Characteristics of suspended flocs and the combined action of contributing factors in Yangtze Estuary: A case study on the significant differences between the inner estuary and the mouth area

doi:10.3969/j.issn.1000-5641.2017.04.013

Abstract

Abstract: Flocculation plays a vital role in the transport of estuarine fine suspended sediments. To study the natural situation and the main influencing factors of fine suspended sediment flocculation, in-situ observations were carried out along the South Branch to the North Channel of the Yangtze Estuary from 19th to 23th October 2014 (During that time, river discharge, tidal range and wind waves have same value to annual mean value). Floc size, dispersed particle size, volume concentration (VC), suspended sediment concentration (SSC), salinity, temperature and flow velocities were measured at four characteristic moments at four sites. We study the relation between median floc size, as well as effective density, and the five influencing factors with the Grey relational analysis.The results shows that,in the same water volume, flocs in the Turbidity Maximum Zone has more floc numbers and smaller floc size; that floc inside has less clay particles, larger gap and more free water compare to the inner estuary. In the inner estuary,critical factors influencing floc sizes are SSC, dispersed particle size, VC, and critical factors influencing effective density were dispersed particle size, SSC, velocity. In the Turbidity Maximum Zone of the mouth area, the critical factor influencing floc sizes is velocity and the critical factors influencing effective density are salinity and SSC.

Key words: suspended flocs, influencing factors, grey relational analysis, Yangtze Estuary

CLC Number:

P343.5

YANG Tian, YANG Shi-lun, YANG Hai-fei, ZHU Qin, ZHANG Wen-xiang, ZHANG Chao-yang, WANG Ru-sheng. Characteristics of suspended flocs and the combined action of contributing factors in Yangtze Estuary: A case study on the significant differences between the inner estuary and the mouth area[J]. Journal of East China Normal University(Natural Sc, 2017, (4): 149-159.

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