JUSTIFICATION OF A COMPLEX OF MEASURES AIMED AT REDUCING DIFFUSE POLLUTION IN SMALL RIVER BASINS

Purpose: to substantiate a complex of water protection and reclamation measures aimed at preventing the negative impact of diffuse pollution sources on water quality in small river basins, reducing soil erosion and restoring ecological framework elements using the Kazanka River basin as an example. Materials and methods. The methodological basis is the analysis of studies covering the main issues of runoff and soil erosion formation, regulatory documents and guidelines. Results. The need for a comprehensive task on reducing diffuse pollution in river basins is substantiated, namely: the use of interrelated organizational, agrotechnical, forest reclamation, and hydraulic engineering measures to prevent erosion and restore elements of the ecological framework. Calculations of environmental sustainability for the Kazanka River basin were performed, which made it possible to identify the most unstable sub-basins. The sub-basins of Sula (KESL = 0.22) and Shimyakovka (KESL = 0.32) are characterized by pronounced instability. Degradation processes leading to soil erosion and formation of diffuse runoff, which lead to deterioration of water quality in the Kazanka River, are also observed there. Only the Kis’mes’ sub-basin (KESL = 0.52) can be considered stable; the Atynka, the Verezenka, the Iya, located in the upper reaches of the river, are of low stability. The performed calculation of the Sula sub-basin sustainability (representative section) of the Kazanka River showed that the planned measures make it possible to transfer the agrolandscape from a state of pronounced instability to a low-stability state (KESL = 0.4). Conclusions. The main sources of diffuse pollution of water bodies are agricultural lands, the use of fertilizers in fields, agricultural enterprises, including livestock farms, leading to a decrease in the ecological sustainability of agricultural landscapes. Measures to increase agricultural landscape sustainability and reduce diffuse runoff significantly are substantiated.