A Study on Flood-induced Sediment Transport and Its Sluicing Methods in a Reservoir

• Main Authors: Ching-HsienWu, 吳慶現
• Other Authors: Chyan-Deng Jan
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/17784055639747952403

博士 === 國立成功大學 === 水利及海洋工程學系 === 103 === The best time for sediment sluicing operation is decided by accounting for the actual transport of high-concentration turbid density current at the bottom of the reservoir during floods. However, reservoir operation is also responsible for the flood control and water supply. Thus, it is important to achieve the objectives of keeping clear water while discharging turbid water and stabilizing water supply through proper sediment sluicing operation during floods. This study shows that the critical problem is to capture the sediment inflow and outflow hydrographs in the reservoir during floods, the transportation of turbidity density current in the pool, as well as sediment lofting and settling of stagnant muddy pool, which can provide the basis for sluicing operation of multi-objectives, including flood prevention, stable water supply, and timely desilting. Hence, the reservoir needs to establish an extensive monitoring system for suspended sediment transport, which can provide quantitative information on sediment inflow and outflow, as well as temporal and spatial variation of sediment concentration related to characteristics of density current and stagnant muddy water. This would serve as the important basis for the first stage of desilting operation. At the second stage, it is suggested to construct passageways for sluicing early settled sediments (before consolidation), under condition that the stability of water supply is accounted for. The third stage is to use mechanical dredging to remove consolidated sediments in the pool bottom or coarse materials in the delta. By means of these multi-stage approaches, reservoir sedimentation can be better managed and the goal of sustainable reservoirs may be achieved.