Browsing by Author "Hsieh, Tung-Chou"

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Investigation of Morphological Changes in the Tamsui River Estuary Using an Integrated Coastal and Estuarine Processes Model
(2020-04-01)
Hsieh, Tung-Chou
;
Ding, Yan
;
Yeh, Keh-Chia
;
Jhong, Ren-Kai
;
土木工程學系
This study is to investigate morphological changes in the Tamsui River Estuary in Taiwan driven by multiple physical processes, such as river flows, tides, waves, and storm surges, and then to study the impacts of sediment flushing operated at the Shihmen reservoir upstream on the river estuary. An integrated coastal and estuarine processes model (CCHE2D-Coast) (Center for Computational Hydroscience and Engineering Two-Dimensional-Coast) was validated by simulating these physical processes in the estuary driven by three historical typhoons in 2008. The site-specifically validated model was then applied to simulate morphological changes in the estuary in response to reservoir sediment flush scenarios from the upstream. For the impact assessment of sediment flushing, a synthetic hydrological event was designed by including a historical typhoon and a typical monsoon. It was found that during the typhoon, the sediments will be mostly deposited in the estuarine river reach of Tamsui and the Wazihwei sandy beach. During the monsoon period, most of the sediments tend to be deposited in the second fishing port of Tamsui, the northern breakwater, and the estuary, while the Wazihwei sandy beach in the river mouth would be scoured by backflow. Simulations of the complex flow fields and morphological changes will facilitate the best practice of sediment management in the coastal and estuarine regions.
Modeling Morphological Changes due to Multiple Typhoons in the Danshui River Estuary
(2015)
Ding, Yan
;
Hsieh, Tung-Chou
;
Yeh, Keh-Chia
;
土木工程學系
;
Department of Civil Engineering
This paper presents a preliminary study on morphological changes in the Danshui River estuary driven by tides, waves, and river floods during the period of three typhoons in 2008 (Fung Wong, Sinlaku, and Jangmi) using an integrated coastal process model. The submodels for wave, current, and sediment transport were validated by comparing the simulation results with available observation/survey data. Model validation results indicate that the simulated water levels, flow velocities, and wave heights are in good agreement with the measurements at gages, and the simulated bed changes have captured the major features of deposition and erosion in the river, the estuary, and adjacent coasts.