RAINFALL-RUNOFF SIMULATION BY USING DISTRIBUTED INSTANTANEOUS UNIT HYDROGRAPH DERIVED FROM APPLYING FLOW ACCUMULATION VALUE OF DEM

Abstract

Flow Accumulation Value (FAV) denotes water accumulates along the flow paths dictated by the topography. For any specific location in a basin, by adjusting FAV to proper units, the flow accumulation is synonymous with drainage area. In this study, by combining DEM and Kinematic Wave routing method, discharge of the surface runoff of specific location inside the basin within given rainfall intensity has been calculated, and water depth and velocity also has been derived. By adopting the concept of IUH and through describing the runoff mechanism, the traveling time of water movement from any specific location of the basin to the outlet is examined; consequently, a distributed instantaneous unit hydrograph of the basin is derived.