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ROMAN DAM OF ALMONACID DE LA CUBA

 

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The knowledge and the existence of the Roman dam of Almonacid de la Cuba is connected to a Roman town whose name we don’t know (maybe Beligio) and that is was located in a close hill called Cabezo de Nuestra Señora del Pueyo in Belchite.  At the same time the dam is only one of the several elements of an hydraulic system that the Romans built in all the Ebro valley and some of its tributary rivers, such as the Aguasvivas river in the case of this dam, not only to supply water to the cities and its inhabitants, but to the agricultural exploitations all around the valley.

 

Hydraulic Roman resources in the Ebro valley, according to BELTRÁN LLORIS, Miguel: “El agua profana en la cuenca media del valle del Ebro: AQUA DUCTA.  La captación del agua, presas, embalses, conducciones”, en AA. VV.: Aquaria:  Agua, territorio y paisaje en Aragón, Zaragoza, 2006

The dam of Almonacid de la Cuba is located in the middle watercourse of the Aguasvivas river, north of the Belchite hills, in a gully in a limestone area and it supports the road from Belchite to Almonacid de la Cuba.

Its final aspect, which we can observe at the present, shows walls that adapt a rectangular section in the top; in the middle of its downstream face –where the water is evacuated- the dam is shored up by a buttress cut in a series of steps; in its upstream face –where the water is collected- there is another buttress cut in a series of steps too, but it is not visible due to the sediments.  The narrow gully where the dam was built gives to it the wedge-shaped aspect, leaning on the natural rocky walls; this fact helped to protect and preserve the dam undamaged.

 

(Photo:  Roberto Lérida Lafarga 19/11/2007)

The dam should basically be built in three phases to reach its definitive aspect.  First of all, the ancient dam should be a dam “of arches”, built under Tiberius (I century a. C.) with arches and two perpendicular buttresses in the downstream face.  The central part of the dam is made with opus caementicium –strong mortar- and opus incertum –stones with small and irregular size pressed together with mortar- and this part is recovered by blocks of stone, making a wall in two different ways:  opus vittatum –small blocks of stone put in courses- and opus quadratum – cube-shaped blocks of stone with a aesthetic effect-  A section of the upstream face –with system of dressed ashlars with plane surface- and the horizontal platform of the downstream face –the overflow channel in the top of the dam- belong to the firs phase.

 

Plan of the dam “of arches” of Almonacid de la Cuba, according to Arenillas M. et alii, La presa de Almonacid de la Cuba. Del mundo romano a la ilustración en la cuenca del río Aguasvivas, Zaragoza, 1996

The first reform was made in one of the most damaged parts, the downstream face wall and the overflow channel; in this reform rustic ashlars were used, a building way used in the age of the emperors Claudius and Nero (still in the I century a. C.); this ashlars give a bigger sensation of hardness.  From this reform we can see the holes of the cramps that joined the ashlars. In addition, the courses on the bottom of the buttress were lightly cut in a series of steps to increase the wideness of the support.  The superposition of stone faces means works of maintenance in the dam, wore down by the water pressure, especially in the overflow channel.

 

Hole of a metallic cramp to join ashlars in opus quadratum

(Photo:  Roberto Lérida Lafarga 19/11/2007)

In a second reform the dam became a dam of faces (upstream and downstream faces).  This modification took place in the II century a. C. (in the age of the emperors Trajan and Hadrian).  The top of the dam and the overflow channel were elevated 1,80 metres; the width of the downstream face was reinforced with a terrace in steps with opus caemeticium –it is preserve with six courses- and a vertical wall in opus vittatum.  Soon, in that century, it was necessary to build a buttress cut in a series of steps with big ashlars in opus quadratum in the downstream face.  With these modifications the dam had the same aspect upstream and downstream.  This system with buttress cut in a series of steps responded to the situation of the dam, in a narrow gully with rocks.  The accumulation of sediments filled the damm upstream, so in the III century d. C. it left off being used.

