Quantifying of water erosion and sediment yield by SEAGIS model in Rmel watershed (north-eastern Tunisia)

Water erosion in Tunisia is influenced by climatic irregularity and torrential flows, caused the loss and fragility of soil and the reduction of dam life. To fight against this scourge, Tunisia has adopted national strategies for water and soil conservation, in particular anti-erosive measures such as banks and mountain lakes. The objective of this study was the modeling of water erosion by the SEAGIS model (Soil Erosion Assessment using GIS) in Rmel watershed which covers an area of 680 km 2 subdivided into six sub-watersheds (RM1–RM6), according to the hydrographic network, which allows to spatialize the risks of soil erosion and to quantify the annual sediment yield in the Rmel dam. The result attain demonstrate that the average annual soil erosion was 26.74 t ha −1 yr −1 estimated by incorporating the revised universal soil loss equation (RUSLE) into the SEAGIS model. The means annual sediment yield by SEAGIS is 14.92 t ha −1 yr −1 . The results in dry year, for soil erosion and solid charge are, respectively, 11.76 t ha −1 yr −1 and 6.41 t ha −1 yr −1 and during wet year, 79.15 t ha −1 yr −1 and 43.43 t ha −1 yr −1 show that the factor has a great effect on soil erosion is atmospheric precipitation. Thus these results are able to simulate the quantity of the solid charge transferred to a dam and constitute a database to fight against soil erosion and ensure sustainable agriculture in north-eastern Tunisia.