El Ojo del Canal (The Eye of the Canal)
The load bearing parts of this historic 18th century canal aqueduct has largely been hidden from view by 20th century road construction.
El Ojo del Canal is an aqueduct on the Imperial Canal of Aragon, one of the most important canal projects constructed in Spain.
Because of the desire to save money canal builders usually narrow the canal width across the length of the aqueduct, to the width of only slightly wider than one boat. On this, 68 mile long, late 18th century, canal, however, navigation was a secondary concern. Its main function was as an “acequia” with the main requirement being to transmit irrigation water from higher reaches of the Ebro, as effectively as possible. The Ojo del Canal aqueduct in Zaragoza, Spain, was thus constructed at full canal width to carry the canal waters over the Rio Huerva with minimal impediment to flow.
The canal is carried over the valley on an impressive single elliptical arch with an opening 30 feet wide with the canal carried about 60 feet above the river. The construction was of masonry, mainly limestone, and the historic pictures show it to be an impressive structure. The “eye” shape of the void through which the river flows is believed to have given rise to the name.
Unfortunately, in the 20th century, roads were constructed either side of the canal between the Cassablanca lock complex and a point just downstream of the aqueduct (as a one way system for vehicles). The bridges carrying these two roads over the Huerva were placed close alongside the aqueduct allowing pedestrians at road level only able to get a view the aqueduct through a narrow slot on the eastern side of the structure. In fact, because the canal does not narrow, if you were to walk past the aqueduct on one of these two modern road bridges you could easily miss the fact that an aqueduct was there at all. It does not change its width and the roads stop you getting the impression that you are above a river valley. Growth of trees on the river banks mean that you need to get quite close for a view of the arch.
What does identify the aqueduct is the presence on the eastern bank of the canal of a small building marked above its door ” Almenara del Nostra Señora del Pillar”. This historic structure houses a control gate system that can rapidly release canal water down a steep spillway into the river when canal levels are becoming high, as a means of preventing overflow of the aqueduct or down stream flooding. It is not clear whether release of canal water into the river would also be used to supplement river water flow in times of local droughts.
As the Passeo de las Reys de Aragon, on the eastern side of the canal, passes the building it turns to the left to become Passeo de Colon and between this road and the river is a small (unamed) park containing an outdoor gym. The park also contains information boards (in Spanish but with some excellent images) about the aqueduct and the park also provides a (quite difficult) access to the river which can afford a better view of the aqueduct’s engineering (which is impressive for it’s time).
Know Before You Go
Bus service 58 runs either side of the canal between the Casablanca locks ( on the tram route) and the aqueduct but it is a nice stroll down the canal from the locks if you want to walk.
On this route is a well maintained lifting footbridge which seems to indicate some degree of current navigation but in mid May 2024 none was apparent and the mooring points were displaying signs that they were not allowed to be used.
Whilst there are lots of images on the internet of people kayaking in the canal and even a Wikiloc kayak trail available for the stretch just upstream of Zaragoza the navigation rights are unclear.
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