 

Vertical section of the dam where the two dams and the two buttress cut in a series of steps can be seen, according to Arenillas M. et alii, La presa de Almonacid de la Cuba. Del mundo romano a la ilustración en la cuenca del río Aguasvivas, Zaragoza, 1996

The dam of Almonacid de la Cuba has not parallels in the hispanic dams nor in the dams from other Roman provinces, because this shape is very singular:  two faces cut in a series of steps in opus caementicium and opus quadratum and the evolution from a dam “of arches” to a dam “of buttress in steps”.  Typologically the drain excels:  here it is a double with an overflow channel in one of the laterals and with a deep outlet of water through a tower (castellum ad caput, “tank in an extreme”) that disappeared in this dam and it should be upstream.

 

(Photo:  Roberto Lérida Lafarga 19/11/2007)

The researchers have seen the remains of two channels (rivi) of immediate derivation: one of them could be a former overflow channel later covered; but the other channel is preserved in two sections on the natural limestone and must have supplied water to the lands of Belchite and probably urban water to the tank (castellum) and the thermae of the unknown town in the hill of the Cabezo de Nuestra Señora del Pueyo in Belchite (maybe Beligio).  In fact the main ditch of Belchite, between this village and Almonacid de la Cuba, is the original Roman channel that in the present irrigates these lands, until the hill of the unknown Roman town and has been maintained up today.  In the close gully of Barcalien there are remains of an original Roman aqueduct with sections hollowed out on the natural rock with 0,65 and 0,75 metres wide and other sections with a covered gallery with semicircular vault; the floods through a near gully destroyed seriously this covered gallery.  The aqueduct should reached the old Belchite through the Tercon, by the bitch of the Playa –an area of natural gravel- up to the fields at the foot of the hill of he Cabezo de Nuestra Señora del Pueyo, crossing the gully of the Viñas with stone pilasters –unfortunately no preserved- and with specus (the channel on an aqueduct) in limestone.

 

Two channels go out from the dam:  a now dry channel leads to the mill –the building where the channel disappears-; the channel with water is the irrigation ditch of Belchite and the aqueduct.

(Photo:  Roberto Lérida Lafarga 19/11/2007)

In 1787 a fulling mill and a cereal mill were built; so it was necessary to repair the dam downstream to adapt the primitive overflow channel and to divert it to a new channel for the mills; in addition, then a new reform was made: in the top of the dam another big overflow channel was made perforating the dam’s faces and putting again the Roman ashlars in their place

 

(Foto:  Roberto Lérida Lafarga 19/11/2007)

Technically the size of the dam is 120 metres long, 34 metres high and 27 metres wide, with a capacity of 6.000.000 m3 of water, not only for urbane use, but for agricultural use –up to 7.000 hectare (=17.297.000 acres) approximately-; the dam is made with opus caementicium, opus incertum, opus quadratum and opus vittatum; the limestone ashlars came from a quarry near a modern village called Fuendetodos (where the famous painter Francisco de Goya was born in the XVIII century); the dam had an overflow channel that became the eye of the dam, with a drain –a diversion channel- known as “bottom of gallery” and with a outlet of water through a tank (castellum ad caput).  This dam is the highest dam of the dams known in its age of building around the Roman empire:  34 metres high with more than 100 metres long.

 

 

Sources:

- BELTRÁN LLORIS, Miguel: La presa romana de Almonacid de la Cuba, Zaragoza, 2006

- BELTRÁN LLORIS, Miguel: “El agua profana en la cuenca media del valle del Ebro:  AQUA DUCTA.  La captación del agua, presas, embalses, conducciones”, en AA. VV.: Aquaria:  Agua, territorio y paisaje en Aragón, Zaragoza, 2006

- ORTIZ PALOMAR, M.ª Esperanza y PAZ PERALTA, Juan Ángel: “La vida corriente de las aguas en el Aragón romano.  Trabajos públicos y placeres privados”, en AA. VV.: Aquaria:  Agua, territorio y paisaje en Aragón, Zaragoza, 2006