渠江流域水质特征及模糊综合评价

Water Quality Characteristics and Fuzzy Comprehensive Evaluation on Qu River Basin

为准确掌握渠江流域水质现状及时空分布特征,选取30个包含DO、COD_(Mn)、NH3-N和TP 4个水质参数的采样断面,以2021—2022年的逐月水质数据为基础,基于模糊综合评价法对渠江流域的水质状况进行综合评价。结果表明,在30个采样断面中,COD_(Mn)和TP为渠江流域的主要污染物。模糊综合评价结果发现渠江流域2021—2022年符合Ⅰ~Ⅲ类的断面占比93.3%,渠江流域水质总体上分布在Ⅰ~Ⅳ类之间,Ⅰ类所对应的采样断面位于渠江流域上游,Ⅳ类所对应的采样断面位于中游和下游,且2022年30个采样断面水质位于I~Ⅲ类的比例较2021年提升了3.3%。改进的模糊综合评价法、传统的模糊综合评价和单因子指数评价结果一致的断面占比介于83.3%~90.0%。研究结果也发现改进的模糊综合评价法对高污染区域的水体水质评价结果更能反应水体实际状况,评价结果具有更稳定的优点。

To accurately investigate the current situation and temporal-spatial distribution characteristics of water quality in the Qu River Basin,30 sampling sections containing DO,COD_(Mn),NH_(3)^(-)N and TP were selected in this paper.Based on the monthly water quality data from 2021 to 2022,a comprehensive evaluation of water quality in the Qu River Basin was carried out with the fuzzy comprehensive evaluation method.The results showed that COD_(Mn)and TP were the main pollutants in the 30 sampling sections.The results of fuzzy comprehensive evaluation showed:93.3%of the sampling sections in Qu River Basin meet the Classes I-Ⅲwater quality standards from 2021 to 2022;the water quality in the Qu River Basin was generally distributed between Classes I-Ⅳ;the sampling sections of Class I water quality were basically located in the upstream of the Qu River Basin;the sampling sections of ClassⅣwater quality were located in the middle and lower streams;and the proportion of Classes I-Ⅲwater quality in 30 sampling sections in 2022 was increased by 3.3%,compared with that of 2021.The proportion of sections with the same results of the improved fuzzy comprehensive evaluation,fuzzy comprehensive evaluation and single factor index evaluation was between 83.3%and 90.0%.The results also showed that the improved fuzzy comprehensive evaluation method reflected the water quality evaluation results in highly polluted areas better,and its results were more stable.