Roman Aqueduct of Ancient Nikopolis: Water Supply for a Roman City in Greece
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- Infrastructure
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- Aqueduct
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History
The Roman Aqueduct of Ancient Nikopolis is a Roman water-supply network in Greece, built to provide drinking water for Nikopolis after its foundation by Octavian Augustus following his victory at Actium in 31 BC. Construction of the city is dated to 30–29 BC, while the aqueduct itself may have begun in the late first century BC or the first century AD and reached its principal form during the second century AD. Its route extended for approximately 50 kilometres from the springs of Agios Georgios in the upper Louros valley to Nikopolis.
Foundation and expansion of Nikopolis
Augustus, the first Roman emperor, established Nikopolis after Actium, the naval victory that secured his control over the Roman world. The new city became a major Roman centre in northwestern Greece and helped extend Roman political and cultural influence across western Greece. Communities from several cities in Epirus and Acarnania were forcibly relocated there, causing rapid growth and creating a substantial demand for water.
The population of Nikopolis has been estimated at about 100,000 to 150,000 people, although earlier estimates reached 300,000. Before the long-distance aqueduct was built, residents depended on wells, small springs, and water gathered around the Louros River, including water carried in barrels. Ancient descriptions of inadequate supplies for the city’s baths point to the pressure created by its expanding population and public buildings.
Construction and Roman development
The date and sequence of the aqueduct’s construction remain debated. It was traditionally connected with Augustus, but differences in masonry and building methods show that the system developed through several phases over a period of decades. The first phase may not have delivered water as far as Nikopolis, and later sections were renewed or repaired. Another interpretation places the completion, and possibly the main construction phase, in the reign of Hadrian, the emperor who ruled from AD 117 to 138 and was associated with extensive infrastructure works.
The engineers drew water from the Agios Georgios springs and used the natural fall of approximately 80 to 81 metres between the source and Nikopolis. The route was carefully graded so that water could descend toward the city and ultimately toward the sea. At Nikopolis, the system served the northern suburb of Proasteion, where the theatre, stadium, the Aktian Games, and two public baths were located. Within the city, it fed fountains, baths, and other distribution points. Water management also supported urban hygiene, with wastewater channelled directly toward the sea.
Late Roman and Byzantine use
By the fourth century, extensive damage had reduced the aqueduct’s effectiveness. In AD 362, Emperor Julian, who ruled from AD 361 to 363, undertook major urban renewal at Nikopolis and included the aqueduct in the repair and recommissioning programme. The system probably continued to operate into the early Byzantine period.
By the fifth century, the aqueduct had fallen into disuse as Nikopolis declined and its Palaeo-Christian fortifications were constructed. The wider deterioration of the region after the Ostrogothic invasion of AD 551 is also associated with the abandonment of the water network. In the smaller Byzantine settlement, which survived until its abandonment by the Bulgarians in the eleventh century, water was probably obtained mainly from a local spring. The lack of a later settlement over the ancient city helped preserve the aqueduct’s remains.
Rediscovery and protection
Evliya Çelebi described the aqueduct in 1668. During the nineteenth century, François Pouqueville and William Martin Leake examined its remains, followed by further archaeological investigations. Work in the 1960s led to its registration as a protected cultural monument. Maintenance was undertaken on the large bridges near the beginning of the route between 1978 and 1980, while later research traced the watercourse more precisely and excavated several locations.
Between 2011 and 2015, an enhancement project documented the aqueduct, excavated six sites, and conserved remains that were generally in poor condition. The surviving elements extend across the Preveza regional area, including Agios Georgios, Thesprotiko, Rizovouni, Stefani, Louros, Sfinoto, Archangelos, Kanali, and Nikopolis. Archaeological authorities mapped and defined the surviving sections as a protected archaeological area.
