密云县蛇鱼川小流域地表水水质变化的规律

Variation of surface water quality in Sheyuchuan small watershed of Miyun County

为了向生态清洁小流域建设、水源保护及生态环境建设提供理论依据,以北京市密云县蛇鱼川小流域地表水近5年监测资料为基础,分析评价小流域河流水质时间、空间变化及湖库水质时间变化规律,并对流域水质总体情况进行评价。监测结果表明:1)河流水体NH3-N质量浓度冬春季变化较大,夏季中期以后质量浓度比较稳定。2)TN、TP和CODMn冬春季质量浓度较低,夏季汛期质量浓度显著上升,秋季降雨结束后,各指标回落;在塘坝水质变化上,塘坝水体氨氮、总氮都呈现冬高夏低的规律,总磷和高锰酸钾指数在冬季和夏季质量浓度都较高;总体上流域地表水质除局部区域受到污染外,小流域地表水质良好,氨氮属Ⅰ～Ⅱ级,总磷属Ⅱ级,高锰酸钾指数属Ⅱ～Ⅲ级。

To provid theoretical basis for construction of ecological and clean watershed,protection of water resource and ecological environment construction,temporal and spatial variation of surface water quality were analyzed by using data monitored in last five years in Sheyuchuan small watershed of Miyun County.The results show that the mass concentration of NH3-N in river water changed greatly in spring and winter,while it was stable after midsummer.The mass concentration of TN,TP and CODMn were lower in spring and winter,but increased significantly during flood season in summer.After rainfall ended in autumn,the value of each index decreased.In small reservoir,the mass concentration of both NH3-N and TN were realtively higher in winter and lower in summer,while mass concentration of TP and CODMn were higher both in summer and winter.In general,the quality of surface water in small watershed was good except some area.NH3-N belongs to Class Ⅰ-Ⅱ,TP belongs to Class Ⅱ,CODMn belongs to Class Ⅱ-Ⅲ.