National Water Census: Groundwater
Science Center Objects
The National Water Census (NWC) is leveraging a long history of groundwater studies and is accelerating ongoing regional studies to assess the Nation's groundwater reserves, studies that formerly were conducted under the USGS Groundwater Resources Program. The NWC is also increasing the ability to integrate groundwater and surface-water analyses into watershed-level assessments of water availability.
Water Census • Streamflow • Groundwater • Water Use • Environmental Flows • Evapotranspiration • Focus Area Studies
Regional Groundwater Availability Studies
Map of Regional Groundwater Availability Studies from the USGS National Water Census.
A major element of the National Water Census is regional analysis of groundwater availability, continuing a series of studies begun under the USGS Groundwater Resources Program. Current plans call for studies of 30–40 principal aquifers that collectively account for more than 90 percent of the Nation's total groundwater withdrawals. The regional scale of these studies enables information to be integrated and consistent, so the resource can be analyzed and understood on an aquifer–wide scale. Therefore, it provides decision–makers with a better understanding of the status and trends in the Nation's groundwater availability. Water managers are now looking for ways to better manage known groundwater resources while also identifying supplemental sources of water. These multidisciplinary studies of regional groundwater availability across the United States will provide resource managers and policy makers with essential information needed for management of a limited resource.
View the list of regional groundwater availability studies
Groundwater Recharge, Storage, and Discharge Rates for Water Budgets
The National Water Census also will develop estimates of groundwater recharge, storage, and discharge at the watershed scale, as much as possible. These estimates will be made using a combination of information from large–scale studies, observed data on groundwater levels collected in well networks, analysis of streamflow records, water use, and other available information.
Brackish Water Sources
Predicted depth to brackish groundwater from Brackish groundwater In the United States
Brackish groundwater, as a resource for direct use or for desalination, potentially represents an increasingly important component of the Nation's water supply. Relatively little is known, however, about brackish groundwater as compared to fresh groundwater. A better understanding of the distribution and characteristics of brackish groundwater can provide information for future development of this resource. To satisfy requirements of the SECURE Water Act, the National Water Census provided funding to conduct the National Brackish Groundwater Assessment.
Read more about the National Brackish Groundwater Assessment.
Water Availability and Use Science Program: National Water Census
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.
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Date published: July 22, 2021Status: CompletedNational Water Census: Brackish Groundwater Assessment
All water naturally contains dissolved solids that, if present in sufficient concentration, can make a water resource "brackish", or distastefully salty. The amount of fresh or potable groundwater in storage has declined for many areas in the U.S., leading to concerns about the future availability of water. Using brackish groundwater could supplement or, in some places, replace the use of...
Attribution: Water Resources -
Date published: March 2, 2019Status: ActiveNational Water Census: Streamflow
The USGS National Water Census complements the USGS national network of more than 8,000 streamgages by estimating streamflow for ungaged locations throughout the country, by analyzing streamflow records, and by providing tools for analysis of streamgage data to end users. The USGS National Water Information System (NWIS) makes the actual...
Attribution: Water Resources -
Date published: March 2, 2019Status: ActiveNational Water Census: Water Use
Through the National Water Census, USGS will provide more comprehensive reporting of national information on withdrawal, conveyance, consumptive use, and return flow by water-use category. Water-use data enables water managers to plan more strategically and enables the analysis of trends of over time. It is also vital to water-availability studies such as watershed and groundwater models.
Attribution: Water Resources, Water Resources Research Act Program -
Date published: March 2, 2019Status: ActiveNational Water Census: Environmental Flows
Environmental water studies refer to understanding the quantity, timing, and quality of water flows, as well as the water levels and storage required to sustain freshwater and estuarine ecosystems and the human livelihoods that depend on these ecosystems. The concept of ‘environmental flows’ in stream ecology are the basis of these studies, but they go beyond the understanding of surface flows...
Attribution: Water Resources -
Date published: March 2, 2019Status: ActiveNational Water Census: Evapotranspiration
No water budget would be complete without accounting for evaporation and related processes, such as transpiration and sublimation. Evapotranspiration, or "ET," refers to the combined flux of plant transpiration and evaporation from the adjacent soil. It is especially important for understanding water used by irrigated crops, and is related to crop productivity. Consumptive water use for...
Attribution: Water Resources -
Date published: March 2, 2019Status: ActiveNational Water Census: Focus Area Studies
Focus Area Studies are stakeholder-driven assessments of water availability in river basins with known or potential conflict. They contribute toward ongoing assessments of water availability in large watersheds, provide opportunities to test and improve approaches to water availability assessment, and inform and ground truth the National Water Census with local information. Common to each of...
