River Basin Management for Flooding and Inundation Using Traditional Flood Control Technology

River Basin Management for Flooding and Inundation Using Traditional Flood Control Technology

(Abstact) The first full-scale countermeasures against flood disasters were carried out at 17th century in Japan. The Saga Plain is one of the places that include such flood damage prevention facilities. At present, several facilities are left and can be seen as historic remains. It is significantly useful to find out and restore these remains and clarify their functions to consider a future flood control including catchment basin operations. In this study, overflow embankments and open levees are focused on the investigated field for estimating a controlled water flow spreading the retarding basin with sediment transports. A geotechnical sampling method is adopted in this research to obtain a plate-like sample that can be easily analyzed for estimating water flow velocity, flow direction and a process of sediment settling. An additional investigation of numerical simulation is implemented to estimate water flow on the retarding basin from the overflow embankment. Flow analysis of theriver gave a boundary condition for anotherdetail simulation of flood flow on the retarding basin. The results of geotechnical investigation and hydraulic approach show the inundated water flow is controlled in the retarding basin of the residential area. The result of this study gives a quantitative evaluationof the flood control including catchment basin operations for the river basin management.