摘 要
本文对长江水质的评价和预测问题进行了探讨。通过对附件3 中的数据进行定性和定量的分析得到水质的总体评价及各地区的.污染状况。首先通过建立了忽略弥散系数的1维稳态水质模型分别计算得出高锰酸盐指数(CODMn)和 氨氮（NH3-N）污染较大的主干地区，然后再具体分析此地区的支流污染和当地污染情况，找出了其源头。在未来10年水质发展状况预测上，我们采用直线拟合法分析，最小2乘法求解，得出未来10年的发展趋势。在未来10年的污水处理量问题上，我们采用不考虑混合区来计算水环境容量的模型，根据长江的年水环境容量来构建线形模型进行求解。最后根据统计分析结果，对未来如何解决长江地区水质污染问题，提出了合理的建议和意见。
关键词：长江水质;高锰酸盐指数;氨氮浓度;水环境容量;
Abstract
This thesis explores the evaluation and forecast of the water quality of Yangtze River. The general evaluation of water quality and the pollution situation of related regions are concluded by analyzing the attachment qualitatively as well as quantitatively. Firstly, by building the water quality model to neglect the dispersion coefficient of one-dimensional steady state, we can calculate the index of CODMn and the main region polluted greatly by NH3-N respectively. Then, by analyzing the pollution at the branch and local region, we can find the origin. In the respect of the forecast for the development in the following ten years, we adopt the method of line-fitting process and least squares to analysis and solve, so we can master the trend. And, in the respect of disposal of the polluted water, we adopt the model of calculating the capacity ignorant of the mixed area, so we can solve the problem by building new model. Finally, according to the result of statistics analysis, we put forward the reasonable proposal and suggest to solve the problem of the problem of the water pollution in Yangtze area.
Keyword： Fluid matter of Yangtze River; sour salt index number of high manganese; the ammonia nitrogen density; environment capacity of water
