USGS IN YOUR STATE
USGS Water Science Centers are located in each state.
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.
7-Day Running Average Flows for Regulated Streams