本研究主要建立水庫集水區降雨逕流模式，模式中將二維逕流模式及一維河川模式結合，針對颱洪降雨事件進行集水區水文。模式以水文方程式為連續方程式，曼寧公式為動量方程式，輔以數值地形模型(Digital Terrain Model，DTM)之數值高程為基本資料建構分散式(Distributed-parameter)數值模式，以應用於水庫集水區。 以石門水庫集水區為研究範圍，分別考慮不同DTM解析度、演算時距大小、不同河道斷面修正方式及空間降雨估計方式進行模擬檢定。結果顯示模式於網格間距160公尺、演算時距10秒以下、平均坡度設定之河道斷面高程及徐昇氏多邊形法所得之降雨資料於模式中有較佳之模擬結果。 This study combined one-dimensional river model and two-dimensional runoff model to simulate surface runoff and channel flow of a reservoir watershed during typhoons. The continuity equations of both runoff and river modules were described by the distributed water-budget. The momentum transfer of water was estimated by the Manning’s equations. The Shihmen reservoir was selected as the domain of interest. Different spatial resolutions, time step sizes, channel bottom gradients and cross-sections, spatial rainfall distributions were considered for simulations. Results of the current model showed a DEM resolution of 160 m, a time step size of less than 10 second, and average-slope approach of channel bottom gradient, and Thiessen polygons approximation of rainfall can provide a better solution for the Shiehmen watershed.
