基于聚类分析的典型城市湖泊水质综合评价与分析

Comprehensive Evaluation and Analysis of Water Quality of Typical Urban Lake Based on Cluster Analysis

以某典型城市湖泊为例,通过层次聚类分析法将2013-2018年3个湖区216个样本点分成8组,以每组样本点的均值为基础,得到各组的综合标识指数,并将其分解到各组对应的水质样本点,以实现对多断面、长时间、大量样本的综合评价。在此基础上,进一步分析了该湖年内、年际的水质变化规律。其评价结果表明:2013-2018年各湖区的综合水质标识指数表现为先降低后升高的趋势;除2018年外,各湖区不同水期的综合水质标识指数表现为丰水期>平水期>枯水期;除南湖在2013年、西湖在2017-2018年外,各湖区的水质仍能维持在Ⅲ类水水平,但综合水质标识指数在2017、2018年明显高于其他年份,说明水质存在变差的趋势。该水质评价结果与当地实际情况相符,进一步说明了基于聚类分析对湖泊水质进行综合评价是可行的。

A typical urban lake was taken as an example and 216 sample points in 3 areas from 2013 to 2018 were divided into 8 groups by hierarchical cluster analysis.Based on the average value of each sample points,the comprehensive identification index of each group was achieved.The index was resolved into corresponding water quality sample points of every group to evaluate comprehensively the multi-section,long time and large number of samples.The annual and interannual variation laws of water quality in Lake Y were analyzed furtherly.The evaluation results showed that the comprehensive water quality identification index of each area showed a trend of decreasing firstly and then increasing from 2013 to 2018.Except in 2018,the index of different water periods in each lake is in the order of high water season>mean flow season>dry season.Except South Lake in 2013 and West Lake in 2017-2018,water quality of each lake still were at the level of class Ⅲ.However,the index in 2017 and 2018 were obviously high than those in other years and water quality tended to get worse.The result of water quality evaluation was consistent with the local actual situation,which further proved that it is feasible to evaluate lake water quality comprehensively by cluster analysis.