Gully Erosion Zoning in the Middle Volga Region

The study presents a new scheme of zoning of modern gully erosion in a large region of the Russian Federation. Automated landscape zoning by means of artificial neural networks was carried out in order to determine the natural and anthropogenic conditions for the development of the gully network. Erosion zoning was implemented on the basis of large-scale geoinformation mapping of gullies with visual interpretation of high- and ultra-high-resolution satellite images for 2017-2021. The basins of small rivers (1314 in total) with an average area of 91 km(2) were taken as operational territorial units. 22 688 gullies (including their lateral branches) were identified in the study area; their average length was 65 m, and the total length of the gully network was about 1500 km. The mean density of the gully network constituted 12 m/km(2), and the maximum density reached 301 m/km(2). This indicator indirectly reflects the intensity of gully formation and was used for the zoning of gully erosion. Most of the studied river basins (84%) had either no gully dissection or very weak and weak gully erosion. The main reasons for the widespread damping of gully erosion are related to changes in land use and in the climate system, as well as to an evolutionary factor-the transition of many gully forms to the balka stage of development.