由於目前的水文數值模式大多以降雨-逕流演算模式為主，此類模式大多忽略地下水的模擬演算，所以利用此類模式進行模擬集水區非降雨時期的水文情況並不適用。為合理探討集水區水文循環之逕流、河川水流、入滲、蒸發散與地下水流動，及不同水體間之交互作用。本研究將集水區內的水文循環以地表水與非挶限含水層的耦合機制進行模擬。在地表水部分進一步分為河川水流及地表逕流模式，而非挶限含水層部分則考慮非飽和含水層及飽和層地下水流來模擬，期能有效模擬集水區水文循環。 本研究以石門集水區為研究範圍，並分別選擇暴雨事件、暴雨事件過後洪峰退水段與長時間的水文模擬，以驗證模式的適用性。結果顯示本模式進行三種時段的水文模擬後，其所模擬的流量與觀測值的誤差皆在合理範圍，證明本研究可以有效地進行集水區長期的水文數值模擬。 Most hydrological models focus on rainfall-runoff simulations during extreme rainfalls, and neglect the subsurface regime and its interaction with surface water. For periods without rainfalls or right after extreme events, these models often fail to capture basin response due to the neglectness of groundwater discharge. In order to investigate the hydrological processes, including surface runoff, river flow, infiltration, evapotranspiration, and groundwater flow, at different temporal resolutions and the interactions within these processes, a coupled surface-water and subsurface-water model was developed in this study. Surface water module contains an overland runoff model and a river flow model. Subsurface water module considers the moisture content of unsaturated zone and the groundwater flow of saturated zone in an unconfined aquifer system. Surface water and subsurface water are fully coupled and allow for two-way interactions at spatially distributed grids in this newly developed model. The Shihmen Reservoir Watershed is the domain of interest in this study. Extreme rainfall events, recession periods after extreme rainfalls, and long term events are simulated by the coupled hydrological model developed in this study to investigate its applicability on modeling complicated hydrological cycles in real watersheds. The modeling errors of predicted reservoirs inflows are within acceptable tolerances for all events at different temporal scales. This demonstrate the coupled surface water and subsurface water modeling system is suitable for future investigation of watershed hydrological cycles at different temporal scales.
