Microbes in the coastal zone of the reservoir. Quantitative ratios of microorganisms in the water of the Kuban River. Comparison of microflora composition of water samples and silt of the Kuban River in the city of Krasnodar. Data from microbiological studies in water and in sediments. microbiological research, obtained for four seasons in the city of Krasnodar, or rather in the center and on the outskirts of the city of Krasnodar. High rates of coli-index in the city, especially in recreation areas. Self-purification of flowing water bodies occurs more intensively. The rate of self-purification of reservoirs is influenced by competitive relationships that develop between different groups of microorganisms in the struggle for free oxygen and nutrients. The formation of biocenoses of aquatic microbes occurs in the coastal zone and at the bottom of water bodies. In the bottom sediments, the microflora is not very different from the water content.