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Persistent drought and chronic over-allocation of the Colorado River’s water is causing water levels at Lake Mead to drop. Hydrologists have identified specific levels beyond which the River and lake’s health may be in crisis. Arizona’s water resources manager, the Department of Water Resources, and the manager of the state’s Colorado River delivery system, Central Arizona Project, are taking steps to help ensure the lake’s long-term viability.

ADWR-02Yesterday, Wednesday, May 18, the two agencies held a joint public briefing on the issue in an effort to provide the public with answers about conditions facing the Colorado River and Lake Mead, the great reservoir from which Arizona, Nevada and California receive much of their river allocations.

Questions addressed included:

  • What is Lake Mead and what purpose does it serve? Along with its upstream complement, Lake Powell, Mead is key to storing and distributing the vast majority of Colorado River water allocated to Arizona, California and Nevada, as well as to Mexico. In order to do its job as a reservoir, Mead needs water in storage to distribute. As a result of drought and over-allocation, it has less of it. In recent years, a lot less of it.
  • What does the term shortage mean? The formula for distributing water among the three “Lower Basin” states of Arizona, California and Nevada, as well as to two states in northern Mexico, is complex. Not all rights to Colorado River water are equal. The system has priorities, many of them anchored in in almost a 100 years of legal agreements. As written, the agreements place most of the responsibility for a shortage reduction on Arizona’s shoulders. Arizona’s water managers are seeking more burden-sharing among the system’s many users.
  • What has Arizona done to prepare for potential shortage? A top priority of Arizona water management for the last 36 years can be viewed as preparation for this here and now. Legally codified groundwater/aquifer protections, “water banking,” and mandatory municipal drought-response plans have been tools in Arizona’s drought-preparedness toolkit for decades. All of which helps explain why Arizona may face substantial water-distribution challenges, but not a water-supply “crisis” such as what other states now face.
  • ADWR-03How has the Central Arizona Project prepared for having less water to deliver to its customers? The 336-mile diversion system delivers up to 1.6 million acre feet of Colorado River water from Lake Mead to customers as diverse as Pinal County farmers and urbanites in southern Arizona. CAP water deliveries support approximately 5 million residents in central Arizona and is vital to supporting the state’s economic engine.  As early as 2018, it may not have sufficient water to fulfill those obligations.
  • What is Arizona and its Lower Basin partners doing cooperatively to prepare for potential shortfalls? The goal of the Colorado River states and water user partnerships is:  Come up with a fair approach to resolving issues among yourselves before the feds do it for you. Ultimately, the Secretary of the Interior is the arbiter of how best to protect Lake Mead. A cooperative solution among water users and states, and their respective stakeholders, will be far more preferable than awaiting an edict from on high.

The bottom line from CAP’s perspective? Arizona and its water users are prepared for potential shortages on the Colorado in the near term. Arizona’s cities, towns, industries, mines and tribes using CAP water are not likely to suffer supply reductions during the next five years. A shortage in that timeframe will eliminate CAP water supplies to the Arizona Water Banking Authority and a portion of the CAP water supply for groundwater replenishment, will impact agricultural users in central Arizona and cause an increase in CAP water rates. We will need to increase our efforts and investments in order to address the growing risks of deeper shortages in the future.  Arizona, including CAP, is working hard to address the challenges of extended Colorado River shortage.  We will all need to work together, both within Arizona and with interstate partners, to sustain and protect the Colorado River system for our future.

For more information about what CAP and Arizona are doing about potential shortage, visit the CAP website.

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