Document Type : Research Paper
Authors
1
Professor, Department of Physical Geography, Faculty of Social Sciences, University of Mohaghegh Ardabili, Ardabil, Iran
2
Ph.D Student, Department of Physical Geography, Faculty of Social Sciences, University of Mohaghegh Ardabili, Ardabil, Iran, Iran
10.22034/gp.2026.69434.3459
Abstract
The aim of this study is to estimate the amount of soil erosion and analyze its changes over a twenty-year period (2004–2024) in the Quri-Chay watershed in Ardabil Province using the Revised Universal Soil Loss Equation (RUSLE).
Methods: n this regard, the five main factors of the model, including rainfall erosivity, soil erodibility, slope length and steepness, vegetation cover, and management practices, were calculated and integrated within the ArcGIS environment. The data used included Sentinel-2 satellite images for 2024, Landsat 5 TM images for 2004, a 12.5 m digital elevation model (ALOS PALSAR), twenty years of rainfall statistics, and the soil texture map of Iran. To examine land use changes, supervised classification with the Random Forest algorithm was performed in the Google Earth Engine environment, and classification accuracy was evaluated using the Kappa coefficient.
Results: The results indicated that during the 2004–2024 period, significant changes occurred in the land use of the watershed. Rain-fed croplands, irrigated lands, and residential areas increased considerably, while rangelands, forests, and water bodies experienced a decline in area. These changes reflect human pressure and unsustainable exploitation of natural resources. The implementation of the RUSLE model showed that the average annual soil erosion increased from 26.65 tons per hectare in 2004 to 37.18 tons per hectare in 2024. In addition to the increase in the maximum amount of erosion, the erosion risk classes also changed. The areas with low and moderate risk expanded, while zones with high and very high risk, though relatively small, spread sporadically in steep and mountainous regions.
Conclusions: These findings reveal that the conversion of natural lands into human land uses, the reduction in vegetation density, and the intensification of rainfall patterns have been the most influential factors in increasing soil erosion in the watershed. T
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