In Brazil, many smaller dams disrupt fish more than large hydropower projects

The development of small hydropower dams is widespread throughout Brazil and elsewhere in the world, vastly overshadowing large hydropower projects. The proliferation of these smaller dams is a response to growing energy and security needs. Their expansion, however, threatens many of the remaining free-flowing rivers and biodiverse tropical regions of the world—interrupting the migrations of freshwater fishes, on which millions of peoples' livelihoods depend.