The National Sea Grant Law Center


  • Historic Call on the Colorado River Highlights Water Management Concerns

  • September 23rd, 2021 — by Olivia Deans — Category: Natural Disasters

  • Many states are facing historic drought conditions, drastically magnifying the importance of water use and allocation in the western states. Water shortages affect the people and ecosystems of many states that rely on the Colorado River. For the first time in history, the Bureau of Reclamation announced a call on the Colorado River due to low water levels. The Colorado River stretches 1,450 miles from the Rocky Mountains of Colorado to the Gulf of California, and provides water for approximately 40,000,000 people. When certain low water levels are reached, the Bureau of Reclamation can place a “call on the river.” This means there is a need for upstream users to use less water in order to provide for adequate water to meet downstream uses. Along the Colorado River, certain water levels must be maintained in major reservoirs, such as Lake Powell and Lake Mead. When water levels drop below the established level, a “call” may be made to manage water allocation along the Colorado River to make sure that the water level in these reservoirs does not drop even further.

    While many federal laws, contracts, and regulatory guidelines regulate the Colorado River, the primary regulatory tool is the Colorado River Compact (Compact). The Compact is an agreement between Colorado, New Mexico, Utah, Wyoming, Arizona, California, and Nevada that provides a water management framework for the Colorado River. The Compact splits the river into the Upper and Lower Basins, and water is allocated to each basin. States are also allocated a specific portion of water. Under the Compact, the Bureau of Reclamation is responsible for monitoring and studying water levels in large reservoirs used for hydropower generation. In August, the Bureau of Reclamation released the “Colorado River Basin August 2021 24-Month Study,” which found the water levels of Lake Mead were below 1,075 feet. The Bureau of Reclamation consequently announced a Level 1 Shortage and is now implementing water allocations to protect the water levels of Lake Mead and Lake Powell. This means that Arizona, Nevada, and Mexico will be required to reduce water consumption. If drought conditions continue, other states could face supply reductions as well.

    The Level 1 Shortage has major implications for agriculture, hydropower, and aquatic ecosystems. Healthy ecosystems require instream water flow in order to sustain fish and wildlife and protect endangered species. Water shortages can lead to difficulties in balancing instream water for aquatic species with municipal, agriculture, and hydropower uses. Traditionally, states subject to the Compact manage water under a prior appropriation system. In a prior appropriation jurisdiction, water rights are granted based on when water is put to “beneficial use.” Traditionally, states did not include water rights for instream flows as a beneficial use. While western states allocate water differently, today some states include fish and wildlife use as a beneficial purpose that can receive water rights under a prior appropriation system. As water allocation is reduced, it may be challenging for states to maintain in-stream flow rates and balance beneficial uses between ecosystems and human use.

    The states in the Colorado River Basin states are unlikely to be the only states forced to reduce water use and make difficult management decisions due to drought. Drought conditions are affecting many states throughout the United States, and major rivers such as the Snake River in the Pacific Northwest and the Rio Grande in the Southwest may soon face similar water use hurdles. The call on the Colorado River and subsequent management decisions may present key challenges and lessons that can inform other river compact management decisions moving forward.

  • Olivia Deans
    Ocean and Coastal Law Fellow

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