草岭堰塞湖下游河道动床水理分析研究

Study on sedimentation in alluvial channel of landslide induced at Tsao-lin

本研究系拟藉由数值模拟演算 ,评估在不同重现期距年洪峰流量作用下 ,草岭潭崩坍土体之冲刷趋势及水理、土砂变化 ,并评估对下游河道可能影响。草岭先前经过三次崩坍 ,第四次 92 1地震后崩塌形成之草岭堰塞湖经梅雨期及多次豪雨 ,堰塞湖容积高达 4 6 0 0万m3。NETSTARS模式经检定、验证后 ,并进行各种设计案例之模拟演算。模拟分析结果显示 ,本模拟研究除能在崩塌区复杂陡峭河段预测不同重现期距洪峰流量作用下之水理输砂变化趋势 。

The earthquake measuring 7.3 on the Richter Scale that occurred in central Taiwan on September 21, 1999 with epicenter located in Chi Chi has triggered a series of large_scale landslides in and around the Tsao_Lin area in Yunlin County Gukeng Township during the quake eruption, leaving behind collapsed earth and rocks that blocked the once clear riverbed of the Chishui River and a closure reservoir created at its upstream. The study was based on the simulation of NETSTARS fluvial model to research the topics of fluvial process and sediment aggradation / degradation of Chishui River downstream the closure reservoir. Rivers downstream the closure reservoir are dynamic balances whose characteristics vary over time and space with changes in the environmental controls, such as bed and hydrological conditions. Influences of river downstream the closure reservoir are variable, depending on the flood peak, sediment transport characteristic, and bed slope of the river. The simulation results show that the changes of river dynamic downstream the closure reservoir under different flood peak condition. It also provides some points for assistance to establish the master plan of closure reservoir management and flood prevention.