扇状地における土砂氾濫災害危険度の評価

Abstract

A method to make sediment hazard risk mapping on a debris fan area is pre-sented. The risks in this method are divided into several categories such as thosethe houses will be completely destroyed, the deposit thickness of stones, gravels, orsand will exceed some scored figures for certain categories, the houses will be partlydestroyed and sediment will intrude into them, and so forth. If, by some othermethods not described herein, the hydrograph, sediment concentration and particlesize distribution in the flow are given, the computer simulations which comprise themain part of this paper render possible giving rise to the processes of debris fanformation accompanying spacial distribution of particle sizes and following erosionof it and redeposition as an alluvial fan, and thus, mapping of risk zones accordingto the predetermined risk categories.