Evaluation of Rainfall Concentration Time in River Basins

The travel time (Tc) is an important and highly sensitive parameter in hydrological runoff simulations in rivers. Therefore, runoff can vary greatly depending on the value of the travel time. Since rainfall-runoff is not measured in most river basins, empirical equations developed in some gauged basins or indirect methods are applied to estimate the time of concentration in ungauged basins. Although various methods have been presented in the literature, the calculated values vary depending on the empirical formula applied, even to the same river. This highlights the importance of understanding each formula to select an appropriate method. This study aims to contribute to practical selection of travel time formulas by examining the development conditions and constraints of travel time formulas used in Korea and by analyzing the characteristics of parameters applied in calculations for 43 local rivers in Korea.