CHARACTERISTICS OF INUNDATION WATER CONSIDERING SEWERAGE DURING COMPOUND WATER DISASTERS DUE TO SIMULTANEOUS INUNDATIONS BY RAINWATER AND RIVER WATER

Abstract

 Superimposed inundation simulation was carried out for the Gobo River, a second-class river in Takamatsu City, Kagawa, Japan, under the condition of 1000 years probable precipitation, taking into account the sewerage system, for a compound water disaster in which rainwater and river water inundations occur at the same time. As a result, even when the sewerage was taken into consideration, the inundation area became the largest during the superimposed inundation. It was also found that by considering the sewerage, the inundation depth decreased, but there were places where the flow velocity increased. In addition, in the case of superimposed inundation, the results showed that a wider area was inundated than simply adding the inundation areas of inland waters and foreland waters.