It begins about 500 m beyond the nymphaeum of Bergantino, and comes out on the other side in the Mole di Castel Gandolfo locality, where the water flow drove multiple watermills.

If the waters of the lake were scattered in an inland direction, Veii would fall; but if they were to overflow through the usual streams or channels toward the sea, this would be unfavourable to the Romans as well.

[7] Dumézil ascribed this story to the Roman custom of projecting religious legendary heritage onto history, considering it to be a festival myth aimed at giving relevance to an exceptional event which would have happened during the Neptunalia.

This legend showed the scope of the powers hidden in waters and the religious importance of their control by man: Veientans too knowing the fact had been digging channels for a long time as recent archaeological finds confirm.

There is a temporal coincidence between the conjuration of the prodigy and the works of derivation[clarification needed] recommended by Palladius and Columella at the time of the canicula, when the waters are at their lowest.