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Contact: Daniel Munch | Associate Economist (202) 406-3669 | dmunch@fb.org
First-Ever Colorado River Water Shortage Declaration Spurs Water Cuts in the Southwest The Western U.S. is no stranger to extreme drought. It’s been several generations, though, since farmers’ and ranchers’ ability to produce food and fiber have been hampered to this degree by dry conditions. Crop acreage reductions, orchard tree removals and livestock herd liquidations have been common responses from farms and ranches facing drought. In the Colorado River Basin, which covers over 246,000 square miles and provides vital water resources to Arizona, California, Colorado, Nevada, New Mexico, Utah, Wyoming and northern Mexico, the largest reservoirs have reached their lowest water levels in history. Under the Colorado River Basin guidelines, low reservoir levels have triggered the first shortage declaration in history and with it a range of water allocation curtailments. The Colorado River Basin is a primary source for farm and rangeland irrigation across 5.5 million acres of land and is also used for municipal and industrial purposes by the region’s 40 millionplus residents. The region’s hydroelectric infrastructure provides up to 42 gigawatts of electrical power annually to area customers. As a result of the Colorado River Compact of 1922, the basin was split into two separate water apportionment regions, the Upper Basin, which covers Colorado, New Mexico, Utah, Wyoming and a small section of Arizona, and the Lower Basin, which covers the majority of Arizona and provides water to populated sections of Southern California and Nevada. Under the compact, each basin is allocated 7.5 million acre-feet (maf ) yearly, with an additional 1.5 maf dedicated to Mexico. The Bureau of Reclamation, a federal agency within the Department of the Interior, oversees water resource management including the delivery, diversion and storage of Colorado River Basin water flows. The bureau monitors conditions, such as inflow, water storage capabilities, elevation and evaporation, and manages total releases from the basin’s numerous reservoirs, with a particular focus on the two largest reservoirs: Lake Powell on the southern border of Utah (created by Glen Canyon Dam) and Lake Mead on the border of Nevada and Arizona (created by Hoover Dam). Multi-year drought has impacted the level of Rocky Mountain snowpack, which the Colorado River relies on for its flows. Reduced inflow from snowpack results in reduced reservoir levels and a reduction in the amount of water available for downstream users especially as population and associated water demand increases. A Reclamation study estimated 64-76% of consumption demand growth was expected to come from municipal and industrial use by the area’s growing population, rather than from increased agricultural demand. In an effort to avoid future water shortage disasters and improve storage decisions, the Upper and Lower Basin states worked collaboratively with Reclamation to agree to and implement a series of water shortage mitigation procedures called the Drought Contingency Plans (DCPs), which were approved by Congress in 2019. For the Upper Basin, states agreed to the operation of regional units to keep the elevation of Lake Powell above 3,525 feet (35 feet above the minimum needed to support hydroelectric production). This goal would be achieved through drawdowns of other Upper Basin water storage facilities and voluntary buyer agreements for paid water use reductions. Figure 1 shows the elevation of Lake Powell from 2017-present. To date, Upper Basin states have been successful at preventing Lake Powell’s elevation from dropping below 3,525 feet. That said, the reservoir is still at its lowest recorded level, reaching 32% of its 24.3 maf max capacity (compare to 48% of capacity in September 2020). In the Lower Basin, Arizona, California and Nevada reservoir usage is governed by a more complex framework, and the secretary of the Interior is the watermaster of the lower Colorado River, giving the federal government a significant role in water management. In 2007, the region adopted a series of mitigation
24 NOVEMBER/DECEMBER 2021
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