If we accept that controversial dams will continue to be built for economic benefit, how can we limit their damage on the environment?
Dams stop the flow of vital sediments as well as fish migrations. While the formation of reservoirs may benefit some bird species, the effect on wildlife is generally negative. Formation of reservoirs can drown plants, leading to nutrients being leeched into the water and killing the fish that live in it. Blocking the flow of water also kills wetlands, which are important to many ecosystems.
Via Seth Dixon, Jerry Xu