三峡库区野外模拟降雨条件下弃渣场土壤侵蚀特性

Soil Erosion Characteristics of Dumping Sites Under Simulated Rainfall Conditions in Three Gorges Reservoir Region

[目的]揭示三峡库区弃渣场土壤侵蚀规律,为该地区弃渣场的土壤侵蚀治理提供依据。[方法]通过现场搭建径流小区并采用人工模拟降雨的方法进行研究。[结果]降雨量同侵蚀量存在极显著的线性关系;降雨强度同渣场产流时间呈极显著的幂函数关系,同径流含沙率呈极显著的指数函数关系;渣场表层较高的细砾石含量,一定程度上可以减少溅蚀与面蚀量,但在强降雨或持续降雨条件下会促进坡面沟蚀的发育;渣场侵蚀具有一定季节分布,非雨季时,渣场侵蚀以面蚀与轻微沟蚀为主,坡面主要发育为细沟与浅沟,侵蚀量较少;雨季时,渣场坡面浅沟迅速转化为切沟,泥沙流失严重。[结论]研究区渣场侵蚀具有一定的季节性,渣场施工时应根据气候特征适当调配,主动避开雨季,并在雨季前完成渣场的水土保护设置;采取相应防护措施抑制或减缓雨季沟蚀的发育是研究区渣场水土保持防护的重点。

[Objective]The objective of this study is to reveal the soil erosion characteristics of dumping sites in Three Gorges reservoir region in order to provide basis for the management in this area.[Methods]Runoff plots were constructed and simulated artificial rainfall was used in this research.[Results]A significant linear relationship was found between rainfall and erosion amount.The rainfall intensity showed a significant power function correlation with the runoff time,while it showed an exponential regression correlation with the sand content.Fine gravel with high concentration in the dumping sites surface soil reduced the splash and sheet erosions in some extent,however,it intensified the gully erosion under the condition of heavy or continuous rainfall.Furthermore,soil erosion in the dumping sites presented seasonal variations.During the dry season,soil erosion was dominated by sheet erosion and slight gully erosion,and the erosion amount was little.In contrast,in wet season,shallow grooves were converted into ditches rapidly,and the erosion became more severe.[Conclusion]As soil erosion in dumping sites of Three Gorges reservoir region changes seasonally,constructions can be done according to the changes of season to avoid the rainy season.Taking the protective measures to prevent or slow down the development of gully erosion in the rainy season is the focus of soil and water conservation in the study area.