METHOD FOR CREATING A DIGITAL RELIEF MODEL FOR THE SMALL RIVER WATERSHED AREA

Purpose: to develop and test a method for constructing a digital relief model for the small river watershed using AutoCAD Civil 3D software, as well as to conduct a spatial analysis of the hydrological characteristics. Materials and methods. The object of the study was the basin of the small Loknash River (Moscow Region) with a length of 14 km. The initial data were topographic maps. To create a digital relief model, the AutoCAD Civil 3D automated design and drawing system was used. Results. In the course of research, a methodology for creating a digital relief model, including: 1) converting contours into vector form and establishing an elevation point for them; 2) creating a digital relief model using the surface generation module; 3) determining the watershed area; 4) creating thematic maps of elevation and slopes differences of the watershed territory, watershed areas, runoff directions, etc., was developed. As a result of the research, the boundaries of the watershed area for the small Loknash River basin, based on the obtained digital relief model, were determined – 2477 hectares, the types of watersheds were classified and a slope map, a map of watercourse directions and a longitudinal profile of the river were constructed. Four zones were determined by the slope of the river bed, for which the flow velocities were calculated using the Chezy formula: from 0.25 to 0.80 m/s with an average value of 0.40 m/s. Areas with increased slopes, most susceptible to erosion and diffuse washout, were identified. Conclusions. The developed approach made it possible to obtain more accurate spatial data compared to space imagery data used to determine watershed areas in GIS. The proposed method for creating a digital relief model in AutoCAD can be effectively applied for analysis of small river basins, which provides justification for reclamation measures, assessment of hydrological risks and planning for sustainable environmental engineering.