河道の水理

[II-169] Enhanced rainfall-runoff-flood simulation with RRI model by introducing the evaluation methods of river roughness coefficient using 2D numerical calculation results and slope direction surface flow flux

〇Ritsuki Shimizu¹, Kento Kaida², Mizuki Matsuda³, Tatsuhiko Uchida¹, Yoshihisa Kawahara¹, Takahiro Sayama⁴ (1.Hiroshima University, 2.LIXIL Corporation, 3.Hiroshima Electric Railway Co., Ltd., 4.Kyoto University)

Keywords:RRI model, 1-D flood flow calculation, slope direction surface flux, Manning’s roughness coefficient

The 1-D flood flow calculation method used in the RRI model has a limitation in the accuracy of water level prediction.In addition, the RRI model employs the unclear assumption in surface flux vectors. This study develops a method to improve the accuracy of water level calculation during floods using the RRI model. From 2-D analysis results, it is clarified that the roughness coefficient considering vegetation can be expressed as a function of water depth. The analysis results of the RRI model using the roughness coefficient showed that the water level hydrograph and the vertical water surface profile of the 2-D analysis results could be almost reproduced.