The distributed hydrological model Hydrograph was applied to simulate runoff formation processes in the mountainous conditions of the Crimean Peninsula. The study object is the Derekoyka River watershed (49.7 km², the altitude difference 14-1398 m). Streamflow simulations were carried out with daily time step for the periods of 1967-1988 and 2016-2017 using the data of two weather stations Ai-Petri and Yalta. Though mean and median Nash-Sutcliffe efficiency was only 0.28 and 0.33, in some years it exceeded 0.60. The analysis has shown that the precipitation input interpolated from weather stations was not always adequate affecting the quality of streamflow simulations. The results of the model verification were accepted as satisfactory. The hazardous flood of 2018 in Yalta was simulated. According to simulations, maximum daily discharge amounted to 14.9 m³/s and exceeded previous maximum value observed in 1962. The results confirm the possibility to apply the model Hydrograph to assess t