Surface Runoff Hydrograph Equation

Bloomsberg's equation for the description of surface runoff hydrographs is modified and a methodology is developed to express the shape and profile of rising limb, crest segment, and recession limb of a hydrograph in algebraic terms. Variables of concern for such a description include time to peak, peak rate of runoff, point of recession, recession constant, and the percentage ratio of flow volumes in recession to the total volume of surface runoff. A computerized procedure, based on the derived formulations and working rules, would facilitate tracing of the surface runoff hydrograph free of reliance on graphical procedures. The method is applied to nine arbitrarily chosen drainage areas in the Great Basin region in order to investigate the reproducibility of observed unimodal flood hydrograph events.