Flocculation Population Dynamics of Cohesive Houston Ship Channel Sediments

Aggregation and breakup processes play a major role in defining the settling velocity and transport properties of fine, muddy sediment. The inclusion of flocculation effects on the distribution of fine particles is, therefore, important in the interpretation and prediction of sediment and pollutant transport in harbors and estuaries. This study experimentally measures floc size populations as a function of time, turbulent shear rate and salinity using Houston Ship Channel sediments that have clay-silt-sand percentages of 50%-50%-0%. Quantification of the floc size population was accomplished using a non-intrusive floc camera capable of capturing particles in the range of 5–2000 microns and image processing. Turbulent shear rate and salinity were both found to play a significant role in governing floc size and the time to a constant particle size distribution. Observational results are presented according to the clay and silt contribution in aggregation that describe the effect of flocculation on the time dependent median floc size.