Estuary is unique habitat ground under substantial changes of water quality, river side, bed material, and
micro topography. Construction of SinGok underwater weir with excessive dredging for downstream of weir has
changed hydraulic conditions of Han River. This study investigates spatial changes of estuary and expansion process
of vegetation on sandbar for JangHang estuary in Han River through analysis of physical and ecological
characteristics. As a result of investigation, we found that area of sandbar in JangHang estuary is expanded six
times compared between 1985 and 2006, and area of Phragmites australis is gradually decreased while area of Salix
subfragilis Anderson. is increased. Also the analysis result of soil layer shows that the Jang-Hang wetlands are
created by effect from river, and woody plants are settled from middle part of wetlands, then spread to upper and
lower part of wetlands.