Inundations due to river overflows are becoming more frequent; management of flood is thus an important task belonging to the set of preventive measures allowing the protection of people and goods downstream. The flood situation management method proposed in this paper was designed to reduce the flood impact at its early arising stage. The river is supposed to be equipped with reservoirs in which water excesses are stored and then released only when the flood episode ends. The supervisory control scheme allows calculation of the water volumes through the use of a network flow. Management objectives, such as the maximum discharge level allowed in the river, the order of priority for the reservoir storage or release, the measured levels and discharge in the river and in the reservoirs, and the assessed parameters such as time delays, are combined to configure the network flow. Then, the optimal flow in the network is computed and supplies the reservoirs’ gate opening setpoints. Finally, the method was applied to a simulated case for which the time delay during the flood varied and remained efficient for flood attenuation compared with the case when the gates were always open, thanks to the network configuration.