Oligochaetes constituted 91-98% of the numbers and 78-97% of the biomass of the macrofauna, the remaining part were Chironomidae, while Chaoboridae, Sphaeridae, Ephemeroptera, and Coleoptera occurred sporadically. The highest density (14.5 thous. indiv. m-2) and biomass (13 g m-2) were observed near the dam. 14 species of the Oligochaetes (the most numerous being Potamothrix hammoniensis, Limnodrilus claparedeanus, and L. hoffmeisteri) and 5 taxa of Chironomidae were determined in the samples.