不同石漠化程度土地坡面产流特征分析

采用人工模拟降雨试验,研究了不同石漠化程度土地坡面产流特征。结果表明:中度和重度石漠化土地地表径流特征相似,但其与潜在、轻度和极重度石漠化土地差异明显。当雨强小于40 mm/h时,潜在石漠化土地难产生地表径流,当雨强达到55 mm/h,连续降雨34 min其开始产流;当雨强在51～60 mm/h之间时,其径流强度围绕3 mm/h小幅波动,当达到61 mm/h以上时,其径流强度随着降雨时间的延长而增大。轻度石漠化土地产流时间随着雨强的增大而变短,但其径流强度差异不大,介于2～5 mm/h之间。中度和重度石漠化土地地表径流呈现峰谷相间的特点。极重度石漠化土地裂隙、节理极为发育,洼地内多漏斗、落水洞,集流面积小,雨强增大后产生的径流变化幅度不明显。

Characteristics of Slope Runoff Yield under Different Conditions of Rock Desertification

The paper studied the characteristics of slope runoff yield under different conditions of rocky desertification by using artificial simulation rainfall tests.The outcomes show that the characteristics of surface runoff of moderate and severe rocky desertification land are similar,but it is great difference for the potential,slight and extremely severe rocky desertification lands.When the rainfall intensity is smaller than 40 mm/h,the potential rocky desertification land is difficult to produce surface runoff.When the rainfall intensity reaches to 55 mm/h and continuous rainfall for 34 minutes,it begins to produce runoff.When the rainfall intensity is between 51 mm/h and 60 mm/h,the runoff intensity slightly changes around 3 mm/h and the runoff intensity increases along with the extension of precipitation when the rainfall intensity is greater than 61 mm/h.The runoff yield time of slight rocky desertification land becomes shorter along with the increase of rainfall intensity,and the difference of runoff intensity is not great,just between 2 mm/h and 5 mm/h.The variations of runoff intensity of moderate and severe rocky desertification lands have the characteristics of peak and valley with certain waviness.The fissures and joints of extremely severe rocky desertification land are well developed.There are more funnels and sinkholes in the low-lying area.The catchment area is small and the variation range of runoff generated by the increased rainfall intensity is not obvious.