Abstract

 Sediment transport is recognized as an important toxic management issue in the Baltimore Harbor. However, the component in transport, transformation and fate of contaminated sediment within Baltimore Harbor and between the Harbor and the Chesapeake Bay are not fully understood. In this study, a three-dimensional hydrodynamic/sediment transport model developed previously for Baltimore Harbor was modified to include non-point source and major point source inputs. The model is used to explore the impact of the new sediment inputs to sediment transport pattern in the Harbor and identify whether or not the Harbor serves as a source or a sink of different size classes contaminated sediments to the adjacent Chesapeake Bay. This study is one of various studies for the development of toxic TMDLs in Baltimore Harbor. The model is set to simulate the transport of a dissolved tracer as well as three sediment classes representing particles with fast, slow and intermediate settling velocities. Model results are averaged on a coarse box-grid and transfer coefficients that describe the exchange processes between adjacent boxes are derived. Net sediment concentration, erosion, and deposition are presented on a box-scale and brought into context with different non-point and point sources inputs in various scenario runs. The framework for the model with non-point and point sources and techniques for estimating all of the required coefficients have been developed. Additional work is on going, with model testing using field measurements collected in1999 and 2000.