Critical Shear Stress for Deposition of Cohesive Sediments in Mai Po

A series of tests was conducted to investigate the deposition behaviors of the cohesive sediments collected from Mai Po (Hong Kong) in wet seasons when the salinity was low. The sediment suspended by high shear stress in water with zero salinity was allowed to deposit by lowering the shear stress level. The results show that the sediment has a unique transport characteristic. The sediment began to deposit steadily once it undergoes a weaker shear stress. The underlying reasons of this phenomenon and the application to a sediment transport model are discussed in this paper.