- 期刊
石門水庫水庫排砂操作影響鳶山堰取水之研究
The Impacts of Water Withdraw at Yuanshanyan during Sediment Venting in Shihmen Reservoir
摘要
近年來石門水庫受到極端氣候影響，使得石門水庫原水濁度超過自來水可處理之程度，同時入庫流量所帶入之大量泥砂也造成水庫淤積嚴重及水庫庫容急遽減少之情況，因此利用颱風時期之洪水適時排放入庫泥砂進入下游，且不影響下游取水工取水及水庫蓄滿之原則相形變的刻不容緩。本研究之主要目的係利用經濟部水利署水質觀測站之觀測數據與石門水庫各出水工之泥沙濃度觀測值，進行二維水理與污染物傳輸之模擬分析，建立石門水庫排砂操作及穩定鳶山堰取水之操作策略。由水質觀測站在颱風事件之迴歸關係得知，石門水庫後池堰尖峰濁度到達鳶山堰的時間，約為後池堰泥砂濁度之0.001倍；而鳶山堰之泥砂濁度約為後池堰泥砂濁度之0.89倍；此外，經由模擬分析結果顯示，石門水庫出流量造成鳶山堰之泥砂濁度折減比例介於0.99倍至0.89倍之間。本研究亦探討石門水庫排洪隧道及溢洪道對於降低後池堰泥砂濁度之成效，由分析結果顯示，當排洪隧道顯外增排流量達到2600 m^3/s時(此為假設值)，額外增加出流量以降低後池堰泥沙濁度效果已跟原本操作之後池堰泥砂濁度差異不大，且將排洪隧道之增加排放量與泥砂關係式，應用於海棠颱風及韋帕颱風穩定鳶山堰供水操作時，可將鳶山堰之泥砂濁度達到自來水處理標準6000 NTU以下之成效。
並列摘要
In recent years, the climate change leads to high inflow discharge with high turbid sediment concentration from the watershed of Shihmen reservoir. Therefore, the water quality of Shihmen reservoir exceeds 6000 NTU that water treatment plant can deal with. At the same time, a mount of sediment would deposit in reservoir bottom and lead to serious sedimentation problem of losing storage. As a result, using flood discharge to flushing sediment during Typhoon or rain fall duration is important. On the other hand, maintaining the stability of water supply and keeping more water resources are also important at the same time. This study adopts the data of water quality observation station from Water Resources Agency, MOEA and field observation data form outlet structures of Shihmen reservoir combining 2D numerical model to establish the operational strategies of flushing sediment and maintaining water supply. Based on regression relation of water turbidity between Afterbay and YuanShan weir and duration time from Afterbay to YuanShan weir, the water turbidity of YuanShan weir is about 0.89 times and propagation time is about 0.001 times of the water turbidity of Afterbay, respectively According to the simulation results, the water turbidity of YuanShan weir is about 0.99 to 0.89 times of the discharge of Afterbay. This study also focuses on the turbid influence in Afterbay by tunnel spillway and spillway. Based on the analysis results, when the extra discharge reaches 2600 m^3/s (assumed), the influence of reducing water turbidity in Afterbay by tunnel spillway is almost the same to normal operation. When using the extra discharge of tunnel spillway to reduce water turbidity in Afterbay of Typhoon Haitang and Typhoon Wipha, the water turbidity of YuanShan weir can reduce water turbidity lower than 6000 NTU that water treatment plant can deal with.