圖書典藏及影音數位平台

台灣地區受限於先天地質、地形條件，水庫淤砂問題嚴重，在新水源開發不易與氣候變遷影響供水條件等背景因素下，如何延長既有水庫運轉壽命，儼然成為當前水資源供需平衡之關鍵。其中，水庫清淤為維持水庫運轉重要方式之ㄧ，經濟部水利署(以下簡稱本署)歷年來針對水庫防淤戮力不懈，然受限於淤泥之後續處理，致水庫清淤量有其上限，如何提升清淤量已是目前各水庫管理單位最急迫之課題。 目前國內針對各種不同淤泥處置方式進行諸多研究，其中以回歸河道(放淤)最為自然且具補助下游河道砂源，避免河床裸露及海岸退縮等優點，為進一步探討放淤作為對下游河川環境之影響及研擬減低影響對策，本署特研議進行「水庫放淤對河川環境影響之探討(1/2)」，期能收集相關案例之應用實績及其相關監測數據，並據以分析評估後，供相關管理單位參據。

In Taiwan, various research studies focused on the problem of reservoir dredging materials are undergoing. Among the feasible alternatives, to recharge (or return) the reservoir sediment back into the downstream channel of the reservoir has several advantages, including maintaining the sediment continuity, as the sediment source of downstream channel supplement, avoiding channel bed erosion, and prevention of seashore degradation. This project aimed at the investigations of the downstream channel environmental impacts caused by the action of recharging reservoir dredging materials. After this project collected the application case and related observation information, the impact reduction strategies will be proposed for the management authorities. The key research issues of this year project are listed as follows. 1. Review on the previous related studies and research project. 2. Information/data collection and integration. 3. Establishment of the numeric model for the recharging reservoir sediment into channel. 4. Field observation for the experimental case of recharging sediment. 5. Effect analysis for the experimental case of recharging sediment. 6. Assistance on the related routine analysis. With the comparison of the observation information on the conditions before and after the sediment recharge, the channel environmental impacts can be identified along with the analysis results of numeric model which had been calibrated and verified by historical data. If the observation data revealed that there is no obvious negative influence at downstream channel, i.e., increase of water quality or pollution, and sediment did supply the channel to prevent channel bed scouring. Then, this action of recharging sediment should be recognized as the human-aided process to restore the natural sediment continuity in channel. Finally, the operation guidelines and procedures for the recharging reservoir sediment back into downstream channel were also suggested for the reservoir management agents.