岔巴沟淤地坝小流域重力侵蚀产沙量分析

摘要

以黄土高原典型流域中重力侵蚀产沙量为研究对象,选择岔巴沟流域中6个淤地坝小流域作为研究流域,以坝库中1978-2001年共22年泥沙淤积量作为流域总泥沙侵蚀量,采用中国土壤侵蚀流失模型(CSLE)并考虑沟蚀因素计算水力侵蚀量,将水力与重力侵蚀产沙量区分开来.研究结果表明:6个小流域中重力侵蚀产沙分别占流域总侵蚀产沙量的0％、51.0％、54.1％、59.0％、65.0％和67.0％;小流域中重力侵蚀产沙量与＞32.的沟坡面积具有显著的线性正相关关系,沟坡坡度是重力侵蚀的控制性因素,降低沟坡坡度能够显著地减少流域产沙量.%Gravitational sediment yield in the typical watersheds of the Loess Plateau is the study object in this paper.Six small watersheds controlled by check-dams are selected as the study basins.Sediment deposition data in the reservoirs of 1978-2001 are used as the total amount of erosion in the six basins.Chinese Soil Loss Equation mode (CSLE) is used to calculate erosion amount by water,and the gully erosion factor is added in this model.Through this method,gravitational sediment yield is distinguished from total erosion amount.The result shows that the percentages of gravitational sediment yield in total sediment yield in the six check-dam watersheds are about 0％,51.0％,54.1％,59.0％,65.0％ and 67.0％,respectively.It has significant linear positive correlation between gravity erosion sediment yield and the gully slope areas of steeper than 32°,and gully slope degree is the controlling factor of the gravitational erosion.Therefore reduce gully slope degree can significantly lower sediment yield in the watersheds of Loess Plateau.