SEDIMENT PROPERTIES AND DYNAMICS IN THE TAIHU LAKE,CHINA

Time-series measurements of wave, current and suspended sediment concentration (SSC) weremade at three sites (Sites 1-3) and sediment samples were collected at different locations (Sites 4-7)in Lake Taihu. The significant wave height, length and period during the observation were 0.155 m,3.45 m and 1.9 s and the mean current speed was 0.08 m/s. The size distribution results show thatthe sediment is well sorted, coarse-skewed and very leptokurtic in the upper 10 cm and clay andfine silt can account for more than 70 % of the total within this depth. The median size remainsconstant vertically in the top 10 cm in the eastern, southern, and northern areas of the lake, butchanges significantly in the eastern area resulting from the short retention time of water in this area.The realistic settling velocity of suspended particles varies in the range of 0.01~0.05 cm s-1 andthey sink in a flocculated form rather than individually. Based on a simple mass flux model, thesediment erosion rate was estimated to range between 10-7 and 10-5 kg/m2.s. The results in thisstudy can be a great contribution to the development of a sediment transportation model in LakeTaihu.