The earliest irrigation
works in Spain descend from the Romans. After the downfall
of the Roman empire and the arrival of the Visigoths (4th
century) a large part deteriorated.
How? Canals digged out of the rock
(sometimes 1 m wide), small gutters, concrete grooves, 'diversions'
made of pvc, hollowed out tree trunks. The walls
of the canals are often made of natural materials (twigs,
ground and sods). That's why the slopes and sources
are "fed" with part of the water that oozes
away. Sometimes the flow is canalised between walls
of rocks, put there ages ago.
The arabic-islamitic immigrants ('andalusíes'), who
brought their irrigation techniques to Spain in the 8th
century, re-established and improved what
was left of the Roman system and built a new irrigation
(not just the acequias, but also the agricultural terraces in the
Alpujarras). Acequia means litteraly
'irrigation canal'. Acequias are a irrigation network of main and secundary
canals. Through these canals flow rain and meltwater of
the mountain tops to the agricultural terraces on the
slopes and the farms in the valleys, via branches and
sluices. You can still find a working acequia-irrigation
system in Alpujarras, on the southern flank of the
Sierra Nevada mountains in Andalusia (Southern Spain).
on the photographs for more information on the splendid
aqueducts of Segovia and Alhambra
In 1574 in Plasencia
this "Acueducto de San Antón" was finished.
Four kilometers northwest
of Tomar (Portugal)
one can find the remains of the "Aqueduto de Pegòes Alto", (1593-1614, architect Filippo
Terzi). It took care of the water supply of the convent. The aqueduct is 5 km long
and has 180 arches. You can walk on it, if you are not afraid of heights!