Analysis of sediment deposition in Lushui Reservoir to guide dredging

Abstract

In recent years, sedimentation dredging has received extensive attention as an effective way to extend the life of reservoirs and to address the global shortage of sediment resources. Thus, sediment deposition analysis can inform reservoir sedimentation dredging. Based on a series of field data for 10 fixed sections observed over 6 years and two topographic observations in the Lushui Reservoir, Hubei Province in China since 1959, the characteristics of sediment deposition, including the amount, the longitudinal distribution, and the transverse distribution in different periods, were analyzed in this study. The results show that sedimentation mainly occurred within 15 km of the dam with an equal thickness along the wetted perimeter during the flood detention period. After the impoundment of the reservoir, sedimentation mainly occurred in the central 7 km section of the reservoir, which is about 15 km away from the dam. In addition, the main deposition is on the primary channel with a small amount on the beaches. In general, the sediment deposition of the Lushui Reservoir is not significant, accounting for only 4% of the total reservoir capacity. However, the siltation in the local reservoir sections is more prominent. Some measurements should be taken to control the sediment deposition to maintain the effective storage capacity of the reservoir, and four dredging zones were proposed based on the analysis.