Water Supply and Demand

Since 1950, the USGS has regularly produced nationwide water‑use data, creating one of the most comprehensive pictures of how water is used across the United States. Building on this rich historical record, these data give water managers a critical foundation to evaluate long‑term trends, plan strategically, and identify and quantify water availability so they can design more adaptive, resilient...

The USGS National Water Availability Assessment consists of reports, which provide a scientific summary and interpretation of water quantity, quality and use, and the data companion, which delivers model-based estimates of water supply and demand.

Regional Water Availability Assessments are scientific assessments of water availability in different hydrologic regions across the Nation. They are designed to capture a range of conditions in major drivers of water availability.

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 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 National Water Availability Assessment Data Companion (NWDC) delivers model-based estimates of water supply and demand.

As of October 2024, the USGS Groundwater and Streamflow Information Program supports the collection and (or) delivery of both streamflow and water-level information at 8,705 sites and water-level information alone at 3,460 additional sites. The data are served online—most in near real-time—to meet many diverse needs including the protection of life, property, the environment, and our economy.

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.

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.