IMPROVEMENT OF CASC2D MODEL FOR RAINFALL-RUNOFF SIMULATIONS IN A FORESTED CATCHMENT

摘要

CASC2D model is a widely used event-based hydrologic model to simulate rainfall-runoff and sediment transports, but it is challenge for this Hortonian overland flow based model to simulate hydrologic processes in forested catchments. In this study, CASC2D model was improved for continuous simulation in forested catchments by considering evapotranspiration, subsurface flow, groundwater storage, and modifying infiltration and interception methods. The model was applied to the Kuchibuto River catchment, Fukushima Prefecture. Four storm events in 2011 and seven events in 2012 were selected for model calibration and verification, respectively. Simulated hydrographs showed a good agreement with those of observed. Comparing with original CASC2D model, modified model significantly improved accuracy of simulation due to the inclusion of subsurface flow and groundwater storage processes and modified infiltration constraint condition.