This project builds upon a Border 2020 Program project funded in 2019 which focused on the Goodenough Spring (Texas). The goal of the project is to develop a more robust hydrologic characterization of the water resources of the Amistad Reservoir, with an emphasis on filling in critical data gaps pertaining to the Mexican state of Coahuila bordering with Val Verde County, Texas region. Additional water samples will be collected from wells, springs and surface-water in the Coahuila-Texas border, to expand the understanding of the region’s hydrogeochemistry and water quality. By understanding the hydrochemistry of the region, water agencies will have additional information to make decisions to better protect these water resources which sustain diverse human and ecological communities. Project results will be shared with binational stakeholders in the region.