Morphometric characteristics of the relief and assessment of erosional hazards of the Kalaus River basin, Russia, based on digital modelling

Abstract

In this work, the main goal was to analyse the erosional hazards within the boundaries of the Kalaus River catchment area.The paper analyses the erosive state of the region's lands, for which industry and cadastral maps, a digital elevation model and satellite images were used. Official data of ministries and departments were used. Geographic information systems – QGIS and SAGA GIS – served as the basis for modelling. The article presents the results of GIS modeling of erosional hazards in the territory of the Kalaus River basin. Based on the (DEM) SRTM digital elevation model, the basic morphometric indicators of the relief were calculated: steepness of the slopes and vertical and horizontal dissection of the relief. Based on morphometric indicators, an integral calculation of the energy of relief and erosion hazard was carried out and a series of relevant thematic maps was created. The values of slope steepness obtained within the boundaries of the basin range from 0° to 51° with average values of 2.5°. The horizontal dissection varies in the range from 0 to 0.84 km/km2, and the erosion bases are characterized by a range of values from – 15.0 to 248.6 m, with an average value of 33.0 m. The formation of the erosional potential of the basin’s relief is facilitated by the location of a significant part of the region on the spurs of the Stavropol Upland, which have widely developed slopes. Based on the calculated raster of the integral energy index of the relief, 3 categories of erosional hazard are identified. Most of the basin of the Kalaus River (58.4 %) is characterised by a low erosion hazard, another 39.0 % of the territory presents an average erosion hazard, and the remaining 2.9 % belongs to territories with a strong erosion hazard. The classification of relief surface shapes based on the Iwahashi and Pike method, which was carried out on the basis of a DEM, shows a much greater prevalence of steep slopes with high convexity in the southern part of the Kalaus River basin.The identified features of the level of erosional hazard of the lands of the Kalaus River basin are recommended to be taken into account in preinvestment, pre‐design and urban project planning of the territories of administrative units located within the boundaries of the basin. Despite the fact that the results of GIS analysis cannot completely replace field erosion surveys, their value as a tool for planning rational land use is obvious. The results of the work can be used to carry out a similar assessment in other regions, primarily in the organisation of agricultural production.