بررسی کارآیی مدل EPM و EPM اصلاح شده جهت برآورد فرسایش آبی در مناطق خشک

Soil erosion by water is considered one of the major land degradation factors worldwide. One of the challenges in controlling erosion in watershed areas is the lack of statistical data for accurate estimation of erosion and sedimentation rates. Therefore, the use of effective empirical methods is crucial. Modeling water erosion can reduce the complexity of this issue. Nowadays, soil erosion models are increasingly utilized and can serve as practical tools for policymaking. In this study, erosion and sedimentation were compared using two quantitative models, EPM and modified EPM, in the upper Dez watershed area with observed sediment statistics. The EPM method, considering four factors: current erosion status, soil and rock sensitivity to erosion, land use coefficient, and slope, quantifies erosion for each area. Additionally, a modified EPM (mEPM) was used, excluding the air temperature coefficient, suitable for mountainous regions. Specific erosion rates were estimated using the sediment delivery ratio (SDR) coefficient. Observed sediment values were collected from a sediment monitoring station. The estimated specific sediment for EPM and modified EPM models and observed values were calculated as 3.57, 2.71, and 3.73 tons per hectare per year, respectively. Although the EPM model has been adjusted in recent years, it still demonstrates higher accuracy in execution, particularly in dry regions, and can be used as an empirical model.