Discussion of “Discussion of "Infiltration Formula Based on SCS Curve Number"”

IR4distributed.To be sure, it is the hope of the hydrologist that representative values of these properties may be obtained.However, considering the spatial random distribution of conductivities, degrees of saturation and porosity, it is not surprising that fitted parameters such as / 0 and kf vary considerably from plot to plot.This variation is not sufficient to condemn Horton's equation and is irrelevant in arguing for use of the authors' model.A lack of correlation was noted by the authors between the Horton coefficients and land slope.We can see no reason for suspecting that such a correlation should exist.Infiltration capacity is a function of soil properties and moisture conditions .Slope plays an important role in runoff, but we see no physical reason for slope to affect infiltration capacity.The authors' comment that the early infiltration history does not appreciably affect the simulation of runoff from urban and rural watersheds perhaps reflects their modeling experience.However, it has been our experience that the simulated runoff is often very sensitive to the character of the infiltration response.In fact in watersheds of less than about 500 acres, the simulation of infiltration response may be the most critical factor in correctly modeling surface water runoff.We submit that the excessive early infiltration predictions noted by the authors may indeed present a serious drawback.