The Role of Geological Formations and Topography in Development of Forms of Water Erosion in Golidagh Watershed, Golestan Province

Different forms of water erosion can be observed in many parts of Iran, and the specific role of each factor in sediment delivery can be presented. This research was conducted to investigate the effect of geological formations and topographic features on creating important forms of water erosion in the Golidagh watershed in the Golestan Province.

At first, we used the Google Earth images, aerial photos, maps, and field surveys of the area, so that the forms of erosion and their quality were determined. Lithology, elevation, slope, and aspect were selected as independent variables, and each form of water erosion, including sheet erosion, rills, gullies, and badlands, were determined as dependent variables. After, independent variables information layers were overlay with a layer of erosion forms in the ArcGIS and the relationship between them was obtained through Chi-square (ϰ2 ) distribution using SPSS software.

Overlay analysis of the maps showed that the advanced forms of water erosion, including gully erosion and badlands, are dominant as the loess formations in altitudes less than 800 meters, and were more than expected. Also, an area of all forms of erosion is low at the slope of 0-10 percent and their area increases at the slope of 10 percent and higher. investigation of forms of water erosion in relation with the aspect showed that advanced erosion of the gully and badland had more in southwest area and were more than expected, while the surface lacks erosion predominates in the north, northwest and northeast areas. The relationship between variables with different forms of erosion in the area was determined through the chi-square test. The results showed that the relationship between the studied variables and forms of water erosion in the area is significant at 1%. The intensity of the relationship based on the contingency coefficient indicates the more importance of elevation (0.631) and geological formations (0.461) in the region.

The created forms of erosion are dependent on elevation and lithology in the area, and these variables can be used in selecting appropriate methods and executive strategies for managing forms of erosion and controlling their intensity.