Water Supply and Demand

Centennial Streamgages are USGS streamgages that have been in operation for more than 100 years.

The Willamette River Basin reflects the conflicting water demands between humans and ecosystems—particularly salmon— and the challenge resource managers face throughout the Pacific Northwest.

The National Water Availability Assessment Data Companion (NWDC) will deliver routinely updated water availability information in the United States.

Through the Water Availability and Use Science Program, USGS will provide national information on withdrawal, conveyance, consumptive use, and return flow by water-use category at spatial and temporal resolutions important for risk-informed water management decisions. Water-use data provide a foundation for water managers to analyze trends over time, plan more strategically, identify, and...

Water use estimates for 2000 through 2020 are now available for the three largest categories of use in the United States: self-supplied thermoelectric power generation, self-supplied irrigation, and public supply. Five additional categories of use (self-supplied industrial, domestic, mining, livestock, and aquaculture) will be available in 2025.

From the second half of the 19th century, land reclamation has transformed the Sacramento-San Joaquin Delta (Delta). The landscape of the Delta has gone from a network of shifting waterways and tidal marshland to channels and islands fixed in position by hardened levees.

Regional Water Availability Assessments are scientific assessments of water availability in different hydrologic regions across the Nation. In the Upper Colorado River Basin, the USGS will conduct a focused assessment of how snowpack and snowmelt influence hydrology and water quality, and an integrated and comprehensive assessment of multiple water quantity, quality and use factors.

Regional Water Availability Assessments are scientific assessments of water availability in different hydrologic regions across the Nation. In the Delaware River Basin, the USGS will conduct a focused assessment of increasing freshwater salinity and an integrated and comprehensive assessment of multiple water quantity, quality and use factors.

The United States faces growing challenges to its water supply, and we need to know where there is not enough water, where we have more than we need, and the quality of the water. The USGS is charged with understanding and reporting on water availability including influences on water supply (how much water and of what quality) and water demand (how much water do humans and ecosystems need).

The USGS Water Resources Mission Area is assessing how much water is available for human and ecological needs in the United States and identifying where and when the Nation may have challenges meeting its demand for water.

The Delta of the Sacramento and San Joaquin rivers provides drinking water supplies to two-thirds of Californians, and is a fragile ecosystem home to threatened and endangered species. The CASCaDE project builds on several decades of USGS science to address the goals of achieving water supply reliability and restoring the ecosystems in the Bay-Delta system.

The USGS Water-Use Data and Research (WUDR) program provides financial assistance through cooperative agreements with State water resource agencies to improve the availability, quality, compatibility, and delivery of water-use data that is collected or estimated by States.