Drought Contingency Plans for the Colorado River Basin

INSIGHTi Drought Contingency Plans for the Colorado River Basin Updated February 15, 2019 The Colorado River Basin is a critical source of water and power supplies for seven western states and Mexico. The basin is in the midst of a long-term drought. Water levels at the basin’'s two largest reservoirs, Lake Mead and Lake Powell, could reach critically low levels. Building on prior agreements, recently the basin states and the Bureau of Reclamation (Reclamation) recently announced drought contingency planstransmitted to Congress drought contingency plans (DCPs) that aim to decrease the likelihood of major water and power supply curtailmentsdisruptions for users. Colorado River Basin in Context The Colorado River Basin (Figure 1) covers approximately 246,000 square miles, 97% of which are in the United States. It includes the Colorado River and its tributaries, which cross the U.S. border into Mexico before discharging into the Gulf of California. Pursuant to federal law, multiple federal facilities (e.g., Hoover Dam) store and convey water from the river and its tributariesbasin waters and generate hydropower for the southwestern United States. The primary federal agency with jurisdiction over the river is Reclamation, an agency within the Department of the Interior (DOI). Congressional Research Service https://crsreports.congress.gov IN10984 CRS INSIGHT Prepared for Members and Committees of Congress Congressional Research Service Figure 1. Colorado River Basin and Major Facilities .

Figure 1. Colorado River Basin and Major Facilities Source: Bureau of Reclamation. . Based on observed data, average natural Colorado River flows in the 20th20^th century were about 15 million acre-feet (maf) annually. Flows have dipped during an ongoing,a long-term drought dating fromto 2000; Reclamation estimatedestimated that from 2008 to 2018, flows averaged 12.9 maf. 2 Congressional Research Service Colorado River Compact The

The Law of the River

The Colorado River Compact of 1922, agreed to by the basin states and the federal government, is the foundation of the “"Law of the River,”," which governs Colorado River water management. Under the compact, water supplies are divided equally between the Upper Basin and the Lower Basin (Figure 2), with the dividing line at Lee’s Ferry, AZ (near the Utah Border). Each basin was apportioned 7.5 maf annually. Congress approved the compact in the Boulder Canyon Project Act of 1928. Multiple other compacts, federal laws, court decisions, and regulatory guidelines have since been added to the Law of the River. State-level apportionments were established by documents approved subsequent to the Colorado River Compact. Lee Ferry, AZ (near the Utah Border). Congress approved the compact in 1928. State apportionments were established in agreements approved subsequent to the Colorado River Compact, and other laws and court decisions have further added to the Law of the River. Pursuant to a 1944 treaty with Mexico, an additional 1.5 maf per year wasis reserved for flows to Mexico.

Figure 2. U.S. Colorado River Apportionments by State Sources: Sources: Colorado River Compact of 1922, the Boulder Canyon Project Act (43 U.S.C. 617), and the Upper Colorado River Basin Compact of 1948. Notes: Assumes Colorado River Compact apportionment of 15 maf (7.5 maf to each basin). Does not reflect 1.5 maf to Mexico under the Mexican Water Treaty of 1944. Supply/Demand Imbalance Consumptive use in the basin typically exceeds natural flows, and studiesstudies project this trend will lead to a long-term imbalance in basin supply and demand. The basin has thus far avoided major impacts on supplies due in large part to its significant storage (60 mafdue to its significant storage capacity in two lakes (Lake Powell and Lake Mead), coupled with the fact that Upper Basin states have not fully developed their entitlement. However, less water is in storage as a result of the drought. Additional supply/demand imbalance could result from projected population increases and the development of tribal water rights, among other things. 3 Congressional Research Service 4 Drought Contingency Plans In October 2018, after several years of negotiations, draft DCPs were announced for the Upper and Lower Basins. The DCPs aim to decrease the likelihood of major supply curtailments and other basin impacts. They build on a series of prior agreements  2003 water in storage is dropping as a result of the drought (Figure 3). Population increases and tribal water rights are likely to further increase demand, and recent studies have concluded that Colorado River flows are unlikely to return to their 20^th century averages.

