Sediment resuspension in Saginaw Bay

An integrated hydrodynamic and sediment transport model was applied to Saginaw Bay for the ice-free portions of 2009 and 2010. Observations of surface waves and suspended sediment concentration made during the spring of both years were used to constrain the model and to validate the model output. The results show that sediment resuspension in both the inner and outer bay is due almost entirely to surface wave action, and that the bulk of the resuspension events occur during the fall of each year. Although the model accurately predicted the occurrence of resuspension events, it did not always accurately simulate the amount of material resuspended. Because resuspension mixes bottom sediment into the water column and makes it and associated nutrients available to the biota, the effects of sediment resuspension need to be accounted for in any water quality model of the bay. Better specification of both the surface waves and the initial specification of the bottom sediment would probably improve the performance of the model.