A Field Study of Flocculation as a Factor in Estuarial Shoaling Processes

Abstract

Simultaneous measurements of currents, salinities, and suspended sediment concentrations were made at locations upstream, inside and downstream of an area of rapid shoaling in Savannah Harbor throughout a tidal cycle during each of three tide ranges to learn the importance of flocculation processes to the formation of shoals. The sampling stations were located in the zone of mixing of river and ocean waters. As shown in the data, chemical and hydraulic conditions prevail that together with an abundant supply of suspended particles provide the cohesion, frequency of collision, and time for formation necessary to form aggregations of large numbers of mineral particles. Changes of concentration at slack and concentration profiles at the strength of flow showed that particles have settling velocities much greater than those of the individual particles that comprise the shoal. Flocculation determines the settling velocities of suspended material at Savannah.