2011年深層崩壊発生後の赤谷川流域からの土砂流出と川原樋川との合流点での河床上昇について

抄録

Due to the disaster of the Kii Peninsula in 2011, a deep-seated landslide occurred in Akadani River basin. So, a large amount of sediment flew out to the downstream area. Especially, the riverbed rise is conspicuous at the confluence of Akadani River and Kawarabi River. In this study, using the topographical data obtained by the laser profiler, we investigated the river bed variation at the confluence of Akadani River and Kawarabi River.

First, laser profilers were taken around Akadani River and Kawarabi River every other year from just after the disaster. By comparing the data with the past one (taken before 1 year), we investigated the erosion or sedimentation area of riverbed around Akadani River and Kawarabi River.

We found that due to the sediment discharge after the landslide, river bed rise has been remarkable near the confluence point of Akadani River and Kawarabi River. And, we found that riverbed rising occurs upstream and downstream of the confluence point of Kawarabi River, too.