IMPACTS OF VARIABLE CLIMATE AND EFFLUENT FLOWS ON THE TRANSBOUNDARY SANTA CRUZ AQUIFER

The Arizona-Sonora border region is subject to limited water availability, water quality issues, and climate uncertainties. The objective of this study is to assess the impacts of changes in groundwater demand, effluent discharges, and climate uncertainties within the Transboundary Santa Cruz Aquifer from downstream of the Nogales International Wastewater Treatment Plant to the northern boundary of the Santa Cruz Active Management Area. Perennial flows in the area depend on the effluent discharges from both the U.S. and Mexico. Population growth and residential construction have increased groundwater demand in the area, in addition to wastewater treatment and sanitation demands. These human activities, coupled with climate uncertainties and possible reductions to effluent discharges influence the hydrology of the Transboundary Santa Cruz Aquifer. We use a conceptual water budget model to analyze the long-term impact of the different components of potential recharge and water losses within the aquifer. This research improves the understanding of the impact of natural and anthropogenic variables on water resources.