Floods are a natural phenomenon of rising water levels of rivers or lakes, where the water level reaches and exceeds the upper level of the coast and spreads to coastal areas. In the Republic of Croatia, floods occur almost every year and are among the most frequent and most dangerous natural disasters, given that they cause many negative consequences such as human and material losses, destruction of cultural property and environmental disasters. The Republic of Croatia is characterized by a considerable floods hazard, and the area of the City of Karlovac stands out as one of the most endangered parts. In terms of the length and the river basin area, the area is dominated by the Kupa River, with its main tributaries - Korana and Dobra, and the Mrežnica River, a left tributary of the Korana River. In the City of Karlovac area, several large and devastating floods have been recorded in the past, which, given the harmful effects they leave in the area, are a limiting factor in its development. Therefore, in order to ensure maximum protection of the area from floods, as well as the optimal functioning of the population, various measures and activities are implemented and planned for flood protection and minimization of their harmful consequences.