Controls on effective settling velocities of mud flocs in the Changjiang Estuary, China

✍ Scribed by Z. Shi; H. J. Zhou

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 377 KB
• Volume: 18
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.1500

✦ Synopsis

Theoretical and experimental studies were undertaken to gain insight into physical parameters controlling the flocculation and settling properties of mud flocs in the Changjiang Estuary, China. The Rouse equation is applied to vertical profiles of suspended sediment concentration to determine the bulk mean settling velocity (w s ) of sediment suspended in the Changjiang Estuary. Both in situ point-sampled and acoustically measured profiles of suspended mud concentrations were fit selectively. The calculated settling velocities w s mainly ranged from 0Ð4 to 4Ð1 mm s 1 for the point-sampled data set, and from 1Ð0 to 3Ð0 mm s 1 for the acoustically measured data set. Furthermore, the settling velocities of mud flocs increased with mean concentration (C) of mud flocs in suspension and were proportional to increasing bottom shear stress ( b ) of tidal flow. The best equation for the field settling velocity of mud flocs in the Changjiang Estuary can be expressed by the power law: w s D m C n (m, 1Ð14-2Ð37; n, 0Ð84-1Ð03). It is suggested that C and b were the dominant physical parameters controlling the flocculation and w s of mud flocs in suspension.