Impacts in Mexico of Colorado River management in the United States - A history of neglect, a future of uncertainty

The Colorado River terminates in Mexico as a threaded delta above the Sea of Cortez (Gulf of California). Decades of water depletion, enabled largely by water projects in the United States, resulted in little or no water flowing in the channel. This lack of water has caused losses of wetlands, riparian vegetation, and estuarine habitat, reducing fish and wildlife populations, including some endangered species. Cucupa Indians who depended on fishing and gathering lost their traditional occupations. Recent years of high runoff revitalized the ecosystems of the Colorado River Delta and this animated nongovernmental organizations and scientists to call attention to the issue. Water users in the United States have objected in principle to addressing the issue because they resist the concept of ensuring the delivery of additional water to Mexico beyond current legal requirements, even in the small quantities needed for ecological maintenance. Mexico has not formulated a clear official position on the issue. Past transboundary water conflicts between the two countries over the quantity and quality of Colorado River water owed by the United States to Mexico have been characterized by neglect, followed by vigorous protest from Mexico, strong U.S. resistance from states and water users, and finally belated concessions at a high diplomatic level. There are several possible remedies to the delta problem that would help the countries avoid the conflictive approach of the past.