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Abstract

Land use and land cover (LULC) play an important role in the hydrological and ecological balance of a watershed. The conversion of conservative land classes like forests into pastures or farmlands can alter the hydrologic cycle, changing the balance between rainfall, evaporation, infiltration, and runoff. In the Hodna basin in Algeria, the impact of LULCC on surface runoff was evaluated between 2000 and 2020 using Landsat images data, the soil conservation services method, and the curve number model. A maximum likelihood supervised classification was applied to the Landsat data to classify the LULC. The confusion matrix of image classification indicates an overall accuracy of 85% and a kappa coefficients range between 0.82 and 0.96. Lithological discrimination on Landsat images of the study area was applied, and infiltrability class was assigned for each soil type. The resulting hydrological soil groups (HSG) were related to the Soil Conservation Service methodology to quantify infiltration. Agricultural lands in the Hodna watershed decreased by 2.16%, while sandy soils increased by 9.45% between 2000 and 2020, indicating an expansion of desertification. LULCC was found to contribute to 60% of the generated runoff, with the remaining portion attributable to precipitation. These results can provide diagnostic tools for decision support to address floods and soil erosion. By improving the monitoring of LULCC, this study will contribute to the development of effective strategies for sustainable water resource management in the Hodna Basin