Development of a fully-distributed daily hydrologic feedback model addressing vegetation, land cover, and soil water dynamics (VELAS)

A simple hydrologic feedback model has been developed to simulate daily responses of hydrologic processes including interception, runoff, evapotranspiration, infiltration, and recharge under various conditions of vegetation, land cover, and soil in a fully-distributed manner. The daily soil water balance is a key element to link surface and subsurface models as it calculates infiltration and groundwater recharge by considering a time delay routing through a vadose zone down to the groundwater table. MODFLOW is adopted to simulate groundwater flow and interaction with surface water components as well. The model also can easily be localized by simple modification of soil and crop properties. The actual application of the model for a watershed in the Geum River Basin in Korea showed reliable hydrologic feedbacks between the surface and subsurface hydrologic systems.