Investigating the Effect of Land Use Change on Soil Erosion and Sediment Yield in Razeychay Watershed During Past 20 Years

Soil erosion is a global problem that threatens water and soil resources and land use change is one of the important factors in soil erosion intensification. The aim of this study was to evaluate the effect of land use change on soil erosion in Razeychay watershed of Meshginshahr located in Ardabil province. First, Landsat images of the study area in May 1999, and 2019 and were obtained from USGS website. In the image processing stage, atmospheric and radiometric corrections have been conducted, and then the land use maps of the study area has been prepared for study years using support vector machine (SVM) as a supervised classification method. Then, the RUSLE model was used to estimate the amount of erosion in the two time span. SPSS, Excel, Arc GIS 5.4, Archydro and ENVI 5.3 software were used to spatial analysis and data processing.The results showed that, rangeland, irrigated farming and bare lands have decreased during the last twenty years. While, the extent of dry farming and residential area have increased. Meanwhile, the highest change is related to dry farming (an increase of 27.69 hectares). According to the results of erosion modeling, the rate of erosion from 1999 to 2019 has decreased from 6.49 to 6.46 tons per hectare per year.