New U.S.-Mexican agreement on allocation of Colorado river water.

• Author: Crook, John R.

The International Boundary and Water Commission, United States and Mexico (IBWC), is responsible for implementing the boundary and water treaties between the two countries. (1) In November 2012, at a ceremony in San Diego, U.S. and Mexican commissioners signed Minute 319, a complex agreement addressing uses of Colorado River water in times of low and high flows through 2017. The Minute amends portions of the 1944 U.S.-Mexican Colorado River Treaty, which allocates 1.5 million acre-feet of Colorado River water to Mexico annually. (2)

The system established by the Minute provides for the two countries to share both water shortages and surpluses. Mexico will forgo some of its agreed allocation during times of low water supplies when the water level of Lake Mead in Nevada and Arizona drops below 1,075 feet above sea level. During times of higher supplies when the lake's level reaches 1,145 feet, Mexico will receive additional amounts of water and be authorized to store up to 250,000 acre-feet in the lake. Water agencies in Arizona, California, and Nevada will buy water from Mexico. Under a scheme to restore the Colorado River delta, each country will supply 5,000 acre-feet of water a year to the delta. (3)

According to a U.S. Department of the Interior press release:

As part of the ongoing dialogue on Colorado River issues, delegations from the United States and Mexico have been working over the past three years to reach an agreement on a set of cooperative measures for management for the next five years. [Secretary of the Interior Ken] Salazar joined principals to the agreement from the seven Colorado River Basin states, representatives from the U.S. Department of State and the U.S. Department of the Interior, U.S. IBWC Commissioner Edward Drusina, Mexico IBWC Commissioner Roberto F. Salmon, and U.S. Bureau of Reclamation Commissioner Michael L. Connor to commemorate the effort.

The five-year agreement approved by both governments provides for a series of joint cooperative actions between the United States and Mexico. Elements of the agreement include:

* Implementing efforts to enhance water infrastructure and promote sharing, storing, and conserving water as needed during both shortages and surpluses;

* Establishing proactive basin operations by applying water delivery reductions when Lake Mead reservoir conditions are low in order to deter more severe reductions in the future;

* Extending humanitarian measures from a 2010 agreement, Minute...