洪水流出モデルの最適定数

Abstract

This paper discusses some properties of the optimum parameters of the two typical floodrunoff models, such as the kinematic model with two parameters and the storage functionmodel with three parameters. The optimum set of the parameters is identified under thechi-square criterion of errors by the SP (Standardized Powell) method which is one ofthe mathematical optimization techniques. Both flood runoff models are applied to simulatehydrographs at the outlets of the Echi mountain river watershed of 108 km2, the Shimokarihill river watershed of 1.3km2, and the Tenjin urban watershed of 2.6km2. Main resultsare summarized as follows:1) From the parameter relating to the flow regime, it has been clarified that the Manninglaw is applicable to the kinematic model for flood runoff of peak discharge larger than4 m3/sec/km2.2) The optimun parameters of the storage function model are related to the ones of thekinematic model. The formulae combining them are obtained theoretically under someassumptions and proved by optimum parameters obtained.3) The functional expression of trough in the response surface composed of parameters isgiven experimentally and theoretically under some assumption. This result suggeststhe possibility of the development of the new technique for parameter optimization.