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The USGS National Water Census (NWC) is designed to systematically provide information that will allow resource managers to assess the supply, use, and availability of the Nation’s water. The goal of the NWC is to provide nationally-consistent base layers of well-documented data that account for water availability and use nationally.

The Water Availability and Use Science Program (WAUSP) supports the NWC goal through work to understand and quantify the inputs, outputs, and changes in the water budget. The primary building blocks of the water budget are base layers of precipitation, streamflow, evapotranspiration (ET), water use, and change in groundwater storage. Measurements or estimates of water budget components provide a means for decision makers to evaluate the water available for human and ecological needs as well as where stresses to the budget exist or may develop. Ideally, the WAUSP seeks to provide estimates of selected water budget components that are compiled via the National Water Census at consistent spatial and temporal scales. Through development of advanced techniques and new accounting methods for the NWC components, the WAUSP strives to provide resource managers with more accurate and finer scale information to support near-real time, local management decisions related to water availability and use.

Highlights of recent (fiscal year 2019) accomplishments and planned (fiscal year 2020) activities:

  • In 2019, two water budget components (soil moisture and recharge) were simulated using the National Hydrologic Model and made publicly available.
  • In 2019, several updates to USGS modeling software and supporting tools for working with hydrographic data and pre- and post-processing of model input and output were released. These include new versions of iRIC, PRMS, MODFLOW 6, GSFLOW, MT3D-USGS, and others.
  • In 2019, multiple assessments of groundwater availability in principal aquifers across the Nation continued or were completed. Ongoing assessments including the Mississippi Alluvial Plain (MAP), Transboundary Aquifer Assessment Project (TAPP), Colorado Plateaus, California Coastal Basins, Coastal Lowlands, and Northwest Volcanics. Recently completed work includes the Ozark Plateaus and Hawaii Volcanic-Rock aquifers. 
  • In 2019, techniques were developed for the estimation  of public-supply, thermoelectric, and irrigation water use. These techniques will be further refined and applied for the goal of sub-annual estimates of these water use categories across the nation.
  • In early 2019, daily delivery of natural water storage was made available from operationalizing the National Hydrologic Model (NHM). This work is part of a pilot for a national Integrated Water Availability Assessment
  • Plans for the pilot national Integrated Water Availability Assessment include adding metrics for the quality and use of water in late 2020.

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