Mills in Alto Aragón - central eléctrica


Sagarillo is a former village in the Hoya de Huesca county. Sagarillo is located at the northern end of the new embalse the Montearagón on the Río Flumen. The site is probably best reached from Apiés. From Huesca city take the HU-324. Then at the church of Apiés turn to roughly the East in a gravel road —the Camino de Liendas— which will first cross the Barranco de Barzón and then go for a more southerly course. Drive as far as you wish, but a good spot to park your vehicle may be near an old abandoned agri­cultural complex. Walk the rest of the way and soon you will have the view of (1).

(1) The aquaduct deep in the valley of the Río Flumen.
vertical stroke : site of the building before it was demolished — horizontal stroke : restitution canal

(2) The end of the canal with the pressure pit at right.

(3) Situation around 1980 — larger image
© – Vuelo interministerial
Only parts of the old hydroelectric powerplant have survived. The power plant is located just where the water from the new Montearagón reservoir will reach eventually. Therefore, the buildings (❶ in 3) were demolished and only the water works remain. The site nevertheless remains worth a visit.

In the aerial photo from around 1980 (3) we see in the corner top right the walls of the old village. At the bottom in the middle are the former buildings of the power plant (❶). The channel is the white stripe that runs from top to bottom. It starts upstream from Sagarillo (❹ shown on larger image) and is over 900 m long. It is deep and wide and where it is not overgrown, one can easily walk in it (15). Where the acequia has to cross the Barranco del Mont, a solid aqueduct (❸, 16) has been built with two arches. The rest of the route runs between earthen dikes and is reinforced with masonry.

The last 100 m of the canal (❷) rise above the ground and become an aqueduct supported by arches (6). At the end of the aqueduct, if you look closely, you can distinguish a black square, the pressure pit or cubo (10–11). Also a gray line which is the tube that feeds the turbines. To the left of the number ❷, a white comma is visible: an overflow. In that place the edge of the channel is a bit lower (7, 9) and there is also a wooden trap door (8) to divert all the water to the flat terrain next to the canal.

(4) The aquaduct of Sagarillo seen from the pressure pit.
The rock formation of the Salto de Roldán in the background.

(5) The aquaduct looking towards the pressure pit.

(6) The arches of the aquaduct near the overflow.

(7) Overflow and flush.

(8) Door making it possible to flush the canal.

(9) Flush (left) and overflow (❷ in picture 3).

(10) Pressure pit and feeding tube for the turbines.

(11) End of the canal with feeding tube. The mill stood at left side of picture.

The buildings have been demolished, but the parts underground are still there. The bed of the Río Flumen is densely covered in that place (below the mill in 3) with tall and dense Caña común (Arundo donax, Spanish cane) and unruly blackberries and it took some time to clear the exit of the underhouse (cárcavo). But it was worth every scratch.
The gravel road from Apiés to San Julián de Banzo runs between the mill and the river. The drain must therefore pass under the track and at that point (13) it is several meters deep and covered by a barrel vault supporting the road. Closer to the mill, the roof is much lower (14) and the corridor runs in a slight bend to the discharge pipes of two turbines (12). A small colony of bats is living there, deep inside.

(12) Discharge pipes of the turbines.
(13) Tunnel with restitution channel.

(14) Restitution channel

(15) The watersupply channel

(16) Canal crossing the Barranco del Mont (❸ in picture 3).

If we take the maps of the Instituto Geográfico Nacional (Nos. 246, 247, 285, 286; editions of 1929, '30, '35), we see that two lines leave from Sagarillo (17). One to the south serving Chibluco, Barluenga, Sasa del Abadiado, and Loporzano . Another branch first heads north via Apiés and Sabayes to Nueno and then descends south again, serving Arascués, Lierta, Puibolea, Esquedas, Lupiñen, Ortilla and finally Montmesa. In the maps of 1953, branches are added in the southern sector to San Julián de Banzo and also Santa Eulalia la Mayor via Castilsabás.
From Loporzano, the network was extended to reach Bandaliés with Ayera and Arbaniés with Castejón de Arbaniés. West of Huesca it has only been extended with a short branch to Castillo de Olura near Lupiñen. Such an extensive network (17) explains why the construction was built so large with a very wide supply channel and two turbines. Fifteen villages around 1930 and nine more in the 1950s could demand much power, even then long before the explosion of home appliances. A lot of water must have been available to make this power plant a somewhat reliable source of electricity.

(17) Extension of the grid served by Sagarillo in the 1950s.

: Which is remarkable because also on the Río Flumen and much closer to Loporzano there is another mill (grain mill and powerstation) which operated until more than halfway the 20th century.

More about this mill in: A la búsqueda de molinos: Obras hidráulicas particulares
el Gurrión I.2017, N° 146, p20–24 — Download PDF (Spanish)

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