Identification of expansion Rate in Active Gullies using Remote Sensing

The gully erosion is one of several water erosions which their expansion causes significant changes in terms of land, land degradation, and destruction of the environment. To study the diversity and expansion of gullies and the development of gully erosion from one place to another, remote sensing and geographical information systems were used. To achieve the current research objectives, the spatial and temporal extent of gully erosion and expansion of the eroded areas were investigated using the Landsat 7 and 8 satellite images with a resolution of 30 m in the period of 2001 (1380) and 2014 (1393). The spatial resolution has been enhanced from 30 m to 15 m using the band PAN (15 meters) and technique Resolution merge. This method was applied to all bands and pictures for two different time periods. The results from combining two layers of waterways, in the period of 13 years, applied on the Shordareh basin located in Golestan province, showed an increase in the length of the gully and the drainage density of sub-basins. The erosion rate in the assumed period is estimated at 0.99 meters per year. The gully expansion is directly related to the geological formations, land use, and other human activities such as unprincipled construction of rural and inland roads.