洪水流出モデルの適用比較 -丘陵山地流域及び市街地流域を対象として-

Abstract

This paper discusses the interrelations of three typical flood runoff models, such as the tanksmodel of series type, the storage function model and the kinematic runoff model, through the resultsof flood runoff analysis in the River Shimokari of natural hilly watershed, and the River Tenjin ofurban area. The optimum parameters of the tanks and storage function models are estimatedby applying the Powell's conjugate gradient method. The main results are summarized as follows:Runoff from the first tank of the tanks model in the Shimokari basin is equivalent to surfacerunoff and subsurface runoff, that from the second tank to interflow, and that from the third andfourth tanks to groundwater runoff.The tanks model composed of the two tanks gives the accurate results in the sense of engi-neering practice in the Tenjin basin where surface runoff is the most important component.There exist several tanks models obtained by the optimization technique. The models arediffer from each other in the parameters but show almost the same relation between storage anddischarge.The storage function models in both basins correspond to the kinematic runoff model foroverland flow of the Manning's or Chezy's type. The parameters of the storage function modelare estimated from the kinematic runoff model or the practical formula for the time of concentration, and yet the estimated values are closer to the optimum parameters.Comparing the tanks and storage function models in both basins, it is clear that the storageeffect on direct runoff of the Tenjin basin is less than that of the Shimokari basin.