Sediment resuspension under action of wind in Taihu Lake, China

A field study was undertaken to investigate the changes of the current speed, wave parameters and sediment resuspension under different wind speeds in the Taihu Lake. The Acoustic Doppler Current Profiler (ADCP) and MIDAS DWR Wave Recorder were used to collect the data of currents and waves, respectively. The characteristics of sediment resuspension were investigated by a layered sampling technology. The measurement results showed that the current speed increased in direct proportion with the wind speed. Vertical distributions of the current speed represented significant inflection points at 0.4 of the relative water depth. Both the upper and lower layers followed logarithmic distributions. The mean wind speed and wave parameters (wave height and wave energy density) showed exponential distributions, meanwhile similar distribution was found between the mean wind speed and current speed. With rising surface wind, a corresponding increase in the concentration and particle size of the Suspended Particulate Matter (SPM) was observed in the water column. Different kinds of particles could influence the SPM concentration in the water column. The critical wind speed of sediment resuspension and the corresponding sediment incipient shear stress was found to be 3.7 – 4.0 m s−1 and 0.011 N m−2, respectively. The results of this study can be used to help understand and predict the changes of flow structure and water quality induced by different wind disturbances in shallow lakes.