Physical Habitats and Environmental Flows

FORT aquatic scientists analyze rings of riparian trees relating tree growth and establishment to historical flow. They then use the tree rings to reconstruct the flow in past centuries. Flow reconstructions discover the frequency and magnitude of past droughts and floods—information that is essential for management of rivers and water supplies. They have pioneered the use of cottonwood, a...

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.

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).

Wildfires pose a substantial risk to water supplies because they can lead to severe flooding, erosion, and delivery of sediment, nutrients, and metals to rivers, lakes, and reservoirs. The USGS works with federal and state land managers and local water providers to monitor and assess water quality after wildfires in order to help protect our Nation’s water resources.

In 2019, the USGS began a water-quality monitoring program in Lake Koocanusa (also known as Koocanusa Reservoir) and at a site on the Kootenai River downstream of Libby Dam to provide high-frequency water-quality data for Federal, State, Provincial, and Tribal entities in the United States and Canada.