Proposal of erosion control scenarios for the reduction of soil losses in the Wadi Isser basin using the RUSLE model, northwest Algeria

Soil erosion is a devastating phenomenon; soil conservation is a very effective control strategy to remedy this problem. The main objective of this study is to propose scenarios of erosion control for the reduction of soil losses using the Revised Universal Soil Loss Equation (RUSLE) model of the Wadi Isser basin, in the area of the Sidi Abdelli dam (1102.2 km2, northwest Algeria). Thematic maps of the different factors of the model were obtained using geographic information systems and remote sensing techniques. The average annual soil loss rate is estimated at 3.3 t ha−1 year−1 with a maximum value of 195 t ha−1 year−1 located in the southern part of the basin. The automatic extraction of the study area into 29 sub-basins reveals three levels of priority for intervention, namely low priority located in the north, medium priority, and urgent priority located in the south of the basin. The proposed erosion control scenarios for the areas classified as medium and urgent priorities are contouring, strip cropping, and terraces. The variation of the values of the factor of the crop management factor “Pi” according to the proposed technique reveals that the scenario of terraces gives remarkable results for the reduction of soil losses, and contouring reveals that the area to be developed has decreased by 25% of the average of soil losses, which is 4.93 t ha−1 year−1. Strip cropping reduces the average soil loss by up to 150% (2.46 t ha−1 year−1). The terraces show an efficiency to reduce the average annual erosion because the erosion at the level of the area to be developed is 0.97 t ha−1 year−1 and the average erosion of the study area is 0.8 t ha−1 year−1. This study summarizes a Priority Action Plan (P.A.P.) of intervention for the public authorities in order to face the phenomenon of soil and basin degradation.