INSTITUTIONAL FRAMEWORKS FOR EFFLUENT WATER USE IN THE AMBOS NOGALES REGION OF ARIZONA AND SONORA

Perennial flows in the U.S. portion of the Santa Cruz River downstream from the Nogales International Wastewater Treatment Plant (NIWTP) depend on its effluent discharges. The U.S. portion is subject to high variability in flows due to both wastewater overflow events resulting from heavy rainfall and decreases in flow resulting from treatment and discharge of Mexican wastewater by Mexico. The diversion of wastewater generated from the NIWTP has the potential to have social, institutional, hydrological and ecological effects to the Ambos Nogales region (Nogales, Arizona and Nogales, Sonora). Coupled with this change in discharge are potential stressors due to climate variability. The difference in institutions and legal frameworks north and south of the border further complicate water management efforts. This analysis focuses on the institutional setting for wastewater treatment and effluent in the Santa Cruz Aquifer Basin. The presentation describes the physical and legal background of the region and how those factors will impact future management decisions. The presentation will also discuss future plans regarding effluent water on both sides of the border.