EN
The essencial problem of this article is reduction of flood hydrograph by the system of ponds, located in urban catchment of Służew Creek: Berensewicz Ponds, Wyścigi Pond and Służewiecki Pond. The estimations of transformation of the flood hydrographs by reservoir was made with the use of the Puls method. Flood flow hydrograph, generated by rain events of probability of 10% and duration 2 hours in part of the catchment and then in the whole catchment, has been taken into account. The infl ow to the Berensewicz Pond has been calculated from measurement infl ow-outflow. The results of computation have shown that the reduction rates of flood hydrographs by the reservoires are insuffi cient for flood protection. Only Berensewicz Pond has significant importance on reduction of the flood flow hydrograph. To improve the efficiency of work system, it is sugessted to consider a designe of hydraulic structure with bottom outflet and overflow at Służewiecki Pond. Proposed solution would be useful, especialy for big flow hydrographs, what has been confirmed by results of computation.