Change of Flood Runoff form for Long Term and Run-off Model Parameters in Reclamation Area

本研究旨在建立改良坡面复垦土地径流特征的定量评价方法。研究结果的主要观点如下：1。提出了一种集总径流模型KiWS模型（combined runoff model combined Kinematic Wave and reservoir Tanks），用于洪水径流和低水位径流的先后分析。在径流分析的输入降雨序列中引入延迟函数，求解集总KiWS模型和LST-II模型（长短期径流模型）模拟的峰值流量及其发生时间问题。从流域模型的坡长分布特征和滞后时间方程出发，采用实用的浓缩时间公式对该函数进行求解。通过对增田垦区流域数据的处理，表明问题得到了改善。考察了省略河道流量计算的坡面流型简化径流模型，并对集总流域模型的适用性进行了评价。提出了有序流域模型中与贡献坡长h有关的最优模型参数的估计公式。指出利用所提出的径流模型和分析方法，可以定量讨论改良坡面复垦土地径流特征的变化。利用水文频率分析方法，确定了1988年7月15日滨田地区局地强降水的回归期。

This study aims to establish the quantitative evaluation method of runoff characteristics in reclamation land at improved slope. Main points of the study results are as follows :1. A lumped runoff model named KiWS Model (Runoff Model combined Kinematic Wave and Storage Tanks) is developed for analyzing both flood and low water run-off successively.2. A delayed function is introduced to input rainfall sequence of runoff analysis for dissolution of the problems on peak discharge and its occurrence time simulated by the lumped KiWS model and LST-II model (Long and short terms runoff model). The function is evaluated from the distribution characteristics of slope length in a basin model and the equation of lag time applied the practical formula for the concentration time. And it is showed by dealing with the date in MASUDA Reclamation basin that the problems are improved.3. Simplified runoff model of overland flow type omitted the calculation of channel flow is examined and the applicability is evaluated in relation of lumping the watershed model. And the estimating formulae for optimum model parameters have been proposed in relation to the contributing slope lengt h in the ordered watershed model.4. It is pointed out that the quantitative discussion on change of runoff characteristics in reclamation land at improved slope is possible by the proposed runoff model and analytical method.5. The return period for the amount of historical localized heavy rainfall at HAMADA in July 15, 1988 is evaluated by a hydrologic frequency analysis.