Résumé:
The area of tertiary marls of watershed of Oued Mina is characterized by a semi-arid
climate with a temperature sometimes reaching the threshold of 41,2 °C between July and
January, rare and irregular torrential rains. During the last decades, the insecurity and the rural
exodus leaving the soils exposed to severe degradation of the soil. The sediments from this
erosion were transported and contributed to silt up the dam of Es-Saada.
The integration of thematic maps on various factors of the universal soil loss equation
(USLE) in the Geographic Information System (GIS) helped us to locate the source areas of
sediments.
Our study has permitted us the evaluation of the rate of erosion at 5.1 t/ha/yr and the
establishment of the distribution map for the vulnerability levels of the marls to sheet erosion.
Depending on the impact of each factor on soil losses, we have ranked by their importance
order, the slope (R²= 0,98), the vegetation cover (R²= 0,97), the soil erodibility (R²= 0,91) and
the cultural practices (R²= 0,89).
