Evaluating the Impact of Land Use Changes on Erosion and Sedimentation using the EPM model (Case Study: Kal-Aji Basin, Golestan Province)

The present study was conducted to investigate the trend of land use changes and its impact on erosion and sediment, using Landsat satellite images of 1987, 2010 and 2019 and EPM model in the Kal-Aji watershed of Golestan province. Land use map was prepared using the maximum likelihood method. Training data were used to evaluate the accuracy of the results. Then, the most important methods of accuracy assessment, including total accuracy and classification kappa coefficient, were extracted. Those for 1987, 2010 and 2019, the total accuracy were 95, 98 and 95 and kappa coefficient were 0.93, 0.96 and 0.93, respectively. Erosion and sedimentation zoning maps were performed using the resulted land use maps, and such factors as slope, lithology, soil and precipitation were performed using the EPM method. The results showed that one of the most important factors in the Kal-Aji watershed is the loss of rangeland vegetation and its conversion into agricultural land. According to the hypothesis, the role of land use changes in the amount and increase of erosion and sediment was significantly determined. That is, with the change of land use, erosion and sediment have also increased. The reasons for the increase in the amount of sediment in the Kal-Aji area are the development of agricultural land uses and the decrease in rangeland between 1987 and 2019 (16.83%). These changes have reduced the important role of rangelands and vegetation of Kal-Aji watershed and have increased the amount of sediment in the outflow of sub-watersheds. Based on the obtained results, the total amount of special sediment was related to the period of 1987 (4353 cubic meters), which increased to 5164 cubic meters in 2019, which indicates the changes in land use that occurred in the watershed.