RIO GRANDE WATER APPORTIONMENT

Apportionment of water of the Rio Grande between the United States and Mexico is determined by various compromises and treaties made between 1904 and 1944. The first attempt at apportionment of the waters was the Compromise of 1904, which divided the waters above and below El Paso. In the treaty of 1906 the United States promised to deliver 60,000 acre-feet of water annually for irrigation in the Juárez valley, peak period of delivery falling in April, May, and June. In return Mexico waived all claims for any purpose to the waters of the river between the head of the Mexican Canal and Fort Quitman, Texas. The 1944 treaty dealt with the Rio Grande between Fort Quitman and the Gulf of Mexico. The following order of preference in joint use of the international waters was set up: (1) domestic and municipal uses, (2) agriculture and stock raising, (3) electric power, (4) other industrial uses, (5) navigation, (6) fishing and hunting, and (7) any other beneficial use to be determined by the International Boundary Commission. Under Article IV Mexico received all of the waters of the San Juan and Alamo rivers, one-half of the flow in the main channel of the Rio Grande below the lowest major international storage dam; two-thirds of the flow in the main channel from the Conchos, San Diego, San Rodrigo Escondido, and Salado rivers and Las Vacas Arroyo, provided that the United States receive from these same six streams not less than 350,000 acre-feet annually as an average in five-year cycles, and one-half of all other flows not otherwise allotted, occurring in the main channel of the Rio Grande. Also under Article IV the United States was given all of the waters of the Pecos and Devils rivers, Goodenough Spring, and Alamito, Terlingua, San Felipe, and Pinto creeks; one-half of the flow in the main channel of the Rio Grande below the lowest major international storage; one-third of the flow reaching the main channel of the Rio Grande from the Conchos, San Diego, San Rodrigo, Escondido, and Salado rivers and Las Vacas Arroyo, provided that this be not less than 350,000 acre-feet annually as an average in five-year cycles, and one-half of all other flows not otherwise allotted, occurring in the main channel of the Rio Grande. The quantity of water allotted to the United States not only took care of existing needs but also permitted expansion of irrigated areas. In 1993 the 1944 treaty remained in effect. See also RIO GRANDE COMPACT. 

BIBLIOGRAPHY: Wallace Hawkins, "Water Rights in United States-Mexico Streams," Temple Law Quarterly 5 (January 1931). Norris Hundley, Dividing the Waters: A Century of Controversy between the United States and Mexico (Berkeley: University of California Press, 1966). Douglas Robert Littlefield, Interstate Water Conflicts, Compromises, and Compacts: The Rio Grande, 1880-1938 (Ph.D. dissertation, University of California, Los Angeles, 1987). J. Simsarian, "The Diversion of Waters Affecting the United States and Mexico," Texas Law Review 17 (December 1938). Charles A. Timm, "Some International Problems Arising from Water Diversion on the United States-Mexican Boundary," Southwestern Social Science Quarterly 13 (June 1932). 

Jacqueline E. Timm