Potential soil loss evaluation using the RUSLE/RUSLE-runoff models in Wadi Saida watershed (N-W Algeria)

Soil degradation has become a major worldwide environmental problem, particularly in arid and semi-arid climate zones due to irregular rainfall and the intensity of storms that frequently generate heavy flooding. The main objective of this study is the use of geographic information system and remote sensing techniques to quantify and to map the soil losses in the Wadi Saida watershed (624 km(2)) through the revised universal soil loss equation model and a proposed model based on the surface erosive runoff. The results analysis revealed that the Wadi Saida watershed showed moderate to moderately high soil loss, between 0 and 1000 t/km(2)/year. In the northern part of the basin in the region of Sidi Boubkeur and the mountains of Daia; which are characterized by steep slopes, values can reach up to 3000 t/km(2)/year. The two models in comparison showed a good correlation with R = 0.95 and RMSE = 0.43; the use of the erosive surface runoff parameter is effective to estimate the rate of soil loss in the watersheds. The problem of soil erosion requires serious interventions, particularly in basins with disturbances and aggressive climatic parameters. Good agricultural practices and forest preservation areas play an important role in soil conservation.