潭江水质时空变化特征及其驱动因子

Spatial and temporal variation characteristics of water quality in Tanjiang River and its driving factors

为掌握潭江水质的变化特征,采用Mann-Kendall趋势检验以及水质综合污染指数等方法分析了潭江干流2001—2019年的水质年际变化特征,利用主成分分析方法识别了影响潭江水质变化的主导水质参数,通过相关性模型分析了影响水质变化的主要驱动因子。结果表明:潭江上游的水质最好但有一定的恶化趋势,下游的水质次之且无明显的恶化趋势,中游的水质最差恶化趋势也最为显著;主导潭江上游水质变化的水质参数是COD和BOD_(5),中游为TN和NH_(3)-N,下游则是TN、NH_(3)-N和TP;人口和森林覆盖率是影响潭江上游水质变化的主要驱动因子,而影响潭江中、下游水质变化的驱动因子除人口和森林覆盖率外,还包括GDP和水温;受人类因素的影响,潭江中、下游水质变化与自然驱动因子之间的关系有所改变。

To master the variation characteristics of water quality in Tanjiang River(TJR), the Mann-Kendall test and water quality comprehensive pollution index were adopted to analyze the interannual variation characteristics of water quality in TJR from 2001 to 2019. The principal component analysis method was employed to identify the dominant water quality parameters influencing the water quality variation in TJR. The main driving factors influencing the water quality change were analyzed by correlation model. The results show that the water quality in the upper reaches of TJR was the best but it had a certain tendency of deterioration. The water quality in the lower reaches in TJR took second place and the tendency of deterioration was not obvious. The water quality in the middle reaches in TJR was the worst and the tendency of deterioration was the most significant. The water quality parameters dominating the water quality variation were COD and BOD_(5) in the upper reaches and TN and NH_(3)-N in the middle reaches as well as TN, NH_(3)-N and TP in the lower reaches of TJR. Population and forest coverage rate were the main driving factors influencing the water quality variation in the upper reaches of TJR, while GDP and water temperature were also the driving factors influencing the water quality variation in the middle and lower reaches of TJR besides population and forest coverage rate. Additionally, the relationship between the water quality change and natural driving factors were changed due to the impact of human factors.