2004 Volume 57 Issue 4 Pages 26-32
Concerning the storage function method applied to runoff analysis at large, we tried to analyze by considering the effect of forest, on reference to the nine cases of dam-plan in Nagano Prefecture. As a result, we could propose the method of runoff analysis, which placed great importance on the initial constant of runoff model determined on the basis of the observed data, applied the value of the effective storage estimated by soil pore analysis to saturation rainfall, treated the coefficient of first runoff as the primary factor when identifying runoff model, and used properly the different model by raining antecedently or not. We calculated the flood discharge of Susuki-gawa river basin in Matsumoto city by this method, these results supported to use properly the different model and suggested to be able to estimate the discharge based on the limited rainfall period. Moreover, the lower flood discharge was estimated compared to the current method, therefore, we concluded that the effect of forest influenced this result.