Parameter identification for two conceptual hydrological models of upper Dau Tleng River watershed in Vietnam

Selection of hydrological models to calculate the rainfall runoff for a river watershed with particular characteristics is not an easy task. Especially in recent years, there have been many conceptual hydrological models to calculate rainfall runoff. The study and analysis of hydrological models that are applied under suitable conditions for appropriate watersheds are necessary to improve the accuracy and applicability of each model. In this research, two hydrological models, namely the Tank model and the NAM model, were used to model the rainfall runoff process of the river system upstream of the Dau Tleng River watershed located along the upper Saigon River in southeast Vietnam. Based on the relationship between model parameters and watershed characteristics, a set of preliminary model parameters was found. The final estimation of the optimal parameters was carried out by calibration through comparison between the simulated time series and the observed data of the overall water balance, overall hydrograph shape, peak flows, and low flows.