Volume XIX |

Assessment of Soil Erosion by RUSLE Model using Remote Sensing and GIS – A case study of Ziz Upper Basin Southeast Morocco

Abstract: cause many environmental and socio-economic problems on -and off-site: loss of biodiversity, reduced productivity of agricultural land, siltation of dams, increased risk of flooding. The quantification of soil erosion is essential in the management and conservation of the soil and water resources. Modeling soil erosion can provide a lot of information to estimate soil loss and sediment yields at large-scale. In this study, the Revised Universal Soil Loss Equation (RUSLE) integrated into a GIS was used to quantify soil losses in the large upper watershed of Ziz (4435 km2) in southeastern of Morocco. The RUSLE parameters were estimated based on data from satellite imagery, DEM-SRTM and national watershed management plan studies. The results show that annual average of the potential soil erosion is 489.5 t. ha-1. yr-1 and the specific sediment yield is 36.4 t. ha-1. yr-1. The main sources of sediment are in the watershed upstream parts and some deposition zones are located before the catchment outlet. These soil losses contribute to the annual siltation of the Hassan Eddakhil dam by a rate of 3.5%. The application of principal components analysis to soil erosion factors shows an important influence of the soil erodibility factor (K) followed by the topographic factor (LS) then crop management factor (C). These modeling results will provide data within the Moroccan southeastern High Atlas that can constitute a road map for future soil erosion projects and it can be a useful tool for proposing soil conservation strategies.