Estimation of Water Erosion Volume in the Abbasan Watershed Using (EPM) Model

Abstract

The aim of this study is to model and analyze water erosion in the Abbasan Basin using the Erosion Potential Method (EPM), which is considered as one of the modern models for quantitatively estimating water erosion in any given area. This model relies on several variables in its calculations, particularly: soil erodibility, land cover, erosion development, drainage network, slope, temperature, and total annual precipitation. Based on these variables, the study estimated the volume of water erosion and assessed its severity, with the goal of utilizing the results to understand its impact on various human activities within the basin, especially agricultural practices. The study showed that the potential erosion factor (Z) develops across all slope categories. The evaluation results identified five erosion severity classes, ranging from very slight to very severe. Very slight erosion occupied the largest area, representing 29.17% of the total basin area, while very severe erosion accounted for the smallest area at 12.83%. According to the EPM model results for estimating the volume of water erosion (W), five levels of erosion were identified, with no occurrence of catastrophic erosion as per the Gavrilovic classification. The average annual soil loss in the Abbasan Basin was estimated at 3866.08 m³/km²/year. Generalized erosion occupied the largest proportion (58.54%), while areas with no erosion represented the smallest proportion (0.32%) of the total basin area.