综合水质指数法在上海水源水库水质评价中的应用

Application of Comprehensive Water Quality Index Method in Water Quality Assessment for Water Source Reservoir in Shanghai

针对现有综合污染指数法在水源地水质评价中未考虑指标权重的情况,本文利用3类(水源受污染程度、藻类及典型致嗅物质、一般水质情况)共15项水质指标,将改进的综合水质指数(CWQI)法应用于上海市水源水库水质分析及评价。结果表明:(1)该水源水库2018年—2021年输水口水质整体趋好,但受来水水质波动性大的影响,2021年输水口CWQI变幅大于2018年—2020年;(2)2018年—2021年输水口较取水口CWQI中位值下降率分别为37%、46%、48%、45%,表明该水源水库对水质改善具有显著效果,库区水体自净能力强;(3)取水口和输水口CWQI存在明显的四季变化趋势,CWQI的夏秋季变幅显著大于冬春季,且取水口和输水口水质冬春季均明显优于夏秋季,库区对水质的改善率呈现冬季>夏季>秋季>春季的变化趋势。

In view of the fact that the comprehensive pollution index method did not consider the index weight in the water quality evaluation,this paper applied the improved comprehensive water quality index(CWQI)method consisting of 15 water quality indices classified into three categories(characterize the pollution degree of water source,algae and typical odorants,general water quality)to the water quality analysis and evaluation of a water source reservoir in Shanghai.The results showed that:(1)The water quality at the water outlet of the water source reservoir tended to be better from 2018 to 2021,but the variation range of the comprehensive water quality index at the water outlet in 2021 was greater than that from 2018 to 2020 due to the large fluctuation of the incoming water quality;(2)From 2018 to 2021,the median values of the CWQI at the water outlet were declined by 37%,46%,48%and 45%compared with the water intake,respectively,indicating that the water source reservoir had a significant effect on the improvement of water quality and the self purification capacity of the water in the reservoir area was strong;(3)CWQI at the water intake and outlet had obvious changes in four seasons,the change range of CWQI in summer and autumn were significantly greater than that in winter and spring,the water quality at the water intake and outlet in winter and spring was significantly better than that in summer and autumn,and the improvement of water quality in the reservoir area showed a change trend of winter>summer>autumn>spring.