The Palomas, Mesilla, and Conejos-Médanos Basins in New Mexico, Texas, and northern Mexico compose a geologically and hydrologically complex region. The conjunctive use of surface water and groundwater takes place under a myriad of legal and operational constraints, including the Rio Grande Compact, an international treaty, and the U.S. Bureau of Reclamation’s Rio Grande Project. New demands are being placed on the interconnected water system, even as the region is experiencing an extended drought.