Environmental evidence of surface manifestations of regional groundwater flows in the lower Colorado River Basin: the case Mexicali Valley, Mexico

Transboundary water in the Lower Colorado River Basin, shared between Mexico and the United States, demands robust, collaborative governance frameworks to address drought and increasing water demands. Although groundwater resources have become increasingly strategic for meeting water demands in both countries, they rarely receive formal consideration in official studies. Through geospatial analysis, this research delineates for the US portion of the Lower Colorado River Basin, the spatial distribution of recharge and discharge zones within the interconnected groundwater and surface water systems to characterize the regional components of groundwater flow. Employing a methodology based on the Tóthian framework of gravity-driven groundwater flow systems, the study emphasizes the interconnection of groundwater with perennial surface water, soil taxonomy, land use and land-forms as indirect evidence of its surface manifestation throughout this basin. The results are represented in discharge and recharge zones related to regional groundwater flow. Results highlight the need for binational data homologation and integration process to strengthen the available groundwater assessment tools for sustainable management in the U.S.-Mexico border.