Flood Risk Analysis of River Basins Shakti P.C., Storm, Flood and Landslide Research Division, NIED 2020.2.13 令和元年度 成果発表会■ The most important input for the hydrological model is a detailed overview of the river basin’s hydrographic features. ■ River geometries of Oda River basin was generated. ■ Development of river geometries and river flood risk in any basin is a goal of this study. Although different types of hydrological models can be adopted in a selected river basin, the most important input for the model is a detailed overview of the river basin’s hydrographic features. This plays a crucial role in flood inundation analysis. For example; information on river geometries, i.e. Embankment height (EH), River width (RW), and River depth (RD) are necessary parameters that should be correctly incorporated into the model. In Japan, a large number of embankment structures have been built along several rivers for flood protection. Both the RW and RD parameters within the city area, are often modified and, in certain cases, workers have changed the course of the river. Hence, the ability to consider all of these factors is a significant challenge when performing hydrological modeling of any river basin. Fig. Embankment heights (EH) along the left bank of main river in the basin (Upper panel) and preliminary results on spatial distribution of river flood risk profile over the Oda River basin at 16:00 JST on 30 September 2018 (Lower panel). Categories of river flood risk level are based on statistical analysis of 30 independent simulated events only. Extraction of river geometries in the Oda River basin, and adoption of this idea to other river basin, can be valuable references for the proper management of water related disasters. Hence, such study will be applied to other river basin this year for the application purpose. Then, river geometries of Japanese river basins will be generated. Preliminarily results on development of river flood risk have carried out for the Oda River basin. Further validation and calibration of simulated events and framework on flood risk design need to be address. The considerations of flood scenarios also need to address for this basin. Moreover, other river basin will be studied to develop such scenarios. Overview Prospects River flood risk map for Oda River basin was generated and applied for the rain event of 30 Sept 2018 which is based on the statistical analysis of past 30 independent simulated events (Fig). Torrential rain caused heavy flooding from July 5–8, 2018, over the Oda River basin, which caused severe flood inundation over the Mabicho region and lower parts of the basin, significant loss of life, and severe infrastructure damage. In this study, river geometries of the Oda River were generated and applied in the simulation. Simulated and observed water level, and discharge followed identical trends.
元のページ ../index.html#95