Study on an Inundation Prediction Medel Withlocalized Torrential Downpour and He Slight Topography in Urban Areas

Inundation damages have recently occured by heavy rain fall in urbanized
area such as Tokyo, Osaka, Nagoya et al in Japan. Precipitation and flow
rate excessing the plan of the sewer system in urban area overflows to
ground surface from the sewer pipes. To predict the inundation with damages
is recognized the very important issue. Many researcher have studied on the
mechanism of the overflow water of the earth surface from a sewage trachea,
structural and nonstructural countermeasure. The purpose of this study is
to develop the more effective and easily hydraulic model in order to
predict the inundation of the urban area. This study was reffered with the
points of view of the following studies; 1) The study that elucidated the
phenomenon in an object between space-time of the high definition, 2) the
study on Method to estimate an inundation point based on topography
analysis. The objection of this study is the drainage district
administrated by the Osaka city. We suggest a method of the mesh generation
in consideration of the topography properties, the characteristics of
run-off and hydraulic in the objective district. We show the validation and
reproduction of the run-off, inundation model in consideration of the sewer
network and the ground surface based on a thought of the new mesh
generation. Furthermore, we show the result that estimated the inundation
damage of the drainage district caused by the extreme heavy rain to exceed
the drainage plan of the sewer system.