Author(s): Wei-Bo Chen; Wen-Cheng Liu; Ming-Hsi Hsu
Linked Author(s):
Keywords: Suspended sediment transport; Hydrodynamics; Numerical modeling; Local turbidity maximum; Calibration and verification; Danshui River estuary
Abstract: A three-dimensional, unstructured grid, time-dependent hydrodynamic and suspended sediment transport model was developed and applied to the Danshui River estuarine system and adjacent coastal sea of northern Taiwan. The model was calibrated and validated with observed water surface elevation, longitudinal velocity, salinity, and suspended sediment concentration in 2010. The model simulated results quantitatively agreed with the observational data. The calibrated and verified model was then implemented with a series of model diagnostic analyses to investigate the influences of vertical mixing, spring-neap tide, different freshwater discharges, and bathymetric change on suspended sediment dynamics in the main Danshui River estuary. More vertical mixing makes that the concentrations of suspended sediment are higher than those with stratification in the water column. Large-scale erosion and resuspension occur during the spring tide and result in the high suspended sediment concentration comparing to the neap tide. When the freshwater discharges increase at the upstream boundaries, the limits of salt intrusion pushes downriver toward Danshui River mouth. Suspended sediment concentrations significantly increase at both top and bottom layers in the estuary. The model predictions indicate that the local turbidity maximum slightly moves to upriver reaches after the bathymetric change around the Guandu.
Year: 2012