Study on the generalization of stream discharge, water velocity and water temperature by river network analysis

开发并测试了一个用于河流流量、温度和水质模型分析的GIS软件。该模型基于这样的假设，即平均流速和平均深度可能对每个流阶都有特定的值。在东京附近山间溪流的约130个站点进行了流速和深度调查。平均流速由流量、平均深度和平均宽度导出。结果表明，这些参数随流阶数的增加而增大，并取其平均值进行模型分析。该模型涵盖了流的3^<rd>至6^< >阶，因为在一般情况下，2^<和>阶流中没有永久流。通过GIS软件分析各段的连接和各段的长度，然后将数据传输到Excel或Lotus中进行计算。用归一化形式对水的走时进行分析，发现在盆形系数较大的流域，时间谱呈集中形态。在狭长盆地中得到平坦分布。利用简单的热平衡方程和流量的加权平均值估算了水流温度的分布。结论是，约60%的测试病例是成功的；这些是有许多分支的盆地。引入自净和与分支清水混合，计算了BOD的稀释。可以说，该模型也可用于水质分析。

A GIS software for the model analysis of stream discharge, temperature and water quality has been developed and tested. The model is based on the assumption that mean velocity and mean depth may have specified values for each stream order. Investigations on velocity and depth were carried at about 130 stations in mountain streams near Tokyo. Mean velocity was deduced from amount of discharge, mean depth and mean width. It has been concluded that these parameters increase with the stream order and the mean value of each parameter is taken into the model analysis. The model covers 3^<rd> to 6^<th> order of streams, because permanent flow is not found in 2^<nd> order flow in general case.Conjunction of segments and length of each segment have been analyzed by the GIS software, after then, data are transferred to Excel or Lotus for the calculation. Analysis on travel time of water by normalized form reveals that spectrum of the time shows concentrated shape in basins with large basin shape coefficient. Flat distributions are obtained in narrow and long basins. Distribution of stream temperature has been estimated by simple heat balance equation and weighted mean of the discharge volume. It has been concluded that about 60% of the tested cases are successful ; these are basins with many branches. Dilution of BOD is calculated introducing the self-purification and mixing with clear water from branches. It may be said that the model is also useful for water quality analysis.