Prediction of water erosion sensitive areas in Mediterranean watershed, a case study of Wadi El Maleh in north-west of Algeria.

Water erosion phenomenon has significant effects on productivity and environment in Algeria. This contribution presents interesting study on soil erosion risk of Wadi El Maleh watershed using RUSLE model based on original data. The erosion process results from effects of several factors, including rainfall erosivity, soil erodibility, land slope length, land use, and conservation practices. Soil erosion map in the entire watershed area is obtained by the superposition of the generated maps of each previous factor. The obtained results showed that the mean soil loss rate is about 9 t/ha/year in the whole watershed area. These results are comparable to those reported in watersheds having the same hydrologic characteristic. Based on 2017 couples of (Q-C) recorded over 17 years (from 1981 to 1998), we have estimated the suspended sediment transport of Wadi El Maleh to be annually about 2.94 t/ha/year which represents just 32.6% of the eroded rate, i.e., two thirds of the eroded sediment are deposited, especially in the plains. This high values of deposited sediments is mainly due to relatively moderate slopes and dense vegetation.