HYDRODYNAMICS ESTIMATION OF WEAK SECTION IN RIVER OF SMALL AND MEDIUM SIZES

Abstract

On rivers of small and middle sizes in Japan, spatial information of river geometries and hydrological records for understanding basic characteristics of rivers have not been accumulated, river management officers can’t decide a priority of river improvement works based on an objective index. Especially it is quite difficult to immediately estimate damages of the area stricken by a heavily flood disasters. In this study, authors show that spatial data which are freely distributed on the internet can be extracted river geometries for conducting 2-dimensional hydraulic calculation to estimate variation of water level and deviation of river bed. This study was also proposed that variance of time integrated friction velocity can presume weak sections which will be damaged on heavily flood.