Optimization of aeolian soil erosion control with sand fences

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This project is motivated by the need for a reliable numerical tool to optimize measures for protecting sediment soil from wind erosion. Control of soil erosion by wind often requires the erection of different arrays of sand fences, which may be applied in combination with vegetation cultivation to reduce wind power and induce deposition. However, evaluating their efficacy to protect large-scale aeolian landscapes based on experiments alone is difficult both due to the long-term processes involved in the bed evolution and because soil morphodynamics depends strongly on local topography and wind behavior. Therefore, a numerical tool for designing optimized strategies to protect soils against wind erosion is required and shall be developed in the present project. The numerical tool couples Computational Fluid Dynamic (CFD) modeling of the average turbulent wind field over the soil and the erected fences with state-of-the-art morphodynamic modeling of sediment landscapes. To validate the simulations, field measurements of the average basal shear stress, height-integrated sediment flux and bed profile evolution shall be performed in the dune field of Jericoacoara, Northeastern Brazil, and the results compared with numerical predictions. Subsequently, the numerical tool shall be applied to derive strategies for optimal soil protection using arrays of fences of different porosity, spacing and height, and under different wind regimes and conditions of sand availability. To investigate the effect of sand fences on the development of vegetation cover, the simulations shall be then extended to include a model for the interaction between wind, particles in saltation and vegetation. This is important to develop improved anti-desertification measures and to address the long-standing problem of dune immobilization.