Remains
Watercourse and construction
The aqueduct formed a roughly 50-kilometre network between the Agios Georgios springs above present-day Filippiada and Nikopolis. Although the endpoints are about 30 kilometres apart in a straight line, the channel followed the terrain through hills, valleys, streams, and lowland areas. Covered channels, tunnels, elevated arcades, bridges, and retaining walls alternated along its course, maintaining a gradual descent toward the city.
The principal conduit was usually a covered channel. Its enclosed water passage, known in Roman engineering as a specus, was approximately 75 to 90 centimetres wide and about 1.2 metres high internally. The wall on the valley side consisted of rubble and mortar, while the floor and upright sides were coated with waterproof mortar. Brick vaulting or cast concrete formed the roof. In other stretches, one side was cut into the rock and the opposite side was built with terracotta bricks. Regular ventilation and access shafts allowed cleaning and maintenance, and in tunnels they also helped builders establish the required gradient.
Agios Georgios and the Louros crossings
Spring basin and northern channel
At Agios Georgios, water emerges from a karstic mountain at the northern end of the Louros valley. The spring is the outlet of a large aquifer and has a discharge of approximately 2.8 cubic metres per second. A collection basin once gathered the water before it entered the aqueduct. The basin is estimated to have measured about 9 by 10 metres, and part of it may survive beneath the church courtyard paving. Its exact position has been proposed either on the hillside behind the church or beneath the church and courtyard.
About 80 metres northwest of the church, a surviving conduit forms part of a roughly 230-metre stretch running north along the eastern slope of the valley. Several metres of its covering remain, including the only surviving vault of the former long-distance conduit. A short extension beyond the northern bridge may have acted as an overflow and helped regulate pressure in the watercourse.
Parallel Louros bridges
More than 200 metres northwest of the church, two parallel bridges carried the aqueduct across the Louros River to the opposite side of the valley. They run southwest, almost at right angles to the river, and survive to a maximum height of about 14 metres. The northern bridge is approximately 140 metres long, while the southern bridge extends for about 120 metres.
The northern bridge is the earlier structure. Two piers survive at its eastern beginning and four on its western side, while plans indicate that the bridge once bent slightly southward at a wider central pier. Its single row of arches may have required reinforcement during the first half of the second century under Hadrian, possibly because of structural instability, and the bridge may later have collapsed during the Roman period.
The southern bridge is better preserved, although several arches have fallen. Its alignment differs from the northern bridge by approximately 35 degrees. Fifteen piers supported the structure, whose upper arches were substantially higher than the lower ones. Two large arches at the eastern end crossed the ancient river channel, which followed a much broader bend toward the east than the modern Louros. Construction methods place this bridge in the late second or early third century, possibly during the reign of Commodus or under the Severan dynasty.
Brick formed the visible structure of both bridges, with rubble and mortar filling their interiors. The piers measured approximately 3.80 by 3.60 metres and were strengthened by buttresses measuring about 2.40 by 1.80 metres. Gaps of roughly 3.80 metres separated the piers, and superimposed arches connected them. A cornice-like feature ran around the principal piers and buttresses at the level of the arches.
Tunnels and valley structures
Kokkinopilos tunnel
About 1.5 kilometres south of the Louros bridges, the aqueduct entered the eastern side of the Kokkinopilos tunnel and crossed westward through a hill into the next valley. The passage is estimated to have been 400 to 500 metres long. Its entrance is about four metres high, but the roof quickly descends to approximately 1.5 metres. Tool marks remain visible on the walls, and the tunnel follows an S-shaped course rather than a straight line.
Surface shafts were cut at intervals of approximately 40 to 50 metres for ventilation and access. One section was lined with masonry, possibly to narrow the passage and increase the water’s flow speed or to support the shaft above it. Beyond the tunnel, the conduit crossed Dichalo Rema on a bridge about two to three metres long. Small structural remains and sinter deposits, formed by mineral-rich water, identify this crossing as part of the aqueduct.
