Comparison of rational formula alternatives for stremflow generation for small ungauged catchments

Abstract

The suitability of the Rational Equation for the derivation of steamflows for small ungauged watersheds is studied. A unit Hydrograph can he derived using the peak discharge obtained front the Rational Equation and using unit depth of rainfall in calculating the Rainfall Intensity. Possible alternatives for selection of sub catchments, selection of a guideline lo determine the Runoff Coefficients and the Time of Concentration were taken into account. A significant variation of the results was observed with the selected alternatives. In order to select a better alternative comparison of generated streamflows with the observed values is required.