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| Influence of forest vegetation on runoff and sediment transport of watershed in loess area |
| Zhang Xiaoming,Yu Xinxiao,Wu Sihong,Liu Huifang,Zhang Xuepei,Wei Tianxing |
| Key Laboratory of Soil and Water Conservation and Combating Desertification,Ministry of Education;College of Soil and Water Conservation,Beijing Forestry University,100083,Beijing,China |
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Abstract In order to deeply study the relationship between vegetation and runoff and sediment transport at the scale of watershed,and to provide theoretical basis for vegetation restoration of Loess area,forested watershed and rangeland watershed with similar terrain and topographical features are selected using method of clustering analysis to inlaid Caijiachan catchment which lies in Jixian county of Shanxi province in Loess area,and runoff and sediment transport of which are contrasted and analyzed.The results showed that runoff was delayed dramatically at beginning time,and the peak flow of watershed reduced for forest vegetation played role in holding up and absorbing precipitation depending on canopy layer and litter.Besides,with increase of forest coverage,the amount of runoff,runoff depth and runoff coefficient in rain season decreased.It clarified that runoff depth and runoff coefficient of rangeland watershed in rain season were 5—20-fold as much as those of forest watershed,and those of less forest watershed were 2.7—2.9-fold as much as those of more forest watershed.And sediment yield from less forest watershed by storm was 2—5-fold than those from more forest watershed.(Besides),the variation of sediment transport hydrograph of the former was more acute than those of the latter.For the reason of complexity and scaled dependence of runoff influenced by forest vegetation,assess of forest hydrological functions based on regional scale or watershed scale was worth of further research challenges.
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Received: 01 April 2005
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