A first planning hypothesis provided the digging of a canal that would let the lake waters flow out through the low Cesolino hill flowing them into the Salto River. This easily feasible plan was discarded quickly, because the considerable amount of water, flowing first into the Velino River, then into the Nera River, and finally into the Tiber, would represent a flood threat for Rome. A second but harder plan provided instead to let the lake waters flow into the Liri River along a tunnel dug in Mount Salviano.