Investigating suspended-sediment transport in a shallow lake using a three-dimensional hydrodynamic and sediment model

Abstract

A three-dimensional, unstructured-grid hydrodynamic and suspended-sediment transport model was developed to simulate the temporal and spatial variations of suspended sediment and was applied to the subtropical subalpine Tsuei-Feng Lake (TFL) of Taiwan. The model was validated with measured water level and suspended-sediment concentration in 2009, 2010 and 2011. The overall model simulation results are in quantitative agreement with the observational data. The validated model was then applied to explore the most important parameter that affects the suspended-sediment concentration and to investigate the effect of wind stress on the mean current and suspended-sediment distribution in this shallow lake. Modelling results of the sensitivity analysis revealed that the settling velocity is a crucial parameter and the erosion rate is less important in the suspended-sediment transport model. Remarkable lake circulation was found based on the strength of wind speed and wind direction. A strong wind would result in a higher mean current in the top layer and suspended-sediment distribution in the top and bottom layers. This study demonstrated that wind stress played a significant influence on mean circulation and suspended-sediment transport in a shallow lake.