 Soil Conservation Service Curve Number, SCSEN, approach is widely used as a simple method for predicting direct runoff volume for a given rainfall event. Previous researchers indicated that the CN values calculated from measured rainfall runoff data vary systematically with the rainfall depth. They suggested the determination of a single asymptotic CN value observed for very high rainfall depths to characterize the watershed's runoff response. This article was authored by J. D. Valliances and K. X. Suleys.