International Water Law Project Blog

The following post is by Regina M. Buono, an associate attorney with the law firm of McGinnis, Lochridge, & Kilgore L.L.P in Austin, Texas. She can be reached at rbuono [at] mcginnislaw.com or found on Twitter as @ReginaBuono.

The Colorado River provides water to more than 36 million people in the western United States and Mexico.  Management of the river is governed by the Treaty for the Utilization of Waters of the Colorado and Tijuana Rivers and of the Rio Grande, which was signed in 1944 (“1944 Water Treaty”).  While the treaty is generally viewed positively for having served as a basis for successful cooperation for nearly 70 years, efforts to comply with its terms have occasionally been strained.  This was especially evident early last decade when Mexico fell behind in treaty-mandated water deliveries to the Rio Grande as a result of a prolonged regional drought.

In response to ongoing climatic changes and uncertainties, the 1944 Water Treaty was recently amended by Minute 319 to provide for both nations to share surpluses and water shortages, permit Mexico to store some of its allotted water in the United States, facilitate investment in Mexico’s water infrastructure, and restore the environmental flows of the Colorado River to the Gulf of California, albeit on an experimental scale.

Minute 319 allows Mexico, which has a dearth of storage capacity, to store some of its Colorado River allotment in Lake Mead, located in Arizona and Nevada.  This arrangement is an extension of Minute 318, which modified the 1944 Water Treaty after an earthquake in the Mexicali Valley in 2010 severely damaged Mexico’s canal-based water distribution system.  In addition to enhancing Mexico’s storage capacity and water security, the deal helps keep the water level in Lake Mead more predictable, which in turn protects the water intake pipes that supply the vast majority of Las Vegas’ drinking water.  Minute 319 also grants the U.S. a one-time allotment of 124,000 acre-feet of water in return for U.S.-financed infrastructure improvements in Mexico.  The infrastructure improvements are intended to generate water savings that will benefit all river users.

In addition, the amendment permits the U.S. to send less water to Mexico in drought years, thereby sharing the burden previously borne solely by U.S. water users.  It allows for the creation of an Intentionally Created Mexican Allocation (“ICMA”), wherein Mexico may adjust its water delivery schedule to allow for later use.  Mexico may adjust its order in dry years to offset the mandated reduction with deliveries from the ICMA or other water previously deferred. In years in which Lake Mead is projected to be at or above certain elevations and in which Mexico has deferred delivery of or created a certain minimum amount of water, Mexico may increase its order for river water in specified increments based on the water elevation. However, the annual delivery of deferred water may not exceed 200,000 acre-feet and total annual delivery may not exceed 1.7 million acre-feet.

Finally, the amendment creates a pilot program to provide water to be used as environmental flows for the Colorado River delta, which will benefit the river and the myriad species that are found there.  The delta has been largely dry for decades; most years the flow of the river is diverted before reaching its mouth at the Upper Gulf of California, leaving the river channel completely dry more than 90 percent of the time and damaging the delta ecology and wetlands that once covered the region.  Minute 319 requires water users in the U.S. and Mexico to provide a one-time high-volume “pulse” flow of 105,000 acre-feet, which will augment base flows secured by a water trust since 2008.  Scientists and advocates hope that the pulse and base flows will create 2,000 acres of new wetland habitat and will lay the groundwork for more extensive restoration projects.

Minute 319 offers a number of benefits for both nations, as well as the water utilities and environmental organizations that depend on and care for the river.  On a practical level, Minute 319 provides water departments, cities, states, and other political subdivisions that rely on the Colorado River for fresh water with the added benefit of certainty and peace of mind, which will allow them to make better business decisions and allocate risk more precisely.  Moreover, investment in Mexico’s infrastructure (e.g., concrete-lined canals instead of the current dirt channels) will benefit water users throughout the basin as a result of greater efficiency and reduced waste, which will allow conserved water to be shared with those entities that helped finance improvements.

Although the amendment has generally been received favorably by water and governmental entities alike, it is not without its critics.  Not everyone shares the opinion that allowing Mexico to store water in the lake is an unqualified good, and some have voiced resentment that domestic water users have not been granted the same flexibility.  The Imperial Irrigation District, a primarily agricultural water district in California and the largest single recipient of Colorado River water, refused to sign the agreement because it wanted to have the same ability as Mexico to bank its water in Lake Mead.  Some parties have expressed concern that keeping more water in Lake Mead means that less water will be available for hydroelectric power generation and, because water levels in the lake serve as a drought indicator, that changes in the lake’s levels due to Mexico’s ability to store water could delay a declaration of drought, in turn postponing necessary distribution reductions.  The Confederación Nacional de Campesinos, Mexico’s national farmers’ association, has also expressed concerns, calling upon farmers to present a “united front” against the agreement, which it believes will harm agricultural producers’ economic interests.

Despite differences of opinion over its impact, the most important aspect of Minute 319 may be the basis it creates for future cooperation as the river is further impacted by overuse, drought, and climate change.  Scientific research and environmental models have demonstrated that the American southwest has been impacted by and will continue to suffer from the effects of climate variability.  It is also an area with a rapidly growing population.  While the region presents a challenge to water and environmental scientists and managers, as well as for society generally, this agreement may serve as an example of creative cooperative management for other countries facing water-related challenges.  Disagreements over water resources are projected to be a leading cause—if not a primary cause—of cross-border social and political conflict in decades to come.  Accordingly, strengthening ties between Mexican and U.S. governmental officials, scientists, and water managers is critical for facilitating future cooperation and minimizing tensions.  The successful completion of this negotiation presents a precedent for cooperation going forward, and the relationships forged in the process will be valuable for future compromises over the management of the Colorado River, as well as other transboundary waters on the border.

Minute 319 is limited to a term of five years.  The short duration may have been necessary to facilitate the amendment’s acceptance by Mexican officials, as Mexico has long considered the 1944 Water Treaty to be inviolable and complained about American management practices.  Nevertheless, officials on both sides have expressed the hope that the Minute’s implementation may be extended in the future.