Quantifying Erosion Risk for Little Washita River Watershed Using GIS Technique Integrated with USLE Model

Universal Soil Loss Equation (USLE) erosion model has been utilized in order to quantify soil erosion risk in Little Washita River Watershed, Oklahoma. The objectives of this study were to 1) quantify the average annual soil loss in Little Washita River Watershed using Geographic Information System (GIS) technique integrated with USLE model, and 2) compare the erosion risk in 2006 with those in 1992 for Little Washita River Watershed. Huge amount of information and data, usually pending from different sources and available in different formats and scales were utilized to determine erosion risk. Topography, vegetation type, soil properties and land use/cover influenced the soil erosion in this watershed. Average annual soil losses were performed by multiplying six factors of USLE model: slope steepness factor, slope length factor, rainfall runoff erosive factor, the soil erosive factor, cover management factor, and support practice factor. The highest soil erosion risk values were 35.4 and 17.7 tons/ha/yr with mean value equal to 0.03 and 0.017 tons/ha/yr for 2006 and 1992, respectively. The percentage change between soil erosion risk in 2006 and 1992 give us the idea about the variation in the soil loss during this duration.