堤防決壊による洪水危険度の評価に関する研究

Abstract

In Japan, about 50% of its population is living and 70% of properties are existing in floodhazardous zones. Although continuous efforts have been devoted to construct the structures toprevent from flooding, the risks to suffer from the hazard caused by river bank breach are stillvery high or even more than before due to progress of concentration of population and propertiesin the hazardous zones. In this circumstances, the soft measures to mitigate the disaster arevery important. Among the various soft measures which are the generic term of the non-structuralmeans, the prediction of the flood areas and their scales, such as the ranges of houses to be sweptaway, severely inundated, severely affected by the sedimentation etc. would be the most importantbecause it gives us a correct understanding of the present state of safety of life and properties whichis the starting point to construct the strategy against the hazard.In this study, we propose a numerical simulation method of the floodings, in which the effectsof existance of houses to the flow behavior are taken account. In addition, the criterion whichdetermines whether the wooden houses will be swept away is discussed. We predict the floodhazardous zones in an actual basin by combining the simulation method with this criterion.