Ensuring Arizona’s Future Today: The Lower Basin Drought Contingency Plan and its Implementation in Arizona

Abstract

The Colorado River provides water to over 40 million people and to nearly 5.5 million acres of farmland in seven states, and more than 4,200 megawatts of electrical generating capacity from hydroelectric facilities, before providing water to approximately 2.8 million people in Mexico and irrigating around 207,000 hectares (over 511,000 acres). The river is vital to the economies of the southwestern United States and Mexico and has become one of the most regulated and managed rivers in the United States. The Colorado River Basin is divided into two basins: the Upper Basin (consisting of areas of Arizona, Colorado, New Mexico, Utah, and Wyoming) and the Lower Basin (consisting of areas of Arizona, California, and Nevada). The Colorado River was allocated in the first half of the twentieth century, during one of the highest-flow periods in its known history. Since that time, it has become apparent that the Colorado River is overallocated. Additionally, the River is a highly variable system, subject to dramatic change in runoff from year to year. Based on tree ring studies, the period from 2000 to 2015 ranks as the fifth driest 16-year period in the last 1,200 years. Recognizing the gravity of the situation, representatives from the Lower Basin States and the Bureau of Reclamation (Reclamation) have been working on plans to avoid and mitigate shortage since the early 2000s. Although the 2007 Interim Guidelines helped to coordinate operations of Lake Powell and Lake Mead and provided tools to conserve and augment supplies on the river, by 2013 there was broad recognition additional work remained to be done. Due to the junior priority of much of its Colorado River allocation, Arizona has been preparing for shortages for decades. For many Arizona users, the greater threat has been deeper shortages that could be catastrophic. The Colorado River supplies approximately 38% of Arizona’s water needs. If a shortage is declared on the Colorado River, Arizona bears the brunt of the reductions, with the Central Arizona Project (CAP) water users taking most of the reductions. Collective efforts to conserve water in Lake Mead have been hugely successful and have been instrumental in avoiding shortages since 2015. The proposed Lower Basin Drought Contingency Plan (LBDCP) would continue these conservation efforts through additional reductions to all three Lower Basin States, along with conservation by Reclamation, into 2026, with a goal of reducing the risk of Lake Mead elevation falling to 1020 feet. Mexico has already agreed to participate in corresponding additional reductions, should the LBDCP become effective in the U.S.13 Arizona’s future, economic and otherwise, depends on the ability of its water users to come together and agree to the LBDCP through one voice.