decline by as much as 30% by 2050. As a result, without massively reducing water usage, Lake Mead has a 50% chance of declining to “dead pool” by 2036. At that level, water deliveries to millions of people in California and Arizona and to millions of acres of farmland will cease, and hydroelectric production at the dam will already have stopped. It is incredible to consider that this could happen in our lifetime, as the Colorado is the same river that carved the Grand Canyon over tens of millions of years, and it is one of the rivers on which the Ancient Puebloan depended until around 1300, when drought, decreased rainfall, and a drop in water table levels appeared to drive the people away from their civilization. (See also this article in National Geographic about ancient “megadroughts” in human history.)

The largest fraction of water consumption is due to agriculture, power plants, and industry. Considering the fact that we indirectly need water because of our need for energy, this points to the issue of the “water-energy nexus.” The average U.S. family of four directly uses 400 gallons of freshwater per day, while indirectly using 600-1800 gallons through power plant water withdrawals. We need energy for water production and distribution (and the desalination plant being constructed near San Diego will require quite a bit), and we also need water for energy-related infrastructure. Coal and nuclear power plants use large amounts of freshwater to cool the plants: for example, a typical 600-MW coal-fired plant consumes more than 2 billion gallons of water per year from nearby lakes, rivers, aquifers, or oceans. In addition, as we discussed in my previous blog post, fracking techniques for extracting shale gas require millions of gallons of water to be injected into a well, and they can contaminate groundwater as well. Fortunately, wind turbines and solar photovoltaic modules require essentially no water at all, but other renewable energies, like hydroelectric, bioenergy, and geothermal, can be water intensive. As argued by Laura Wisland, since we expect climate change to increase the frequency and severity of droughts in California, it will be important to hedge our electricity supplies with predictable, renewable resources, especially wind and solar.

What can be done? As a “silver lining” of the current situation, the ongoing drought in the Southwest provides a window for reform, and here are a few ideas. We should shift toward less water-intensive sources of energy such as wind and solar. Water should cost more: we should modernize water measurement and pricing with better estimates of water use and prices that reflect water’s economic value. We could learn from cities in dry places elsewhere (such as Australia) about how to make urban areas more water efficient, and we could have tiered water rates with higher prices for greater use. In agriculture, crops that cannot be grown without subsidies should not be grown. We need improvements to local groundwater management. Since surveys show that most Californians believe that there are environmental inequities between more and less affluent communities in the state, it’s also important to consider environmental justice issues while developing new water policy programs (see this article, for example). We need to develop more reliable funding (through state bonds or local ratepayers), especially for environmental management, flood protection, and statewide data collection and analysis. Finally, as argued in this PPIC report, water management agencies at all levels should aim to develop more coordinated, integrated approaches to management and regulatory oversight, drawing on scientific and technical analysis to support sound and balanced decisions.