A Physically-based Coupled Hydrologic Model for Clear Creek Watershed

Devastating floods brought economic, social, and environmental impacts to many watersheds across Iowa, USA. In this study a physically-based model was developed for the Clear Creek Watershed to assess potential flood reduction alternatives. The model, based on the Generic Hydrologic Overland-Subsurface Toolkit, takes into account interception, throughfall, infiltration, recharge, evapotranspiration, and infiltration. The model was calibrated and validated using a 15-year continuous simulation with hourly climatological data. Simulated hydrographs were compared against measurements taken at two USGS stations. The model was able to reproduce satisfactorily the measured hydrographs as well as seasonal and annual trends. Model parameters were modified to represent implementation of cover crops and native vegetation in the study area. In addition, the model was used to evaluate a system of distributed storage and a hypothetical scenario with increased precipitation. Model results highlight the flood reduction benefits of maintaining a vegetation cover all year round and more generally the potential of implementing nature-based flood protection systems.