The American West is in the grip of a deep and prolonged drought, resulting in unprecedented water shortages.
Almost 93 percent of the western United States is experiencing drought or abnormally dry conditions, and more than 70 percent of the western states are experiencing severe or extreme drought conditions.
The Southwest has undergone its driest two decades in 1,200 years. Ninety percent of New Mexico is in extreme or exceptional drought.
California has just experienced the driest first five months on record, with record-setting wildfires forecast.
The drought is particularly acute in the Colorado River Basin, which supplies water to 40 million people across nine states and irrigates 4 million acres of farmland. The Colorado River Basin is in the 23rd year of a historic drought.
Water levels in both Lake Mead and Lake Powell – the two largest reservoirs in the United States – have dropped to the lowest levels in history.
In response, the federal government last August issued its first formal “shortage” declaration triggering mandatory water-delivery reductions to Arizona (18 percent of its annual allocation) and Nevada (7 percent ). Additional cutbacks are likely coming soon.
These reductions jeopardized farm and ranch operations in Arizona and Nevada.
Lake Mead (Hoover Dam) and Lake Powell (Glen Canyon Dam) are now below 28 percent of capacity —and falling. If water levels drop much farther, their dams’ turbines will no longer be able to generate electricity, creating additional power-supply challenges for a region already at elevated risk of rolling blackouts this summer because of extreme heat and increased reliance on intermittent wind and solar energy.
Drought is the proximate cause of today’s water shortage, but in the Colorado River Basin, the root of the problem goes back a century.
In 1922, the Colorado River Compact divided up the river’s water, allocating 7.5 million acre-feet to the Upper Basin states of Wyoming, Utah, Colorado, and New Mexico and 7.5 million acre-feet to the Lower Basin states of California, Arizona and Nevada. Nevada’s allocation was 400,000 acre-feet (2.67 percent of the total).
The compact anticipated annual flows of 17 million acre-feet; this century the annual flows have averaged 12 million acre-feet.
By 1960, it was clear the river had been overallocated – but the damage was done. Renegotiating the compact has proven difficult.
Despite these challenges, the West has a remarkable ability to adapt to water scarcity.
Water use in the Colorado River Basin has declined over the past two decades, even as the region’s population has grown.
Cities have become more water-savvy, by recycling wastewater, conserving stormwater runoff, or investing in more efficient water-distribution systems.
Las Vegas, often mocked as a symbol of environmental excess, has cut its per capita water use almost in half since 2002, and its overall water use has declined by 26 percent.
Phoenix’s water consumption has declined by one-third since 1980, even while its population has doubled. San Diego now uses 40 percent less water than it did in 2007.
The biggest opportunity to continue this progress is in the agricultural sector, which uses more than 80 percent of the water consumed in the West.
In California, markets have shifted more water to higher-revenue crops, like nuts, grapes and fruit. Because of this, farm earnings in the state are increasing with agricultural water use declining.
Higher water pricing and water use restrictions are obvious ways to encourage conservation.
Six million people in sprawling Los Angeles, Ventura and San Bernardino counties were told by the Metropolitan Water District of Southern California to cut their outdoor watering to one day a week, effective June 1, or face stiff fines.
Desalination technology is now a viable solution for coastal cities – although approving desalination plants has proven difficult with the Coastal Commission in California.
The West must, and can, adapt to a predicted even drier future.
E-mail Jim Hartman at firstname.lastname@example.org.