Soil Erosion Hazard Assessment and Its Relationship with Environmental Factors (A Case Study of the Virmooni Watershed, Guilan Province)

Soil erosion is one of the most common types of soil degradation that has destructive effects on the environment and human life. The severity of soil erosion is usually estimated using various models. Therefore, the aim of this research is to analyze the intensity of soil erosion hazard and its relationship with environmental factors in the Virmooni watershed in Guilan province,To achieve the research goal, the Revised Universal Soil Loss Equation (RUSLE) model was used, which includes the factors of rainfall erosivity, soil erodibility, topography, vegetation cover, and soil conservation practices. For this purpose, data from rain gauges of the Iran Meteorological Organization, 1:250000 soil texture map of Iran, 30-meter ASTER Digital Elevation Model (DEM), and Landsat 8 OLI satellite image were prepared in the GIS environment. After overlaying the layers, the annual soil erosion amount in the watershed was estimated.In the next step, environmental factors that are effective in soil erosion occurrence were created in the GIS environment, including topographic wetness index, stream power index, slope curvature, profile curvature, surface curvature, and normalized difference vegetation index (NDVI). Finally, zoning maps were prepared. The results of this study showed that the soil erosion rate for the entire watershed was estimated to be between 0 and 1/80 tons per hectare per year. Among the effective factors of the studied model, the topography factor had the highest correlation (0/91) with soil erosion compared to other factors.In another study, the relationship between environmental factors and annual soil loss was investigated. The results showed that the NDVI had the highest correlation (R2=0.62) with soil erosion compared to other factors. The stream power index had the lowest correlation (R2=0.11). This research confirms the possibility of integrating environmental factors affecting soil erosion.