Pompeii (Italy)

Pompeii rises on a plateau at about 30 metres above sea level, formed by a flow of Vesuvian lava, overlooking the valley of the River Sarno (ancient name Sarnus) at the mouth of which was a busy port.
A mixed population of Etruscans, Greeks and indigenous people led to the development of the city and the construction of a fortified limestone wall (5th century BCE). Towards the end of this century, the Samnites descended from the mountains and conquered the cities near Mount Vesuvius and the coast in a league with Nuceria (Nocera) as capital.
Pompeii was highly urbanised during the Samnite period. A new fortification constructed in Sarno limestone, which dates back to the 4th century BCE, had to trace a path similar to the previous one.

Towards the end of the 4th century BCE, the movements of the Samnite population unsettled the political order, thereby forcing Rome to intervene in southern Italy: alliances and successful military campaigns led to its hegemony throughout the Campania region (343-290 BCE). Pompeii then joined the political organisation of the Roman res publica as an ally, however, in 90-89 BCE, together with other Italic cities, the city rebelled and demanded equal social and political status as Rome. Pompeii was besieged by the troops of Lucius Cornelius Sulla, the city surrendered and became a Roman colony by the name of Cornelia Veneria Pompeianorum (80 BCE). Once the colony was founded, Pompeii was enriched with private and public buildings and further embellished particularly under the ruling of Emperors Augustus (27 BCE - 14 CE) and Tiberius (14-37 CE).

A violent earthquake struck in 62 CE and shook the entire area surrounding Mount Vesuvius. Reconstruction work in Pompeii began immediately, however, it took a long time to be completed due to the extent of the damage and the seismic swarm that followed. The sudden eruption of Vesuvius 17 years later, on August 24, 79 CE, buried Pompeii under ash and lapilli, creating what seemed to be an open construction site.

The city was rediscovered at the end of the 16th century but explorations only began in 1748, under the King of Naples, Charles III of Bourbon, and continued systematically throughout the 19th century, right up to the present excavations, restorations and enhancement of the city. The archaeological site of Pompeii spreads over 66 hectares, of which 49 have been excavated.
In 1858, due to the necessity of study and direction, Giuseppe Fiorelli divided the city into regiones (neighborhoods) and insulae (blocks). The names of the houses when the owner was not known, were coined by the excavators according to the particular discoveries or other criteria.

Aqueduct and water Supply

• In ancient times deep wells were used in combination with rain water catchment from the roofs stored in private subterranean cisterns; perhaps the water in the Sarnus (present Sarno) played also a role
• During the time of Sulla (around 80 BCE) Pompeii became a colony and was embellished with an aqueduct with its source in the (lower) Abello region and its terminus in a simple water distribution station at the end of the Via del Vesuvio (see drawing below)
• In a later phase (around 27 BCE) Pompeii was connected to the new and large Aqua Augusta aqueduct from Sante Lucia di Serino to Misenum. But now less water (a decrease from max. 4.000 to a constant 2.000 m3 per day) was available which made a reconstruction of the castellum necessary
• The earthquake of 62 CE caused a disruption of the water supply leading to a reduction or a total shut down of the water supply followed by a revision of all water infrastructure in the city including the structures inside the houses
• About 17 years later the 79 CE eruption took place. At that time one was fully active in the construction of a new public water supply system.

The main elements

• The castellum divisorium, the first order distribution station situated on the highest point of the city, near the Vesuvian gate, guarded by a so-called castellarius who had a special seat near the entrance, see photo below. The castellum regulated and distributed the aqueduct water through three outlets which served different area‘s in the down. The regulation took place inside the building by means of shutters or wedges in horizontal openings in flow control slabs, which could regulate and stop the flow in the three outlets.
• Three major lead pipe-lines with diameters greater that 0,20 m, left the castellum heading south; they are considered the main artery of the water supply. There are at least three views on the exact course within the city but the general picture is the same.
• The large height differences inside Pompeii - from 42 m a.s.l. at Porta del Vesuvio to 6 m at its lowest point - caused undesirable pressure differences in the water system, which was solved by introducing open water towers resulting in different pressure zones within the city. Until now 14 towers have been excavated, see below. Each tower was 5 - 8 m high, with some vertical grooves and a footprint of about 1 x 1 m (3 Roman feet in square). On top a lead box was placed from about 1 x 1 x 1 m.
• By means of lead pipes each tower was connected to the main or with an other tower. From every tower smaller lead pipes led the water to the street fountains, the bath buildings, the private houses and the workshops.

