Development of a coupled sediment transport and re-suspension model for Lake Michigan

PIs: Keith W. Bedford, David Welsh, Philip Chu, Panagiotis Velissariou, Vasilia Velissariou, and Yong Guo

Dept. of Civil and Environmental Engineering and Geodetic Sciences
The Ohio State University, Columbus, OH 43210
Tel: 614.292.6919 FAX: 614.292.3780

To study cross-margin transport in southern Lake Michigan during episodic events and to identify transient and permanent particle sinks along the path of suspended material plumes, a multi-grain, multi-source sediment transport formulation has been considered. Five control volumes with an 18 km width and with variable lengths were selected along the western and the southern shores of the Lake Michigan and three representative grain sizes, one from each sediment size class (sand silt, clay) were assigned to the bottom of the Lake and to each control volume. Calculations were performed using the Coupled Marine Prediction System developed at the Ohio State University. CO.MA.P.S. consists of the WAM wind wave model, the CH3D hydrodynamic circulation model, the CH3D-SED sediment transport and re-suspension model and the BBLM bottom boundary layer model. All four models are fully coupled and parallel versions of the codes are used to minimize the CPU and the real time requirements. Four diagnostic components were considered during the analysis which in increasing degree of complexity are as follows:

  1. model runs with no waves and no shore erosion terms included,
  2. model runs with waves but erosion terms are not included,
  3. model runs with shore erosion terms but waves are not included , and
  4. model runs with waves and erosion terms included.
The scope of such an analysis is to evaluate the impact of the diagnostic components on the transport and the distribution of the suspended sediment classes. The fully coupled model was run on a 2-Km spatial grid for the test period from March 1st , 1998 to March 31st, 1998. Model outputs include: 3-D velocity, temperature and concentration fields, vertically integrated velocities and grain size distributions at the Lake bottom, from which hourly trajectory maps are generated.