An Innovative Study on the Effects of Land Management Practices on Rill Erosion Using an Instantaneous Profile Laser Scanner

Rill erosion is a major form of soil and nutrient loss that affects the productivity of agricultural lands and threatens our environment. In this study, laboratory experiments are currently being conducted at a plot scale level to identify the effects of different types of land use and agricultural management practices on soil surface roughness, which in-turn affects rill erosion processes and the fluxes of both water and sediment. Identification of the role that management practices has on erosion processes will lead to more sustainable agriculture practices, thus avoiding the loss of vital nutrients and reduction of the soil's water-holding ability. A state-of-the-art laser scanner technique is utilized to determine the soil surface roughness, providing an accurate spatial resolution of 0.5 mm. Based on this technique, a laser beam is projected vertically onto the bed surface while an infra-red camera detects the light spot reflected from the surface. Knowledge of the bed topography allows us to determine the associated drainage networks, flow direction, and stream segmentation via GIS (Geographic Information System) modeling. Data sets obtained from this study will be used as input files to simulate the development of rills using a newly developed 1-D hydrodynamic and sediment transport model namely, RILL1D, which handles transcritical flows over abrupt changes in rill bed and predicts changes in rill bed elevation.