Dams are affecting the environment and biodiversity in many different ways, the fate of the salmon exemplifies the essence of what’s wrong with dams.
Dams can impact fish in the rivers in several different ways. The most obvious one is that the huge installations create a barrier for the fish. Fish that migrate up and down the stream like salmon aren’t very likely to complete their journey. Dams are equipped with fish passages, that allow some migration to happen, but their natural environment is still destroyed. Furthermore, the dam makes water accumulate in an unusual way for their habitat. The water of the dam is deep and therefor much cooler. This is problem for fish that haven’t evolved to survive under such condition. The dam releases cold water with lower oxygen levels, which deteriorates the conditions for life downstream. Dams are threatening the salmon both in Europe and in the United States.
The Danube river is a major artery teeming with life that flows through central and south-eastern Europe. The salmon that is common in its waters is called the huchen (Salmon of Danube), a very large and very endangered species. A mature fish can reach from 30 to allegedly 50-70 kilos from reports from the end of the 19th century. An article in the Deutsche Welle is quoting a study that claims the river has already lost two thirds of the huchen populations. The salmon in the United States is meeting a similar faith. A study in the Scientific American noted that wild salmon numbers in the Pacific Northwest’s Columbia River basin are down some 85 % since the big dams were constructed there a half century ago.
Humans have developed the incredible power to control mighty rivers. We create channels and use them for navigation, we reduce the risk for flooding and we divide the river with dams. Dams produce electricity and they do have value, but we have to recognize the fact that healthy ecosystems also have a very real value. Understanding and assessing all the negative effects that a dam can have on the environment and on the people that live in the surrounding areas is absolutely necessary. Dams that are very small in size usually avoid all scrutiny due to the way that the regulations are designed. The combined effect of many small dams on a river can become really damaging.
Unfortunately massive dam construction is under way in the Balkans, most of the 3000 dams that are set to be build are small scale projects. The Blue Heart of Europe is a massive information campaign launched by the company Patagonia that puts the focus on the future of last pristine rivers in Europe, home to unique and vital ecosystems.They have produced a documentary movie that raises awareness about the various environmental impacts of dams and it also calls for action. Find out more about the movie by following this link, you can sign the petition here. Dams affect the environment in many different ways, you can discover some of them in the following articles: