大暴雨作用下黄土高原典型流域水土保持措施减沙效益研究

正确评估大暴雨条件下流域水土保持措施的减沙作用,可为科学揭示流域侵蚀产沙变化的驱动机理提供理论支撑。综合采用改进的水土保持成因分析法、林草植被减沙模型和分布式土壤侵蚀模型,对近10年大暴雨作用下4个典型流域的水土保持措施减沙作用进行了系统分析和研究。结果表明:佳芦河流域水土保持措施在"2012.7.27"大暴雨中减沙效益为65.4%;杏子河流域在"2013.7.12""2013.7.25"和"2013.7.27"三场连续降雨中,水土保持措施减沙效益分别为56.5%、40.7%和36.5%;西柳沟流域上游在"2016.8.17"大暴雨中,林草植被措施减沙效益达84.2%;岔巴沟流域在"2017.7.26"大暴雨中,水土保持措施减沙效益为79%。大暴雨作用下水土保持措施减沙效益明显,但遭遇连续极端降雨情况,水土保持减沙效益会降低。

Study on sediment reduction benefits of soil and water conservation measures in typical watersheds in the Loess Plateau under the heavy rainfall

A correct assessment of the sediment reduction effect of soil and water conservation measures under extreme rainfall conditions can provide theoretical support for scientifically revealing the driving mechanism of erosion and sediment yield changes. Using the improved method of soil and water conservation measures analysis, reduction equation of vegetation and the distributed soil erosion model, the effects of soil and water conservation measures on sediment reduction in four typical watersheds in the Yellow River basin in recent 10 years are systematically analyzed and studied. The results showed that the sediment reduction benefit of soil and water conservation measures in the Jialu River watershed is 65.4% in the rainstorm of "July 27, 2012"; The sediment reduction benefits of soil and water conservation measures in the Xingzi River watershed were 56.5%, 40.7% and 36.5% respectively in the three successive rainfalls of "July 12, 2013", "July 25, 2013" and "July 27, 2013"; In the "August 17, 2016" rainstorm in the upeer reaches of Xiliugou watershed, the sediment reduction ratio of soil and water conservation measures was as high as 84.2%; During the "July 26, 2017" rainstorm in the Chabagou watershed the sediment reduction rate of hillslope soil and water conservation measures was 79%. The sediment reduction effect of soil and water conservation measures is obvious under heavy rain, but it will be reduced in case of continuous extreme rainfall.