It
takes around six hours to drive from Porto to the Spanish border and reach the
Aldeadávila Dam on the Douro River. The landscape changes surprisingly, from green to rocky. You cross plantations of eucalypts and get inebriated by their heady
scent. You get to minutely ordered vineyards and olive groves. You encounter fewer and fewer cars the more you drive, but you have to keep your eyes on the road, which is narrow and winding. Sooner or later the falling rocks signs get to you and with one eye you check for what is hanging over your head. It is only when you cross over to Spain at the Saucelle Dam and get to the Castilian plateau, that you finally see the dark granite boulders emerging from the ground. These rounded shapes described by Miguel de Unamuno as an antediluvian landscape of giant mushrooms, where used for generations to build low walls that demarcate property boundaries.
I visited Aldeadávila in late August: it was a very hot afternoon and the place looked deserted. From the power plant's viewpoint I could clearly see the three main elements that shape the landscape. The concrete parapet stands for all that was man made, the additions and the alterations; the rocks embody what appears to be permanent in nature; and the ever-changing sky adds a temporal rhythm to the scene. There is also the water, green and quiet, at the bottom, but I had to lean forward to see that.
In 1910 the Spanish government initiated conversations with Portugal to exploit the hydroelectric potential of the area. In 1927 they signed a trans-boundary waters agreement: Spain got the drop between the mouth of the Tormes and the Huebra Rivers, while Portugal got the stretch until the Tormes and after the Huebra.
The further delay in tackling the exploitation of the international section of the Douro had the enormous advantage of allowing the engineers to benefit from the extraordinary progress of the hydroelectric technique in the second quarter of the century.
Pedro Martinez Artola finally designed a concrete arch-gravity dam crowned by eight spillways that can release up to 12,500 m3/sec of water. It was built between 1956 and 1963 and like the Saucelle dam, it was placed at the end of one of the few granite massifs that cut the gneiss formations predominant in the Douro Valley, downstream from Zamora. Although the heroic story of its construction has always fascinated me, I will refer you to the interesting book by Alvaro Chapa and I will focus instead on the structure as it is today and on how it appears to the naive eyes of a visitor that comes here for the first time. Looking down is mesmerizing. At first glance the concrete and the rocks are seamless but a closer examination shows the sixty-years-old traces of construction: the access road for the trucks, the anchoring structures of the rock crushers and the trommel screen, the bases for the blondins.
Once the construction was completed and the machinery was removed, Nature regained its role as a main actor. Today the Portuguese side is protected by the Parque Natural do Douro Internacional and the Spanish side by the Parque Natural de Arribes del Duero.
But if you really want to understand how much the landscape has changed since then you have to go twenty kilometres further and visit Pozo de los Humos. When you reach the falls you will realize what is now missing at Aldeadávila. The river has been silenced. Its song, very much present at Los Humos, has been replaced by the surreal hum of the power plant. This persistent sound is the only element that today seems out of context: while the sculptural structure can be perceived as one with the granite, the electric buzzing is not a good match.
It is also worth considering that it is what we don't hear and what we don't see that matters the most. We don't see the hundreds of meters that were excavated below our feet to accommodate the Francis turbines. We don't hear the waters constantly pushing through the six penstocks that feed the power plant. What we do know is that Aldeadávila alone generates ten per cent of all hydroelectric power produced in Spain.
During the twentieth century the hydrology of the Douro has been greatly transformed.
Fifteen dams have been built along its course. In Spain Iberdrola operates San Román (1907), Ricobayo (1933), Villalcampo (1949), Castro (1953), Saucelle (1956), Aldeadávila (1963), and Villarino (1970). In Portugal Energias de Portugal operates Picote (1958), Miranda (1960), Bemposta (1964), Carrapatelo (1971), Régua (1973), Valeira (1976), Pocinho (1982), Crestuma-Lever (1985).
References
Artola, Pedro Martinez. "El Salto de Aldeadávila." Revista
de Obras Públicas (December, 1962).
Artola, Pedro Martinez. "El Salto de Aldeadávila." Revista de Obras Públicas (January, 1963).
Chapa, Alvaro. La Construcción de los Saltos del Duero, 1903-1970: Historia de una Epopeya Colectiva. Barañáin: Ediciones Universidad de Navarra, 1999.
El Gran Cañón del Duero: la Construcción de Aldeadávila (1957-1987). Iberdrola, 1987.
Luces del Duero 1900-1970. Aprovechamientos Hidroeléctricos de la Cuenca Hidrográfica del Río Duero. Madrid: Fundación Iberdrola, 2009.
Olaguibel, Luis. "La Construcción de la Presa de Aldeadávila." Revista de Obras Públicas (April, 1964).
Unamuno, Miguel de. "Los Arribes del Duero. Notas de un Viaje por la Raya de Portugal Ilustradas con 15 Fotografias." Hojas Selectas, No. 37 (1905).
