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How (and why) is Europe removing its dams?

Written by Rafaela Fabris
Published 16/06/2024 às 14:29
How (and why) is Europe removing its dams?
Discover why Europe is removing its dams and the benefits of this action for the environment. Image: Bricklayer in Construction/Disclosure

Discover why Europe is removing its dams and the benefits of this action for the environment.

For centuries, Europe built a vast network of more than 150.000 dams. These structures, some dating back to the early XNUMXth century, were a symbol of progress and power. They generated electricity, controlled floods and fueled industrial growth. However, at a hidden cost: dams disrupt the natural rhythms of rivers, damaging ecosystems and threatening the survival of migratory fish. Now, many of these structures are reaching the end of their useful life and becoming dangerous and expensive to maintain.

Removing dams helps restore rivers to their natural condition, benefiting the environment. Without dams, rivers can flow freely, which is crucial for the health of aquatic ecosystems and the survival of species such as migratory fish. Dams also accumulate sediment that can contain pollutants. When removed, these sediments are released and can revitalize habitats downstream.

The Hiitolanjoki River in Finland is an example of successful dam removal

This 53 km river, which flows into Lake Ladoga, is home to the last population of salmon naturally isolated from the sea in Finland. For more than a century, dams like Kangaskoski, Lahnasenkoski and Ritakoski have disrupted the river's flow, making it difficult for salmon to migrate.

In 2021, the Kangaskoski Dam was demolished, resulting in an immediate ecological response: within weeks, salmon nests appeared in the new section of the river. In 2022, the Lahnasenkoski dam was also removed. The last step involved the removal of the Ritakoski dam in 2023. The total cost of the project was approximately €750.000, funded by public and private donors.

Removing a dam is a major engineering challenge. Each dam is studied individually to determine the best approach. Here are some common methods:

Notch and release method: Engineers make strategic cuts in the dam, allowing water to gradually escape. This helps redistribute sediment in a controlled way, revitalizing downstream habitats.

Quick release method: A tunnel is created at the base of the dam, quickly releasing water and sediment. It is a faster and cheaper method, but it can cause flooding and erosion.

Excavation and drainage method: The reservoir is emptied and the accumulated sediment is removed with heavy machinery. It is an expensive and slow process used when sediments are contaminated.

Bypass method: In some cases, a new channel is built to divert the river around the dam, leaving the sediment in place.

In 2022, a record number of 325 dams were removed in Europe

Reopening important waterways. Countries such as Spain, Sweden and France are leading these efforts, with new entrants such as Latvia and Luxembourg joining the cause. Dam removal improves biodiversity, helping to reverse species loss and creating healthier habitats.

Europe is removing its dams to restore rivers and benefit the environment. This movement, although complex and expensive, brings enormous ecological benefits, helping to reverse decades of damage to river ecosystems. Dam removal symbolizes a commitment to sustainability and preserving nature for future generations.

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Rafaela Fabris

Talks about innovation, renewable energy, oil and gas. Updates daily on opportunities in the Brazilian job market.

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