Thursday, February 26, 2004
"Numerical modeling of mixed sediment resuspension, transport, and
deposition during the March 1998 episodic events in Southern Lake
Cooperative Institute for Limnology and Ecosystems Research (CILER)
University of Michigan
GLERL Main Conference Room
2205 Commonwealth Blvd.
Ann Arbor, MI 48105
A two-dimensional sediment transport model capable of simulating sediment resuspension of mixed (cohesive+noncohesive) sediment is developed and applied to simulate quantitatively the March 1998 resuspension events in southern Lake Michigan. Some characteristics of model are capabilities to simulate several floc size classes, physically-based settling velocity formula, bed armoring, and sediment availability effect. Important resuspension parameters were estimated from field or laboratory measurements. Model results were verified with field measurements (ADCPs and sediment trap) and SeaWIFS satellite images. The model successfully reproduced the resuspension plume (observed by SeaWIFS satellite and field instruments) and recently measured sedimentation rate (using radiotracer techniques). Wave conditions and sediment properties (such as critical shear stress, fine sediment fraction, and limited sediment availability or source) determined the concentration distribution and width of resuspension plume. The modeled sedimentation shows the preferential accumulation of sediment on eastern side of the lake agreed with the recent measurement, despite a predominance of particles sources on the western side. Main physical mechanisms determining the sedimentation pattern are two counter-rotating gyres producing offshore mass transport around southeastern coast during northerly wind and settling velocity of
sediment flocs also controlling the dumping location.
For more information, contact:
Dr. David Schwab
David F. Reid, Ph.D. NOAA Seminar Series Co-Chair Senior Research Scientist Task Leader, GLERL Nonindigenous Species Program Member, NOAA Invasive Species Matrix Program Management Team Director, NOAA National Center for Research on Aquatic Invasive Species U.S. Department of Commerce National Oceanic and Atmospheric Administration Great Lakes Environmental Research Laboratory 2205 Commonwealth Blvd. Ann Arbor, MI 48105-2945 Voice: 734-741-2019 FAX: 734-741-2055 GLERL home page: http://www.glerl.noaa.gov