DATA CENTER

• USGS Real-time data
  • Streamflow
  • Ground water
  • Water quality
  • Precipitation
  • Lake/Reservoirs

• WaterWatch
  • Floods | Droughts
  • Current conditions

• Ground-water networks
  • Real-time data
  • Active ground-water levels
  • Climate Response Network

• USGS Historical data
  • Annual Data Reports

USGS IN YOUR STATE

USGS Water Science Centers are located in each state.

Duration Graphs

Duration graphs characterize the state of the hydrology of a stream with respect to time. To quantify the state of the hydrology for the current year, the current daily mean flows or running 7-day averages of flows are compared to selected non-exceedance percentiles computed for each day of the year over the history of the gaging station. In addition, the 7-day minimum flows with recurrence intervals of 10 years (7Q10) are shown on the graphs.

Explanation of Duration Graphs

Mean Daily Flow for Unregulated Streams

Mean Daily Flow for Regulated Streams

7-Day Running Average Flows for Regulated Streams
(Best suited for determining low-flow frequency of regulated streams)