常州滨江区域城镇径流污染对河道水质的影响

Influence of Urban Runoff Pollution on River Quality in Riverside Area of Changzhou

德胜河是常州市重要的应急饮用水水源,应急取水口附近存在城镇集中建设用地,降雨期间污染物随城镇径流进入德胜河,对城市应急供水安全构成潜在威胁。2018年和2019年对德胜河及其周边城镇径流进行了多个位置和多个降雨场次的水质监测,通过对监测数据的综合分析,研究德胜河周边城镇径流污染状况及城镇径流对德胜河水质影响的特征和规律。德胜河全年水质总体良好,但是在汛期和降雨期间水质波动明显,部分污染物浓度上升的频次和幅度较大,Cr、Pb、Mn、Fe等重金属指标出现超标情况;由于城镇区域人口密度和车流量大,存在较多工业、仓储物流和码头用地等原因,德胜河周边城镇径流中COD、总氮、总磷、Zn、Cr、Pb、Mn、Fe等污染较严重;城镇径流对德胜河城镇段COD、SS、浊度、总磷、Zn、Pb、Mn、Fe、As、苯等污染物浓度的上升贡献较大或发挥主要作用,但是当降雨量很大时城镇径流污染的影响会被河道激增的水量所稀释并迅速流向下游。在此基础上,提出基于海绵城市的城镇径流污染控制及应急水源运行管理优化建议。

Desheng River is an important emergency drinking water source in Changzhou.There is concentrated urban construction land near the emergency water inlet and pollutants enter the Desheng River along with urban runoff during rainfall,posing a potential threat to urban emergency water supply safety.In 2018 and 2019,water quality of Desheng River and its surrounding urban runoff was monitored at multiple locations and rainfall events.Through comprehensive analysis of the monitoring data,the status of urban runoff pollution around Desheng River and the impact characteristic and regularity of urban runoff to its water quality were studied.The water quality of the Desheng River is generally good throughout the year,but it fluctuates significantly during the flood season and rainfall,and the increase frequency and amplitude of some pollutant concentrations are significant.Some heavy metal indicators such as Cr,Pb,Mn,and Fe have exceeded standards.The indicators of COD,total nitrogen,total phosphorus,Zn,Cr,Pb,Mn,and Fe in the urban runoff around Desheng River are polluted heavily,due to the large regional population density and traffic flow in urban areas,and the existence of many industrial,warehousing,logistics,and dock land.Urban runoff contributes or plays a major role in the increase of COD,SS,turbidity,total phosphorus,Zn,Pb,Mn,Fe,As,benzene and other pollutant concentrations in the urban section of the Desheng River.However,when the rainfall is too large,the impacts of urban runoff pollution will be diluted by the surging water of the river and quickly flow downstream.On this basis,suggestions for controlling urban runoff pollution and optimization of emergency water source operation and management are provided.