Erosion process and spatial distribution characteristics of erosion-deposition on the loess slope
XU Zhenjian1, QUAN Xin1, SHI Hongwei2, HE Jijun1*, CAI Qiangguo3, SUN Liying3
(1 State Key Laboratory of Urban Environmental Processes and Numerical Simulation, Capital Normal University; Resources Environment and GIS Key Lab of Beijing, Beijing 100048, China; 2 Ministry of Water Resources Construction Management and Quality and Safety Center, Water Conservancy Engineering Management Department, Beijing 100038, China; 3 Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100101,China)
Abstract:
In this study, indoor simulated rainfall test and 3D laser scanning technology were used to study the spatial distribution and change rule of soil erosion-deposition under different slopes and rainfall intensity and the erosion process of loess slope was analyzed by combining traditional water and sediment observation. The results showed that the rainfall intensity is the main factor affecting the initial runoff yield on loess slope and the gradient can affect the runoff yield by changing soil infiltration rate, runoff kinetic energy and received rainfall. The total runoff increased significantly with the increase of rainfall intensity and it increased first and then decreased with the increase of gradient. When the rainfall intensity was 1.0 mm/min, the total erosion increased with the increase of gradient. When the rainfall intensity was 1.5 mm/min,the total erasion first increased and then decreased with the increase of gradient, which was consistent with the trend of runoff. For each slope, the runoff yield showed a trend of faster growth in the early stage of rainfall and a slower growth in the later stage. Erosion rate increased first and then decreased with the increase of runoff yield rate, and the increase of gradient significantly reduced the time for erosion rate to reach its peak especially when the rainfall intensity is 1.5 mm/min. Heavy rain intensity and large gradient made it easier to reach an equilibrium state in the process of sediment detachment, transport and deposition. The spatial distribution of erosion-deposition of loess varied with different rainfall intensities and gradients. Generally speaking, the erosion gradually weakened from the top to the bottom of the slope and there is a strong and weak zone of erosion-deposition among which the soil erosion is more obvious when the gradient is steep, especially for the middle and upper part of the slope.
KeyWords:
artificial simulated rainfall；slope erosion；3D laser scanning；spatial distribution