Xiropotamos and Stefani
Further remains survive in the Xiropotamos valley. Sections have been identified north of the acropolis of Kastro Rizovouni and in an underground course near Thesprotiko on the opposite side of the valley. The route between these points has been interpreted through alternative courses, including a longer northern curve following the valley contour and a shorter alignment that crossed the valley on engineered structures.
At Stefani, a tunnel approximately 20 metres long led into an above-ground channel supported by a retaining wall about 60 metres in length on the steep slope of Mount Valaoritis. The wall used opus mixtum, a combination of masonry materials including brick and rubble, and was later reinforced for about 30 metres in opus testaceum, a brick-faced concrete construction. A second retaining-wall section was probably abandoned and replaced by a parallel channel cut into the mountain.
About 900 metres farther west, near the church of Agia Paraskevi above Skala Louros, a deeply cut and well-preserved channel remains in the hillside. Near Sfinoto, three bridge piers survive. Additional underground sections and stream crossings continue along the eastern slope of Mount Zalongo.
Archangelos to Nikopolis
Bridge remains at Archangelos
Two groups of bridge remains survive around Archangelos. Northeast of the village, an above-ground channel became a bridge over a depression. A pier line extends for about 50 metres, with 19 piers identified and 11 still visible. Surviving sections reach up to seven metres in height. Two piers stand about 3.5 metres away from the line formed by the other nine, suggesting that a parallel replacement bridge was constructed.
The aqueduct also passed underground beneath the present village. At its southern entrance, another line of piers survives on both sides of the national road. Thirteen piers remain, while further piers were removed during road construction. Foundations representing a second parallel bridge may belong to a later restoration phase.
Kanali and the approach to the city
Farther south, the aqueduct again entered an underground course and crossed a stream on a bridge east of Kanali. From there, channels and elevated piers carried the water toward Nikopolis. On the plain northwest of the city, the conduit was raised on a line of piers. About 1.5 kilometres before the city wall, the line divided, and four surviving piers display different brick types that probably reflect later repairs or the replacement of earlier supports.
The eastern branch served Proasteion and its public facilities, including the baths associated with the Aktian Games, athletic and cultural competitions held at Nikopolis in memory of Augustus’s victory at Actium. Pier remains south of the stadium indicate a connection with the city’s northern baths. The main branch continued south along the edge of Nikopolis, following the line of a city wall that was never built in this sector.
Fountains and urban distribution
The west-gate nymphaea
Two matching nymphaea, monumental public fountains, stood beside the west gate of Nikopolis on opposite sides of the city’s main east-west street. The southern fountain complex probably belongs to the first half of the second century, while the northern one probably dates to the early third century. The structures stood about 26 metres apart across the street.
Each fountain had a rectangular basin and high, thick walls on the three sides facing away from the street. Marble faced the walls, which contained seven large niches positioned about 1.85 metres above ground level for fountain taps. Other niches held statues of emperors, donors, and deities. The buildings were probably about seven metres high and consisted of a single storey.
The aqueduct crossed the street at the upper level of the destroyed west gate. Raised storage and control basins, called castella aquae, stood behind the rear walls of the fountains. Lead pipes carried water from these basins to the outlets, while overflow flowed into an open stone channel.
City distribution points
The main conduit continued along the western and southern edges of Nikopolis, with pier remains immediately inside the city walls. Repairs are visible along this route, whose comparatively rough construction may reflect a later building phase. A distribution basin known as a castellum divisorium would have divided the supply among the city’s districts and southern baths. Two other water towers or distribution basins, called castella, have been found within Nikopolis, including one at a central meeting point of the principal streets.
A small fountain complex was excavated in the northeastern part of the city near the House of Ekdikos Georgios. It may have served religious rituals and had a water-distribution basin on its roof. Together with the surviving channels, tunnels, retaining walls, bridges, elevated piers, collection basins, and public fountains, these urban structures show how the long-distance system was converted into a network serving different parts of Nikopolis.
