The aim of the thesis was to determine the effect of flood control reservoir on runoff hydrograph of the stream Ločivnica. Increasing urbanization of the environment and particularly flood-prone areas increases the risk of floods in these areas, while reducing the possibility of proper regulation of the area. Part of the town Poljane nad Škofjo Loko extends into the area of higher flood risk. In studies of flood regulation of this area is proposed as the only measure, that would have a greater influence on flood safety of Poljane, would be the construction of flood control reservoir above Poljane. The main importance of the flood control reservoir is an effective reduction of flood wave and flood protection of the downstream areas. Dry flood control reservoir is a type of reservoirs in which the pool or area intended for the retention of flood, fills only during high water. In the thesis we made hydrological model, based on rainfall, its distribution in precipitation event and type of the terrain determines runoff hydrographs from the contribution area of Ločivnica. With hydrographs we determined forms of flood waves and their peak. By selecting the right input hydrograph with certain return period and setting the maximum outflow from the reservoir, we calculated the minimum required volumes of the flood control reservoir. Analysis of the influence of the calculated volumes of the reservoir in case of actual rainfall event in the past, was made. On the basis of field examination of the area, we determined the proposed location and type of construction of a flood control reservoir on the stream Ločivnica above Poljane nad Škofjo Loko. It has been found that the proposed reservoir has a positive influence on the retention of the 100-year flood water of stream Ločivnica, thereby increasing the flood protection of downstream areas.