Inverstigation of the process of land use change and its effects on soil erosion system in Khiavchay basin using remote sensing and geographicinformation system

Research Aim:One of the consequeces and environmental problem of changes in land use and land cover is soil erosion that threaten soil and water resources of watershed seriously. Therefore it is necessary that the spatial dimensions of land use and land cover are identified regularly so that the policy makers and researched able to take the necessary decisions.Satellite data is one of the fastest and most cost-effective methods for mapping land use that is available for researchers.This study was carried out for assess changes in land-cover and land-useand its effect on erosion from 1984 to2017 in the Khiavchay basin of Meshgin Shahr. Research Method: For this purpose, initially using Landsat satellite images of TM and OLI images, percent of vegetation cover map was provided and after atmospheric and radiometric correction, land-use maps was prepare using pixel-based(nearest neighbor algorithm) and object-oriented (maximum Likelihoodalgorithm)methods.Then the most important methods for evaluating the accuracy including precision and coefficient Kappa classification was extracted. The erosion zoning map was carried out using land use maps and the factors including slope, lithology, distance from the road, distance from the river, rainfall and soil using critical weighing method and WLC method. The average overall accuracy for the produced maps of pixel-based and object-oriented methods was estimated as 95.84 and 96.1% respectively and Kappa'scoefficients were 0.94 and 0.95, respectively indicating that the object-orientedmethod in comparison with pixel-based method has more advantage. Findings: The results showed that in the map of use between 1984 and 2017, the increase of rainforests with decreasing rangelands was associated and The largest change was in the use of pasture, which had a decrease of 3670 hectares. Alsoaccording to the erosion zoning map of 1984, 8/79 and 28/28 percent respectively, and with 2017 erosion zonation, 11.04 and 34.08 percent of the Khiavchay basin are located in two high risk and high risk categories. Conclusion:The reason for increasing the area of high-risk and high-risk erosion classes in the studied basin can be the conversion of lands with rangeland cover to dryland, the increase of residential areas along the river's margin and the non-observance of river boundaries that This process accelerates the erosion event.