Duration Graphs

(Updated Bi-weekly)

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, 7-day minimum flow with a recurrence interval of 10 years (7Q10) is 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)

U.S. Department of the Interior, U.S. Geological Survey New Jersey Water Science Center, 810 Bear Tavern Road, Suite 206, West Trenton, NJ 08628 Maintainer: NJ Webmaster Last update: 09:10:09 Fri 28 Sep 2007 Privacy Statement || Disclaimer || Accessibility URL: http://nj.usgs.gov/drought/duration.plots/