Calibration of RWEQ in a patchy landscape; a first step towards a regional scale wind erosion model

Abstract

Despite the fact that wind erosion seriously affects the sustainable use of land in a large part of the world, no validated wind erosion model that predicts windblown mass transport on a regional scale exists. Vegetation has the potential to decrease soil loss by wind erosion through the protection of the soil surface, through the reduction of wind speed and through the entrapment of saltating particles. Simulation of wind erosion process will differ at regional scale from field scale and as a result it will represent by different parameters. These parameters include vegetation cover, wind barriers, soil surface roughness and some other soil properties. The interaction of wind erosion with vegetation is the best example of a process that changes from plot to regional scale. The objective of this research was to make a starting point for a regional scale wind erosion model by establishing relations between the intensity of windblown mass transport and vegetation cover in a patchy landscape in Syria. Measurements on windblown mass transport were executed at 9 different land uses (and thus vegetation cover) in agricultural stabilization zones 4 and 5 in Khansser valley, Syria. At each plot 16 MWAC (Modified Wilson and Cooke) sediment catchers were installed and wind speed was recorded with five-minute intervals. The RWEQ (Revised Wind Erosion Equation) was translated into the dynamic modelling language of PCRaster and applied to determine the relations between vegetation density and pattern and intensity of mass transport. The results of this application showed that RWEQ in PCRaster (RiP) gave acceptable predictions for the uniform fields without incoming sediment sources. So, the predicted and observed results are in the same magnitude. However RiP needs more calibration to improve its prediction of the spatial variation of the windblown mass transport. With completing the calibration process, RiP will have the potential to form the basis of a regional scale wind erosion model