Andelos (Spain)

Roman aqueducts: Andelos (Spain) Muruzabal de Andion - ANDELOS
For the photo's, see below
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It could have been such a nice example of the water supply system of a Roman city: the dam, the aqueduct channel, the water reservoir, the arcade or siphon, and the castellum divisorium of Roman Andelos, see the drawing below. BUT:
1. There are severe doubts whether the (first) dam of Iturranduz (2 km west of Andelos) was of Roman origin - as always presented in the literature, see below -
and the remains of the aqueduct channel from the dam to the 'deposito' (reservoir) are still missing, so it is more likely that the water behind the dam was for local irrigation;
2. There is a Roman core present in the water reservoir close to the city, but in its present manifestation it is of Late Roman date or even later.
3. According to the present views, the so-called castellum aquae was for sure not a water distribution station but the base of a (Roman) temple.

So, what do we know of the water supply of the city of Andelos in Roman times?
- The Roman (and pre-Roman) origin of the city
- A modest water reservoir close to the city and a series of supports heading to the city
- The preference of the Romans to have clean and running water nearby for which they built aqueducts
- The presence of at least one Roman bath house in Andelos, a major consumer of running water.
And the rest is speculation, whether we like that or not.

About the separate elements:

The dam of Iturranduz

The vestiges of a great 150 meters long dam are to be found at a distance of some 3 km from the city of Andelos. This dam was used to contain water that would have come from nearby streams and gullies, however it was probably not strong enough and therefore, several decennaries later, another dam was constructed at the downstream side as a reinforcement.

Located at the border between the villages of Mendigorria and Cirauqui, the dam is commonly named as 'Puente del diablo' (Devil's bridge). Excavations have brought to light the remains of two containment works build in consecutive periods. The first one was made in ashlar, with 13 internal buttresses. Its total length is 150 m and it was built in the first century CE.
Due to the deficient water-resistance, the dam has been reinforced by a stronger wall, made of opus caementicium and 9 new external buttresses had been added. The total length of the reinforcement is 102 m and its extreme points are based on the rocks. The total theoretical storage capacity is estimated on 15.000 - 20.000 m3 water en it was built in the early 2nd c CE.

The water reservoir

The exit channel of the 'deposito' (reservoir), upstream view.
An enormous water reservoir was located outside the town, 300 meters away. With a 7.000 cubic meter capacity, this reservoir was used for water storage and settling. This reservoir is located in a wide excavated area of 85 m x 37 m. Two phases can be distinguished in its construction. In Roman times the reservoir was smaller and the walls and floor were made watertight using a layer of hydraulic mortar. On a later moment - Late Roman or later - it was enlarged, and the walls were reinforced with 37 internal buttresses in order to offset the horizontal forces of the ground when the reservoir was empty. The inspection chamber and the control device belongs to this time.

Via this inspection chamber the water went into the aqueduct. The small valley that runs between the reservoir and the village made it necessary to build an arcade or a siphon system. The water runs through a lead pipeline that was placed in a stone channel. Only the bases of this arcade / siphon are left and heads towards the city of Andelos.

The aqueduct in the city

Following the direction of the Decamanus, joining the south-west sector of Andelos, a branch of the aqueduct was constructed for the purpose of supplying water to the lower part of the town. During the excavation process, nine supports were found comprising large ashlars, with the upper part in the shape of a diamond tip.
Each of these stones had been prepared to support the first voussoirs (springers) of two arcades. These nine supports could hold up a section of eight arcades over which the lead pipe or channel carrying the water would have been constructed. This hydraulic construction has been dated to the early 2nd century CE and the arch bases are directly embedded in the pavement, which has been dated to the 1st century CE. The 6 meter width of the Decamanus, parallel to the row of supports, made it possible to combine the supply of water with pedestrian and vehicle traffic, with 4 meters available for use as a public thoroughfare.

Historical background

The Ebro valley was one of the first areas in Spain to be settled by the Romans. Around the 2nd century BCE Pompaelo (Pamplona) was founded and the existence of Andelos was clearly documented. The Roman town of Andelos experienced its golden age during the 1st and 2nd centuries CE, reaching civitas status in 74 CE and achieving considerable urban development.

Andelos was founded on a former human settlement dating back to the Iron Age (4th and 3rd centuries BCE) which appears to have progressively and pacifically assimilated Roman culture. Religion is a good example of this gradual romanisation: the inhabitants adopted the Roman era (an altar used to make sacrifices to the gods) as part of their ceremony of worship. Although these altars were initially dedicated to indigenous divinities (Larrahi, Losa, Erensa), over the years they were consecrated to purely Roman gods, such as Apollo.
The discovery of a number of milestones in the vicinity indicates that Andelos was located at an important crossroads, between Gracchuris / Gracurris (present Alfaro), Calagurris (Calahorra), Pompaelo / Pompalo (Pamplona) and other towns and cities.

It is estimated that Andelos could have had as many as 2,500 inhabitants, distributed amongst its various neighbourhoods, streets and houses. In Andelos there is a residential quarter with spacious houses, well paved streets, public buildings and shops, and a craftsmen's district, with stores, and even a laundry.
An exceptional finding was an interesting inscription in the Iberian alphabet, made on the floor of one of the houses which however has not yet been satisfactorily translated 'likine abuloraune ekien bilbiliars'.
The name [Muruzabal de] Andion seems to be derived from Andelos - as named by Ptolemy (II,6,66) - via Andelon.
Little is known of Andelos between the 4th and 10th century. During the Middle Ages it was inhabited and was called Andion (64 families in 1330). However in 1348 a great plague left the town uninhabited and it was then almost forgotten until the start of the archaeological work in the 2Oth century.

Wilke D. Schram
Part 2 is mainly based on the publications below; part 3 stems from the museum leaflet (with some alterations)

Wilke D. Schram

Modern - LATIN

Item Info
Length 0,3 km?
Cross-section Unknown (lead pipe?)
Volume Unknown
Gradient Unknown
Period Augustan and later
  • Post-Roman dam
  • Modest Roman / voluminous
    post-Roman reservoir

Recommended literature :
  • M.A. Mezquiriz Irujo and M. Unzu Urmeneta (1988; reprinted in 2004) : El abastecimiento de agua a la ciudad romana de Andelos (in: Arqueologia Navarre vol 7 separata (1988) pag 288ff)
  • E. Sanchez Lopez and J. Martinez Jimenez (2016): Los acueductos de Hispania, construccion y abandono ((only ?) from the web)
  • M. Unzu, P. Prieto and M.G. Barberena (n.d.): Andelo, the hydraulic system (poster presentation)
  • N.N.(n.d.): Roman town of Andelos (leaflet of the Andelos museum)
Recommended websites   :
How to visit                  : Andelos is situated 1 km SW of Muruzabal de Andion.
Note that the (excavation of the) city of Andion is only accessible during office hours of the museum.
Both the reservoir ('deposito') and the dam are signposted and permanent open to the public

HOME More literature on more aqueducts Last modified: November, 2016 - (webmaster)


Iturranduz dam

Plan of the dam

Double dam


Altar stone?

Between two dams


View into the outlet


South side

Plan of the deposito




View on the outlet 1

View on the outlet 2

Model of the outlet

Outlet pipe 1

Outlet pipe 2

Front view

Taking the picture

Exit channel

Pillar foundation


Bases and springers

Castellum aquae?

Hypothetical view

Bath house