USGS Water Data Discovery

The National Water Information System (NWIS) is the Nation's principal repository of water resources data. It includes data from more than 1.5 million sites, some in operation for more than 100 years. Most NWIS data can be accessed directly at:

Additional tools are provided here to help find data in NWIS, in other USGS products and services, and from other federal partners and national organizations. If you do not find what you need try contacting a local USGS Water Science Center.

Water Now

Real-time streamflow
Where is the USGS collecting and transmitting real-time streamflow data right now? How does flow today compare with historical streamflow? How can I see these sites on a map and get to the data? (Fact Sheet)

Real-time flood data
Where in the Nation are floods or very high flows occurring now? How can I see these sites on a map and get to the data?

Real-time drought data
Where in the Nation are droughts or very low flows occurring now? How can I see these sites on a map and get to the data?

Real-time ground-water levels
Where is the USGS collecting and transmitting real-time ground-water levels right now? How do levels today compare with historical levels? How can I see these sites on a map and get to the data?

Recent ground-water levels
Where in the Nation is the USGS currently collecting ground-water level data? How can I see these sites on a map and get to the data? Data shown on these maps may be as recent as a few minutes old or may be from as long as a year ago.

Ground-water response to climate
Where are the wells that are highly sensitive to climate variations where the USGS is currently collecting ground-water level data? What are the long-term and short-term trends in water levels?
How can I see these sites on a map and get to the data? (Fact Sheet)

Real-time surface water quality
Where is the USGS collecting and transmitting real-time water quality data? How do levels today compare with historical levels? These data are limited to measurable characteristics such as temperature, turbidity, specific conductance (salinity), dissolved oxygen and pH (acidity).
How can I see these sites on a map and get to the data?

Recreation
I want to find streamflow or water-level data that will tell me if a particular river will be suitable for rafting, kayaking, or fishing today. Some recreation links leave the USGS web sites.

USGS has a general information page at recreation.usgs.gov

Private organizations such as American Whitewater provide alternative resources that use USGS and other information for planning water-based activities.

Water Then

Annual water data reports
Can I see all of the locations where the USGS has published water resources data for a particular year? How can I see these sites on a map and get to the data?

You can retrieve data using a map or a search form.

Instantaneous streamflow data
I want to find long-term streamflow data reported in short time intervals (such as 15 minutes or 1 hour) rather than as daily averages. Where can I see a list of those sites and get to the data?

National Water Quality Assessment
The NAWQA program provides a search to physical, chemical, sediment, and biological data that have been collected as part of the national program, including some aquatic ecological data that can not be stored in NWIS. (Fact Sheet)

Water use in the United States
Use of water in the United States is tracked by USGS in cooperation with state, tribal, and local governments.

Some notable collections of USGS water data

Sediment data collected by USGS is stored in NWIS and is also described in a dedicated web page and report.

The Hydro-Climatic Data Network provides streamflow data between 1874 and 1988 and is useful in studying climate change.

The National Stream Quality Accounting Network provides ongoing characterization of the concentrations and transport of sediment and chemicals in the Nation's largest rivers.

USGS is the lead federal agency for monitoring of acid rain and related issues as part of the National Atmospheric Deposition Program.

The Ground-Water Atlas and National Atlas provide many maps that summarize water resources data and related information.

Water Tomorrow

USGS collects most of the water data in the Nation, but official forecasts are made by other agencies. Forecasts are subject to any limitations and disclaimers made by the issuing agencies. In all cases, professionals should always be consulted concerning decisions that may affect safety of people or property or economic risk.

Forecasts

Water-resources planning and forecasts are done by other federal, regional, state, local, and tribal agencies. In most cases, USGS partners with these agencies to provide reliable current and historical water data that are essential for making accurate forecasts. These links leave the USGS web sites.

The National Weather Service is the primary federal agency for water resources forecasting, including:

• A National overview of river forecasts
• Forecasts from each of 13 River Forecast Centers
• Seasonal western water supply forecasts summarized from 5 River Forecast Centers
• Forecasts of western water supply include data provided by the Natural Resources Conservation Service, which also provides state-by-state data and monthly reports for 12 western states, including Alaska.

Statistics

USGS water data and statistics are used by other agencies to estimate future conditions and to assess risks such as flooding and drought. Planners and engineers use USGS water data, statistics, and other data for design of systems for water supply, flood control, environmental protection, and recreation.

Streamflow statistics at USGS gages Where can I find an analysis of long-term flow statistics for USGS streamgages? WaterWatch provides basic flow statistics computed from daily streamflow values, including the daily average, minimum, and maximum streamflow; and flow duration curve for the period of observed data. Additional statistics are computed from daily streamflow values, flood peak flows, and measured low flows, and include, for example, 100-year flood; 7-day, 10-year low flow; and mean annual flow. Statistics such as these are commonly used to help estimate reliability of water supplies and risks of floods or droughts, and may be available in published reports or from StreamStats. However, all flow statistics will vary over time due to extreme floods or droughts, so a local USGS Water Science Center should always be contacted for up-to-date information.

Estimate streamflow statistics anywhere Where can I obtain estimates of streamflow statistics for locations where USGS streamgages are not operated? National Streamflow Statistics is a downloadable computer program that requires user input of drainage area and other watershed characteristics. Statistics that are available vary among states. (Fact Sheet) StreamStats provides tools to estimate required inputs for the National Streamflow Statistics computer program, and is currently available for 15 states, with additional states being added regularly. (Fact Sheet)