Figure 3. Lake Powell and Lake Mead Storage and Inflows

(as of fall 2018)

Source: Bureau of Reclamation, 2018.

Drought Contingency Plans

On March 19, 2019, the basin states signed and transmitted to Congress Upper and Lower Basin Drought Contingency Plans (DCPs) that aim to decrease stress on basin water supplies. They build on a series of prior efforts:

The 2003 Quantification Settlement Agreement (QSA) provided that California would reduce its California's Colorado River water use to adhere to its water allocations under the Law of the River. The 2007 (QSA). California agreed to reduce water use to adhere to its Colorado River water allocation and committed to a path for restoration of the Salton Sea in Southern California.  2007 Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead. These guidelines included criteria for “balancing”"balancing" releases frombetween Lakes Mead and Powell and a Powell and Mead and a created a mechanism for storing conserved water in Lake Mead. They also included a schedule of Lower Basin curtailments in Arizona and Nevada if Lake Mead drops to an elevation of 1,075 feet or less (i.e., a “"shortage condition”"). As of January 2019, there was a 69% chance of a shortage condition beginning in 2020. 2014 The Pilot System Conservation Program. This was initiated in 2014 as a DOI-led effort providedto provide cost-shared funding for projects to conserve water supplies in the Lower Basin. 2017 Minute 323 agreement with Mexico. This agreement extended and replaced the previous Minute 319 agreement (2012 It was reauthorized by Congress in 2018. The 2017 Minute 323 agreement with Mexico replaced a previous 2012 agreement (Minute 319) with Mexico. It included increased U.S. storage opportunities for Mexico and a binational plan that would commitcommitting Mexico to new delivery curtailments parallel to those inthat would go into effect upon approval of the Lower Basin DCP.   The Upper Basin DCP would establish a Demand Management Program for the Upper Basin by authorizing storage of conserved water in Lake Powell. It also would establish 3,525 feet as the target operational level for Lake Powell. Together, these efforts would decrease and coordinate operations with other Upper Basin reservoirs so as to reduce the risk of Lake Powell’s 's elevation falling below 3,490 feet, (a point at which point reduced hydropower generation and cutbacks to water users are possible. ). The Lower Basin DCP would require that when Lake Mead reaches predetermined elevations, Lower Basin states would forgo deliveries beyond previously agreed-upon levels. It would further incentivize the levels agreed to in 2007 (and includes for the first time cutbacks for California). It would also further incentivize voluntary conservation of water to be stored in Lake Mead and commit DOI to conserving 100,000 acrefeetacre-feet of water that willper year to be left in the system. The agreement aims to avoid Lake Mead elevations falling below 1,020 feet. DCP implementation requires approval by basin states and stakeholders of the DCPs and a number of related intrastate agreements. Federal actions in the DCPs also require authorization by Congress. On February 1, 2019, Reclamation Commissioner Brenda Burman announced that basin states had not completed all of the required steps to approve the DCPs by a previously established January 31 deadline. Thus, the bureau published a Federal Register notice requesting input from basin state governors regarding how DOI might reduce the risk of drought in the basin. If the DCPs are completed by March 19, the notice would be rescinded and the DCPs could be finalized with congressional authorization. If they are not completed, DOI may use its authority to make unilateral water delivery cutbacks in the basin. Congressional Research Service 5 Author Information Charles V. Stern Specialist in Natural Resources Policy Disclaimer This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress. Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the United States Government, are not subject to copyright protection in the United States. Any CRS Report may be reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you wish to copy or otherwise use copyrighted material. IN10984 · VERSION 7 · UPDATED

The DCPs have been approved by all states and most basin contractors. Imperial Irrigation District (a major water rights holder on the Colorado River in Southern California) has refused to approve the Lower Basin DCP without assurances of federal funding for restoration of the Salton Sea.

Before they can be implemented, the DCPs must be authorized by Congress. In a letter transmitting the DCPs to Congress, the basin states requested congressional enactment by April 22, 2019. If the DCPs are not enacted, DOI may choose to make unilateral water delivery cutbacks in the basin.