Fine-Grained Sedimentation in a Shallow Harbor

Abstract

Sedimentation is examined at a potential site for an oil terminal along the Aoshan channel slope in the vicinity of the East China Sea, where fine-grained sediments predominate. A feature of this slope is that due to characteristically enhanced lateral exchange of fluid momentum and suspended sediment mass, vertical profiles of flow velocity and suspended sediment concentration are more uniform than at the center of the channel. It is shown that lateral eddy diffusion at the slope is likely to be the dominant cause of this mixing. Accordingly, a two-dimensional, depth-averaged numerical model was applied to simulate historic rates of sedimentation in the study area by using an approximate method to estimate the annual rate of sedimentation, because long term data on suspended sediment were unavailable. Model-simulated rates are compared with observed patterns of sedimentation.