US and Mexico Pact on Colorado River Water Rights

Water rights are a fairly obscure topic to most lawyers – unless one is in a place like the southwestern United States or northwestern Mexico, in which case water rights are a kind of underlying regulatory structure of many other things, such as patterns of agriculture, urban and suburban development, etc. I can think of lawyers I’ve known in the American Southwest who would think this radically understates matters, however, and who would take the history of region to be, at its core, the history of water and the regulation of its allocation. (Update: And water rights are so obscure a topic to lawyers educated Back East like me that I managed to misuse the term “riparian” – thanks to Ted Orf of Orf & Orf PC for correcting me; I’ve amended it here.)

Certainly I’m prone to forget how important these issues become when rivers cross national borders, and where actions, such as dams or other diversions or pollution or environmental harm by the upstream country can have enormous effects on downstream countries. A senior Egyptian official once told me in passing (years ago) that if, purely hypothetically, there were ever a Sudan that decided to divert significant parts of the Nile, Egypt would regard it as a casus belli if negotiations did not fix it.  I asked on what legal theory, and he merely shrugged.  It’s a reminder that the security interests for which states feel compelled and entitled to war have always included things beyond simply an armed attack upon one’s sovereign territory.  It’s also to note that there is a body of customary law on cross-border water rights – much of it particular to bilateral relationships around unique river and water systems, codified by treaty in some cases but not in others.

In any case, water rights tend to structure things at the infrastructure and development level – oftentimes large numbers of people’s expectations for the long term are set around long run expectations about water supply, so that disruptions across borders might not occasion merely a marginal change of degree in behavior, but trigger institutional crises. People’s livelihood are often at stake, but sometimes, not just livelihoods but a whole way of life for a region.

In the field of bilateral sovereign water rights, the United States and Mexico (which have had serious disagreements and significant tensions over water rights in the past) have signed a new five year set of amendments to their 1944 Colorado River pact. (The treaty text of the 1944 agreement is here; the website from which it is drawn, the Mexico-US International Border and Water Commission, offers a fascinating set of documents and history.)  The amendments essentially bring Mexico into an arrangement created by US states sharing Colorado River water, to address times of drought. The essence of the pact, as with the inter-US-state agreement, is to allow a party to “bank” water during wetter periods in reservoirs upstream, and then draw on that water in times of drought.

Whether this will work as planned, or whether it will address the generally drier conditions or greater total demands for water in the region, I don’t know. I did a quick check of Mexican press online, and there seemed to be a cautious endorsement of the new pact there; I’m definitely no expert on water rights, let alone cross-border water rights between Mexico and the US. But I thought it was an interesting and important instance of international agreements over water rights. Here is how the WaPo (AP) story describes it:

The far-reaching agreement gives Mexico badly needed water storage capacity in Lake Mead, which stretches across Nevada and Arizona. Mexico will forfeit some of its share of the river during shortages, bringing itself in line with western U.S. states that already have agreed how much they will surrender when waters recede. Mexico also will capture some surpluses when waters rise. Also under the plan, water agencies in California, Arizona and Nevada will buy water from Mexico, which will use some of the money to upgrade its canals and other infrastructure.

The agreement, coming in the final days of the administration of Mexican President Felipe Calderon, is a major amendment to a 1944 treaty considered sacred by many south of the border. The treaty grants Mexico 1.5 million acre-feet of river water each year — enough to supply about 3 million homes — making it the lifeblood of Tijuana and other cities in northwest Mexico. The pact represents a major departure from years of hard feelings in Mexico about how the U.S. manages the 1,450-mile river, which runs from the Rocky Mountains to Mexico. In 2001, U.S. states established rules on how to divide surpluses but set aside nothing for Mexico. Several years later, the U.S. government lined a border canal in California with concrete to prevent water from seeping through the dirt into Mexican farms.

“We have chosen collaboration over conflict, we have chosen cooperation and consensus over discord,” said U.S. Interior Secretary Ken Salazar, who called the new pact the most important international accord on the Colorado River since the 1944 treaty. Mexico will begin to surrender some of its Colorado River allotment when Lake Mead drops to 1,075 feet above sea level and begin to reap surpluses when it rises to 1,145 feet. Mexico will be allowed to store up to 250,000 acre-feet of water in the reservoir and draw on nearly all of those reserves whenever needed. The agreement expires in five years and is being billed as a trial run, potentially making it more palatable in Mexico.

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