Large hydropower developments are not considered to be environmentally friendly due to large landscape flooded by their reservoirs. There is a certain carbon footprint related to this, in the phase of construction and of the operation of the reservoirs. This paper presents GHG emissions related to an iconic reservoir from Romania, Vidraru, and demonstrate that values are close to those determined around the world and that comparing with other conventional power plants producing electricity is the best environmental option. Furthermore, must be considered the other water uses related to reservoirs as flood mitigation, water supply for population, irrigation, and industry, where reservoirs cannot be replaced by anything else.