Torrential flood as a rainfall precipitation driven natural hazard occurs in the watershed that responds within several hours due to a rugged topography. The extraordinary torrential flood event from September 15 2014 in the Eastern Serbia with its severe consequences, widespread material damages and casualties, draw an attention of the Serbian public and is a topic of this work. The combined method of Soil Conservation Service and synthetic unit triangular hydrograph is used to calculate the effective rainfall and peak discharges in five affected watersheds (Podvrška, Velika Kamenica, Slatinska, Zamna, and Mala Kamenica) in order to define the extremeness of this event. Special attention is given to the determination of the lag time defining the unit hydrograph and the curve numbers of the studied watersheds on the base of land use and hydrological class of soils with regard to geology, considering antecedent soil moisture conditions. Taking into account the high curve number (due to the high share of soils with an unfavorable hydrological conditions and high share of agriculture areas in land use), the shortest time to peak (due to the highest mean slope of river bed), the highest specific maximal discharge on subject date (4.58 m³s⁻¹ km⁻²) as well as sediment transport data, the highest priority for erosion and torrential flood control works is attributed to the Mala Kamenica watershed. The results of this work may be a significant contribution to the flood risk assessment on a watershed level in this part of Eastern Serbia that should always start with reviewing and analyzing the historical torrential flood events.