Fence height control on sand trapping

Sand fences are widely used to control sand deposition to initiate or stabilize dunes. Previous studies on sand fences are often focused on the porosity control of their trapping efficiency, however, there exists very little research on the fence height effect. We deployed fences with three heights and equal porosity at a field site near Jericoacoara, Brazil, and examined the variation of their topographic profile and trapping efficiency. We identified two stages of dune development around fences. During stage I, dune topographic profile area is proportional to the fence and dune height, and the trapping efficiency decreases substantially with time. During stage II, dunes continue to grow horizontally and the trapping efficiency decreases with time, but at a slower rate compared to stage I. Coarser sand tends to deposit close to the fence. The findings from this study can enhance the understanding of the complex wind-sand-structure interactions and provide insights for future dune recovery applications.