The National Sea Grant Law Center


  • Dropping Water Levels in Colorado River Basin Raise Prospect of First-Ever Federal Water Shortage Declaration

  • June 15th, 2021 — by Mikayla Mangle — Category: Natural Disasters

  • The Colorado River (the “River”) is a crucial resource to many western U.S. states. The River provides water to over forty million people and more than five million acres of farmland in seven western states, including Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming. These seven states are divided into two basins: the upper basin, which includes Arizona, Colorado, New Mexico, Utah, and Wyoming; and the lower basin, which includes California, Arizona, and Nevada. According to the U.S. Bureau of Reclamation, the River provides more than 4,200 megawatts of electrical generating capacity from hydroelectric facilities and serves as the “lifeblood” for at least twenty-two federally recognized tribes, seven national wildlife refuges, four national recreation areas, and eleven national parks. As a result of these overlapping interests and authorities, the River is managed in accordance with the Law of the River, which comprises treaties, compacts, decrees, statutes, regulations, contracts, and other legal documents applicable to the allocation, appropriation, development, and exportation of the River’s waters.

    Since 2000, an extended drought has impacted water supply in all of the states across the River Basin. Both Lake Powell and Lake Mead, two artificial lakes that store water within the Colorado River Basin and supply water to millions of people, are shrinking. The Bureau of Reclamation's models project that levels in Lake Mead will fall below 1,075 feet for the first time since its construction in June 2021, possibly prompting the federal government to declare a shortage in accordance with the terms of agreements negotiated by the seven aforementioned western states. The Bureau of Reclamation has further indicated that during the twenty-one year period between 2000-2020, the River had its lowest water levels over a twenty-one year period since 1963. The average inflow for the 2000-2020 period was 8.62 million acre foot (“maf”); by comparison, the average inflow was 10.83 maf between 1981 and 2010.

    In the event of a water shortage declaration, eastern states who rely on the River may face substantial cuts to their share of the River’s waters. However, many Western states, anticipating a water shortage declaration, have taken proactive steps to ensure the impact of a water shortage declaration will be minimal. For example, Arizona adopted Interim Guidelines in 2007 that incentivize conservation, define criteria for shortages in the lower basin, and implement closer coordination of operations of Lake Powell and Lake Mead. Then, in 2019, the Department of Interior, the Bureau of Reclamation, and representatives from all seven Colorado River Basin states signed Drought Contingency Plans (DCPs) for the upper and lower Colorado River Basins. These plans remain in effect until 2026.

    Each state decides how to implement the DCPs. For example, Arizona's approach to implementing the DCPs emphasizes foregoing a greater quantity of water now before a critical shortage is realized. To do this, Arizona spreads any necessary cuts in water supply across multiple users. For instance, Arizona has a concept known as “mitigation waters.” This water comes from cities that otherwise would have stored the water underground, but instead direct those waters to farmers and other entities. Arizona also provides incentives to water agencies and other entities to encourage them to reduce water use, which results in high water levels in Lake Mead. Arizona even provides monetary compensation to those who contribute some of their allotted water to mitigate the losses of other users. Other western states, such as Nevada, have taken similar steps to Arizona as a way to assure minimal impacts of a shortage declaration.

    In conclusion, the first ever water shortage declaration by the US federal government could be approaching soon for Western states. While projections by federal agencies are not certain to come true, they reveal that a water shortage declaration is a real possibility for the Colorado River Basin. However, the seven western states who will be affected by such a shortage declaration have been taking steps for the past decade, or more, to minimize the impact. While some of these western states have faith in the actions they have taken to minimize the impact of a possible water shortage declaration, only time will tell if these state actions are enough to truly minimize such an impact.

    Mikayla Mangle is a guest author for the National Sea Grant Law Center Blog. She is a rising 3L at Tulane University Law School and can be reached at

  • Mikayla Mangle
    NSGLC Blog Guest Author

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