不同下垫面径流小区次降雨侵蚀特征相关分析

在延安市燕沟流域试验区布设了裸地、荒草地和灌木地3个坡面径流小区,对次降雨雨量、历时、径流深、产沙量、入渗率等数据进行了定位观测,并运用SAS软件对不同下垫面径流小区次降雨的侵蚀特征等相关问题进行了分析研究。结果表明,无论降雨强度如何变化,3个小区的径流量、产沙量均呈依次降低趋势:灌木地<荒草地<裸地;而入渗率呈依次增大趋势:灌木地>荒草地>裸地。其径流量与降雨量之间存在着很好的相关关系;产沙量随降雨量的增大而增大,其中裸地产沙量增大最为显著;入渗率随着降雨量的增大有增加趋向,但雨强增大时,入渗率表现为降低趋势;产沙量与径流量存在较好的相关关系,相关系数最高达到0.928 4,荒草地小区产沙量与径流量的关系可用二次函数很好地描述。

Erosion Characteristics of Plots with Various Underlying Surfaces in Single Rainfall

Three runoff plots of bare land,waste grassland and shrub land were established in Yangou watershed of Yan'an City.Based on observations of total rainfall,rainfall duration,runoff depth,sediment yield,infiltration rate in individual rainfall events,the erosion characteristics of each plot were investigated using the statistic package of SAS.The results indicate that regardless of rainfall intensity,both runoff and sediment yields decreased,and correspondingly the infiltration rate increased in the three plots as listed in order.Runoff were closely correlated with rainfall.Sediment yields increased with total rainfall,especially in the bare-land plot.Similarly,the infiltration rates increased with total rainfall amounts,but decreased significantly in rainfalls with high intensity.The sediment yields correlated well with the runoff.However,a quadratic function performed better in describing the relationship between the sediment yield and runoff of the grassland.