Mapping Water

To manage our water resources effectively, we need to understand how much water is available and its usefulness. The USGS monitors the nation’s water resources through various national observing networks that use a range of technologies and methods to assess real-time water conditions and predict future changes in water availability for human and ecological uses.

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.

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 National Atmospheric Deposition Program (NADP) is a collaboration of atmospheric monitoring networks. The purpose of the networks is to collect data to evaluate air quality. Network data also inform science-based actions to protect human health and preserve ecosystems for current and future generations. The NADP National Trends Network (NTN) quantifies the concentration of eight major ions and...

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.

Karst terrain is created from the dissolution of soluble rocks, principally limestone and dolomite. Karst areas are characterized by distinctive landforms (like springs, caves, sinkholes) and a unique hydrogeology that results in aquifers that are highly productive but extremely vulnerable to contamination.

The U.S. Geological Survey is integrating its water science programs to better address the Nation’s greatest water resource challenges. At the heart of this effort are plans to intensively study at least 10 Integrated Water Science (IWS) basins — medium-sized watersheds (10,000-20,000 square miles) and underlying aquifers — over the next decade. The IWS basins will represent a wide range of...

The Next Generation Water Observing System (NGWOS) supports water availability assessments, management, and prediction by enhancing water observations in basins that represent major U.S. hydrologic regions. NGWOS provides high-resolution, real-time data on water quantity, quality, and use, as well as advance the development and application of new sensor technologies and remote sensing methods.

This website compiles USGS resources and data related to principal aquifers including Aquifer Basics, principal aquifers maps and GIS data, and the National Aquifer Code Reference List.