滇中重要水源区土地垦殖对集水区地表水质特征的影响

Effect of Important Water Source Reclamation of Central Yunnan on Water Quality Characteristics of Catchment Surface

【目的】本文探讨了土地垦殖对滇中重要水源区地表水水质特征的影响。【方法】2017年5-10月期间,以云南省昆明市松华坝水源保护区迤者小流域的集水区为研究对象,采用野外定位监测和室内实验分析结合的方法,对降雨径流中的总氮(TN)、总磷(TP)、铵态氮(NH+4-N)、化学需氧量(COD)进行监测,基于改进的灰色关联分析模型研究了不同土地垦殖强度下集水区地表水水质特征。【结果】强度垦殖状态下混合集水区的总氮、铵态氮、总磷和COD的极值差达到了轻度垦殖状态下林地集水区的6.79、4.29、4.88、2.39倍,土地垦殖对总氮、铵态氮、总磷和COD浓度的影响较大。极轻度垦殖状态的灰色关联序:TP(0.8266)>TN(0.7688)>COD(0.6684)>NH4^+-N(0.6544);强度垦殖状态的灰色关联序:TN(0.8087)>TP(0.7981)>NH4^+-N(0.7698)>COD(0.6758)。【结论】极轻度和强度垦殖状态下集水区的主要面源污染物为总磷(TP)和总氮(TN)。林地集水区满足地表水Ⅰ类水质标准,混合集水区满足地表水Ⅱ类水质标准,由此可得,地表水质状况与土地垦殖强度呈负相关关系。

【Objective】This paper aimed to explore the effects of land reclamation on water quality of surface water in important water source areas of Yunnan province.【Method】During may to October in 2017,the small watershed impressive watershed of loose China dam water source protection area in Kunming,Yunnan province was used as the research object,using the field monitoring and laboratory experiments,the rainfall and runoff water quality of total nitrogen (TN),total phosphorus (TP),ammonium nitrogen (NH4^+-N),chemical oxygen demand (COD) were monitored,and the different intensity of glebe developing fixation of watershed characteristics of surface water quality was studied based on improved gray relation analysis model.【Result】Under the strength condition of glebe developing hybrid watershed,total nitrogen,ammonium nitrogen,total phosphorus and COD of the extremum difference reached mild condition,which were 6.79,4.29,4.88,2.39 times,and the effects of land reclamation on total nitrogen,ammonium nitrogen,total phosphorus and COD were significant. The grey relational order of minimally cultivated state:TP (0.8266)>TN (0.7688)>COD (0.6684)>NH4^+-N (0.6544);The grey relational order of intensive cultivation:TN (0.8087)>TP (0.7981)>NH4^+-N (0.7698)>COD (0.6758).【Conclusion】Total phosphorus (TP) and total nitrogen (TN) are the main surface pollutants in the catchment area under extremely mild and intensive cultivation. Forest watershed Ⅰ meet the surface water quality standard,mixed watershed Ⅱ meet the surface water quality standard,therefore,the surface water quality is negatively related to the intensity of glebe developing.