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Data & Maps

USGS WaterWatch Streamflow Data

Associated Agencies

United States Geological Survey (USGS)

WaterWatch is a U.S. Geological Survey (USGS) website that displays real-time, recent, and past streamflow conditions for the United States. The real-time information generally is updated on an hourly basis. WaterWatch provides streamgage-based maps that show the location of more than 3,000 long-term (30 years or more) USGS streamgages; use colors to represent streamflow conditions compared to historical streamflow; feature a point-and-click interface allowing users to retrieve graphs of stream stage (water elevation) and flow; and highlight locations where extreme hydrologic events, such as floods and droughts, are occurring.

WaterWatch also provides hydrologic unit code (HUC) maps. HUC-based maps are derived from the streamgage-based maps and illustrate streamflow conditions in hydrologic regions. These maps show average streamflow conditions for 1-, 7-, 14-, and 28-day periods, and for monthly average streamflow; highlight regions of low flow or hydrologic drought; and provide historical runoff and streamflow conditions beginning in 1901.

Interactive Map: Streamflow Conditions

Streamflow Conditions
Streamflow Conditions
Streamflow Conditions
Streamflow Conditions

How to

How to use this site:

  • Use the dropdown menus to view streamflow conditions for the entire U.S. or by state or water resource region. You can view maps, tables, and time series graphs.
  • Streamflow data are available in real-time or daily data, or as a 7-day, 14-day, 28-day, or monthly average.
  • Streamflow conditions are displayed based on percentile classes—a value on a scale of one hundred that indicates the percent of a distribution that is equal to or below it. In general:
    • A streamflow which is greater than the 75th percentile is considered above normal.
    • A streamflow which is between 25th and 75th percentiles is considered normal.
    • A streamflow which is less than the 25 percentile is considered below normal.