Experimental measurement of flocculation and settling behavior in fine sediments from the Three Gorges Reservoir, China

作者：Le Wang, D Q Wang, Alan Cuthbertson, Qingxia Chen, Jianzhao Guan, Lei Zhang, Hai Huang, Shanghong Zhang · 发表于：International Journal of Sediment Research · 年份：2025 · DOI：10.1016/j.ijsrc.2025.07.001 · 被引用次数：2 · 研究领域：Coagulation and Flocculation Studies、Groundwater flow and contamination studies、Constructed Wetlands for Wastewater Treatment

: Flocculation of cohesive sediments is widely observed in natural aquatic-sedimentary environments, such as river estuaries and nearshore coastal waters, where salinity, suspended sediment concentration and flow turbulence cause fine sediment particles to aggregate into larger flocs, resulting in intensified sedimentation. In contrast, there is currently very little evidence linking enhanced sedimentation, leading to significant storage loss within large freshwater reservoirs, specifically to fine sediment flocculation processes. Massive fine sediment volumes have been deposited in the Three Gorges Reservoir (TGR), China, which has been impounded over the past two decades. It has not yet been established what role, if any, fine sediment flocculation processes play a role in the amplified sedimentation rates that have been observed. The current study aims to test the hypothesis that fine sediment flocculation processes, which occur under prevalent hydrodynamic (i.e., turbulent shear rate G ≈ 4.67–227.39 s −1 ) and sedimentary (i.e., sediment concentration C ≈ 0.02–2.00 kg/m 3 ) conditions in the TGR, play important roles in sedimentation rates during reservoir impoundment. A laboratory-based, experimental study was conducted within a new, bespoke Couette flow system designed specifically to mimic the environmental shear flow conditions experienced during impoundment. Sediment samples obtained directly from the TGR bed deposits were tested within this facility to ascertain the...