Several transport processes must considered in any evaluation of the behavior of cohensive sediments in estuaries influenced by currents and waves. Focusing on the need to understand the evolution of the suspension concentration profiles to hydrodynamic forcing, it is shown that a physcial framework identifying the various mass transport compoents which govern suspension profile dynamics is begining to emerge. Unfortunately, our knowledge of these components, including those associated with the generation, transport, and dewatering of fluid muds, remains incomplete. A combination of field and laboratory based research is essential for providing data bases free of significant lacunae and for resolving major interpretative ambiguities which arise from laboratory to prototype scaling and from practical limits to field measurements.