The creation of hydropower comes with the necessary destruction of large ecosystems. Damming rivers permanently disrupts the balance of ecosystems, displacing people and animals by destroying the environment which they have depended on for thousands of years.
Coastal Erosion and Sediment Depletion:
Free-flowing rivers and streams carry sediments downstream, ultimately depositing them on ocean and lake shores. Dams and reservoirs built along rivers interrupt this flow, trapping huge amounts of river sediment–in the case of larger dams, up to 100% of it. Subsequently, the sediment is unable to be deposited along riverbeds and shorelines, leading to massive amounts of coastal erosion.
Plants and Animals:
Dams cause an incredible amount of harm to animals and plants that live within these ecosystems. Fish get drawn into turbines, experience increased predation due to the altered habitats, and have been shown to suffer from stress and injuries passing through hydroelectric dams. Reservoirs cultivate excess algae and weeds, crowding out other species. Reservoirs also are lower in dissolved oxygen, which can lead to some parts of the water being unlivable. The impact on animals has been demonstrated in Maine, as ever since the removal of the Great Works Dam in 2012 and the Veazie Dam in 2013 the number of salmon and other fish tripled from the previous year with the dam. This also was a 45 fold increase from the 2012 numbers. Hydro-Quebec’s megaprojects on James Bay are linked to declines in eider ducks. Nalcor’s Labrador projects are linked to declines in the Red Wine and other caribou herds.