Flood risk management by flooding currents using satellite image in the Nakdong basin, Korea
Abstract
Recently, floods have increased due to rapid urbanization and human activity in the lowland. Therefore, river flood control is essential for functional embankments and maintenance of safety concerns. Floods in Korea that occur every year are also caused by heavy rains and typhoons. However, due to lack of hydrologic, hydraulic and geomorphic data, high-magnitude floods is often difficult to compute in terms of the distribution of stream power and discharge per unit boundary area. Actually, it is unable to predict flood occurrence accurately using flood risk information and simulation data. In this study, we arrange a characteristic of the Nakdong river system which is a second largest basin in S.Korea and surrounded by mountain ranges. Most floods are caused by overflow and levee break in Nakdong river. To consider the inundation model, at first, the authors assume that extreme floods only occur within the maximum overflow at peak value. Next, the authors determine the most risk inundation area (Yangsan stream) among the 13 confluence points in Nakdong basin. This study’s purpose is to extract not only GIS-based flood risk factors but also the relationship between main stream and tributary, which is analyzed to generate multiple criteria such as the inundation vulnerable index (IVI), flow capacity (FC), potential flow (PF). Moreover, flood risk is also related to water depth and draining. The weighted inundation model is recalculated to produce the risky rank. Then, raster calculation proceeds to make identifying inundation areas in detail. In order to verify the flood risk, the authors apply to the previous occurred flooding data and satellite image. With correlation analysis of flood risk factors, the authors develop a methodology for determining flood risk index using spatial analysis and image analysis in the Nackdong river basin. As a result, the authors determine the location of most risk area among the 13 confluence point between main stream and tributary, thus the tributary stream overflow bounding discharge capacity of the channel in downstream of Nakdong river. Location of the study area in Nakdong basin, S.Korea
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFMNH43A1290K
- Keywords:
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- 1821 HYDROLOGY / Floods;
- 1928 INFORMATICS / GIS science