Modelling the effect of water harvesting structures on aeolian erosion in the Jordanian Badia

Abstract

Arid and semi-arid regions are prone to wind erosion due to scarce rainfall and low vegetation cover. As transport of sediment by creep, saltation and suspension can lead to problems affecting the environment, climate and human health, methods to reduce aeolian erosion are continuously being researched. Water harvesting techniques have been applied in dry areas for a long time to reduce wind erosion, by increasing water storage and enhancing vegetation growth. In the Jordanian Badia (desert), Vallerani water harvesting structures have been implemented on an experimental site, but the effect on wind erosion reduction remains unclear. This study aimed to quantify the reduction in wind erosion by integrating a small scale cellular automaton model and a large scale model for Badia conditions with and without water harvesting structures. It also compared different transport equations to assess the uncertainty of the obtained values. The results are promising, as reductions in sediment transport of over 88% were obtained for the plot scale model. Outscaling to suitable areas is similarly promising, as the large scale model determined 60-100% reduction in dust concentration near the surface for areas where water harvesting structures are implemented on a regional scale. The coupling between the models can be optimized through the creation of new, specialized land cover classes with plot scale model values to be implemented in the large scale model. Improvements to the plot scale model can be made to include better vegetation spatial distribution, but field measurements are required to verify the use of model governing equations and validate the modelled sediment fluxes.