直接流出成分への有効降雨と低水流出高曲線の一推定法

This paper is concerned with procedures of synthesizing effect rainfall to direct runoff component and curves of base flow height, in which a runoff model named KWST model(Runoff Model combined Kinematic Wave and Storage Tanks) is developed.
The upper zone of the model is composed by kinematic wave runoff model. The lower zone is the same with the storage model proposed by Kadoya and Nagai. The estimation method of the effective rainfall concerned in the surface runoff and/or prompt subsurface runoff is shown in the model.
A runoff cycle of base flow is divided into five stages. The first and second stages are related to rainless periods. The recharge of base flow occurs during other stages. The recharge of delayed subsurface flow and groundwater runoff is evaluated by KWST model. The equations of runoff height of base flow for each stages are derived by using of model pararameters.
The parameters of KWST model are identified by the flood runoff analysis at the Shimokari hilly watershed of 1.3<km>^^^2. It is shown that the estimated curves of base flow are different from the evaluated curves by the usual hydrograph analysis in flood runoff and more rational expression than the usual method for analysis of the base flow phenomena. And it is pointed out that the estimation method of base flow by KWST model is especially useful for the complicated runoff occuring the multipul peak discharge.