摘要
从坡面水动力学角度研究了坡面乔木林、草本植物和林地枯落物对坡面径流流速和动能的影响机理.结果表明,坡面径流水头损失与坡面坡度、林木密度、净雨强、坡长等有关,水头损失与林木间距(b)和树木地径(D)间的关系为:E∝(D/b)4/3;坡面草本植物在水流作用下易弯曲,增大水流底层的阻力,减小床面的切应力;枯枝落叶使径流速度减小,从而大大降低径流挟沙能力.对甘肃省天水市桥子东沟和桥子西沟两个对比小流域的实测单次降雨、径流、泥沙资料分析可见,在相同降水条件下,已治理小流域内的径流量、产沙量、洪峰流量、最大输沙率等指标均小于未治理小流域,说明林草植被在小流域中的涵养水源、保持水土的作用明显.
From the view of hydrodynamics, this paper studied the acting mechanism of tree, grass and forest litter on slope runoff velocity and kinetic energy. The results showed that slope runoff head loss was related to slope gradient, forest density, net rainfall intensity and slope length. The relationship of water head loss with the distance among trees and the diameter at the ground of tree was EOC（D/b）^4/3. The grass onslope turned to be curved with s flowing, and thus, increased the bottom resistance of flow, and reduced the shearing stress of soil surface. Therefore, silt-carrying capacity decreased dramatically. The analysis of actually measured materials of each rainfall, runoff and sediment, and the comparison of Qiaozi eastern gully and Qiaozi west gully in Tianshui city of Gansu Province showed that under same precipitation condition, the runoff, sediment yield, flood peak discharge and maximum sediment transport rate in treated watershed was less than those in untreated watershed, suggesting that vegetation was obviously beneficial to water reservation and water and soil conservation.
出处
《应用生态学报》
CAS
CSCD
北大核心
2005年第9期1618-1622,共5页
Chinese Journal of Applied Ecology
基金
国家重点基础研究发展规划资助项目(2002CB111502)
关键词
流域
林草植被
土壤侵蚀
Watershed, Vegetation, Soil erosion.
