Integrated Water Availability Assessments (IWAAs)

Science Center Objects

The USGS Integrated Water Availability Assessments (IWAAs) are a multi-extent, stakeholder driven, near real-time census and prediction of water availability for both human and ecological uses at regional and national extents.

Graphic showing the four components of water availability

Water availability reflects the quantity, timing, quality, and use of water resources. More specifically, water availability has four components: (1) the need for a certain volume of water to meet the intended purpose, (2) the timing characteristics with which water is delivered, (3) the adequate quality of the water for the intended purpose, and (4) the need for water to meet human and environmental/ecological uses.

The USGS Integrated Water Availability Assessments (IWAAs) will provide nationally consistent assessments of water available for human and ecological needs in the United States and identify factors that limit water availability or could lead to conflict. The IWAAs are designed to provide information to meet the goals of the National Water Census as established through the SECURE Water Act. These goals are to:

  1. Provide accurate assessment of available water resources
  2. Determine quantity of water available for human and ecological needs
  3. Quantify long-term trends in water availability
  4. Provide assessment of change in water availability
  5. Explore factors that limit water availability or could lead to conflict
  6. Forecast water availability for economic development, energy production or conservation, and environmental or other in-stream uses

When fully implemented, the IWAAs will, at national and regional scales:

  • Evaluate current water supply and demand and the factors that influence availability
  • Evaluate long-term trends in water availability and their causes
  • Provide seasonal to decadal forecasts of availability
  • Support water-resource management through design and delivery of management-relevant data and water-availability assessment products.


National IWAAs

The national IWAAs is under development to provide a near-real-time census of water resources at the sub-watershed scale (tracts of 10,000–40,000 acres). When fully realized, the census will provide status, trends and forecasts of the amount of surface water and groundwater available to support various uses over spatial extents including individual watersheds, major hydrologic regions, and the Nation.

The National IWAAs water-availability map (currently offline for updates) is an evolving National Census integrating product showing daily estimates of natural water storage (water on the landscape such as standing water, snowpack, soil water, and shallow groundwater) for the conterminous United States. The IWAAs National map is the first product to visualize a current, quantitative view of water availability at the national scale.

As this National IWWAs census product evolves additional hydrologic parameters will be produced and other indicators of water availability will be included on this representation, as well as water availability predictions.

Animation of the National Integrated Water Availability Assessments concept map from November 2019

This animation highlights the USGS Integrated Water Availability Assessments (IWAAs) Program’s evolving capacity to estimate water availability at a national scale by visualizing daily estimates of natural water storage (water present on the landscape such as standing water, snowpack, soil water, and shallow groundwater) for approximately 110,000 regions across the conterminous United States. The data shown in this visualization were sourced from the IWAAs concept map, which is currently offline for revisions and enhancements.


Regional IWAAs

Models, tools, and supporting data developed for the national IWAAs will be augmented by more refined information from select regional studies and assessments to improve national IWAA water-availability models. The specific information needs of each regional IWAA will be informed by local hydrologic conditions and input from partners and stakeholders regarding information gaps and resource management needs. Work is underway in the Delaware and Upper Colorado River Basin and will begin in FY2022 in the Illinois River Basin. Regional IWAAs plans to intensively assess at least 10  basins—medium-sized (10,000-20,000 square miles) and underlying aquifers—over the next decade.

Map of the Delaware River Basin

Delaware River Basin: The Regional IWAAs study in the Delaware River Basin will develop integrated assessment and modeling approaches in a complex interstate river system.

Map of the Upper Colorado River Basin

Upper Colorado River Basin: A new Regional IWAAs in the Upper Colorado River Basin will provide an opportunity to improve regional water prediction in snowmelt dominated systems.

Map of the Illinois River Basin

Illinois River Basin: A Regional IWAAs in the Illinois River Basin is being added in 2022 to assessment capacity gaps including nutrient delivery and harmful algal bloom prediction.

Map of the national IWS basin candidates, with previously selected basins highlighted

Future Regional IWAAs: New Regional IWAAs will be added as funding is available. Basin selections will consider environmental, and human settings, ecological resources, and water supply, use and quality characteristics.


IWAAs Design

The USGS Integrated Water Availability Assessments (IWAAs) combine resources and knowledge gained from previous and ongoing USGS efforts such as Focus Area StudiesRegional Groundwater Availability Studies; and Water UseEnvironmental Flows, and Streamflow estimation, in addition to utilizing and providing feedback to the National Water Model.

IWAAs will be supported by innovative data collection and delivery, incorporated, in part, through the Next Generation Water Observing System (NGWOS) programs, and by the integrated hydrologic cycle and water-quality modeling capacity developed by the USGS Integrated Water Prediction Program. For Regional IWAAs specifically, these three programs, with support from other USGS activities, will combine in an Integrated Water Science (IWS) Basin approach to provide the observations, understanding, predictions, and information delivery necessary for sound decision-making related to water availability management.

IWAAs also works through collaborative agreements with State and local partners with the support of Cooperative Matching Funds. In FY 2019, 10 projects were selected across the U.S. that will help to support development of National and Regional IWAAs. These projects will focus on improving the data, tools, and information stakeholders need to make water-resource management decisions.


Featured Water Availability Data, Maps, and Tools

Screenshot of the National Water Dashboard

National Water Dashboard: View over 13,000 USGS real-time monitoring stations in context with current weather and hazard conditions.

Map showing U.S. irrigation water use by county

Water use in the U.S.: View 2015 water withdrawals by county, state comparisons, and other information in this interactive data visualization.

Screenshot showing national lowest annual 7-day average streamflow trends from 1941-2015

Surface Water Flow Trends in the Nation's Streams and Rivers: Trends in low and high streamflows in the Nation's streams and rivers over the past 100, 75, and 50 years.

Screenshot of the Delaware River Basin water-quality trends mapper

Multisource Water-Quality Trends in the Delaware River Basin: Changing water quality in rivers and streams across the Delaware River Basin from 2008-2018.