三峡库区低等级土质道路侵蚀研究

Research of the soil erosion on the low-volume unpaved road in the Three Gorge Reservoir area

  • 摘要: 以三峡库区界垭小流域内不同交通荷载土质道路为研究对象,通过自然降雨观测研究其侵蚀规律和污染物流失特征。研究结果表明,交通荷载大的干道产流率和侵蚀率均高于交通荷载低的支道,对产流率影响显著的因子主要为降雨量,对产沙率影响显著的因子为降雨量、雨强。雨型对污染物的流失特征影响显著,前期集中型降雨下,污染物流失过程线与降雨过程线同步性较好,泥沙、总氮、铵态氮、泥沙结合态磷和溶解态磷均发生了较强的初始冲刷效应;中期集中型降雨下,污染物流失浓度峰值优先于雨强峰值,且氮和磷等初始冲刷强度低于前期集中型降雨,泥沙无初始冲刷效应。

     

    Abstract: The road network plays a great role in altering the erosion processes and water quality. In this paper, two rural roads with different traffic load, which located in the Jieya watershed Three Gorge Reservoir area, were selected to discuss the road soil erosion and non-point source pollutants loss under the nature rainfall events. The results show that both the runoff rate and erosion rate were higher on the high traffic load roads than that on the low traffic load roads. The rainfall precipitation significantly affected the runoff generation and sediment yield, and the rainfall intensity and rain energy also played great role in affecting the sediment production. The rainfall type had a significant impact on the non-point source pollutants loss, the pollutants loss processes were almost simultaneous to the rainfall under pre-centralized rainfall event, and the first flush effect on the Total Nitrogen, NH4-N, particulate phosphorus, and dissolved phosphorus were much stranger than that under the mid-centralized rainfall event. Slightly first flush effect happened on sediment and the appearance of pick concentration of the pollutants lost was much prior to the pick rainfall intensity when under mid-centralized rainfall event. The nitrogen was lost in the form of Total Nitrogen, which contained of 80% of the total quantity, most of the phosphorus was lost in the form of particulate phosphorus.

     

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