The proliferation of artificial barriers (dams, dams, all kinds of walls and other human structures) in rivers is an ecological problem that alters the natural functioning of these river channels.. According to a recent study, there would be around 5,700 such barriers of this type scattered throughout the region in Spain. there is river barriers In addition to disrupting the drift of sediments towards the coast, it causes the migration of native species and the arrival of exotic species. But Spain is leading efforts to remove these barriers, according to a European study.
Specifically, the Dam Removal Progress 2021 report, produced annually by a number of European conservation organizations, reveals that Spain was by far the State with the most river obstructions removed that year.
A total of 108 jobs, infrastructure and other constructions that changed rivers in 2021 were destroyed or removed. This is frankly modest compared to the total number of items to be removed, but well above second place Sweden with 40 obstacles removed from their river. These are followed by France (39), Finland (16) and the United Kingdom (10).
The main elements that disrupt the natural fluidity of rivers (as well as their natural mechanics and biodiversity) are dams, dams, weirs (walls to divert water to crops), as well as any structure, often including houses or warehouses. abandoned.
Some of the examples of river restoration in Spain included in the report are the demolition of the dams on the river Pámanes (Cantabria) and the river Oria (Guipúzcoa) in 2021, as well as the demolition of the Matabosc embankment on the river Ter. .
A total of 239 barriers, dams and dams were removed in 17 European countries last year. According to the report, this is the highest figure drawn in Europe as these organizations are responsible for the restoration work.
“Removing barriers to restore longitudinal connectivity of rivers is currently a trend in Europe,” the authors of the report say. “The accelerated rate of removal of these stream barriers, ithe multiple impact such barriers have on natural ecosystemsincluding changing sediment loads and flow regimes and temperatures, nutrient modification, habitat degradation, transformation of aquatic communities, and reductions in species abundance,” he adds.
When a dam, reservoir or any other river barrier is built, the flow of the river is brokenrecalls that WWF has on several occasions requested greater agility from management in these actions, driving the migration of local fish species, promoting the prevalence of exotic fish, and reducing the drift of sedimentary material towards shore.
“Over the years, these structures, which were once a function of collecting water, preventing overflows, transfers … wear out over time and are left to their fate, let alone retire, seriously damaging rivers and creating a negative visual impact on the natural environment,” they add. .
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