Hydrograph Analysis

The various contributing components of a natural hydrograph are shown in figure 7.1. To begin with there is baseflow only; that is, the groundwater contribution from the aquifers bordering the river, which go on discharging more and more slowly with time. The hydrograph of baseflow is near to an exponential curve and the quantity at any time is represented very nearly by Q _t = Q₀e-αt where Q_o = discharge at start of period Q _t = discharge at end of time t a = coefficient of aquifer e = base of natural logarithms.