Hydroelectric dams
Manufacturing and materials
Concrete is often used in making dams, its main materials is gravel collected from gravel pits.
Fossil fuels are burned when transporting and building the dams. Ex a cement mixer.
animals
The dams prevent fish from reaching their breeding grounds, interrupting the food chain.
Contributes to significant loss of aquatic biodiversity.
Habitat is changed drastically in unreversible ways.
Plants
Can flood forests causing a loss of a major carbon sink.
Change water quality can kill the plants living there.
Water
Over all O2 levels go down, With in the large body of water and further down stream.
Controls when the water flows
Water tempter can be altered
Greenhouse gases
Dam reservoirs create Greenhouse gases from microbial process that decompose organic , but in some cases they can act as carbon sinks.
Additional info
Land the dam is built on
More dry land is created as parts of the body of water are sectioned off by the dam.