Anthropogenically Changed Water Entering Water Bodies in the Don Basin

Based on the data of water balance stations and water management statistics, the total amount of anthropogenically altered water entering the water bodies of the Don basin has been calculated for a period from the 1980s until recently. These are industrial, domestic and agricultural waste and return (collector-drainage) waters entering rivers and water bodies from the so-called point sources and usually containing certain pollution even after treatment, as well as diffuse runoff from agricultural (non-irrigated) lands and urban areas which inflows to the hydrographic network (ravines, gullies, river valleys) with the pollutants washed out from these territories. Diffuse runoff is usually not purified. It is found that the volume of uncontrolled diffuse runoff from agricultural lands and urbanized territories in the Don basin is comparable to the volume of waste and return water or even exceeds it. This largely explains the unsatisfactory water quality in this basin, because water protection measures are mainly aimed at reducing pollution from point sources.