The length of the reservoir area on the banks of the Zarafshan River and the presence of all biotopes inhabited by molluscs of the Unionidae and Corbisulidae families have made the basin a comfortable aquatic ecosystem for molluscs. The influence of rivers and fisheries on the formation of the fauna of bivalve molluscs in reservoirs is significant. We found that 10 species and 2 subspecies of bivalve molluscs were distributed in the Kuymazor reservoir and 8 species and 2 subspecies of bivalve molluscs in Shurkul. Reservoirs of Sinanodonta species are shown for the first time by us. These molluscs belong to the ecological groups like peloreophilic, rheophilic and pelolimnophilic. In the water reservoirs of Uzbekistan, the spread of bivalve molluscs by groups has common features. In all water reservoirs, an ecological group called peloreophil prevails, but the species belonging to the ecological group atre different in different water bodies. Such species of pedloelphils as Sinanodonta gibba, S. orbicularis, Corbiculina tibetensis and C. ferghanensis are predominantly found in rivers, fish farms, and water reservoirs. The most common species in the canals are Corbiculina tibetensis and C. ferghanensis. The next frequent occurrence in water reservoirs is the ecological group of rheophiles.