Study on water erosion from two small watersheds with and without management on Loess Plateau

YUAN Cui-ping1,LI Shu-qin1,LEI Qi-xiang2,CAO Quan-yi 2,HE Ai-dong2,SU Guang-xu2(1.College of Hydraulic and Civil Engineering,China Agricultural University,Beijing 100083,China;2.Tianshui Soil and Water Conservation Management and Monitoring Bureau of Yellow River,Yellow River Conservation Commission,The Ministry of Water Resource,Tianshui 741000,China)

parallel small watershed;soil and water conservation management;event based rainfall;runoff process

In order to study the effect of soil and water conservation management on water erosion and runoff process at small watershed,the Qiaozi-East watershed with management and Qiaozi-West watershed without management at third sub-region of Loess Plateau were selected as studying area.Rainfall and runoff data were collected and the annual change of soil erosion and runoff processes were analyzed at different stages of management.Times of runoff at QiaoziEast watershed were reduced by 42.86% as compared with that at Qiaozi-West watershed.Annual runoff modulus at Qiaozi-East watershed accounted for 5%-63% of that at Qiaozi-West watershed.Annual mean runoff coefficients of Qiaozi-East and Qiaozi-West watershed were 1.80% and 4.03% respectively.The ratios of annual runoff depths at Qiaozi-East watershed to that at Qiaozi-West watershed decreased slightly and decreased slightly to less than 0.6 finally.Runoff initiated and peak flow occurred at Qiaozi-East watershed all later than at Qiaozi-West watershed with years of management.The ratios of peak flow and runoff duration at Qiaozi-East watershed to that at Qiaozi-West watershed were decreased to 0.41 and 0.61 respectively finally.