Fresh water is becoming a precious resource and drought increasing in many areas, but unnecessary blocking of water should be thought about. While often dams are “run of river,” meaning what goes in comes out, sometimes they can reduce or even stop a river’s flow, leading to bad consequences for people, fish and wildlife downstream

Dams trapping sediment and nutrients, create algal growth. Town's using dams to create drinking water often battle these water quality issues at a high cost to taxpayers. Slowed water and growth of algal reduce the oxygen in the water behind a dam leading to kill fish

The Amazon rainforest is know has the lungs of the world and the Dam will destruct over 1500 square km of it. This will kill a lot of plants and animals because of this deforestation of their natural habitat. Even though there will be parks built to make for up it it will not add up to the amount of 1500 square km. 25% of our medicine comes from the plants being destructed. The black bearded saki monkey and the white cheeked spider monkey are two endangered animals who live in the amazon rainforest

Dams cost a lot of money, for example the Belo Monte dam was supposed to cost 13 billion dollars but by the end of construction it will go up to 18 billion dollars, which will cause the government to ask for more tax. This will increase crime rates because the people won't be able to afford food which makes them want to steal.

Dams can cause people living in the are to move from their homes, for example 20,000 people will be moved out of the area where the Belo Monte dam will be built. The natives will protest against the government for destroying their homes, lots of human rights organisations will be on their sides. On top of that hundreds of tribes living on the bank of the river are dependent on the river for transport, fishing and trade.