Cella (Spain)

Roman aqueducts: Albarracin -> Cella (Spain)
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The Roman aqueduct of Albarracín - Cella

The Roman aqueduct of Albarracín to Cella is probably the biggest work of Roman engineering preserved in present time in Aragon and one of the most important hydraulic works in the Iberian peninsula. At the same time it is an unusual and mysterious work to us because we do not know exactly what was its purpose given its high water capacity. It seems that initially the aqueduct supplied only water to a small Roman town that should be under the modern Cella and there are no archaeological remains that give us testimony of other Roman cities in this area. So scholars think that, besides the urban use, the aqueduct had also (an) industrial and/or agricultural tasks(s), although we do not know for what kind of activity it was used. Some scholars think that the aqueduct water was used for fulling, forges or wheat mills which should be located in the area near modern Cella.

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Nine detailed maps of the Roman aqueduct from Albarracin to Cella. From: Almagro(2002)

One should realize that tunnels in Roman aqueducts were particularity in the public works of that time. The tunnel of the aqueduct of Gea de Albarracín to Celia was almost five kilometers in length, and comparable to the 5,64 km long drainage tunnel of lake Fucino (Italy); that one was equipped with shafts up to 122 m deep.
There are greater lengths of tunnels in the Empire, for example we know that the tunnel in one of the aqueducts of Aix-en-Provence (France) was about seven km long with 80 m deep shafts; the Drover-Berg-tunnel (Germany) was only 1,66 km long but it is suspected that the one in Bologna (Italy) had an impressive 20 km length.
The present tunnel between Gea and Cella was equipped with about 140 shafts which were up to 50 - 60 m deep.

On the other hand, one can say that this aqueduct could be one of the first water diversions in history between different river basins, because the aqueduct took water from the basin of the modern Guadalaviar-Turia and diverted it into the basin of the modern Jiloca-Jalón-Ebro.
The aqueduct of Albarracín-Cella is dated in the first century BCE, as most of the big works built in Hispania and in the modern Aragón in the Roman age.

The Fuente de Cella (the Cella Fountain) is an artesian well, probably the work of the Templars, settled in this town after the Reconquista at the end of the 12th century by the troops of King Alfonso II. Originally, the Fuente was probably an excavation carried out on a small pre-existing spring in order to maintain its flow during one of the frequent droughts of that time.
However, its current appearance is the result of the reform carried out by the Italian engineer Domingo Ferrari between the years 1729 and 1730. It has an elliptical shape (major axis of 34,83 m and the minor of 24,23 m) and has two caves at both ends of its major axis, through which its water is poured into two irrigation canals. Inside, they look like two large 'mouths', excavated in limestones.

The flow of the Fuente de Cella is greatly influenced by the variations in the rainfall regime of the Sierra de Albarracin. During dry periods, it decreases drastically and to the contrary, after a period of rain it soon recovers. It is usual that flows above 2000 l / s (173.000 m3/d) alternate with periods in which the spring dries up. For the period between 1974 and 1992, its average flow was 600 l / s (52.000 m3/d), which means an average annual discharge of 19 million m3 / year. Along with the spring of Ojos de Monreal, the Fuente de Cella is thus one of the largest outbursts of underground water in the province of Teruel.

From the local information tablet (in Spanish).

The biggest problem in the building of the aqueduct was the combination of the long distance between its two extremes (about 25 km between Albarracín and Cella) and the geomorphology in its route, because the aqueduct, following partially the river bed of the Guadalaviar river, penetrated into the rocks of the Albarracín Sierra, so that the work became more complicated, and was forced to make a route adapted to the geomorphology, and to exploit the level curves to keep an incline enough for the water to flow through the aqueduct.

