Watershed Environmental Hydrology (WEHY) Model: Model Application

The Watershed Environmental Hydrology (WEHY) model was applied to the Shiobara-Dam watershed for model validation for four historical events. Based on the analysis of the established geographic information system (GIS) database, which consists of the digital elevation model map, the land use map, the soils map, and the Landsat TM images, along with information on soil depths and soil properties, the modules of the WEHY model for the Shiobara-Dam watershed were selected and configured. A system of model computational units and stream reaches formed the basic building blocks for the watershed model. Using the model parameters, which were estimated from the established GIS database of the Shiobara-Dam watershed directly, good results were obtained when the WEHY model watershed runoff predictions were compared against their observed counterparts for several historical rainfall-runoff events. Interactions among the hydrologic flow processes at the watershed were examined in some detail.