Physical and chemical characteristics of suspended sediment in plain river network

Abstract The suspended movement of sediment in the plain river network is a major part of the river's sand transport, and the associated movement of suspended sand particles also influences the associated movement of pollutants in the water column. This paper selects plain river network and lakeside river network as the research area: In this paper, a plain river network and a lakeside river network are selected as the study area: the flow velocity zones are divided; the particle characteristics (geometric mean particle size GD, roundness RO, roughness FD) of the different flow velocity zones are compared; the influence of the flow velocity characteristics of the river network on the physical characteristics and enrichment capacity of suspended sand particles is assessed; the differences in elemental species and contents between different flow velocity waters are compared; the influence of the physical and chemical characteristics on the enrichment capacity of particulate heavy metals Ni is assessed. The results show that (1) The highest grain GD (5.77), roundness (1.32) and roughness (1.080) were found in the strong flow area of the Liangxi River. There was little difference in particle roughness between flow zones. (2) The average percentage content of the characteristic elements in the different flow velocity regions is generally consistent from highest to lowest, with Mg being the characteristic element with the highest average percentage content in each region. (3) The GD, FD, RO of suspended sand particles are independent of TN, TP, V, SSC and are positively correlated with flow velocity, with the particle size larger and more spherical in shape at high flow velocities in the lakeside network. (4) The enrichment factor AE = aF1(GD, RO, FD) was used to better characterize the sorption capacity of suspended sand particles for Ni than the GD factor alone, with the highest Ni sorption by suspended sand particles in the slow-flowing plain river network (EF = 3.65; AE = 4.74).