STUDY OF FLOW REPRESENTATION METHOD BASED ON D4PDF FOR MULTI-STAGE INUNDATION ASSUMPTION

Abstract

 For comprehensive disaster prevention and mitigation measures, multi-stage inundation estimation is needed nationwide, including for small rivers. d4PDF is useful for this purpose because it provides various rainfalls with small extensions, including in areas with little observed rainfall. However, it is too large a workload to define a rainfall return period for each individual river in a large d4PDF ensemble, and to perform runoff and inundation analysis. To reduce this workload, this study investigated a method to represent the flow rate of a specific watershed using rainfall data that can be shared by multiple rivers in a limited number of d4PDF events. As a result, it was found that by using a maximum of about 30 rainfall data and taking the median or upper value of the obtained flow rates, it is possible to represent the flow rates at multiple locations and at multiple scales with an error of about 10%.