广州流溪河流域典型农业集水区降雨径流污染物输出特征分析

    Characteristics of Output of Non-Point Source Pollution With Rainfall Runoff in Typical Agricultural Watershed of Liuxi River Valley

    • 摘要: 选取广州市流溪河流域典型农业集水区——新田小流域为研究对象,对研究区降雨地表径流进行定点监测,探讨降雨—径流条件下农业非点源污染物的动态变化规律和不同利用类型的地表景观对非点源污染的贡献情况。结果表明:在降雨事件下,污染物输出浓度总体上高于日常非降雨条件的污染物浓度,T-N、T-P和CODCr的平均输出浓度分别是非降雨条件下的3.8倍、7.8倍和32.1倍;整个降雨—径流过程中,降雨初期是非点源污染物流失的高峰期,污染物浓度变化总体趋势滞后于降雨强度的变化,但与径流量变化趋势总体上相似;从不同地表景观径流产污来看,经生活区的径流CODCr输出浓度显著上升,水田田面径流是引起水体环境N、P污染的主要原因。

       

      Abstract: The main processes of non-point source pollution(NPS) are rainfall,runoff,and pollution.A typical agricultural watershed in the Liuxi River Valley,Xintian Watershed,was selected as an object in the research.Stationary monitoring of rainfall-induced runoff was carried out to explore dynamics of agricultural non-point source pollutants in the rainfall-runoff condition and contribution of different land use landscapes to NPS.Results show that 1)generally concentrations of non-point source pollutants in output in the event of rainfall were higher than in no rain days.The average concentration of total nitrogen(T-N)in the former is 3.8 times,of total phosphorus(T-P)7.8 times,and of CODCr 32.1 times as much as that,respectively,in the latter;2)Throughout the rainfall event,output of NPS peaked in the early period. Variation of the concentration of pollutants lagged behind that of the intensity of rainfall,but followed closely that of runoff;and 3)Pollutant output varied with surface landscape.Runoffs flowing through residential areas were higher in CODCr concentration,while the one through paddy fields was the major contributor of N and P pollutions in the water body environment.

       

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