Modeling the Erosion Potential and Sedimentation rate of the Gorganroud Watershed

The Erosion Potential Model (EPM) is a widely used tool for estimating soil erosion and sediment yield in watersheds.It integrates multiple factors such as geological, topographic, climatic, and land use characteristics to predict erosion intensity and sediment transport.The model considers not only sheet and rill erosion but also gully erosion, wind, and tillage impacts.EPM's advantages include simplicity, low data requirements, and compatibility with Geographic Information Systems (GIS) for visualizing erosion-prone areas.Soil erosion in Iran, particularly in the Golestan River Basin, has been a growing concern due to population growth, land use changes, and poor water and soil management.The Golestan Basin has experienced severe erosion in several sub-basins, leading to increased sedimentation and damage to fertile soil.Previous studies have applied EPM in this region, estimating soil loss and sediment yield.This study aims to evaluate the application of EPM alongside three sediment delivery ratio (SDR) equations in the Golestan River Basin to provide more accurate erosion assessments. 2-MethodologyThe study employed a comprehensive set of spatial and hydrometric data for modeling erosion and sedimentation in the Golestan River Basin.Data sources included meteorological, topographic, land use, geological, soil, geomorphological, and hydrometric information.Meteorological data, covering the period from 1981 to 2024, were sourced from the CHIRPS dataset.Topographic data, derived from a 30-meter spatial resolution Digital Elevation Model (DEM), were used to assess the impact of slope and elevation on erosion.Land use maps, based on Sentinel-2 satellite images, tracked changes in vegetation and urban development from 2000 to 2022.Geological maps, soil maps, and geomorphological data were used to assess factors like soil permeability, texture, and basin morphology.Hydrometric data from 11 stations provided sediment concentration data to validate the model's predictions.The study also applied regression analysis to identify the relationship between variables (e.g., area, perimeter, slope, precipitation) and sediment production.All data were processed in GIS software, including ArcGIS, Global Mapper, and SAGA GIS, allowing for spatial analysis and the generation of erosion potential maps. 3-ResultsThe study revealed significant variations in sediment yield across the sub-basins of the Gorganroud watershed, depending on the selected erosion model.For example, the Gavrilovich model predicted higher sediment yields (e.g., 2.465 in the Onq Lghi sub-basin) compared to the Bois and Williams-Brent models,