The large amplified secondary oscillation, locally called abiki, observed in Kyushu and San-in coastal area on 20 and 21 March 2019 as passed the extratropical cyclone. This paper reports on the inundation damages by abiki phenomenon over the urban area of Nagasaki. According to field survey, the water level as high as 2.3~2.6 m above Tokyo Peil (T.P.) in the downtown of Nagasaki, and 2.9 m T.P. in the downstream site of Urakami River. There seemed to be two-staged mechanisms of inundation in Nagasaki city: the backward flow through the culverts in the first stage, and the overflow from small rivers in the second stage.

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􏰧􏰃􏰖􏰃Severe water-related disasters occur in Japan almost yearly due to typhoons and frontal rains; these events often entail evacuation problems. In this report, a questionnaire survey was conducted among local people of Miyagi and Toyama Prefectures to evaluate their awareness of disaster-related information. We also conducted an oral survey encompassing several city hall meetings to investigate problems that have occurred during past disaster responses. As a result of this analysis, we determined that many people do not fully understand locally distributed disaster information. City halls are responsible for many difficult tasks during disaster responses. Therefore, to overcome the evacuation problems investigated in this study, we proposed the distribution of a new hazard information based on probable maximum flood inundation to identify high-risk zones where early evacuation will be required.

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This paper introduces a long-term recovery process of Kizawa village hard hit by the 2004 Niigata-Chuetsu earthquake by paying special attention to local autonomy evidenced by survivors’ evaluations. We classify the 15-year disaster recovery process into four periods named as “livelihood rehabilitation”, “empowerment”, “problem-solving” and “reorganization” and describe how the survivors tried to work collaboratively with outside supporters. We also show results of a process evaluation method for community life improvement and illustrate how the local people of the Kizawa village evaluated their recovery processes from their perspectives. Finally, we discuss the importance of tracing a long-term disaster recovery process and evaluating if endogenous initiatives were formulated and how these could change local community.

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The purpose of this study is to analyze the relationship between hazard risk information and location of victim caused by heavy rainfall disaster in Japan. I have constructed database of victims (1259 persons) by heavy rainfall disaster from 1999 to 2018. In this study, 767 victims of flood and sediment disaster recorded in the database were analyzed. Eighty-seven percent of the victims of sediment disaster have died near the sediment disaster dangerous sites. On the other hand, 42% of flood disaster victims died near the inundation hazardous areas. As a result of analyzing the relationship between the flood disaster victims and the topography, 85% of the victims died in lowlands where there is a possibility of flooding. Most of the victims of flood disaster and sediment disaster occur geographically where disasters can occur. However, the current hazard map alone is not enough to understand the risk of flood disaster in the residence. It is important to construct easy-to-understand landform classification map information.

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This study is based on our previous report in the Japanese Society for Natural Disasters (J.JSNDS, 36-4,2018) that described the extent of damage attributed to floating trees during flooding of the Kuji River due to Typhoon No. 10 in 2016. The motivation for this study was based on the hypothesis that the considerable damage attributed to flooding of the Kuji River may have been less extensive if the floating trees in the floodwaters of the river had not been caught by bridges. To clarify this hypothesis, we examined hydrological, photographic and satellite data of the river and bridges at the time of flooding and two years thereafter, which we obtained from the Iwate Prefectural government and Google Earth. Furthermore, we used a tank model with flow data from the St. 1 water gage to estimate the run-off discharge in 2015. At the same time, tank model parameters were determined. The relation between water level and discharge was estimated based on discharge calculated using Manning’s formula. The roughness coefficient was calculated by anti–analysis of Manning’s formula in order to recreate on the discharge in 2016. As for St. 1, the relation between water level and discharge was also estimated for the St. 2 water gage, which was located close to where the river overflowed its banks. Using numerical run-off analysis, we also estimated whether or not the riverbanks overflowed. Our findings showed that if floating trees had not been caught by bridges, the riverbanks overflowed would had not occurred, or the damage associated with flooding of the Kuji River would have considerably been less extensive.

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