The re-naturalization of rivers and the removal of dams is at the center of world’s attention: in fact, it is a practice that is becoming more and more important in the United States, and Europe is following the American example. The most important project present in our continent is "Dam Removal Europe": about 101 dams were removed in 2020, and it is estimated that by 2030 about 25,000 km of rivers will be restored. Obviously, only dams that are no longer used for energy production and that over time have become obsolete are considered, because in these cases the maintenance costs are exceeding the earnings.