SEDIMENT RESUSPENSION IN LAKE ST-CLAIR

Time-series measurements of water transparency, wave conditions, and current spee at several different sites in Lake St. Clair during five different 1-month periods in 1985 and 1986. Observed changes in suspended sediment concentration were modeled with a simple zero-dimensional, spatially averaged, mass balance model in which local bottom erosion was expressed as a linear function of the bottom shear stress. Estimates of the three parameters required by the model (particle settling velocity, resuspension concentration, and background suspended material concentration) are reasonably consistent for the various data sets, suggesting that the properties of the lake bottom do not change significantly through either space or time. The modeled settling velocities agree with the observed suspended particle size data and the erosion rates are comparable to laboratory results for freshwater sediments. The results show that a simple mass flux model can be used to model local sediment resuspension events in Lake St. Clair with reasonable accuracy.