A sediment transport model (SEDIMENT IIIA) was developed to assist in predicting the fate of chemical pollutants sorbed to cohesive sediments in rivers and estuaries. Laboratory experiments were conducted to upgrade an existing two-dimensional, depth-averaged, finite element, cohesive sediment transport model. The enhanced descriptions should also be useful in predicting the movement of dredged material released in open marine waters, identifying harbor sites in estuaries and bays where shoaling is minimized, predicting changes in sedimentation that may result from proposed changes or developments of an estuary or harbor, and estimating shoaling rates and maintenance dredging requirements in areas of low flow.