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The Oued Lebene watershed is a sub-basin of the Sebou River located in the central part of the Rif region. The objective of this study is the modeling and mapping of areas sensitive to water erosion, using the guidelines of the classical PAP/CAR methodology in comparison with a modified approach based on the introduction of the slope length factor instead of slope, and soil type instead of lithology. This is combined with Geographic Information Systems (GIS) and validation through field observations. The predictive phase, illustrated by the thematic map of erosive states using the classical modeling approach, shows that the average to high erosion degree covers 71.57% of the study area. Modeling with the introduction of the LS factor and soil type highlights a sensitivity to erosion ranging from moderate to high, at an order of 45.26%. Mapping current erosion as a descriptive approach, based on the processing of current satellite images from Google Earth and field observations, allows for the spatialization of different types of water erosion and the creation of a real map of the distribution of erosion forms. Analysis of the latter reveals that linear erosion and surface gullies cover 88.42% of the total basin area. The consolidated PAP/CAR map resulting from the overlay of the previous maps reveals that the localized trend of expansion or intensification is represented by 66.15% in the classical version, decreasing to 33.58% after the modification of input parameters. The approach used has revealed that slope length and soil type significantly influence the spatial distribution of various forms of erosion. This study also highlights the importance of incorporating other factors affecting the erosion process and identifies high-risk areas that require prompt and sustainable intervention in the Oued Leben watershed. [ABSTRACT FROM AUTHOR]

The alarming degradation of soils, particularly in the Moroccan Rif region, is the result of various forms of water erosion processes, leading to significant environmental and economic damage in the area. The Oued Lebene watershed is a sub-basin of the Sebou River, located in the central part of the Pre-Rif. Using GIS, remote sensing, and the universal soil loss Equation modified for North African conditions and validated by field observations, this study aimed to measure soil losses, sediment delivery capacity, and sediment yield rates. The estimation of soil loss reveals that the watershed is exposed to a high degree of erosion, reflected by an estimated total annual loss of 6 379 314 t/yr, with an average annual rate of 46.17 t/ha/yr. The severe erosion class covers 52.25% of the study area, contributing to 90.67% of sediment production with an average of 80.11 t/ha/yr-1. The erosion class below the tolerance threshold according to Wischmeier represents 48 108 hectares, or 34.82% of the total watershed area. Analysis of the synthetic sediment delivery ratio (SDR) map shows that the sediment delivery capacity is approximately 0.17, and the sediment yield (SY) in the Oued Lebene watershed is estimated at 770 440.32 t/yr. This is the outcome of the interaction between multiple causative factors, including steep slopes, friable substrates, severely degraded vegetation cover, etc., which increasingly accelerate the degradation of water resources in the downstream Oued Sebou, a source of irrigation for agricultural lands. [ABSTRACT FROM AUTHOR]