2013 Volume 6 Issue 1 Pages 13-22
A debris flow broke out at 16:40 on Aug. 18, 2004 in the Kitamatasawa, one of the right-bank tributaries of the Namekawa River in the Kiso River system. The flow volume (around 50,000 m3) was safely captured by the Namekawa No. 1 Sabo Dam, located at the downstream end of the tributary. Damage was successfully prevented, proving the dam´s effectiveness. A set of monitoring cameras installed around the site of the Namekawa No. 1 Sabo Dam and at various upstream points captured images of the debris flow. Here, we discuss the features of the debris flow based on analysis of these images.