三峡水库蓄水前后近坝水域的水质评价与分析

根据三峡水库坝上、下游4个代表性断面1998年-2004年的水质监测数据，采用概率神经网络水质评价模型，以氧平衡因子、毒物因子和营养盐类因子作为评价因子，对三峡水库蓄水前后近坝水域水质进行评价和对比。评价结果表明，蓄水初期，氧平衡因子评价结果坝前变化不大，坝后略有好转；毒物因子和营养盐类因子评价结果坝前坝后都略有好转。分析表明，营养盐类因子是制约库区水质的控制性因子。蓄水后，需要防治坝下游的溶解氧超饱和问题，库区的二次污染问题和富营养化问题。

Evaluation of water quality near the dam before and after the storage of Three Gorges Reservoir

Based on the original monitoring data of water quality at four representative sections near the dam of Three Gorges Reservoir during 1998 - 2004, probabilistic neural networks of water quality evaluation model is applied for water quality evaluation near the dam before and after the storage. The oxygen-balance parameters, the poison parameters, and the nutrient salt parameters are chosen as the evaluation parameters. The evaluation results after the storage of reservoir are compared with which before the storage. The results show that, in the early days of the storage, the evaluation results of the oxygen-balance parameters vary a little in the front of the dam, and get a little better behind the dam; the evaluation results of the poison parameters and the nutrient salt parameters become better both in the front and behind the dam. The analysis shows that the nutrient salt parameters make the greatest effect to the water quality among the all. However, after the storage, the DO extra-saturation phenomenon behind the dam, the secondary pollution problem and the eutrophication problem in the reservoir should be paid great attention to them.