The comparison between the Universal Soil Loss Equation (USLE) and the HEUSCH model for the assessment and mapping of water erosion of the Sidi Saad dam watershed in Tunisia

• Published in: Arabian journal of geosciences Vol. 15; no. 6
• Main Authors: Sonia, Gannouni, Hamdi, Kahri, Abir, Marzouki, Mohamed, Kefi
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2022; Springer Nature B.V
• Subjects: Aggressive behaviour; Agricultural practices; Basins; Climatic conditions; Dams; Deforestation; Earth and Environmental Science; Earth science; Earth Sciences; Erosion control; Erosion rates; Erosion resistance; Friability; Global Changes and Groundwater Responses; Mapping; Original Paper; Plant cover; Rain; Rainfall; Rainfall intensity; Rivers; Rural areas; Rural populations; Sediment; Sediments; Soil; Soil erosion; Vegetation; Vegetation cover; Water erosion; Water Quality; Watersheds; Tunisia; USLE; HEUSCH; Mapping; Watershed; Assessment; Erosion
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-022-09668-1

The climatic conditions and the lifestyles of rural populations make Tunisia a vulnerable area to erosion processes. Tunisia suffers from water erosion, which strips its soils and threatens its agricultural activities. The combined effect of anthropic actions (farming practices, deforestation, overgrazing) and natural factors (climatic aggressiveness, steep slopes, soil) weakens the soil and threatens agricultural plots by deposition sediments. Due to the natural and anthroponic conditions of the central-western region in Tunisia, the Sidi Saad dam watershed is seriously concerned by this problem. Therefore, this work aims at estimating and mapping the water erosion of the Sidi Saad watershed based on two approaches: Universal Soil Loss Equation (USLE) and the HEUSCH model. Topography, vegetation cover, rainfall intensity, aggressiveness index, and anti-erosion practices are the factors that have been quantified. The erosion maps obtained by the USLE model show that the lowest soil losses (less than 0.5 t/ha/year) are mostly located in areas next to the rivers (characterized by flat land with very low slope (0° to 5°)) and dense vegetation that maintains the soil and therefore a strong resistance to erosion. However, most watershed areas present significant erosion rates, higher than 2 t/ha/year. These areas are mainly with friable materials stripped of vegetation with rough ground. They are located in the northern, eastern, and southeastern parts of the watershed. However, the HEUSCH model expresses the potential of sediment generation by the sub-basins. The total volume of sediments delivered by the 91 sub-basins is 3845147.87 t/year, and the average is 4.49 t/ha/year. The maximum volume is 8.84 t/ha/year, and the minimum is 1.38 t/ha/year. The spatial identification of sediment rate by sub-basin will be helpful to implement sustainable strategies for erosion control.