BI-NATIONAL WATER ISSUES IN THE RIO GRANDE/RIO BRAVO BASIN

The Rio Grande (called the Río Bravo in Mexico) is the fifth largest river on the North American continent. The river supports extensive irrigated agriculture in three US and seven Mexican states as well as rapidly growing cities. From El Paso, Texas to the Gulf of Mexico the river marks the international border between Mexico and the United States. Treaties for sharing the water of the Rio Grande between the two countries and arrangements for joint management were concluded in 1906 and 1944. Over time, a complex system of water management institutions has emerged. Water problems are pronounced, due to intensive development. Over the course of the last forty years, the population in the border communities has doubled every twenty years. Demographic projections predict another doubling of the population by 2030.The entire Rio Grande basin is arid or semi-arid. Development has already led to a severe loss of biodiversity in parts of the basin. Development of new surface water resources is not a realistic option. The principal water management options include: transfer of agricultural to urban uses of water, conservation and re-use of water, and, in parts of the basin, use of water from aquifers with water of poor quality. Differences in law and levels of development between Mexico and the United States make it difficult to develop basin-wide management strategies. In addition, regional differences in hydrological conditions argue in favor of developing separate strategies for two subbasins with the largest population centers on the international border—the Paso del Norte (Las Cruces, New Mexico, El Paso, Texas and Ciudad Juárez, Chihuahua), and the Rio Grande Valley (Reynosa-Matamoros on the Mexican side, and MacAllen- Brownsville on the US side).The paper concludes with suggestions on how management of river and ground water in this bi-national growth region can assist in making available adequate water, of acceptable quality, in the 21st century.