Evaluation of the erosion risk by means of the RUSLE model case the region of catchment Seklafa (Laghouat)

Abstract

The Seklafa watershed, with an area of 787 km², which is part of the Jebel Amour region (Algeria),is characterized by a spatio-temporal rainfall irregularity, a fairly high thermal gap, a degraded marly lithology and a weak vegetation and inadequate cover, which makes it prone to severe erosion in all its forms. The combination of thematic maps of the different erosive factors according to the Revised Universal Soil Loss Equation (RUSLE) in the GIS by ArcGIS 10.2 software provided a reliable forecast of the annual rates of soil loss by delineating the areas prone to erosion risk in the watershed mentioned above. The estimated average potential annual soil loss is 7.56 t /ha / year. About 70.7% of the watershed was predicted to have a very low to low erosion risk, with soil loss of between 0 and 7.5 t / ha / year. The risk of erosion is moderate over 17.7% of the watershed, where the calculated soil loss is between 7.5 and 12 t / ha / year. The risk of erosion is high to dangerous over 11.6% of the watershed, where the calculated soil loss is greater than 12 t /ha /year. From this study, it became clear that there is a need for rapid action using reliable and effective conservation techniques.