2007-08-162024-05-14https://scholars.lib.ntu.edu.tw/handle/123456789/660359摘要：摘 要 近年來水庫異重流的現象已在台灣的水庫觀察到，根據水利署在93-95年度委辦之科專計畫「水庫異重流與水庫減淤操作試驗研究」，現場觀測成果發現曾文水庫在颱風豪雨期間，確實有異重流運移之現象且形成壩前顯著之淤積；所以當庫區發生異重流且以溢洪道方式排洪操作時，易造成水庫蓄渾排清，加速水庫淤積問題。因此，如能持續觀測入庫渾水運移特性，掌握水庫蓄清排渾時機，則可建立有效水庫減淤操作方式。 由於異重流在庫區運移行為十分複雜，而且曾文水庫僅有壩前電廠取水口斜坡上，有一分層泥砂濃度採樣裝置，但無法即時讀取泥砂濃度，且目前尚無儀器可觀測庫區異重流運移位置及時間；因此，如能在庫區內適當地點增加設置泥砂觀測裝置，以及自動化泥砂濃度量測，則可充分瞭解庫區異重流運移型態及流況。再者，若可配合「曾文水庫越域引水計畫曾文水庫導水隧道排砂效率研究」（96年3月完成）在防砂壩及下游河道所設置之泥砂觀測系統，以及「曾文水庫集水區流量及含砂濃度量測計畫」（95年12月完成）相關成果，所建構之水位、流量及含砂量關係式，則可給予數值模式模擬減淤通道時之邊界條件，對於實際應用在曾文水庫減淤試驗通道之模擬有實質的幫助。 本計畫擬加強曾文水庫泥砂觀測技術與自動化量測裝置之建置，方能逐年蒐集泥砂資料；同時藉由試驗與模型深入了解水庫泥砂運移情形，進一步探求適合於曾文水庫之減淤操作方式及減淤通道型式，以提高排砂效益，且未來將可構成一完整之泥砂濃度觀測系統，作為曾文水庫未來排砂減淤操作之重要參考依據。 <br> Abstract: Abstract The density current has been observed in TsengWen Reservoir according to the project “A study of density current and operations of reservoir deslitation” (2004-2006). These observations suggest that density current will induce turbidity reservoir and leave a large quantity of sedimentation, if it cannot be vented from gates near reservoir bed. The behaviors of density current movement in reservoir are extremely complex, so it is indeed necessary to monitor flow pattern of density current, such as its speed and sediment concentration. However, only sediment acquiring system leaning against dam’s slope was build now. The system contains six pumps at different elevations to obtain sediment samples and then the concentration distributions from bed to water surface are marked manually. Therefore, present project will select several sites in reservoir area and setup designed equipments to acquire the sediment in density current and then automatically measure its concentration. The system will instantaneously and efficiently traces the variations of sediment concentration in reservoir as flood occurring and provide more useful information to both of numerical simulations, such as boundary conditions and validation data. The present project aims to improve the monitoring and measurement system for density current in TsengWen Reservoir. In addition, the project will perform physical model to character the basic patterns of density current in reservoir. Finally, to advance the efficiency of reservoir venting sedimentation, we attempt to seek an available operation based on above measurements and analyses.異重流數值模式模擬水庫減淤density currentnumerical simulationsreservoir deslitation