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Water Resources of Kentucky - Flow Duration HydroGraphs

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, running 7-day averages of flows, or lake elevations are compared to selected non-exceedance percentiles computed for each day of the year over the history of the gaging station.

Explanation of Duration Graphs

UNREGULATED STREAMS

• Mean Daily Flow Duration Hydrographs

• 7-Day Running Average Flows Duration Hydrographs

• Base Flow Duration Hydrographs

• Cumulative Flow Hydrographs

REGULATED STREAMS

• Mean Daily Flow Duration Hydrographs

• 7-Day Running Average Flows Duration Hydrographs - (Best suited for
      determining low-flow frequency of regulated streams)

• Cumulative Flow Hydrographs