New Mexico Water Resources Research Institute–Supported Hydrogeologic Studies in the Binational Mesilla Basin

Our review of hydrogeologic research in the binational Mesilla Basin/Rio Grande Valley area of New Mexico, western Texas, and Chihuahua (Mexico) emphasizes the seminal role the New Mexico Water Resources Research Institute (WRRI) at New Mexico State University played in supporting a wide variety of water-resources studies at universities of the upper Rio Grande basin region. Establishment of the WRRI and similar university-based programs throughout the USA in 1964 represents a major advancement in water-science that is particularly relevant to studies of groundwater and surface-water systems in arid-semiarid intermontane basins of the American West. While many federal and state governmental agencies and some universities had well-established water-resource programs, no formal effort had previously been made to promote well-coordinated/financed research programs at state universities. The WRRI-institutional structure was designed to (1) stimulate and support water research at faculty-directed, graduate-student levels, and (2) provide administrative and technical support for funding acquisition and allocation, and project-completion report preparation. Major structural and hydrostratigraphic components of the Mesilla Basin aquifer systems are Rio Grande rift-fault zones, Late Cenozoic Santa Group basin fill, and Rio Grande fluvial deposits in the Mesilla Valley. Basin surface area is about 2850 km², and maximum aquifer-system thickness (including ancestral-river deposits) is 600 m. The Mesilla Valley floor located near the eastern basin border is the sole source of significant groundwater recharge. The Rio Grande exits the valley through El Paso del Norte in the northwestern part of the El Paso/Ciudad Juárez metro area (population about 2 million). Less than 20% of the basin is in Mexico (northern 15% of Chihuahua’s Conejos-Médanos groundwater administrative district) where freshwater aquifers are less than 100 m thick. We conclude our presentation with a brief review of WRRI-supported hydrogeologic research in the Mesilla Basin area. Emphasis is on university graduate-level research, and collaboration with supporting governmental agencies.