Author(s): Margaret Chen
Linked Author(s): Margaret Chen
Keywords: Flocculation; In-situ particle size; Floc shape; Settling; Estuary
Abstract: In-situ particle size is one of the key determinants for sediment transport in estuaries. Direct field observations in the Scheldt estuary show that suspended particles are intensively flocculated. Laboratory simulation experiments were performed in an attempt to reproduce the observed natural phenomenon in terms of the variability of floc formation with respect to the suspended particle locality from areas varying in salinity. Observations from the simulation experiments reveal that in a low turbulent flow field flocculation takes place on 3-hour time scales. Some intrinsic particle properties such as primary grain compositions, specific surface area (SSA), cation exchange capacity (CEC) and organic mater content (OM) as well as biological factors indispensably determine the ultimate size and settling behaviour of floc. Increment in floc size is not necessarily accompanied by an enhanced floc settling behaviour. Floc shape is a significant parameter determining floc settling. The results give an important appreciation for field monitoring and support for numerical modelling of the sediment transport.
Year: 2009