The complex of reservoirs in Zesławice on the Dłubnia river is located in the area of the Krakow agglomeration, near a built-up areas, which on the one hand, reduces the available capacity for flood wave storage and, on the other hand, imposes a high level of protection of these areas. The experience of the flood in 2010 confirmed that this level is not sufficient. The main objective of this study is to evaluate the flood protection effectiveness of the Zesławice reservoirs complex by estimating the maximum flood level, which can be effectively reduced. Numerical calculations were performed on a 1-D computer model of the Dłubnia river built using the MIKE 11 (by DHI) software. Due to the complexity of topographical arrangement of the Zesławice reservoirs, each storage volume was modeled as a separate 1-D object. The hydraulic connections between them were defined and the rules controlling the outflow were modeled. In addition, the evaluation of the Dłubnia river-bed capacity downstream the Zesławice was performed and a general guidelines how to increase the level of flood protection in the impact area of the reservoirs were formulated.