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
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
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.
Below are other science components of the National Water Census.
Water Availability and Use Science Program: National Water Census
National Water Census: Brackish Groundwater Assessment
National Water Census: Streamflow
National Water Census: Water Use
National Water Census: Environmental Flows
National Water Census: Evapotranspiration
National Water Census: Focus Area Studies
National Water Census: Regional Groundwater Availability Studies
- Overview
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
Sources/Usage: Public Domain.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
Sources/Usage: Public Domain.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.
- Science
Below are other science components of the National Water Census.
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.National 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...National 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 streamgage data available to the public, most of it in "near...National 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.National 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 and...National 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 irrigation...National 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 the...National 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. - Publications