戸蔦別川における床固工群と樹林帯の出水時の効果

抄録

The Tottabetsu River had the sharp channel change accompanying sediment discharge in the past. It became clear that the section (“anti-node”) which a river channel moves to a transverse direction greatly, and the section (“node”) where a river channel hardly moves existed periodically (gourd shaped channel). It was decided that main groundsills at the “node” and ancillary groundsills at the “anti-node” would be built. The first groundsills was built in 1988 and 15 sets of groundsill were completed in 2010. However, the sediment transport control effect of these groundsills was not verified until the present. The large-scale flood occurred at this basin in August 2016. In order to verify the effect of the groundsills, the difference of the river channel change at the time of this flood between with and without groundsills was calculated using a numeric simulation model. It was found that the groundsills and forest zone had controlled not only sediment transport but also movement to the transverse direction of channel.