Numerical modeling of gravitational erosion in rill systems  

作　　者：Peng HAN Jin-Ren NI Ke-Bin HOU Chi-Yuan MIAO Tian-Hong LI 

机构地区：[1]Department of Environmental Engineering, Peking University, Beijing 100871, P. R. China

出　　处：《International Journal of Sediment Research》2011年第4期403-415,共13页国际泥沙研究（英文版）

基　　金：Financial supports from the National Basic Research Program of China(2007CB407202);National Natural Science Foundation of China(50579001)

摘　　要：A self-organizing model was developed for simulating rill erosion process on slopes with particular attention to the role of gravitational erosion. For a complete simulation circle, processes such as precipitation, infiltration, runoff, scouring, gravitational erosion and elevation variation were fully considered. Precipitation time （or runoff time） was regarded as iteration benchmark in the model. To specify the contribution of gravitational erosion to the process of rill formation and development, a gravitational erosion module was inserted into the model. Gravitational erosion in rill development was regarded as a Gaussian random process. A model was calibrated by our experimental data, and further validated satisfactorily with 22 runs of experimental results from different investigators. Systematic comparison was made between sediment yields with and without consideration of gravitational erosion module. It was demonstrated that the model could reasonably simulate the rill erosion process under a variety of slope gradients, rainfall intensities and soil conditions upon the gravitational erosion being considered. However, the role of gravitational erosion on sediment yields in rill systems varies significantly under different conditions, although it is of the utmost importance in steeper slopes. The process of gravitational erosion in rill development was studied by a newly-defined parameter o~, which is defined as the volume ratio of gravitational erosion over hydraulic-related erosion. The gravitational contribution to the total erosion could be over 50% for the rill systems with higher rainfall intensity and steeper slopes.A self-organizing model was developed for simulating rill erosion process on slopes with particular attention to the role of gravitational erosion. For a complete simulation circle, processes such as precipitation, infiltration, runoff, scouring, gravitational erosion and elevation variation were fully considered. Precipitation time （or runoff time） was regarded as iteration benchmark in the model. To specify the contribution of gravitational erosion to the process of rill formation and development, a gravitational erosion module was inserted into the model. Gravitational erosion in rill development was regarded as a Gaussian random process. A model was calibrated by our experimental data, and further validated satisfactorily with 22 runs of experimental results from different investigators. Systematic comparison was made between sediment yields with and without consideration of gravitational erosion module. It was demonstrated that the model could reasonably simulate the rill erosion process under a variety of slope gradients, rainfall intensities and soil conditions upon the gravitational erosion being considered. However, the role of gravitational erosion on sediment yields in rill systems varies significantly under different conditions, although it is of the utmost importance in steeper slopes. The process of gravitational erosion in rill development was studied by a newly-defined parameter o~, which is defined as the volume ratio of gravitational erosion over hydraulic-related erosion. The gravitational contribution to the total erosion could be over 50% for the rill systems with higher rainfall intensity and steeper slopes.

关 键 词：Self-organizing model Rill erosion Gravitational erosion Gaussian noise 

分 类 号：S157.1[农业科学—土壤学] N94[农业科学—农业基础科学]