In the paper, results of geodesic and hydrometric measurements were presented, also calculations for need of preparation of rating curve in cross-section of Dłubnia river, located in 10+247 kilometer were made. Geodesic measurements of cross-section and longitudinal water level slope were made with use Topcon AT-G6 leveler, and eight hydrometric measurements were made with use Nautilus C2000 OTT Hydrometrie current meter. Discharge was calculated with use Harlacher method based on hydrometric data and with use Chézy equation. It was ascertained, that low and average flows are medium five times higher to those calculated with use Harlacher method. The cause of such a significant differences in flow calculations for given damming up is a composition of the bottom of the river. It was ascertained, that essential influence on condition of water flows in case of low and average flows has an upgrade of the bottom in clear span, which is 203 m below of gauging section. It was also ascertained, that on shape of rating curve, in this cross section, also a damming up in Zesławice reservoirs has an influence.