Soil erosion is one of the fundamental challenges in sustainable natural resource management, with multiple adverse impacts including the decline of soil fertility, ecosystem degradation, and reduced lifespan of hydraulic structures such as dams.، This study aims to assess land use/land cover (LULC) changes and their effects on soil erosion in the Sahand Dam watershed (Hashtroud) after dam construction, employing the empirical EPM model. The required datasets including elevation classes, slope, land use/land cover, lithology, precipitation, NDVI index, and soil texture—were compiled from various sources and processed using ArcGIS and ENVI software. The results indicate a high potential for soil erosion in the basin due to its physiographic characteristics, such as a large catchment area (874 km²), considerable elevation difference (1,989 m), and steep slopes. LULC change analysis during the period 1996–2024 revealed a reduction in the extent of poor and moderate rangelands, alongside an expansion of rainfed and irrigated agricultural lands, mainly driven by anthropogenic pressures, climate change, and management practices. The EPM model outputs demonstrated an increasing trend in soil erosion intensity (from 581.86 to 1221.43 m³ yr⁻¹ km⁻²) and specific sediment yield (from 221.37 to 426.66 m³ yr⁻¹), consistent with rising precipitation and erosion intensity coefficients. The findings further showed that steep slopes and unstable land uses, particularly degraded rangelands, are the principal factors exacerbating erosion processes. Overall, this study underscores the urgent need for integrated natural resource management strategies, with a particular emphasis on soil conservation and optimized land use planning, in order to mitigate erosion risks and sustain ecosystem stability.