Stages of Barrier Formation at Entrances to the Volgograd Reservoir Bays

The process of shore reshaping has involved derivative processes of alongshore transport and sediment accumulation. The alongshore sediment transfer has initiated the separation of the bays from the main water area of the Volgograd Reservoir by abrasion-accumulative barriers. Classification of the bays by the degree of formation of abrasion-accumulative barriers at entrances is the initial stage of comprehensive research and is necessary to reveal the main patterns of separation process. In addition to field methods, the use of Earth remote sensing data and geoinformation technologies is most effective in studying the process of formation of abrasion-accumulative barriers. The materials for this study included Google Earth satellite images and data of the field research of the bays in 2008, 2010–2016, and 2019–2020. Analytical (cartographic, graphical, and mathematical methods and methods of working with satellite images) and field (geometric leveling of abrasion-accumulative barriers and spits, bathymetric survey of bays, and receiving GPS coordinates) research methods were applied here. The morphometric characteristics of the entrances to the bays of the right and left coasts of the Volgograd Reservoir have been measured based on Google Earth satellite images. We have compared the expedition materials and data received from satellite images. The difference in the absolute values does not exceed double the mean square error. This indicates the reliability of the applied research method. We have calculated two coefficients for the classification of bays. These coefficients took into account the width of the bay at the entrance, width of the shore shallow water area at the entrance, and length of the above-water part of the barrier or spit. We have distinguished six bay classes with respect to the degree of formation of abrasion-accumulative barriers at the entrances: open bays (class 1), bays at the initial stage of separation (class 2), bays at the active stage of separation (class 3), bays at the final stage of separation (class 4), closed bays (class 5), and bays with anthropogenically transformed entrances (specific class 6). The process of bay separation is activated during the growth in the shore shallow area at its entrance. Rapid overgrowth with higher aquatic and herbaceous and tree–shrub vegetation is observed during the intensification of the process of formation of abrasion-accumulative barriers.