Abstract
The Long-and Short-Term Runoff Model (LST Model) is applied to Takayama dam basin of 615km2 in which Syorenji and Murou dams with catchment of 100 and 136km2, respectively, are situated at tributaries. Hydrological data observed at three dams and in and around their basins for ten years from 1978 are used in this study. In the application of the LST Model to the residual basin of Takayama dam except the above-mentioned two dam basins, discharges from the two dams and their traveling times are considered. The effects of the basin lag time defined as the time lag between peaks of input into and output from a basin are examined on the accuracy of simulated flood runoff hydrographs and on the model parameters identified.
Moreover, the basin scale effect on parameters of the top tank of LST Model is discussed theoretically based on the kinematic runoff model for surface and subsurface rainwater flow. Usefulness of the proposed theoretical equations showing the relationship between a parameter of top tank and basin area is verified by the results of above-mentioned three dam basins and another ones of seven basins which have been already reported.
