On a warm day in October in 1961, the U.S. Bureau of Reclamation (USBR) began operating a series of groundwater wells in Arizona's Wellton-Mohawk Irrigation District for the purpose of relieving a buildup of brackish, highly saline water threatening the productivity of the district's farms. The pumped water, with measurable salinity exceeding 4,500 parts per million (ppm), was dumped in the otherwise barren Gila River bed which joined the Colorado River just 4 miles upstream of Mexico's Morelos Diversion Dam, the primary source of Colorado River water for the Mexicali Valley. Though much diluted by the river's stream, the level of salinity at Morelos Dam immediately spiked nearly 60 percent, from roughly 840 ppm to nearly 1,500 ppm. Crop production was soon affected, sparking widespread protests in Mexicali, Baja California. On November 9, 1961, Mexico's commissioner at the International Boundary and Water Commission (IBWC), the binational agency charged with implementing bilateral water and boundary agreements, officially rebuked the U.S. action, and shortly after, in early December, the Mexican ambassador paid a call on the U.S. Interior Department to reinforce the message. The salinity crisis had begun.
The U.S.-Mexican dispute on salinity, settled in 1973, spanned three presidencies in each country. Its protraction is attributable to fundamental differences between the countries concerning how the agreement governing the allocation and use of Colorado River water, the Treaty between the United States of America and Mexico on the Utilization of Waters of the Colorado and Tijuana Rivers, and the Rio Grande (1944 Water Treaty), [End Page 133] should be understood. The treaty, which allocated 1.5 million acre-feet of Colorado River water to Mexico, reserving the rest for the United States, had been in effect just 16 years when the conflict erupted. Its hard-fought terms for allocating Colorado River water remained controversial, particularly in Arizona and California, where politicians thought the treaty too generous to Mexico. Shoring up its approval and ratification in both countries was oblique language related to water quality, a subject the diplomats had agreed to set aside in order to gain binational assent.
The salinity crisis, then, and now, is properly understood as a dispute over the quality of water to which Mexico was entitled on the Colorado River. It was high politics; arguably, and explicitly from the Mexican perspective, the most serious issue on the binational agenda for better than a decade. It remains the most contentious of all the bilateral water issues since the 1944 Water Treaty was signed. Viewed through the lens of scholarship on the politics of international rivers it was a classic great power/small power, upstream-downstream dispute, fought on the sovereign turf of competing notions of contractual obligation established in treaty, not over formal notions of equity, or fairness.
It was high stakes at the domestic level as well. In Mexico it coincided with an upsurge in leftist agitation that challenged political alignments within the Mexican government. In the United States it engaged the Law of the Colorado River, that hard-fought complex of federal and state laws and court decisions predicated on the bedrock of the 1922 Colorado River Compact dividing the river between upper and lower basin states and the 1929 Boulder Canyon Act allocating water in the river's lower basin. Powerful state interests, agricultural and municipal, and powerful politicians well positioned in Washington, D.C., vied for the river's bounty. Some, like Colorado's Wayne Aspinall and Arizona's Carl Hayden, made securing the river's endowment the keystone of their storied careers. Hayden, in particular, had fought since 1919 to secure Arizona's claim to the river, championing a grand scheme, the Central Arizona Project that would tap the river for the development of Phoenix and Tucson and their surroundings (August, 1999: 69). As the salinity dispute unfolded Hayden and his Arizona colleagues found that carefully crafted dream nearly in reach, yet threatened by an even larger basin-wide scheme for water augmentation, the Pacific Southwest Water Plan (PSWP), and by the politics of salinity.
Unlike the 1922 Colorado River Compact governing the riparian [End...