嘉陵江四川中下游段水质时空变化特征及影响因素分析

Temporal and Spatial Variation Characteristics of the Water Quality in the Middle and Downstream Reaches of Jialing River in Sichuan and Analysis on Its Influencing Factors

使用单因子指数法和内梅罗污染指数法分析2016年~2020年嘉陵江四川段中下游10个自动监测断面的水质状况,并使用Spearman相关系数法进行水质时空变化特征及影响因素分析。结果表明,琼江大安2017年为IV类水质,最大超标因子为TP,超标倍数为1.23;西充河彩虹桥2018年为IV类水质,最大超标因子为NH_(3)-N,超标倍数为1.60;其余断面均未出现超标。2017年大安断面内梅罗污染指数为1.00,轻度污染,最大污染因子是TP;2018年彩虹桥断面内梅罗污染指数为1.33,轻度污染,最大污染因子是NH_(3)-N;其余断面均为清洁。西充河彩虹桥断面各年月际内梅罗污染指数呈下降或平稳趋势,琼江大安断面先上升后下降至平稳趋势,嘉陵江沙溪、巴河江陵、渠江团保岭、渠江赛龙、涪江百顷均有平稳或上升趋势。2016年~2020年各年份Spearman相关系数(r_(s))为-0.9~0.3,|r_(s)|≤W p,各监测断面年际水质变化平稳。

Using the methods of the single factor evaluation,the Nemerow pollution index and the Spearman's rank correlation coefficient,the temporal and spatial variation characteristics of water quality and its influencing factors in the middle and downstream reaches of Jialing river in Sichuan from 2016 to 2020 were analyzed based on the automatic monitoring data of ten river sections.The result showed that,the water quality in Daan section of Qiongjiang river reached at level of class IV in 2017,the maximum exceeding standard factor was TP,and the multiple exceeded the standard was 1.23.The water quality in Caihongqiao section of Xichong river reached at level of class IV in 2018,the maximum exceeding standard factor was NH_(3)-N,and the multiple exceeded the standard was 1.60.The results of water quality in other river sections did not exceed the prescribed limit.The Nemerow pollution index of the water quality in Daan section with slight pollution was 1.00 in 2017,and the maximum pollution index was TP.The Nemerow pollution index of the water quality in Caihongqiao section with slight pollution was 1.33 in 2018,and the maximum pollution index was NH_(3)-N.The other river sections had good quality clean water.The result of monthly variation of Nemerow pollution index in Caihongqiao section showed a downtrend or stable trend.The result in Daan section showed tendency to ascend,followed to descend and then remained stable.But the results of other monitoring river sections such as Shaxi section of Jialing river,Jiangling section of Bahe river,Tuanbaoling section of Qujiang river,Sailong section of Qujiang river and Baiqing section of Fujiang river all showed tendency to stable or ascend.The annual Spearman's rank correlation coefficien(r_(s))from 2016 to 2020 was-0.9~0.3,|r_(s)|≤W p,and the yearly water quality in all monitoring river sections remained stable.