The Galyan-Atasu Dam was constructed in order to supply water for the drinking, utility and industrial needs of Trabzon and its surrounding areas. There is a significant relationship between the land cover (LC) and the quality of the surface water of the streams that supply the dam. This study was conducted in order to present the impacts of LC on water quality parameters. Within this scope, a total of eight subwatersheds having low anthropogenic impact were chosen from amongst the upper watersheds of the Galyan and Simsirli streams, which supply Galyan-Atasu Dam. The granite bedrock of Kackar granitoid form outcrops in the subwatersheds. Land cover (coniferous forest, broad-leaved forest and grassland) ratios were determined with the help of Quick-Bird satellite imagery.