The negative effects of mega hydropower in the Amazon region are described in detail in the study – 02/20/2021 – Reinaldo José Lopes

I have found for myself here that a substantial part of the effects of a scientific concept can be traced back to the way in which it is baptized. Although Greek and Latin roots are still widely used for this purpose (nothing against Rome and Hellas, on the contrary), terms in the current language seem much more memorable and clear to me than the ones I have just learned: “Sandwich effect “. Incidentally, with trees in the filling of the snack.

In fact, such a sandwich effect is not appetizing. He describes the billiard pool where certain trees are found that are adapted to seasonal flooding in the Amazon basin and that were affected by the construction of the Balbina hydropower plant from the 1980s. These trees stand before the worst of all possible worlds today – and serve as a warning to what can it do in other parts of the Amazon in front of the great energy companies that are always popular with those in power, regardless of the ideological name they adopt?

The details of the situation are described in an article recently published in the journal Aquatic Conservation: Marine and Freshwater Ecosystems. The team of scientists, including Jochen Schöngart and Angélica Faria de Resende from Inpa (National Institute for Research in the Amazon), as well as researchers from other institutions in Brazil and Europe, mapped the effects of the dam, which is more than 125 km long downstream.

The river in this case is the Uatumã in the state of Amazonas (the hydropower plant is 150 km northeast of Manaus). The reservoir extends over an area of ​​almost 3,000 km2 and causes innumerable effects. One of the worst effects, however, is the vegetation of the Igapós, the sections of forest that spend much of the year underwater.

Under normal conditions, with no dams and no hydropower, the Uatumã River flooded these areas in a reasonably foreseeable manner in a single annual pulse at about the same time. However, in order to generate little variable energy throughout the year, the hydropower storage system was designed in such a way that this natural variability is reduced by the roots (no puns).

The result is such a sandwich effect. The tree species adapted to the downpour were compressed between the end of the flooding in the higher areas of the area (which were previously flooded and now no longer) and the continued flooding in the lower areas. The strip where things are still normal, with the natural impulses of floods and droughts, has brutally shrunk to form the thin filling of the sandwich.

So far, 12% of the Igapó forests along the 125 km long disc downstream of the hydropower plant have died. In the higher areas, tree species that have nothing to do with the original environment and usually grow on desolate stretches have taken over the place. And the end of the natural flood pattern resulted in an accumulation of dry plant material that is the paradise (or rather the hell) of forest fires.

Assumed proponents of such “rational use” of the Amazon’s resources will say that Balbina was very poorly planned (which is a fact) and that hydropower projects are much more cautious in the 21st century.

Well, what happened at the Belo Monte plant makes it clear that the second statement is at most half a truth – there it becomes almost impossible to reconcile an environmentally friendly flow from the Xingu River with energy production targets. The sandwich effect alarm therefore has far more extensive effects. It is good to pay attention to it. We are a family business.

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