The relation between dam releases and dissolved- oxygen concentration, saturation and deficit, downstream from Roanoke Rapids Dam in North Carolina was evaluated from 2005 to 2009. Dissolved-oxygen data collected at four water-quality monitoring stations downstream from Roanoke Rapids Dam were used to determine if any statistical relations or discernible quantitative or qualitative patterns linked Roanoke River in-stream dissolved-oxygen levels to hydropower peak-ing at Roanoke Rapids Dam.