• Journal of Korea Water Resources Association
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• v.43 no.10
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• pp.883-891
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• 2010

More recently, there have been significant changes in the forms of channels due to runoff characteristics driven by climate changes and other alterations in basin/channel environments. Particularly, increasing local deposition in major channels is being observed nationwide. Of such phenomena, it is noteworthy that flood-plains show unidirectional growth and lowering of channels within compound channels in the form of a high-flow plain. These changes are supposed to affect management of the river ecology as well as flood control. In this study, the research on channels in Korea confirmed that the phenomenon of local deposition in those channels is actually taking place, rendering a problem to be urgently addressed. Previous studies on bed changes have been focused on low channels based on bed materials distributed over the channels. However, this research has proved that surface-layer deposition of a high-flow plain is closely related with changes in the conditions of ground surfaces and, ultimately, affects the bed of the entire channel as well. According to the intensive research on the condition of the high-flow plain of the mouth of the Han River, the silt deposited in the high-flow plain was the main cause of settlement/growth of vegetation. And this leads to landforming along with woods-forming, disturbing flood control as well as the normal river ecology.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4B
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• pp.213-220
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• 2012

Old river channels have been formed by engineering a straight channel in Korea. This can be classified as wetland-type or land-type. The wetland-type old river channel uses parts of agricultural water supply. However, the channels have been neglected since there are problems associated with poor water quality, reduced water level, ecosystem disturbance, etc. Thus, river maintenance through preservation and restoration of old river channel can be very effective in watershed management. To achieve this, functional assessment of wetland-type old river channel is a priority need. This study applied the wetland-type channel in Mangyoung river for functional assessment. It was formed these channels with regard to the following four major criteria (Natureless, Habitat, Water-friendliness and Water quality) and 21 indices. The indices managed by measuring depending in weights. Consequently, wetland-type channel in Mangyoung river was in good condition both natureless and habitat, while it was a fragile environment in water-friendliness and water quality. In particular, the areas where it has insufficiency water and water suffering from eutrophication needs urgent improvement. This results will be used to utilize wetland-type old river channel as watershed management.

• Journal of Wetlands Research
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• v.14 no.2
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• pp.277-288
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• 2012

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.