2次元不定流解析における植生倒伏モデルの改良とフラッシュ放流への適用

抄録

The flushing floods from the Haizuka dam in the Jyouge River to remove the algae attached to bed materials are observed in 2009 and 2010. Measurements of water level hydrographs at several points and discharge with ADCP at a weir are carried out during the floods together with the evaluation of toppled vegetation region based on photogrammetry before and after the flood in 2009 and ground truth in 2010. Two-dimensional unsteady numerical simulations are performed for the flushing floods with a flow model taking into account the effect of vegetation toppling and a bed elevation model accounting only bed load transport. It is shown that the calculated discharge hydrograph and water level hydrographs give reasonable agreement with the measured results. It is emphasized through the comparisons of the areas with toppled vegetation that accounting the effects of vegetation toppling can considerably improve the numerical accuracy in reproducing the measured results.