Attribution: Water Resources -
Date published: February 28, 2019Status: ActiveNational Water Census: Regional Groundwater Availability Studies
The National Water Census includes regional analysis of groundwater availability, enabling information to be integrated and consistent so the resource can be analyzed and understood on an aquifer–wide scale. The NWC also seeks to increase capacity to integrate groundwater and surface water into watershed-level assessments of water availability.
Attribution: Water Resources
Generalized hydrogeologic framework and groundwater budget for a groundwater availability study for the glacial aquifer system of the United States
The glacial aquifer system groundwater availability study seeks to quantify (1) the status of groundwater resources in the glacial aquifer system, (2) how these resources have changed over time, and (3) likely system response to future changes in anthropogenic and environmental conditions. The glacial aquifer system extends from Maine to Alaska,...
Reeves, Howard W.; Bayless, E. Randall; Dudley, Robert W.; Feinstein, Daniel T.; Fienen, Michael N.; Hoard, Christopher J.; Hodgkins, Glenn A.; Qi, Sharon L.; Roth, Jason L.; Trost, Jared J.
Groundwater-level trends in the U.S. glacial aquifer system, 1964-2013
The glacial aquifer system in the United States is a major source of water supply but previous work on historical groundwater trends across the system is lacking. Trends in annual minimum, mean, and maximum groundwater levels for 205 monitoring wells were analyzed across three regions of the system (East, Central, West Central) for four time...
Hodgkins, Glenn A.; Dudley, Robert W.; Nielsen, Martha G.; Renard, Benjamin; Qi, Sharon L.
Maps and grids of hydrogeologic information created from standardized water-well drillers’ records of the glaciated United States
As part of the National Water Availability and Use Program established by the U.S. Geological Survey (USGS) in 2005, this study took advantage of about 14 million records from State-managed collections of water-well drillers’ records and created a database of hydrogeologic properties for the glaciated United States. The water-well drillers’...
Bayless, E. Randall ; Arihood, Leslie D.; Reeves, Howard W.; Sperl, Benjamin J.S.; Qi, Sharon L.; Stipe, Valerie E.; Bunch, Aubrey R. Evaluating the sources of water to wells: Three techniques for metamodeling of a groundwater flow model
For decision support, the insights and predictive power of numerical process models can be hampered by insufficient expertise and computational resources required to evaluate system response to new stresses. An alternative is to emulate the process model with a statistical “metamodel.” Built on a dataset of collocated numerical model...
Fienen, Michael N.; Nolan, Bernard T.; Feinstein, Daniel T. A semi-structured MODFLOW-USG model to evaluate local water sources to wells for decision support
In order to better represent the configuration of the stream network and simulate local groundwater-surface water interactions, a version of MODFLOW with refined spacing in the topmost layer was applied to a Lake Michigan Basin (LMB) regional groundwater-flow model developed by the U.S. Geological. Regional MODFLOW models commonly use coarse grids...
Feinstein, Daniel T.; Fienen, Michael N.; Reeves, Howard W.; Langevin, Christian D. Metamodels to bridge the gap between modeling and decision support
Fienen, Michael N.; Nolan, Bernard T.; Feinstein, Daniel T.; Starn, J. Jeffrey A cross-validation package driving Netica with python
Bayesian networks (BNs) are powerful tools for probabilistically simulating natural systems and emulating process models. Cross validation is a technique to avoid overfitting resulting from overly complex BNs. Overfitting reduces predictive skill. Cross-validation for BNs is known but rarely implemented due partly to a lack of software tools...
Fienen, Michael N.; Plant, Nathaniel G. Review: groundwater in Alaska (USA)
Groundwater in the US state of Alaska is critical to both humans and ecosystems. Interactions among physiography, ecology, geology, and current and past climate have largely determined the location and properties of aquifers as well as the timing and magnitude of fluxes to, from, and within the groundwater system. The climate ranges from maritime...
Callegary, J.B.; Kikuchi, C.P.; Koch, Joshua C.; Lilly, M.R.; Leake, S. A.
Bibliography of groundwater resources of the glacial aquifer systems in Washington, Idaho, and northwestern Montana, 1905-2011
The U.S. Geological Survey Groundwater Resources Program is undertaking a series of regional groundwater availability studies to improve our understanding of groundwater availability in major aquifers across the Nation. One of the objectives of the Glacial Principal Aquifers study (proposed) is to provide information on the occurrence of...
Kahle, Sue C.; Futornick, Zoe O.