RUSLE-based model for soil loss modeling and water erosion susceptibility mapping in the Issen basin (west-central of Morocco)

The Issen basin is the largest sub-catchment area in the southern edge of the Western High-Atlas (WHA) Mountain of Morocco. This basin is characterized by flood flows, orographic and climatic contrast and friable substrate sparsely wooded and covered by heterogeneous vegetation making it vulnerable to soil water erosion. This study aims to evaluate soil loss and to determine the areas susceptible to water erosion in this basin based on the Revised Universal Soil Loss Equation (RUSLE). The RUSLE model was achieved by integrating ancillary and remote sensing data in a Geographic Information System (GIS). The analysis of the obtained map indicates that the erosion rate in the studied basin ranges from 0 to 401 t/ha/yr, with an average of 53 tons/ha/year and a total sheet erosion of 6,886825.87 (tons/year). These results are concordant with the results obtained from other parts of High-Atlas Mountain. Spatially, the erosion differs from a zone to another, where 61.2% of the total study area is lowly to moderately susceptible to erosion (subcritical zones), while the rest (38.8%) is highly to very highly susceptible to erosion (critical zones). The current study indicates that the soil loss in the study area has reached an alarming level and demands fast intervention. Consequently, the identification of critical zones in this work can be useful to prioritize these zones in future environmental planning for treatment against soil loss.