Flow Characteristics due to Removal and Shift of Shingok Weir at Downstream of Han River

In this study, the flow characteristics at downstream of the Han River located in Korea were investigated by using a two-dimensional numerical model according to the assumption of shift and removal of the Shingok submerged weir. The two-dimensional analysis has contributed to our understanding of the hydraulic effects induced by shift of the weir on the topography, especially wetlands. The tide and flow discharge data of 2007 and 2012 were adopted as an input data for model validation and simulation. The tidal data contained both spring and neap tides, and the flow discharge condition was divided into monsoon and normal seasons. The boundaries of this study were Jamsil weir at Han River, Tongil Bridge at Imjin River, and Yu Island at yellow sea. The numerical model which was used as a tool to simulate the flow field was calibrated and verified based on the measured data acquired from Jeonlyu station. The simulation results showed that influence area of seawater changed depending on the weir shift, and the water level at particular station fluctuated according to the condition of tide and flow discharge. Especially the low-tide level increases seriously due to the weir shift at Janghang wetland located in Han River Estuary. It is expected that the wetlands where an area of land consists of soil saturated with moisture are transformed into completely submerged land. Due to weir removal, the influence area of the tidal flow is extended slightly at Han River. The impact point of tidal flow and river flow moves toward upstream, from Hangang Bridge to Dongjak Bridge during spring tide.