The exit of a short tunnel in the quarry of Sainta Anna, 2 km south of Peyrolles, part of the Traconnade aqueduct of Aix-en-Provence (France).
View on a part of the 1051 m long Eupalinos tunnel, the major component of the archaic aqueduct (530 BC) which brought fresh water from Agiades (NW of present Pythagorion, Samos island, Greece) to ancient Samos. Note the view on the lower level of tunnel in which the actual water pipe line is still extant.
A nice view into one of the channels of the double bridge crossing a tributary of the Fosso di Gregorio in the Valle Barberini, 40 km east of Rome. Note the peculiar roof and its formwork. Just after this double bridge a 4.000 m long tunnel in the Aqua Anio Novus started.

Longest Aqueduct Tunnels

For a long time the subterranean aqueduct of Bologna (Italy) was the longest known Roman aqueduct tunnel, but recently research by Doring revealed a 91 km long tunnel of the aqueduct of Gadara (partly Syria and Jordan).

A tunnel could be dug from both sides of a mountain, as was done under control of the Roman engineer Nonius Datus in the course of the famous aqueduct of Saldae (Algeria). An other method was derived from the Persian qanat construction: vertical shafts were dug at regular distances and at a given depth horizontal galleries were made towards the adjacent shafts thus forming the aqueduct tunnel. This system was also helpful to maintain the right direction.

The most famous ancient aqueduct tunnel was the one made under supervision of Eupalinos on the Greek island of Samos (550 BC !!) to supply the town of Samos / present Pythagorion: over 1.000 m long, dug in almost straight line from opposite ends of the Kastro mountain.
Apart from aqueduct tunnels the Roman also applied tunnel to drain lakes in ancient volcano craters like at Lake Nemi; this type of tunnel is called emissarium.
The longest Roman road tunnel was the Cocceius tunnel near Naples, 'only' over 900 m long.
Name aqueduct Tunnel length (m) Literature Remarks
Gadara, Wadis es-Sallale 94.000 Doring 2007a Partly Syria and Jordan; up to 80 m deep
Bologne (Italy) over 18.000 Grewe 2008 Up to 18 m deep
Gadara, Et Turra (Jordan) 11.000 Doring 2007a Up to 80 m deep
Aix-enProvence, Tracconade aqueduct (France) over 8.000 Leveau 2006b Vernelles tunnel; over 80m deep
Avezzano, Lake Fuscino (Italy) 5.642 Grewe 2008; Castellani 1991: 5595m Emissarium; up to 122 m deep
Rome, Valle Barberini 4.000 Van Deman 1934, Aicher; Ashby 1935: 2250m In the Anio Novus
Duren (Germany) 1.660 Grewe 2008 Drover Berg; up to 26 m deep
Nemi, Lake Nemi (Italy) 1.600 Grewe 2008, Castellani 1991 Emissarium
Castel Gandolfo, Lake Albano (Italy) 1.400 Grewe 2008, Castellani 1991 Emissarium
Samos, Eupalinos tunnel 1.036 Grewe 2008 Pre-Roman: appr. 500 BC; 170 m below the top
Cuma, Grotta Cocceio (Italy) 906 Doring 2007c Close to the street tunnel
Naples, Grotta Neapolitana (Italy) 750 Doring 2007c  
Ariccia, Lake Ariccia (Italy) 650 Grewe 2008, Castellani 1991 Emissarium
Walferdange (Luxembourg) 600 Grewe 2008 Raspetzer Tunnel; up to 36 m deep
Jerusalem (Israel) 533 Grewe 2008 Hezekiah / Siloam tunnel
Saldae (Algeria) 428 Grewe 2008 Advisor / Engineer: Nonius Datus

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