FLOOD CONTROL EFFECT OF DAMS IN THE UPPER BASIN OF TONE RIVER DURING TYPHOON HAGIBIS

Abstract

 This paper investigated the flood control effect of dams in the upper basin of the Tone River at the Yattajima site during Typhoon Hagibis. In order to investigate the flood control effect, we compared the peak water levels with and without the dams. The presented results showed that the flood control by the dam group reduced the water level by 0.9 m in maximum at the target site. Moreover, the most effective dam among the all dams was Yanba dam, which accounted for approximate 60% of the flood control effect, with a maximum reduction in water level of approximate 0.6m. When dam started test flooding on October 1, 2019, the reservoir was not filled up. However, approximate 100% of the flood was stored in the dam reservoir. We found that the flood control effect was almost the same when the flood control was carried out based on operation manual of Yanba dam.