Roman Aqueduct La Rioja: Ancient Water Management in Alcanadre, Spain
Site at a Glance
- Rating
- 4.1
- Popularity
- Very Low
- Country
- Spain
- Eras represented
- Classical
- Civilizations
- Roman
- Site type
- Infrastructure
- Remains
- Aqueduct
History
The Roman Aqueduct La Rioja is located in the municipality of Alcanadre, Spain. This water channel was constructed by the Romans, likely between the 1st and 2nd centuries BCE, as part of a broader effort to manage water resources in the region.
During the Roman period, the aqueduct served as a key component in transferring water from the left bank of the Ebro River to the right bank. Unlike many Roman aqueducts designed primarily to supply urban centers, this system appears to have been intended mainly for agricultural use, supporting irrigation and farming activities in the surrounding lands. The water source originated in the Sierra de Codes near Lazagurria, in the neighboring region of Navarre, and the channel followed a route parallel to what is now the NA-134 road before crossing the Ebro River.
Some scholars have proposed that the aqueduct may date to a later phase, possibly the very late Roman period or even beyond, based on the irregular quality of the masonry and the size of the stones used in its construction. This suggests that the aqueduct might have undergone modifications or repairs after its initial building phase.
The name “Alcanadre” itself reflects the historical importance of the aqueduct in the area. Derived from the Arabic term “al-Qanatir,” meaning “the bridges” or “the aqueduct,” the name points to the lasting recognition of the structure through successive cultural periods, including the Islamic presence in the Iberian Peninsula.
In the 19th century, the construction of a railway line connecting Calahorra, Alcanadre, and Logroño followed a path close to the ancient aqueduct channel. This modern development impacted the remains of the aqueduct.
Archaeological investigations, particularly those led by Maria-Angeles Mezquiriz, have documented the aqueduct’s remains and provided detailed studies of its construction techniques and eventual abandonment. These studies have helped clarify the aqueduct’s role in the region’s water management and its historical timeline.
Remains
The Roman Aqueduct La Rioja extends approximately 600 meters and originally featured around 118 arches, of which 13 still stand today. These arches are arranged in a straight line running from the modern road toward the shore of the Ebro River. The structure was built using yellowish ashlar masonry, a technique involving carefully cut stone blocks, set around a core of concrete. However, the masonry is noted for its irregular stone sizes and relatively poor quality compared to other Roman constructions.
Each arch spans about 4.44 meters, supported by pillars roughly 1.10 meters wide. The entire width of the aqueduct, including protective parapets, measures close to 3 meters. On top of the bridge, the water channel, known as the specus, is about 1.82 meters wide. Before reaching the bridge, the channel broadens, measuring 2.52 meters at the bottom and nearly 3 meters at the top, with a maximum height of 1.18 meters, allowing a substantial flow of water.
A distinctive feature of this aqueduct is found near a sharp 90-degree turn in the channel, where a branch line includes a set of three grooves carved into the stone. These grooves likely served to regulate water flow and may have functioned as a filtering system, a rare characteristic among Roman aqueducts.
On the right bank of the Ebro River, the aqueduct’s abutment includes a surviving arch approximately 5 meters high. This taller arch was necessary to accommodate the changes in terrain elevation, ensuring the channel maintained a steady gradient for water flow.
Over time, some arches have collapsed, and stones from the aqueduct were reportedly repurposed in the 20th century for the Canal of Lodosa irrigation system. Despite this, several sections of the channel and sluice gates remain visible near the NA-134 road west of Lodosa. The sluice gate features grooves designed to hold wooden planks, which could be used to control water flow or support a filtering screen.
The aqueduct’s capacity to carry water is estimated at nearly 3 cubic meters per second, or about 250,000 cubic meters daily. This volume underscores its importance in supplying water for agricultural irrigation rather than urban consumption, reflecting the region’s reliance on farming during the Roman era.
Together, these remains provide valuable insight into Roman engineering adapted to local needs and terrain, as well as the long-term impact of this infrastructure on the landscape and subsequent water management systems.
