ACTUAL STATE OF THE LOWER DON SPAWNING GROUNDS ACCORDING TO REMOTE SENSING DATA

Abstract

The construction of the Tsimlyansk reservoir in 1952 and the actual climate changes led to significant reduction of spring water flow and the area of the Lower Don River spawning grounds. About 300 thousand hectares of spawning lands were flooded in 1963, while not more than 130 thousand hectares in 1979-1994. In later years water often didn't rise to the floodplain at all. As a result, the fishing industry of the Lower Don River underwent degradation and the spawning grounds were ploughed or built over. The spawning grounds of the Lower Don were the basis for the reproduction of anadromous and semi-anadromous fish of the Azov - Don basin, which has already lost its commercial value for sturgeon and herring. The article presents the results of mapping the modern structure of the floodplain lands of the Lower Don River within the flooding areas in different years. The areas of 1979-2018 floods were determined by processing the Landsat satellite images; the modern structure of their land use was mapped according to Sentinel-2 data. The types of land cover were also analyzed using the global data (GLC30 and ESRI). Within the area of 1979-1994 flooding there are 0,7 thousand hectares of built-up territories, about 30 thousand hectares of arable land and 10 thousand hectares of fallow lands. There is a threat of flooding the buildings and other infrastructure facilities, therefore the floods in the Lower Don River area are now perceived as a negative phenomenon. It is necessary to impose restrictions on the economic use of floodplain lands, and ban the construction activities and stocking of oil products, fertilizers and pesticides within the 1994 flooding area. Application of satellite monitoring technologies is a promising tool for assessing the economic development of floodplain lands and identification of flooded lands. In the future, it is possible to create an automated system for monitoring floodplains of the Don River and other rivers, basing among other on the satellite microwave radiometry data. The advantage of such data is the independence from the presence of clouds, which impedes satellite observations in the visible range