EVALUATION OF FLOOD ADAPTATION AND MITIGATION MEASURES BY THE ORDER OF RIPARIAN VEGETATION REMOVAL

Abstract

 This study estimated the flood damage reduction effects by the order of riparian vegetation removal on class A river systems in Japan. River systems with a high potential for both adaptation and mitigation measures of riparian vegetation removal were evaluated. Flood inundation analyses which reflected the influence of riparian vegetation through roughness coefficients were conducted, and the damage costs were calculated based on inundation depths. The biomass potential was calculated as the normalized vegetation index multiplied by the vegetated area. The results showed that the flood damage reduction effect varied depending on the order of riparian vegetation removal. A relationship was also observed between the order of riparian vegetation removal and the population distribution. The river systems where both adaptation and mitigation measures by riparian vegetation removal were highly effective were estimated to be the Tokachi, Yubetsu and Iwaki River systems.