ABSTRACT
The accurate gauging of streamflow has a long history of practical application to the design of dams and flood-control structures. Modern practice has extended this use to assess the dilution potential of surface-water discharges susceptible to contamination by seeps and spills. A hydrograph is a graphical plot of gauged discharge as a function of time. The flow of rivers is influenced, in the short term, by storm events which contribute to surges in flow. In examining the hypothetical storm event shown, it may be seen that the duration of precipitation is somewhat less than a day and that, as expected, there is a short lag between the onset of precipitation and the rise of the limb of the runoff curve. In other words, prior to the storm the hydrograph may indicate a slow decline in flow that is typical of a stream relying on baseflow for its discharge.
