One less obstacle in the feat of the salmon
ACCIONA has installed a lift for salmon in the Nansa River, allowing them to pass the 20-metre barrier that previously prevented them from continuing upstream to the spawning area.
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An ancient legend from Irish mythology tells that the leprechauns of the forest once hid all the knowledge of the world in nine hazelnut trees surrounding the Well of Wisdom. Some of their nuts fell into the water and were swallowed by a salmon, who, from that moment on, became the wisest being on Earth. The story continues in much more detail in The Boyhood Deeds of Fionn, but let's stop here, as this serves to illustrate an idea to which those Celtic chroniclers surely wanted to bear witness: the salmon is a supernatural fish.
And in its life cycle, everything is a feat. Salmon are born in the headwaters of rivers, then travel hundreds of kilometres downstream to the sea, modifying their metabolism to adapt to salt water. When their instincts tells them to, they set out on a true crusade: the return to the exact spot where they were born to nurture a new generation. How they know the way and where they find the strength to fight the elements without a bite to eat for months is a mystery.
That supernatural gift for knowing which waters were theirs, which gravels saw their birth, may well have fascinated the Irish a thousand years ago, and the Salmon of Wisdom therefore has a privileged place in their popular imagination. A fascination that we too share hundreds of years later.
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"...With the Ulysses salmon of return
retrace their way toward algae..."
José GorostizaIn its return, the salmon, swimming upstream from the sea to the headwaters of the river in search of its own Ithaca, encounters many dangers along the way that turn its journey into an epic feat: predators, the force of a flow that pushes against the current, ascents several metres high...
But of them all, the dams located in the river basins are one of the most difficult, if not impossible, obstacles to overcome.
Until the middle of the last century, the Nansa river in Cantabria (Spain) was considered one of the best salmon rivers in the north of the country. But the Palombera dam, built in 1949, became an insurmountable barrier for the specimens returning to the spawning grounds of the Cantabrian river and left behind a barren and unpopulated riverbed.
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The installation by ACCIONA—owner since 2010 of the hydraulic plants in this area—of a lift to help them overcome the 20-metre-high dam and continue their journey is now the key to restoring the Nansa river to its former glory days of brave salmon making their pilgrimage through its waters.
A three-million-euro investment that solidifies ACCIONA's commitment to protecting the biodiversity of the environments in which its clean energy generation facilities are located.
We're here tell you all about the project.
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Now a fish lift at the Palombera dam on the Nansa river allows the salmon to overcome the 20-metre height of the dam, and two ladders on the Celis and Vendul weirs (small dams to channel the river water) help them to reach the spawning grounds of the river and thus continue their homeric reproduction cycle. Months later, these ladders will also be used by the new specimens that begin their descent into the cold waters of the North Sea.
In addition, the project includes a system for monitoring the ecological flow in real time, i.e. the flow that maintains the life of the fish that inhabit a river and the vegetation along its banks, and a station for recording and measuring the flows at the river's headwaters.
As part of the plan, 13,000 five-centimetre salmon fry have been introduced to populate the Nansa river and become the future generation that will use the facilities to restore the river back to its former glory in terms of salmon life. ACCIONA will also carry out environmental monitoring over the next three years to verify the effectiveness of the process it has set in motion.
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How the Nansa river lift works
On their ascent from the sea, the salmon are met at the base of the dam with a succession of troughs or small staggered ponds where a continuous spill of water acts as a call effect to let the salmon know that the path continues that way. The attracted fish reach a metal cabin submerged in the water, which is raised on rails to the top of the dam and deposits the fish in the reservoir through a system of channels.
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Cameras allows the characteristics of the salmon to be documented before they continue their journey.
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The lift is equipped with a camera system that allows the characteristics of the salmon to be documented before they are returned to continue their upstream journey. The frequency of the lift is manual or automatic and is programmed according to the time of the year, which determines the frequency of the salmon's passage.
Once in the reservoir, the salmon can swim upstream through the ladders built on the Celis and Vendul weirs, thus reaching the spawning grounds documented in the historical records of the river.
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A new hope for the brown bear
ACCIONA collaborates with the Brown Bear Foundation to restore and protect the habitat of this endangered species, originally from northern Spain
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