In the first part of the thesis is a short presentation of Dreta catchment and flood problematics of Dreta river and Savinja river. Dreta river together with Savinja river causes flooding of urbanized areas. As a solution for flooding problematics, we analyzed optimal positioning of dry retention reservoirs for attenuation of flood waters on the floodplains along the Dreta river. We prepared a description of Dreta catchment in order to determin potentially suitable floodplain areas, where dry retention reservoirs could be placed. After choosing two floodplanes, that were in our opinion most suitable for placing the retention reservoir, we made more detailed description of dry retention reservoirs locations, in order to retain flood waters. We preformed dimensioning of flood retention objects and constructed hydraulic model that includes dry retention reservoirs. After placing the reservoirs, we analyzed the maximum capacity of water that can be retained. In the last part of the thesis we present the results of flood water retention analysis. We have achieved effective reduction of hydrograph peak flows and prologned time delay of the hydrograph peaks. We also assessed the influence of dry retention reservoirs along the Dreta river on the Savinja river hydrographs.