2004 年 57 巻 3 号 p. 47-52_1
Heavy rainfalls occurred in Niigata and Fukushima Prefectures during July 12-13, 2004 (Total rainfall at Tochio City, Niigata was greater than 420mm) and in Fukui Prefecture during July 17-18 2004 (Total rainfall at Miyama Town in Fukui was greater than 280mm). Also, Typhoon Namtheun brought heavy rainfalls to the Kinki and Shikoku regions between July 30 and August 1, 2004. Total rainfall in the upper reaches of the Nakagawa River exceeded 1, 000mm. These rainfalls triggered a number of sediment related disasters. The NILIM and PWRI investigated these sediment related disasters shortly after they occurred. Here we report on (1) characteristics of sediment related disasters in Fukui and Tokushima, (2) spatial distributions of sediment related disasters and their relation to rainfall amount variability in Niigata and Fukui, and (3) effectiveness of sabo dams against debris flows.