Tank Model Application to Derive Unit Hydrographs of Quick and Slow Runoff for Rainfall- Runoff Process (Case Study: Navrood Basin, Iran)

In several types of rainfall-runoff models، the unit hydrograph based methods are useful tools for flood estimation in many، except non-gauged، basins. In this study، unit pulse response functions (quick and slow runoff) derived، considering linear system theory concept and using tank conceptual model. The model parameters were estimated with direct search optimization method. The model applicability and validity were verified using observed rainfall-runoff data of Navrood basin in Gillan province. The results showed that the tank model could simulate rainfall-runoff process with acceptable precision by taking into account the antecedent soil moisture conditions and without need to define excess rainfall.