ネットによる軟岩侵食抑制工法の開発と実河川における効果検証

抄録

One of the main causes of bedrock erosion is saltating bedload on the bare bedrock. On the other hand, if bedrock is covered by gravel, bedrock erosion is restrained by decreased collision frequency of bedload particles against bedrock. We focus on use of “net” as counter measure for bedrock erosion. “Net” has two favorable effects in solving bedrock erosion. One is a cover effect of net itself, and other is an effect of capturing bedload particles and increasing the extent of alluvial cover. We have already confirmed the above effects by flume experiments in our previous study. However, method of predicting suitable thickness of “net” for real river has not been developed. And little is known about the effects on “net” for real river. In this study, we predicted suitable thickness to validate thickness of “net” used in MinaminosawaRiver by using constructed model. In addition, we observed changes of the extent of alluvial cover before and after setting net on bedrock in MinaminosawaRiver.