Author(s): Kenji Kawaike, Takumi Sawatani, Hajime Nakagawa
Keywords: Pluvial inundation; Ditch; Stormwater drainage box; Numerical simulation;
Abstract: To predict risk level of urban inundation caused by heavy rainfall, so many numerical models have ever been developed. However, there are few models which considers the effects of ditches on inundation flow, which play a significant role in the process of stormwater drainage and overflow. In this study, assuming ditches and drainage boxes on both sides of all streets, a revised inundation flow model is proposed where the storage effects of the ditches are incorporated into stormwater drainage and overflow process.
Between two simulation results, considering and not considering the capacity of ditches, significant difference can be found. Between two simulation results considering and not considering the capacity of ditches, better simulation results could be obtained by using the proposed model here. From those comparison, significant difference between the overland inundation volume between two models could be found, which means the drainage process through the ditches could be expressed appropriately in the proposed model here. The stored water volume in the ditches, equivalent to one fourth to the overland inundation volume, has significant effects on the stormwater drainage process.