ARS | Publication request: CONTRASTING EFFECTS OF SURFACE ROUGHNESS ON EROSION AND RUNOFF

Submitted to: American Society of Agricultural Engineers
Publication Type: Proceedings
Publication Acceptance Date: January 3, 2001
Publication Date: N/A

Technical Abstract: Soil surface roughness is a key factor in affecting runoff generation and erosion. Nevertheless, contradictory results on the roughness effect are found in the literature: an increased soil roughness can either increase or decrease runoff and erosion. With the recent development of second-generation instantaneous-profile laser scanning technology, it is possible to acquire high-resolution soil microtopographic data rapidly, thus, enabling a further exploration of soil roughness effects on runoff and erosion. Additionally, the development of multiple-box system with controls for the near-surface hydraulic gradient allows us to quantify sediment mass balance relationships under different hydrologic conditions. This study is part of a project designed to identify conditions when soil roughness acts to either enhance or reduce erosion and to further explore how roughness elements interact with dominant erosion processes. The basic concepts are to split the random roughness in two sub-components based on their function and to characterize surface morphology considering the process scale. Simulated rainstorms were applied on the multiple-box system with different kinds of initial roughness, near-surface hydraulic gradient and feeding rate, to cover a wide range of transport conditions from detachment limited to transport limited. Surface microtopography was measured using an instantaneous- profile laser scanner. First results tend to show that a low density of aggregates reduces soil loss. These results will be completed in the near future and extended to others morphologies.