3. Materials and methods.
Various sources of information and observation methods were combined to estimate the intensity of abrasion and landslide processes at the reservoir shores. Shoreline positioning for the past periods (1958, 1985, 1987 and 1993) was obtained from archived aerial images (Kazan University Library); data for 1975, 2010, were obtained from satellite imagery (Table 4) interpretation. Field measurements at the study sites were conducted in 2002, 2003, 2005, 2006 using Trimble M3 total station (2014). Since traditional methods mainly provide information about the planar displacement of the landslide scarp edge, the laser scanning method was additionally used in 2012-2014 to study the volume changes in hard-to-reach and hazardous areas. A Trimble GX TLS used as scanning equipment (Figure 5, Table 1). From 2019 onwards field surveys include a DJI Phantom 4 UAV survey.
Since the slope processes at the studied sites develop differently – a block landslide at Site 1 and a landslide cirque at Site 2, the methodological approaches for their study were also different.