ANTHROPOGENIC LOAD ON THE WATER COLLECTING SHYRETS RESERVOIR

The object of our research is the Shchyretske Reservoir as part of the blue infrastructure of the Lviv agglomeration, which performs not only the function of water supply, but also climate regulation, sanitation, ecological, aesthetic and other functions. The reservoir was created in the Shchyrka River in 1954 and is in permanent use by of Lviv city utility company “Lvivteploenergo”. The territory of the object belongs to the village of Navaria, Lviv district, Lviv region. The load of the settlement on the catchment of the Shchyretske Reservoir was analyzed. The structure of land use in the section of river basins that feed the water body was analyzed. A cartographic model of the Shchyretske Reservoir catchment has been created. In the structure of land use of the catchment area of the reservoir, the largest areas are occupied by arable land - 18.7 km2 (25.3% of the catchment area), 8.2 km2 (11.1%) of land is covered by forests, 8.8 km2 (12%), under gardens - 0.6 km2 (0.8%). The largest areas of arable land are concentrated in the basin of the Malechkovicha River (30.1%), slightly smaller areas (20.0%) in the basins of the Shchyrka and Kovyr rivers. The basin of the Shchyrka River is the most forested (23.8%). The largest areas of land under development are concentrated in the basin of the Malechkovicha River (16.0%). In all river basins, the share of land under gardens is small - less than 2.0%. The traffic load is high, the density of roads exceeds 6.9 km/km2. According to the monitoring results of the Dniester Basin Management of Water Resources, the peculiarities of water use were analyzed and the water quality in the reservoir was assessed. On the basis of the conducted research, it was determined that the basin of the Malechkovychа river has undergone the greatest anthropogenic transformation, this catchment is the least forested and excessively covered by buildings. Malechkovycha River receives the most domestic sewage, which enters the reservoir without treatment and contributes to its pollution with biogenic elements. Analysis of water quality in the Shchyretske Reservoir confirmed that the reservoir is subject to excessive anthropogenic stress due to the discharge of wastewater. We observe an increase in the content of biogenic elements, in particular nitrites - by 8.0 times, BOD5 - by 2.0 times, ammonium nitrogen - by 11.6 times highered than the norm. In addition to biogenic elements, we note the excess of the content of such a heavy metal as zinc - by 5.1 times and the pesticide terbuthylazine - by 5.6 times highered than the norm. Priority measures to improve the ecological condition and preserve the ecosystem of the Shchyretskе Reservoir are proposed. In order to preserve the ecosystem and the reservoir's water level, a complex of environmental protection measures should be implemented within the entire catchment area of the reservoir. This set of measures includes: sewerage of settlements located in the reservoir's catchment area; revitalization of Shchyrka, Malechkovycha and Kovyr rivers; determination of the boundaries of water protection zones and coastal protective strips of the reservoir and its tributaries; liquidation of all spontaneous landfills in the coastal zones of watercourses, etc. The Lviv agglomeration is expanding and these processes will continue in the post-war period, so the area of land under construction will increase in the basin systems and the area of agricultural land will decrease. In 2009–2020, the share of buildings on land used for agriculture increased. The proposed measures should be accompanied by hydrological, hydrochemical, bioindicative, sanitary and hygienic monitoring studies. Key words: Shchyrets reservoir, anthropogenic load, land use structure, wastewater discharge, water use.