Integrated Water Science basins

Selected reference basins—referred to as Integrated Water Science (IWS) basins (labeled watersheds outlined in gray)—serve as regional focus areas for intensive observation, understanding, prediction, and delivery of data and information in support of deep, integrated assessments of water availability that can be extended to the broader region (colored areas) and ultimately to the Nation. To date (2023), five basins have been selected for intensive study: the Delaware River Basin, the headwaters of the Colorado and Gunnison River Basin (Upper Colorado River Basin), the Illinois River Basin, the Willamette River Basin, and the Trinity-San Jacinto River Basin.