Determining the Effects of Rainfall-Runoff on Soil Surface Roughness and Erosion Processes via a Laser Scanner

Soil erosion of hills affects the productivity of agriculture lands and threatens our earth environment. There are several factors that trigger and sustain soil erosion, such as climate, soil type, soil surface roughness, cropping, and land management practices. This laboratory study examines the role of the rainfall intensity on soil surface roughness development and the transport/deposition of the eroded material under different experimental scenarios. Surface roughness is related to management practices and has been one of the factors that did not receive considerable attention. One hindrance of previous studies was the lack of a system and robust methodology for performing adequate acquisition of the soil surface micro- topography. Herein, a state-of-the-art laser scanner technique was utilized, providing a spatial resolution of 0.5 mm. The surface heights for the entire soil surface were imported into the ArcGIS 9.2 software in order to obtain the Digital Elevation Model (DEM), while the built-in Arc Hydro tools were used next to attain the drainage networks, flow direction, flow accumulation, stream definition, and stream segmentation. Data sets obtained from this study will be used as input files for numerical models such as the RILL1D to simulate rill development and reproduce measured values of sediment transport rates.