Representation of Numerical Basin Model in the Rural and Mountainous Region by Image Processing and Its Application to Forecasting of Flood Runoff

本研究的目的是通过计算机工作站提供流域地形信息在径流预报中的应用。特别是对三安区多山农村的观点设置进行了探讨。研究结果如下：(1)考虑流域地形和不透水面积分布的影响，提出了基于长短期径流模型和集总KIWS模型的修正径流模型。(2)利用Unix工作站构建了径流计算系统，实现了数据输入、径流分析、过程线输出等一系列分析功能。2.(1)对采用循环水灌溉系统的稻田流域进行了水量平衡和污染物质量平衡的测定。考虑了额外面积和循环取水、污染物和泥沙的质量平衡对流域环境改善的贡献。(2)在蒸渗仪上对土壤的水文特性进行了评价。结果表明，入渗水量占降水总量的60%，地表径流发生在累计降雨量达到一定程度后。3.(1)对原状水稻土、旱地土壤和森林土壤中的水流进行了软X射线照相。水田土壤中垂直的独立根通道和旱地的网状根通道引导水流，而在森林土壤中观察到团聚体间的大孔道流动。水田和旱地土壤的雷诺数为50~80，表明大孔隙流处于从层流到湍流的过渡区。

The study purposes to provide an application of topographic information in watershed to the forecast of runoff through the computer workstation. Especially, a discussion is developed on setting the viewpoint at moutainous rural area in San-in district. The results are as follows : 1.(1) Modified runoff models based on the long and short term runoff model or the lumped KiWS model were proposed for the analysis considering the effect of basin topography and distribution of impermeable area. (2) Runoff calculation system was constructed, by using UNIX workstation, to cany out a series of analysis including data input ; runoff analysis ; and output of hydrographs. 2. (1) The behavior of hydrological water balance and mass balance of pollutant were mesured in a paddy field watershed, where a circular irrigation system is implemented. The contribution of the water drawn from extra area and circulation, the mass balance of pollutants and sediment to the improvement of river basin environment was considered. (2) The hydrological properties were evaluated in the experimental lysimeters. As a result, the amount of percolation water amounted for 60% of precipitation and the surface runoff occurred after the cumulated precipitation reached a certain degree. 3. (1) Soft X-ray radiography of water flow in undisturbed paddy soils, upland field soils and forest soils were carried out. Vertical, independent root channels in paddy soils and networked root channels in upland fields conduct the water flow, On the other hand, interaggregate macropore flow has been observed in forest soils. Resultant Reynolds number for paddy field and upland field soils showed 50-80, which indicated macropore flow was in a transition region from laminar to turbulent.