Multimedia

Map of the Upper Colorado River Basin —referred to as an Integrated Water Science (IWS) basins—are intensively monitored study basins representing a wide range of environmental, hydrologic, and landscape settings and human stressors of water resources to improve our understanding of water availability across the Nation.

Water availability in the Klamath Basin is shaped by three interconnected factors, like overlapping circles in a Venn diagram. First, upper basin controls—such as groundwater, snowpack, and runoff—determine how much water is available. Second, biological opinions set flow requirements to protect endangered fish and habitats, including flushing and geomorphic flows.

Average daily water use for the top 3 water use categories in the lower 48 states: thermoelectric power generation, public supply, and crop irrigation.

In the lower 48 states, nearly 5,000 billion gallons of water fall in the form of precipitation each day. Most of that water re-enters the atmosphere through evapotranspiration, and about a quarter of our daily water input ends up as streamflow to the Atlantic and Pacific Oceans, Canada or the Gulf of Mexico.

Water limitation across the lower 48. Water limitation is measured as the Supply and Use Index (SUI) which represents the imbalance between water supply and demand. A higher SUI indicates a greater proportion of supply being used. 

A stacked bar chart showing the sources of Nitrogen across hydrologic regions of CONUS (2010-2020). Colors show the total Nitrogen load contributed from agriculture, atmospheric deposition, natural sources, wastewater, and other human sources.