In recent years, Turkey has turned its attention to alternative energy sources rather than fossil fuels. The Eastern Black Sea Region of Turkey has steep mountains with hilly topography and has large potential in terms of energy production with run-of-the-river hydropower plants (RHPPs). In this study, the effects of two RHPPs on some water quality parameters were examined in the Solakl stream watershed. This research was conducted over the course of 12 months (January-December 2014). In total, 12 sampling points were selected and various water quality parameters, such as temperature, pH, dissolved oxygen, total suspended solids, electrical conductivity, total dissolved solid, chloride and salinity, were monitered at each point. Statistically, significant changes occured in water quality parameters such as total suspended solids, pH and temperature. In particular, total suspended solids ranged from 10 to 440 mg/L.These results suggest that the RHPP negatively effect water quality and quantity in the main stream in both the operational and constructional phases.