河川渓流域における水制工による魚道上流入り口の閉塞防止効果

抄録

To investigate the effect of a spur dike installed to prevent the deposition of sediment or driftwood upstream of a fishway inlet, the survey of water level, cross section profile and grain size before and after flood events and the numerical analyses with or without the spur dike were conducted. We found no serious deposition upstream of the fishway inlet after the floods. The numerical analyses showed that water velocity upstream of the fishway inlet with the spur dike was higher than that without the spur dike and a deep scour beside the head of the spur dike was created. Thus, we concluded that the installation of the spur dike contributed to preventing the deposition of sediment by accelerating sediment discharge and lowering the riverbed around the spur dike.