In this study, distribution of epilithic algae assemblages in Lake Kovada and Kovada Channel, their relationships to environmental factors, and biological water quality were investigated. Epilithic algae and water samples were taken from four stations (one in the channel, others in the lake), between June 2012-May 2013 seasonally. Totally 51 taxa were observed belonging to the groups Bacillariophyta (37), Chlorophyta (8), Charophyta (4) and Cyanobacteria (2), respectively. The stations were clustered into main two groups based on UPGMA. The highest similarity value was determined between third and fourth station (94%). Saprobic Index (SI) was applied in order to determine biological water quality. Physicochemical parameters have been evaluated according to the Klee's method and Regulation on the Management of Surface Water Quality in Turkish (RMSWQ). According to the Klee's method, water quality was found unpolluted in Kovada Lake, and its channel while it was found as polluted based on RMSWQ. Biological water quality values indicated Lake Kovada as poorly polluted, but its channel as polluted. According to CCA, 84.6% of the variance was described by the first four axes of the relations of species and environmental variables (r=0.963), and pH, conductivity and Cl- were found to be the most influential variables on distribution of dominant taxa.