Evaluation of the water channel plan in Nagaoka city area of the Shinano River

Abstract

Nagaoka city area in an alluvial fan is dangerous in flood control, because the Shinano River flows fast, meanders and attacks the area. Safety of levees is a serious problem. After the alignment of low water channel was examined in a hydraulic model experiment as well as a training levee, a low water revetment has been executed the work since 1975. About 25 years have passed, the site observation results were compared with the hydraulic model experiment results about changes of a riverbed and reduction of flow attacking effect. The effect of training levee, which is main concern of this planning, is evaluated by numerical simulation.