晋西黄土区不同植被覆盖小流域的产流输沙特性

为了进行不同植被覆盖小流域的产流输沙研究,以山西省吉县蔡家川流域内部嵌套的3个典型小流域为研究对象,采用对比分析的方法,探索降雨特性和植被覆盖条件对流域产流输沙的影响。结果表明:小流域产生的径流量和输沙量均随着降雨量的增大而增大,但并不成一定比例;小流域的径流量和输沙量也随降雨强度的增大而增大,泥沙量的增长幅度大于径流量;在黄土区,短历时的暴雨易产生严重水土流失,应该作为水土流失预防的重点;在不同植被覆盖条件下,以封禁植被为主的小流域产生的径流量和输沙量最小,人工植被为主的小流域次之,水平梯田为主的小流域最大;在封禁条件下自然恢复植被为主的小流域对黄土区典型暴雨的水土流失预防效果最佳。因此,如何在水土流失严重的黄土高原地区仿拟自然进行植被恢复,是有效控制水土流失的关键。

Characteristics of runoff and sediment in small watersheds under different vegetation cover in the Loess Plateau of Western Shanxi Province

To investigate process of runoff yield and sediment transport in small watersheds under different vegetation cover,three typical small watersheds were selected as study area,which belong to Caijiachuan Watershed in Ji County,Shanxi Province.Contrastive analysis was used for the study.The results show that both runoff and sediment yield increased with rainfall,but this was not a linear increase with a certain rate.The runoff and sediment yield also increased with rainfall intensity,and the increase rate of the sediment yield was greater than that of runoff.The rainstorm with short duration may cause serious soil erosion in the Loess Plateau.So more attention should be focus on this type of rainfall.The runoff and soil erosion were the least in small watershed with naturally recovered vegetation,and then followed by the small watershed with artificial vegetations,the runoff and soil erosion of level terrace were largest.The effect of naturally recovered vegetation on reducing runoff and soil erosion resulted form rainstorm was optimum,therefore,how to naturally recover vegetation in the Loess Plateau is the key to control water and soil erosion.