AbstractThe main aim of this study is to make an assessment of the impact of Lake Gopło on a river low-flow regime. Two water gauges were selected, located in an upstream and downstream position to the lake on the River Noteć. On the basis of the daily discharge series from the period 1965–1990, a group of low-flow regime estimators was computed. Analyses involved various aspects of minimum flows and drought streamflow deficits. Comparison of the data between both gauging stations showed the extent of the influence of water management on Lake Gopło on low-flow regime transformation in the River Noteć.