Modélisation de l’érosion hydrique via les SIG et l’équation universelle des pertes en sol au niveau du bassin versant de l’Oum Er-Rbia (original) (raw)

The objective of the present work was to estimate soil losses in the oued Oum Er-Rbia watershed (SW Middle Atlas, Morocco). The adopted method is based on the use of Wischmeier model and geographic information system (GIS). The mean and maximum values of rainfall erosivity factor R were 90 and 119, respectively. The soil erodibility factor K is ranged from 0.01 to 0.54 (mean= 0.33). The topographical factor LS varied from 0 to 216 (mean= 16). Thecombination of different maps related to different parameters (R, K, LS, vegetation cover C and anti-erosive practices P) allowed obtaining the erosion map. The obtained results showed that the erosion affected the entire Oum Rbia watershed, but with different degrees. The mean of rate of soil loss was of 224 t / ha / year, with 45% of the basin area is subject to erosion between 50 and 400 t/ha/year mainly in areas characterized by a steep slope, high erodibility and low vegetation cover which reflects the importance of water erosion in the Oum Er-Rbia watershed. Keywords - Oum Er-Rbia watershed, water erosion, Wischmeier model, GIS.