Focus Area Studies were stakeholder-driven assessments of water availability in river basins with known or potential conflict. They contributed toward ongoing assessments of water availability in large watersheds, provided opportunities to test and improve approaches to water availability assessment, and informed the National Water Census with local information. These studies focused on key water-budget components and the integration of assessment tools, including computer models, to better understand the linkages among budget components—surface water and groundwater—and their relation to the ecosystems they support.