Environmental, social and cultural impacts of hydroelectric projects, with case studies

Introduction

A hydroelectric project dams a river and uses falling water to turn turbines. Its energy is renewable and cheap to run, but a large dam changes a whole river valley: its land, water, wildlife and the people who live there.

Environmental impacts

• Greenhouse gases. Rotting vegetation and carbon washed in from the catchment release greenhouse gases from reservoirs, an impact recognised only recently.
• Submergence of forests and farmland. Large areas of forest and agricultural land go under the reservoir, with their plants and animals.
• Waterlogging and salinity of the land around the reservoir and canals.
• Silting. Silt, worse where catchments are deforested, fills the reservoir and shortens the plant's life.
• A broken river. A dam fragments and physically transforms the river, seriously affecting riverine ecosystems, and cuts off the migration routes of animals while damaging their habitat.
• Earthquake risk. In some regions a large dam can induce seismic activity; there is a real possibility of this around the Tehri dam.

Social impacts

• Displacement. Of the 16 to 18 million people displaced by dams in India, 40 to 50 per cent were tribal people, though tribals are only about 8 per cent of the population. Most dam projects have been unable to resettle those affected, which is why opposition is growing.
• Unequal sharing of costs and benefits. Tribal people and fishermen lose homes and livelihoods while richer farmers downstream get the water; this raises a question of social and economic equity.
• Conflicts over water between power, irrigation, drinking water and industry, and the loss of fishing and boat transport on the dammed river.
• Weak compliance. A national assessment of dams cleared in the 1980s and 1990s found that in 90 per cent of cases the authorities had not met the environmental conditions of their clearance under the Environment (Protection) Act, 1986.

Cultural impacts

Large dams have harmed the lives, livelihoods, cultures and spiritual existence of indigenous and tribal peoples. Being uprooted from a homeland where families have lived for centuries causes emotional and psychological trauma, and resettlement on unfamiliar land breaks the community's ties with its land and its way of life.

Case studies

1. Sardar Sarovar (Narmada, Gujarat). The dam displaced thousands of tribal people whose lives were tied to the river, forests and farmland, and submerged forests in the Narmada valley; the World Bank withdrew from the project in 1993 after protests by the people facing submergence. The Narmada Bachao Andolan is the best-known people's movement against the project.
2. Tehri (outer Himalayas). Sanctioned in 1972, the dam was to submerge Tehri town and nearly 100 villages and uproot nearly a lakh people, with little alternative land for rehabilitation; local people, scientists and environmentalists opposed it for years.

Conclusion

Hydroelectric power is clean at the point of use, but large dams carry heavy environmental, social and cultural costs that fall mostly on forest and tribal communities. Smaller projects, honest assessment and the consent and fair rehabilitation of affected people are the way to keep its benefits.