抄録
Several rivers in the Omote-Rokko district, such as the Toga River and the Sumiyoshi River, are attracting local people to the river space thanks to their water-friendliness. However, the area where people are enjoying is obviously the bottom of river course, which becomes dangerous even for a small rain. It is necessary to properly inform the people about the danger of the flow in such a case. Therefore, we firstly investigated the traffic of pedestrians on the walkways and their behavior when a rain begins to fall with the aid of two monitoring cameras installed in the Sumiyoshi River. Secondly, we developed a runoff model based on a composite rational formula and carried out two dimensional simulations of rapid flow subject to intensive rains as a diagnostic tool. It was made clear that more than two thousands of people are using the walkways in the Sumiyoshi River every day and the river course can be divided into several zones which depend on a relative safety measure of hydrodynamic forces acting on a person.
