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 andsediment transports, but it is challenge for this Hortonian overland flow based model to simulatehydrologic processes in forested catchments. In this study, CASC2D model was improved for continuoussimulation in forested catchments by considering evapotranspiration, subsurface flow, groundwater storage,and modifying infiltration and interception methods. The model was applied to the Kuchibuto Rivercatchment, Fukushima Prefecture. Four storm events in 2011 and seven events in 2012 were selected formodel calibration and verification, respectively. Simulated hydrographs showed a good agreement withthose of observed. Comparing with original CASC2D model, modified model significantly improvedaccuracy of simulation due to the inclusion of subsurface flow and groundwater storage processes andmodified infiltration constraint condition.