The Use of Unmanned Aerial Vehicles to Assess the Intensity of Manifestation of Dangerous Coastal Processes in the Water Protection Zone of the Tsimlyansk Reservoir

The water protection zone of the Tsimlyansk reservoir was chosen as the object of research. The subject of the study was the assessment of the intensity of manifestation of dangerous coastal processes of the reservoir: abrasion-latency, erosion activity. A method for monitoring erosion processes in water protection zones of water bodies using a software and hardware complex based on unmanned aerial vehicles and GIS technologies has been developed and tested. The optimal type of digital elevation models has been determined for assessing the density of the erosion net-work, determining the types of banks and the intensity of manifestation of abrasion and landslide processes, measuring the morphometric characteristics of erosional landforms. The types of erosional landforms were determined and the zoning of the territory of the water protection zone of the Tsimlyansk reservoir was carried out according to the density of the erosional dissection of the relief. Studies have shown that the predominant erosional forms of the relief of the water protection zone of the Tsimlyansk reservoir are ravines and gullies. The maximum average value of the density of the erosional network of the relief within the boundaries of the administrative districts of the reservoir coast falls on the Surovikinsky district. In the Kalachevsky district, the maximum value of the density of the erosion network is noted within the water protection zone of the Tsimlyansk reservoir.

Evaluation of Horizontal and Vertical Erosion of the Water Protection Zone of the Tsimlyansk Reservoir (a Case of Dubovsky District)

The nature and intensity of erosion processes are an important parameter for monitoring water protection area of water body. A technique, based on field and office studies, which were carried out with the use of unmanned aerial vehicles (UAVs) (Phantom 4 Pro and Phantom 4 Advanced), was worked out and the intensity of the manifestation of erosion processes in the water protection area of the Tsimlyansk reservoir was assessed (on the example of Dubovsky district). In our research, the comparative-geographic method was used. That allowed us very accurately to identify erosional objects on the ground, and to determine their morphological and morphometric characteristics. Cameral works processed the data obtained by using UAVs. The tools of the Agisoft Metashape Professional program and the tools of the ArcGIS program were used during the work. These programs make it possible, without labor-intensive instrumental field research, to draw up orthophotoplans for gullies and determine their areas, steepness of slopes, length and width of slopes, depth of gullies, make longitudinal and transverse profiles of gullies, measure the volume of gullies and a number of other parameters. This method gives us a complete picture of the gullying network within the water protection area. In addition, a comparison of survey materials for different periods makes it possible to identify trends in the development of individual erosional forms, as well as the entire gullying network within the water protection area as a whole.

Distribution of Eurytemora caspica Sukhikh & Alekseev, 2013 (Copepoda, Calanoida) in the water reservoirs of the Volga and Don river basins

The zooplankton composition of the Volga, Kama and Don rivers was studied in the summers of 2015-2018. The copepod Eurytemora caspica Sukhikh & Alekseev, 2013, recently isolated from the group of species contained in Eurytemora affinis, represents a widespread (50-100% of samples) and relatively abundant (maximum abundance up to 18 × 103 ind./m3) species. It is found in the Lower and Middle Volga from the city of Astrakhan to the mouth of the Kama River, in the Kama River to the upper reaches of the Kama reservoir, in the lower and middle sections of the Don River within the Tsimlyansk reservoir, as well as in the reservoirs of the Volga-Don shipping canal. In the Kama River, E. caspica was discovered by the author for the first time in 2016. In other habitats, it was previously identified as Eurytemora affinis (Poppe, 1880), although this particular species was not found in any of the analysed samples. The distribution features and habitat conditions of Eurytemora caspica in the rivers of the basins of the Caspian and Azov seas are discussed.

NUMERICAL STUDY OF CURRENTS IN TSIMLYANSK RESERVOIR AT DIFFERENT LEVELS OF RESERVOIR FILLING

A description of the mathematical model of the hydrodynamics of the Tsimlyansk reservoir is given. In shallow water regions, the flows are described by the equations of shallow water, and in deep-water regions by both the equations of shallow water and the three-dimensional equations of motion of an incompressible viscous fluid. The problem is solved by finite difference methods on a uniform difference grid. The calculations were carried out at different levels of reservoir filling. A comparison of the results obtained with the surface currents scheme constructed based on the results of field work performed in the spring of 2019 is carried out. The pictures of currents were obtained at different water edges. For the period of expeditionary field work in May 2019, hydrodynamics was calculated on the near-dam site using wind data obtained for this period and compared with the results of field measurements of currents. Comparison of the obtained results of numerical modeling with the scheme of surface currents measured from the research vessel reveals a high proportion of convergence of the calculated and field data. The obtained estimates of the modeling results allow us to proceed to the problem of predicting unfavorable hydrometeorological conditions in the Tsimlyansk reservoir, which carry the risk of disrupting the operation of the water intakes of Volgodonsk located in the southern part of the near-dam site