圖書典藏及影音數位平台

石門水庫自52年5月開始蓄水迄今約50年，運轉多年每經颱風暴雨侵襲及其他自然或人為因素之影響，造成水庫集水區坡地沖刷與崩塌，該沖刷與崩塌砂石沿河道進入水庫，影響水庫蓄水能力。因此如何導引颱風洪水期間上游高濃度渾水流入下游庫區及如何縮短渾水滯庫時間，為現今水庫操作重點。石門水庫原設計並無水力防淤專用設施，經既有設施更新改善工程及未來石門水庫防淤隧道工程完成後，將提升水庫防淤功能及減緩水庫淤積。爰為瞭解未來增設防淤隧道完工後之排洪減淤操作前之下游河道泥砂濃度與底床沖淤影響之情形，北區水資源局於102年辦理石門水庫放淤對下游河道變遷影響之相關先期調查，執行期間北區水資源局為因應颱洪事件造成庫區原水濁度異常情形，首次操作排砂隧道(電廠改建完成之排砂隧道)以解決高濃度渾水問題，為能追蹤觀察排砂隧道操作後淤泥回歸河道之影響及延續先期調查，持續進行資料蒐集、現地監測及相關數值模擬分析，將有助於瞭解水庫放淤操作對下游河道泥砂濃度變化、底床沖淤情形及提早評估出高泥砂量或超量沖淤之河段，並研擬相關因應對策，提供既有設施及未來石門水庫防淤隧道工程完成後排洪減淤操作之參據，以俾北區水資源局石門水庫之永續經營。

Shimen Reservoir is one of the most important reservoirs in northern Taiwan, but it was originally designed without any hydraulic deposition-prevented facility. After updating of the existed facilities, and finishing the deposition-prevented tunnel in the future, the sediment flushing ability will be promoted. The reservoir sediment deposition will return to the river naturally through floods, and the durable years of the reservoir would be prolonged due to slowing down the reservoir deposition rate. The investigation about the impact to the downstream river channel because of sediment releasing from Shimen Reservoir was executed by Water Resource Agency in 2013. To solve the high turbidity water problem during the typhoons in northern Taiwan, the sediment flushing tunnel were first operated last year. Water Resource Agency have started this project to observe the impact of sediment returning to the river channel downstream the reservoir due to the sediment flushing operating, and continue the investigation started last year. The tasks in this project include data collecting, in-situ monitoring and numerical simulation about related to the river system. The tasks have been done to realize the downstream river channel sediment concentration change and bed erosion/deposition due to the reservoir flood and sediment control operating. And the high tendency river reach of over erosion/deposition were estimated. The related strategies were studied to offer the reference about the flood and sediment control operation, for the sustainable development of Shimen Reservoir.