Author(s): Hisanobu Terao; Koichiro Ohgushi
Linked Author(s): Koichiro Ohgushi
Keywords: Flood simulation; Retarding basin; Drainage pump station; Lowland
Abstract: In recent years, flood caused by unpredictable heavy rain becomes frequent. Lowlands are greatly influenced by the tide. The tidal range of the Ariake Sea reaches to 6 meters. Therefore, drainage of the landside water becomes difficult. As a result, flood damage increases and its control measures have various difficulty. Therefore, tremendous damages caused by flood water and the landside water have frequently occurred in such lowland. In Ushizu River, drainage pump stations and retarding basin were built as countermeasures to reduce the damage. However the damage did not disappear. In this study, the effect of reducing the riverine water level by the retarding basins has been implemented. There are few researches about reduction of water level considering both the river water level and landside water level simultaneously. In this study, we examined the flood control measures in the future by reproducing the flow condition of Ushizu River in Northern Kyushu heavy rains in July 2012. Verifications of the effect of Mutabe retarding basin, and drainage pump stations are considered. After evaluation of the effect of reducing the water level by seven drainage pump stations in order to solve the current problems. Water level exceeded the estimated high water level in the case of the medium scale flood. Mutabe retarding basin can not cover the revealed flood. As a result of the analysis, the drainage by the drainage pump stations does not affect the river water level so much. Therefore it is the first priority to keep the capacity for the pumping by the embankment construction, instead of the new retarding basin.
Year: 2015