Abstract:

At the Mediterranean region, the problems related to the agriculture, the defense of the soil and watershed management, are one of the most significant environmental problems. To solve this problem it is necessary to study, analyze and understand the impact of the erosive action in these semi-arid areas. There are different methods that estimate soil erosion at the plot or watershed level; these methods range from simple to complex. For this work, the analysis has focused on modelling of water erosion by the RUSLE model (Revised Universal Soil Loss Equation) consisting of a modified version of the universal soil loss equation of (USLE) originally developed by Wischmeier and Smith in Predicting rainfail erosion losses—a guide to conservation planning. Agricultural handbook No. 537, USDA, Washington, 1978. A methodology of assessing the various risk indices of erosion around the geographic information system (GIS-Arc Gis 9.3). The RUSLE equation was applied by overlaying, using ArcGIS software, the various appropriate thematic maps for each factor. According to the RUSLE model, over 70% of the study areas are subject to different soil loss levels: low (<5) to very high (50–200). The average loss by water erosion across all study sites is about 8.73 t/ha/year. Total annual losses for the six selected townships are of the order of 33,995.4 t/ha/year. In light of these figures, we can conclude that the unequal distribution of areas with potential risk of erosion in the Aurès center results from the variability of the characteristics of the factors involved in the process and the model used. These results will be used for territorial planning, in reference to the project to reduce the vulnerability of these areas.

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