USGS Integrated Water Availability Assessments: Water Priorities for the Nation

The United States faces growing strains on its water supply, infrastructure and aquatic ecosystems from population growth, climate change, floods and droughts and aging delivery systems. The USGS Water Resources Mission Area created Integrated Water Availability Assessments (IWAAs) to bring its monitoring, modeling and computing advances to bear on these problems.

Water availability has four components: quantity, timing, quality, and human and ecological use. USGS.

What IWAAs will do

Nationally and regionally consistent assessments of water for human and ecological needs, and of what limits it, at many scales. Fully implemented, they will:

1. evaluate current water supplies and demands and what affects them;
2. measure long-term trends in water availability and their causes;
3. forecast availability from seasons to decades ahead;
4. support management with integrated data and assessment products.

Their usefulness depends on working closely with federal, Tribal, state, regional and local partners.

The national assessment

A near-real-time census of water at the subwatershed scale — tracts of 10,000–40,000 acres — with assessments and forecasts of surface water and groundwater available for various uses, from single watersheds to the nation, plus source-water quality and the socioeconomic factors that drive demand. It will rest on next-generation observation systems and growing modeling of the water cycle and water quality.

A national IWAA concept map of daily natural water storage — standing water, snowpack, soil water and shallow groundwater — the first current, quantitative view of water availability nationwide. USGS.

Regional assessments

Regional studies refine the national models with detail shaped by local hydrology and by partners' information gaps and management needs: better regional water budgets, key parts of availability, and controls on water quantity, quality and use.

• Delaware River Basin (pilot, 2019) is testing new approaches:
• • past droughts and future supply under drought;
  • how water quality affects availability for people and ecosystems;
  • new data techniques and models to predict water use;
  • streamflow trends as input for forecasting reservoir storage.
• Upper Colorado River Basin (2020): the first fully implemented regional IWAA, chosen to improve prediction in snowmelt-dominated systems.
• More to come: one new basin a year, as funding allows, until 10 basins chosen by a selection team — weighing environmental, engineered and social settings, ecological resources, demand, water quality and quantity, and change — have IWAA projects.

One of four priorities

The USGS Water Mission Area plays an essential role in managing the nation's water, and IWAAs are one of its four priority programs:

The four USGS Water Mission Area priority programs. USGS.

Sources

Based on Water Priorities for the Nation—U.S. Geological Survey Integrated Water Availability Assessments, by Mark P. Miller, Brian R. Clark, Sandra M. Eberts, Patrick M. Lambert and Patricia Toccalino, U.S. Geological Survey Fact Sheet 2020–3044 (publication page), citing the National Academies of Sciences, Engineering, and Medicine (2018). Figures and the Delaware pilot's list, which arrived garbled, are restored from the fact sheet's PDF; a map on a licensed basemap and a photograph used with permission are left out. A work of the United States government in the public domain.