A new formula of recovery factor for non-equilibrium transport of graded suspended sediment in the Middle Yangtze River

作     者：LI Lin-lin XIA Jun-qiang ZHOU Mei-rong DENG Shan-shan LI Zhi-wei LI Lin-lin;XIA Jun-qiang;ZHOU Mei-rong;DENG Shan-shan;LI Zhi-wei

作者机构：State Key Laboratory of Water Resources and Hydropower Engineering ScienceWuhan UniversityWuhan430072China School of Civil EngineeringArchitecture and EnvironmentHubei University of TechnologyWuhan430068China 

出 版 物：《Journal of Mountain Science》 (山地科学学报（英文）)

年 卷 期：2023年第20卷第1期

页      面：87-100页

核心收录：

学科分类：08[工学] 081502[工学-水力学及河流动力学] 0815[工学-水利工程] 

基　　金：the National Natural Science Foundation of China(Grant Nos.51725902,52009095,U2040215,U2240206,and 52109098) supported partly by the Postdoctoral Research Foundation of China(Grant No.BX2021228) Natural Science Foundation of Hubei Province(Grant No.2021CFA029) 

主　　题：non-equilibrium sediment transport bed material composition transition probability recovery factor Middle Yangtze River 

摘      要：Suspended sediment concentrations in the Middle Yangtze River(MYR)reduced greatly after the Three Gorges Project operation,causing the composition of bed material to coarsen ***,little is known about the non-equilibrium transport of graded suspended sediment owing to different bed material compositions(BMCs)along the MYR,and it is necessary to determine the magnitude of recovery *** the Markov stochastic process in conjunction with the hiding-exposure effect of non-uniform bed-material,a new formula is proposed for calculating the recovery factor including the effect of different BMCs,and it is incorporated into the non-equilibrium transport equation to simulate the recovery processes of suspended load in both sand-gravel bed and sand bed reaches of the *** results show that:(i)the recovery rate of graded sediment concentrations at Zhicheng was slower than that at Shashi during the period 2003-2007;(ii)the mean recovery factors of the coarse,medium,and fine sediment fractions in the ZhichengShashi reach were 0.152,0.0012,and 0.0005,respectively,and the coarse sediment recovered up to the maximum sediment concentration of 0.138 kg/m3over a distance of 15 km;and(iii)the results of the new formula that can consider the effect of bed material composition are in general agreement with the field observations,and the spatial and temporal delay effects are inversely related to particle size and ***,the BMC effect on the nonequilibrium sediment transport in different reaches of the MYR needs to be considered for higher simulation accuracy.