深圳市2015~2021年雨源型河流水质时空变化及其对降雨的响应

Spatial-temporal Variation in Water Quality of Rain-source Rivers in Shenzhen from 2015 to 2021 and Its Response to Rainfall

雨源型城市河流水容量偏小,缺乏动态补充水源,易受污染.基于深圳市2015~2021年全市(不含深汕)9大流域的21个水质指标数据和逐日降雨数据,利用单因子指数评价、综合污染指数、层次聚类分析和Pearson相关分析等方法,研究深圳市河流水质时空分布特征及特征污染物对降雨的响应关系.结果表明:①2015年全区大部分断面水质都是劣Ⅴ类水,2018年10月后河流水质总体得到大幅度改善,与2018年深圳市开展治水专项活动背景一致,到2021年约62%的断面水质达Ⅰ~Ⅲ类水标准;②深圳市(不含深汕)西部人口稠密地区的水质污染较东部更严重,河口和支流下游水质污染较上游更严重;③深圳市坪山河、龙岗河、茅洲河和深圳河的水质受降雨的影响显著;④深圳市河流的主要特征污染指标是DO、COD、BOD5、NH_(4)^(+)-N、TP、高锰酸盐指数、石油类和阴离子表面活性剂;对于坪山河和龙岗河,降雨使TP和NH_(4)^(+)-N指标浓度升高;对于茅洲河,降雨使TP和COD指标浓度升高;对于深圳河,降雨使COD、TP和NH_(4)^(+)-N指标浓度升高.以上结果能够揭示深圳市雨源型河流水质时空变化情况及其对降雨事件引发的非点源污染的响应关系,为深圳市打造更高品质水环境提供科学参考.

Rain-source urban rivers have the characteristics of small water capacity,lack of dynamic water supply,and being easily polluted.This study analyzed the spatial and temporal distribution characteristics of river water quality and the response of characteristic pollutants to rainfall based on daily rainfall data and 21 water quality indicators of nine major river basins in Shenzhen(excluding Shenzhen-Shantou)from 2015 to 2021 by using the single-factor assessment method,comprehensive pollution index method,hierarchical cluster analysis,and Pearson correlation.The results showed that:①in 2015,the water quality of most sections in the whole region was inferior Class V water.After October 2018,the overall water quality of rivers was greatly improved,which was consistent with the background of Shenzhen’s special water control activities in 2018.By 2021,the water quality of approximately 62% of sections reached Class Ⅰ-Ⅲ water standards.②The water pollution in the densely populated western part of Shenzhen was more serious than that in the eastern part,and the water pollution in the lower reaches of the estuaries and tributaries was more serious than that in the upper reaches.③The water quality of the Pingshan River,Guanlan River,Longgang River,and Maozhou River was significantly affected by rainfall.④The main characteristic pollution indexes of the Shenzhen River were DO,permanganate index,COD,BOD5,NH_(4)^(+)-N,TP,petroleum,and anionic surfactant.For the Pingshan River and Longgang River,rainfall increased the concentrations of TP and NH_(4)^(+)-N.For the Maozhou River,rainfall increased the concentrations of TP and COD.For the Shenzhen River,rainfall increased the concentrations of COD,TP,and NH_(4)^(+)-N.The above results reveal the spatio-temporal variation in rain-source river water quality in Shenzhen and its response to non-point source pollution caused by rainfall events and provide a scientific reference for building a higher quality water environment in Shenzhen.