北运河流域水质时空分布特征及综合评价

Temporal and spatial distribution characteristic and evaluation analysis of surface water quality in Beiyun River

为了更好评价北运河在北京市段的水环境质量,准确掌握其时空变化特征,本研究在北运河流域主河道上游至下游及主要入河支流共设置17个监测点位,2019年1—12月逐月监测TP、NH_(4)^(+)-N及COD等3个指标,采用单因子评价模式,在超标倍数法的基础上,运用主成分分析法对该流域的水环境质量进行了详细分析。结果显示:该区域全年的污染物浓度在春季时最高,其次是冬季,秋季污染物浓度最低,其中,春、冬受NH_(4)^(+)-N影响最大,秋季污染相对较低,汛期、非汛期水质差异显著,污染物浓度汛期>非汛期,其中汛期贡献率高于非汛期的主要是COD、NH_(4)^(+)N;空间上,17个监测断面的水功能区达标为64.3%,其中清河口断面达Ⅱ类标准。从流域整体来看,经过治理的支流及管护要求更高的北京城市副中心段水质较好。

In order to analyze the spatio-temporal variation of water environmental quality in Beiyun River,17 monitoring points were set both in the upstream to downstream of the main channel and in the main tributaries,the monitoring data of TP,NH_(4)^(+)-N,COD were collected monthly in 2019.The method of single factor evaluation and principal component analysis is used to evaluate the quality of water environment.The results as follows:In time,the concentration of NH_(4)^(+)-N was high in spring and winter,but relatively low in autumn,and the water quality in non-flood season is better than that in flood season on the whole,the contamination index of COD and NH_(4)^(+)-N were high in flood season.In space,64.3%of the monitoring points water quality up to standard,and the section of Qinghe reachsⅡclass standard.As the whole basin,the water quality of the treated tributaries and the sub-central section higher requirements for management and protection is better.