Saturday, August 13

Norway blows up hydroelectric dam to restore healthy river and fish stocks | rivers


A dam that has blocked Norway’s Tromsa River for more than 100 years was blown up with dynamite this week, freeing up migration routes for fish.

“It’s a big step,” said Tore Solbakken of the Norwegian fishing club Gudbrandsdal Sportsfiskeforening, who has campaigned for five years for the old hydroelectric plant dam to be removed. “I’m very happy. It’s about restoring healthy rivers and fish stocks.”

Built in 1916, the seven-meter-high dam in the small town of Fåvang, in Innlandet, eastern Norway, has not been in use for more than 50 years. The Tromsa is a tributary of the Lågen River, which empties into Lake Mjøsa, the largest lake in Norway. Activists say removing the dam will help fish in the area to thrive again, including grayling, burbot, alpine bull and common minnows. The main beneficiary is expected to be lake trout, which can weigh more than 10 kg and feed in the lakes downstream and in Lågen. So far, the fish have only been able to live and spawn in the lower 950 meters before the dam, while they will soon be able to swim 10 km upstream.

machinery and worker at dam removal site
Tore Solbakken and his local angling club campaigned for five years for the dam to be removed. Photography: Rob Kleinjans

“A few years ago, I saw the Condemnation documentary and that inspired me to try to remove the dams that are no longer in use, ”said Solbakken. “Fish barriers, hydroelectric dams, road construction and the way we protect rivers from flooding are big problems for large brown trout and other fish. It is important to take care of all the small rivers. If we do that, we can have a positive future for our area ”.

The destruction of the dam is part of a trend to remove outdated barriers littering Europe’s waterways. In October, Open Rivers Program, a € 42.5 million project to provide grants to support the removal of small dams and the restoration of river flow across Europe, was launched with the support of the Arcadia charity fund. Last month, the European Commission published A guide for member states to identify barriers that could be removed to help achieve the goal of restoring 25,000 km of rivers to free flow by 2030.

“Dams on rivers block migration routes, swimming routes, fish,” said Herman Wanningen, founder of the World Fish Migration Foundation and Dam removal Europe. “Some species of fish, such as Atlantic salmon, eel and sturgeon, travel thousands of kilometers to complete their life cycle. Dams also impede the important transport of sediments and nutrients, and dramatically change the natural flow of rivers. The hatcheries are lost ”.

It is estimated that there are at least 1.2 million instream barriers in Europe and which are a factor in the massive drop in the number of migratory freshwater fish across the continent, with numbers declining by more than 90% between 1970 and 2016.

“Free-flowing rivers support a great deal of biodiversity,” Wanningen said. “They also provide food for hundreds of millions of people, as these rivers are teeming with life and fish. Free-flowing rivers deliver rich sediments, which are crucial for agriculture and also mitigate the impact of floods and droughts. There is a lot of potential for free-flowing rivers in Europe. “

Norway is an important hydroelectric country. Removing dams here is not normal, ”said Solbakken. “But it is not controversial if old dams that are not in use are being removed, in rivers protected by regulations against new hydroelectric power.”

machinery and workers at the dam removal site
The dam was blown up with dynamite placed in holes throughout the structure. After the debris is removed, a team will begin work on restoring the river. Photography: Rob Kleinjans

The campaign by Solbakken and the 120 members of the fishing club resulted in the government agreeing to pay the 3.4 million crowns (£ 290,000) bill to remove the dam.

On Wednesday, the small team drilled five deep holes in the dam and then shoved 20 kg of dynamite into each one. Dam blasting is unusual in Europe, but it was considered to be the safest method in this case. “As planned, the dam cracked in the middle and above,” Solbakken said. “The next step is to use the excavator. It is a huge dam and it will take days to remove it completely. There is still a lot of work to do ”.

The team will then set about restoring the river directly in front of the dam site. “The Tromsa Dam is in a steep canyon, so our challenge is to build a nature-like stepped pool waterfall to allow fish to swim upstream in the strong current,” said Ulrich Pulg, fish biologist and river restoration expert. “This project will have several steps of one meter. It will look like whitewater rapids during floods, but the large lake-dwelling trout will make it through. “

Other dams are set to be removed across Europe by 2022, including in Spain, France and the United Kingdom. “More and more river managers and NGOs are collecting their tools for digging,” Wanningen said. “Just a couple of months ago, three dams in Montenegro and one in Slovakia collapsed for the first time in the history of these countries. The European research project, Amber, in which we participate, has shown that there are around 150,000 dams and dams in Europe that are no longer working and can be removed without any problem.

Rivers are the veins of the Earth. We have to treat them with care. “

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