Evaluation on the Application of the Estimation of Time of Concentration Using Real Rainfall-Runoff Events in Small Forest Watershed

Abstract

This study was carried to figure out appropriate method for time of concentration used in the Rational method at design flood estimation. For 6 small forest watershed, time of concentration was obtained from time of concentration formulas including Kirpich Rziha, Kraven (I), Kraven (II) and SCS lag method and the results from these were compared to the results from cross correlation function based on real rainfall runoff events. The results of cross correlation function ranged from 12.9 to 28.8 minutes and the average difference between SCS lag method and cross correlation function was 2.5 minutes. SCS lag method would be feasible to estimate time of concentration in small forest watershed.