圖書典藏及影音數位平台

石門水庫自民國52年5月開始蓄水迄今，肩負了北部地區重要的水資源供給重任，石門水庫於颱風豪雨期間進行水庫運轉操作，以維護水庫安全及達成水資源永續發展目標；隨著水庫近年實施更新改善計畫，排砂隧道改建完成、防淤隧道刻正推動…等，水庫正朝向水資源永續的目標邁進。爰此，本計畫期望在水庫進行操作時，能持續監測並掌握與下游水質、生態之關聯性，針對石門水庫下游大漢溪及淡水河河道之影響及變遷狀況，本局已於100年~107年間陸續執行相關計畫之研究，以利掌握下游生態環境、河口地形、易淤積河段及各河段輸砂情形，並有效釐清與下游生態事件之關聯性，消除各界疑慮。 為持續追蹤觀察石門水庫排砂隧道操作還淤於河之沖淤及生態變化，進行水庫排洪操作對下游河道影響及評估分析並延續前期調查，爰辦理本計畫，持續進行背景資料蒐集、水質、底質條件與指標生物調查分析、全洪程水質調查及模擬分析、河道粒徑及懸浮質採樣及分析，預期將有助於累積相關生態背景資料，提供既有設施及未來石門水庫防淤隧道工程完成後排洪操作之參據，俾利本局持續推動石門水庫之永續經營管理目標。

The water quality’s survey show the rainfall by Typhoon Lekima, Typhoon Mitag and front from August to October slightly improved the concentration of ammonia nitrogen and organic matter in the water quality, and increasing the amount of dissolved oxygen at each station. It has a positive impact on the water environment of the river system downstream of the Shihmen Reservoir. Clam’s abundance of each station in the April to September 2019 was lower than 2018. Based on the factors that affect the abundance of clams, such as water quality and sediment, it is found that the biochemical oxygen demand and chemical oxygen demand’s (BOD, COD) value in Tamsui river are not suitable for clam. And the particle size of the substrate exceeded the optimum range of the clam. In response to the onset of typhoons, the distribution of public sentiments in this survey is mainly aimed at issues such as the regulated drainage of reservoirs, effective capacity and effective storage capacity, and drainage and siltation of reservoirs. The negative issues of clam have gradually decreased since 2017, and have dropped to less than 10 as of November 2019. It show the monitoring data of the actual implementation of the project can be used as a reference for discussion with the public, and the general acceptance will also increase. This Project used CCHE model to analysis the influence of river channel change. The result showed that without increasing the amount of flood discharge, most of the excess silt will be deposited between Afterbay Weir and Zhongxiao Bridge, which may cause insufficient total flow area at the Chenglin Bridge.