Some people wrongly used to call only the arches that support a channel an aqueduct, like the 'aqueducts' of Segovia, Tarragona or the Pont du Gard in France, while an aqueduct is the whole work of supplying water from its starting point up to its arrival in an urban nucleus. So the most parts (85%) of the Roman aqueducts were dug in the rock and were subterranean; the arches were only a partial solution to avoid valleys, stream beds or to beat unevenness of the terrain in the route of an aqueduct. The aqueduct of Albarracín to Cella had no preserved arches - and probably never had - that overcame unevenness in some place of its route.

The Cella aqueduct had its source at the north side of Albarracin, near El Casaron de la Fuente, in the riverbed of the Rio Guadalaviar. At present the spring is covered and the center of a modern pump house, still delivering water to the surrounding villages.

The plan of the aqueduct of Albarracín-Cella in its first visible sections (tramos I - V) runs parallel to the Guadalaviar river. Soon it penetrated into the galleries dug into the rock that alternated with channels in the open air. From its almost 25 km length (the distance between the source and Cella is about 15 km as the crow flies) some 9 km of the aqueduct was dug in the rock. The galleries were equipped with 'lumina', windows for ventilation and removal of cut rock.
The circa 5 km long tunnel between Gea de Albarracin and Cella, which galleries were sometimes 60 m under the surface, was equipped with (some 140) vertical shafts (putei) for ventilation, maintenance and cleaning. During construction of the aqueduct, they were used by workmen to enter and to remove mud and residues with pulleys.
Scholars have calculated that during the construction of these underground galleries 35.000 m3 of rock were extracted, galleries, tunnels and shafts together. It has been calculated that the mean gradient of the aqueduct was 0,3% - which is quite usual - and its capacity 24.000 m3/day.

We do not know when the aqueduct stopped being used, but we know that it was not in use in the era of the Reconquista so people had to create their own system of water supply. The wonderful and powerful artesian spring of Cella, dated in the XII century, is a testimony of this need of water. We also know that, after its abandonment, the galleries dug in the rock were used as shelter to shepherds and farmers and as lairs to animals during centuries.

Just east of Gea, along the A-1512, one can find the information center - called Centro de Interpretacion - focused on all aspects of the aqueduct, see the museumwebsite and the one of the province.
More information by mail and telephone (0034) 978 702 100 (town hall)

Opening hours (during the summer):
- Tuesday - Saturday; 10 - 14 and 17 - 20h
- Sunday: only 10 - 14h; Monday closed.

On Saturday and Sunday also guided tours are organized at 11.00 and 13.00h.

A visit

Along the course of the aqueduct, eight sections (tramos) are adapted to visitors, with parking facilities and information panels, see the main map. A signposted footpath has been created between Cella and Gea de Albarracin. Between Gea and Albarracin an adequate footpath is missing, so - for your own safety - it has been advised to use a car to visit section (tramos) I - IV.

Our suggestion is to start the tour in Albarracín. The sections I, II and III are close the secondary road A-1512. Section IV is located just before arriving to Gea de Albarracín and it is advised to visit these spots by the car, sometimes by means of a non-asphalted track but in good condition.
Section V is behind Gea and it is necessary to take another non-asphalted track. Here starts the 9,5 km long path to Cella by foot, bicycle or horse. If you make the route by car, our suggestion is after visiting tramo V to come back to the road A-1512, because, although there are signposts to section VI, these are confusing and one can easy get lost in the land tracks. After coming back to the road A-1512 you better take the secondary road TE-V-9011 up to Cella and from here you can visit the sections VI, VII and VIII, partially using land tracks in good condition.

The sections (tramos)

Tramo (section) I: Azud (dam) del Albergue de Albarracín.
Although the mill dam is modern, the height above sea level, the plan and the remains of the aqueduct suggest that the water collection of the Roman aqueduct should be made in a point near this mill dam.
But according to present insights the source of the aqueduct should have been the spring just north of Albarracin.

