Just briefly, why build a dam? There are three reasons dams are built.
- to generate hydroelectricity
- to create an irrigation reservoir
- to control flooding
The creation of reservoirs is not without costs and impacts.
- seismic effects (earthquakes)
- groundwater effects (salinization of the water table)
- landscape destruction (flooding of forests and arable land)
- destruction of fish habitat and fisheries
- contamination of food chain with methyl mercury and other contaminants
- increased epidemics (tropical dams)
- greenhouse gas pollution
- changes to climate
- changes to the global environment: change in speed of earth's rotation
- changes to the shape of the earth's maganetic field
- destruction of upstream and downstream ecosystems
- destruction of deltas and wetlands critical to migrating wildlife
- changes to coastal ecology
- extinction
The social and economic impacts include:
increased incidence of early 3rd stage diabetes and heart disease in First Nations populations who lose their traditional diets which their bodies are adapted for.
increased incidence of depression and suicide in First Nations peoples, due to loss of livelihood and radical change of lifestyle.
increased social breakdown in First Nations families, due to all of the above.
increased rates of substance abuse due to berakdown of traditional lifestyle.