Secrets of water tower 6 This copy of a photo stems from a report of an excavation in Pompeii (Spinazzola, NSc 1917 pag 247 - 264, fig 7). The dimensions of the lead box were 0,65 m square and 0,56 m high, so with a maximum capacity of 237 liters. In the report this box is called a castellum aquae. Given the description of the location, the lead box should have been attached to what we now call water tower 6. However, this area suffered from an allied bomb attack in autumn 1943: both tower and lead box were hit. So what is the link between the stone structure plus the lead box on the 1917 photo and the present water tower 6 at the crossing of the Via dell‘ Abbondanza and the Vicolo di Octavius Quartio? The structure left, adjacent to the lead box, may have nothing to do with the present tower 6: the structure is not (almost) square as the other towers, no masonry work, no vertical groove(s), too low compared to the present tower; any film or layer of calcareous deposits on the present tower is missing. And the lead box? Its capacity is quite modest given the estimates of the other ones, but not unusual (Olsson 2015). But its dimensions do not match with the structure annex (estimated as 0,40 x 1,20 m) which is too narrow to support the box. Or was the box already placed on its tower of which we see only the top? Tentative conclusions: the present tower is post-Second World War and the structure on the 1917-photo is not suited to support the ancient lead box. But what we do not know is whether this box was used as a distribution box in the public water supply.

The users

Specialty

14 water towers

Water tower 1 Location: VI.16.4, at the crossing of the Via del Vesuvio and the Vicolo di Mercurio. Present height 6.67 m.	Calcareous deposits in water tower 1. Note the imprints of the lead pipes.	Water tower 2 Location: VI.14.17, at the crossing of the Via del Vesuvio / Via Stabiana - Via del Fortuna / Via di Nola. Present height 6.34 m.	Water tower 3 Location: VII.2.1, at the crossing of the Via Stabiana and the Vicolo degli Augustali. Present height 5,96 m.
Water tower 4 Location: I.4.15, at the crossing of the Via Stabiana and the Via dell‘ Abbondanza. Present height 6,15 m.	Lead angle At the subterranean foot of water tower 4 a lead angle was found by Lanciani in 1882 (Tavole X nrs 1-3).	Water tower 5 Pompeii‘s water tower 5. Location: I.6.1, at the crossing of the Via dell‘ Abbondanza and the Vicolo di Pasquius Proculus. Present height 3,33 m.	Water tower 6 Location: II.2.1, at the crossing of the Via dell‘ Abbondanza and the Vicolo di Octavius Quartio. Present height 3,03 m. Note that the original tower has been destroyed by an allied bomb in the autumn of 1943.
Water tower 7 Location: VI.13.16, at the crossing of the Vicolo di Mercurio and the Vicolo dei Vettii. Present height 4,37 m. Photo: R. Olsson	Water tower 8 Location: VII.5.8, in the Vicolo delle Terme. Present height 2,83 m.	Water tower 9 Location: VII.10.7, at the crossing of the Via di Eumachia and the Vicolo del Balcone Pensile. Present height 6,02 m. Photo: R. Olsson	Water tower 10 Location: VIII.1.2, along the Via Marina, at the west side of the Basilica. Present height 3,15 m.
Water tower 11 Location: VIII.5.3, at the crossing of the Vicolo del 12 dei and the Vicolo delle Pareti Rosse. Present height 5,69 m.	Water tower 12 Location: VI.6.11, at the crossing of the Vicolo di Mercurio and the Vicolo della Fullonica. Present height 1,63 m. Photo: R. Olsson	Water tower 13 Location: VI.1.19, in the Via Consulare at the splitting with the Vicolo di Narciso, behind the small building protecting a deep well. Present height 0,80 m.	Water tower 14 Location: IX.10.2, on the south side of the Via di Nola between two buildings. Present height 5,37 m. Photo: R. Olsson

7 proposals for the main water system

Wiggers‘s proposal for a water distribution system in Pompeii with 14 water towers and the suggested position of the main water pipelines (Wiggers 1996)	Jansen‘s proposal for a water distribution system in Pompeii with 14 water towers and the suggested position of the main water pipelines (Jansen 2002)	Schmolder-Veit‘s proposal for a water distribution system in Pompeii with 14 water towers and the suggested position of the main water pipelines (Schmolder-Veit 2009)	Keenan-Jones‘s proposal for a water distribution system in Pompeii with 14 water towers and the suggested position of the main water pipelines (Keenan-Jones 2011)
Olsson‘s proposal for a water distribution system in Pompeii with 14 water towers and the suggested position of the main water pipelines (Olsson 2015)	Ohlig‘s proposal for a water distribution system in Pompeii with 14 water towers and the suggested position of the main water pipelines (Ohlig 2016)	Rasmussen‘s proposal for a water distribution system in Pompeii with 14 water towers and the suggested position of the main water pipelines (Rasmussen 2017)

Pompei - POMPEII aqueduct

Map of Pompeii	Castellum with 3 outlets	Castellum plus manhole	Behind the castellum
Inside the castellum	Control by plugs	Mouth of the aqueduct	Modern castellarius
Predecessor	The 14 water towers	Water tower and fountain	Pipe connections
Lead box of tower 6?	Calcareous deposits	Distribution proposal	Public fountain
The lady and the fountain	Separate water reservoir	As strategic reserve?	In the Forum Baths
Basin in the caldarium	Private connection	Stop-cocks	Opening to the drains
Stepping stones