Modeling of a steep wall of an active cliff using LiDAR survey data (using the example of the Krasnodar Reservoir)

Abstract

Relevance. The banks of the Krasnodar Reservoir in some areas continue to actively form with the destruction of the ledge of the II floodplain terrace of the Kuban River valley. In the coastal zone of the reservoir on this terrace there are numerous development objects belonging to various functional zones (residential, recreational, etc.) of the municipal formation of the city of Krasnodar. Aim. The aim of the research is the development of a methodology for creating and analyzing a digital relief model of an active cliff, focused on a steep cliff with negative slopes, with an assessment of the shape and size of wave-cut notches. Methods. As a result of the LiDAR survey, a point cloud was obtained within a test section of the active cliff with a length of 458 m and a classification of the point cloud was performed, highlighting the “ground” class. In order to exclude negative slopes from the model, a transformation of the point cloud coordinate system was performed, expressed in replacing the coordinates along the X axis by a distance along the edge of the cliff and rotating the array of points around the new abscissa axis by minus 90°. After transforming the coordinate system, a digital model of the steep wall was built with the identification of wave-cut notches based on the TPI index. Results. A technique has been developed for modeling landforms with a negative slope. The shape, dimensions and spatial position of the wave-cut notches have been determined. In total, 14 separate notches were identified within the site with a total length of 394,72 m. The average depth of the niches is 0,51 m, the maximum is 1,79 m; the average length is 28,82 m, the maximum is 84,16 m. The average slope of the slope surface along the site is 57,97°; the average positive slope is 52,12°, the average negative slope is 72,58°. Significant variability in the altitudinal position of wave-cut notches on the slope was discovered (from 33,89 to 37,82 m (Baltic Vertical Datum)). The total volume of soil mass contained above the wave-cut notch between the surface of the slope and the horizontal plane tangent to the deepest point of the notch within the study site is 743,88 m3