Tramo II: Gallery and tunnel near Santa Croche castle.
This is the first preserved section of the aqueduct where it ran through the mountain in dug galleries. After a short section in the open air similar to an irrigation canal, the aqueduct penetrates into the mountain, where the distance of the specus to the outer side of the mountains allowed that many lumina ('windows') were opened to the exterior. In these galleries the average height is circa 1,95 meters and the width is circa 1,25 meters.

Tramo III: Azud (dam) de Gea de Albarracín.
Near the mill dam in the river Guadalaviar the aqueduct runs, dug in the rock, parallel to the steep mountains along the river with many lumina at regular intervals.

Tramo IV: Barranco de los Burros (donkeys ravine).
This is probably the most spectacular section of the aqueduct due to its adaptation to the terrain and to the beauty of this narrow ravine. Instead of building arches to cross the gully - that would have posed problems of conservation of these structures - the Roman engineers preferred, with a tight contour line, that the aqueduct followed the curve of the ravine and kept dug in the rocks, although the entry to the ravine is made with a specus in the open air. In the rock walls of the ravine one can see lumina or luculi - small lumina - for ventilation and to extract debris and residues from the aqueduct.

Tramo V: Cañada (defile) de Monterde and Las Hoyas.
Here starts the 5 km long tunnel. In this section the aqueduct is underground and it is possible to see the ventilation shafts, in some cases of considerable depth.

Tramo VI: La Tejería.
Here you can see the last two shafts of the aqueduct before it comes to light near Cella. From here the aqueduct runs in the open through the Rubiol ravine and it was made as an artificial channel which walls were made of rough stone and mortar.

Tramo VII: Las Eras (thresh floors) de Cella.
For two km the channel of the aqueduct runs in the open, dug in the rock. The channel is circa 1,0 meter deep and 0,60 meter wide. One can see different parts of the aqueduct in the open air, restored in the last years.

Tramo VIII: Urban center of Cella.
This is the end of the aqueduct. We do not know where the castellum aquae was, i. e. the start of the water distribution in the city. Archaeologists have discovered the remains of a big reservoir (cistern) plastered with hydraulic mortar - opus signinum - 15 meters long, 13 meters wide and 2,3 meters high with a capacity of over 400 m3 near the Plaza Mayor in Cella.
The city could (and still can) also boost on a strong spring, but on much lower level than the end of the aqueduct and the reservoir.

Wilke D. Schram
Mainly based on the English text of dr. R. Lerida Lafarga with alterations

Albarracin -> Cella

Item Info
Length 25 km
Cross-section (in tunnel) 0,8 - 1,25 m wide and 1,7 - 2,2 m high
Volume 24.000 m3/day
Gradient 0,2 (0,1 - 0,6) %
Period unknown / 1 c CE
  • Galleries with 'windows'
  • 98% subterranean
  • Tunnel of circa 5 km length
  • circa 140 shafts

Recommended literature :
  • A. Almagro (2002): Acueducto romano de uso industrial de Albarracin a Cella (Teruel) - A. Almagro (see the Traianus website)
  • I. Moreno Gallo (2010): Analisis technico y constructivo del acueducto romano de Albarracin a Cella (see the Traianaus website)
Recommended websites   :
How to visit                  : see above

HOME More literature on more aqueducts Last modified: December, 2017 - (webmaster)

Map of the Cella aqueduct

Spring house

Inside the spring house

Tramo 2-1

Directions Tramo 2-1

Channel and windows

View into the tunnel

In the open air

Tunnel entrance

Tramo 2-2

Directions Tramo 2-2

Open air channel


Protective measures

No remains?

Tramo 3

Directions Tramo 3

Another view

Room with a view


Tramo 4

Directions Tramo4

Six apertures

Five apertures

Second dam

Open channel




Tramo V

Directions Tramo5

Channel from Tramo IV

Start of the tunnel

Two side exits

Exit channel

Top of a shaft

Another shaft top

Signposted trail

Cella spring pool

View into the pool

Exit of the pool