Enhanced runoff curve number model incorporating storm duration and a Nonlinear Ia-S relation

Incorporating the storm duration and a nonlinear relation for initial abstraction (I-a), this paper presents an enhanced version of the Soil Conservation Service curve number-based Mishra-Singh model. The proposed version is compared with existing formulations using a large set of storm rainfall-runoff events derived from the water database of the United States. The results of the paired t-test of related samples and standard error of estimate (S-e) statistic comparison of split sampling-based calibration and validation and simulation on full data set show that the proposed version performs far better than all other existing versions.