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This article provides information about the impact of large dams on society and environment:
There are various debates on the impact of dams on economy, society, ecology and environment. These debates have brought forth arguments both in favour and against the construction of large dams. Here, the impacts of large dams on society and environment can be discussed as follows.
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Large dams have evoked more resistance than approval. The construction of Hirakud was marked by thirty thousand people, comprising of local politicians, bureaucrats and the people who were going to get evicted from the dam site taking to the street, in 1946. Hirakud was in this sense a forerunner of protests against dams in other parts of the country.
Even while these protests focused on specific projects, the arguments raised for and especially against dams have been common. In the newly created tribal state of Jharkhand, there have been thirteen large irrigation projects, hundred and eight medium irrigation projects and six thousand eight hundred and twenty small water projects till date. Most of these projects have failed. Some are incomplete and have been abandoned. Most of these projects have been notorious for high levels of corruption and red tape. Large dam projects, notably the Subarnarekha Project and the Koel-Karo Project, faced tremendous resistance from the local tribal population.
The Koel-Karo Project was commissioned despite the fact that it would have destroyed 200 tribal villages and submerged 45,000 hectares of arable land. The Suvarnarekha Project has been the site of police atrocities and the high level of illegal transactions of funds within the project has been common knowledge. JOHAR, a Human Rights Organisation in Jharkhand, has some very appalling findings on the state initiated nine minor irrigation projects within 1960-90 in West Singhbhum district of Jharkhand. The entire capital outlay of these projects was 14 crores.
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The government had claimed that 47,764 acres of land would gain through the irrigation facility of these projects on their completion. According to JOHAR’s research, the nine projects ‘do not exist’ and there is no accounting for the public money spent on these projects. Till 1997, 22.5 lakh acres of land had been procured from the local tribal population in the name of minor and major irrigation projects. Lakhs have been displaced from their land and have turned towards wage labour in mines and factories in the surrounding areas for employment.
The campaign that drew attention of the world to the politics of large dam construction and its harmful impact on the environment is the Narmada Bachao Andolan or the movement to save the river Narmada. Narmada runs through the three States of India, i.e., Madhya Pradesh, Maharashtra and Gujarat. Worshipped as a holy river, Narmada is the lifeline of thousands of villages and her importance is illustrated in the folk traditions of the region.
In 1985, the World Bank approved $450 million Sardar Sarovar Multi-Purpose Dam Project on the Narmada. According to World Bank estimates, the project was to generate 1300 million cubic-metres per year of water for civic and industrial purposes, an installed capacity of 1450 MW of electricity and provide irrigation to 1.9 million hectares of land.
The project was to submerge 13,744 hectares of forestland, 11,318 hectares of fertile agricultural land, and displace over 100,000 people, mostly persons and families belonging to the category of scheduled tribes and the rural poor. The sheer magnitude and size of the project raised concern among concerned citizens and specialists.
The planners according to the Narmada Bachao Movement had not critically and realistically assessed the ecological, human and financial consequences of undertaking this project. The three main areas identified by the movement as arguments against large dams.
The most apparent ecological effect of large dams is the permanent destruction of vast expanse of forests, wetlands, and wildlife. The dam would submerge vast tracts of rich forest cover. But the lesser-known consequences are equally disturbing. The forests are routes of migration of many animals, the wetland attract various migratory birds, while the river is a channel for migratory fishes.
The destruction of the routes of migration of animals, birds and fishes not only affect the ecosystem, but also affect the lives of the local population. Fish forms an integral part of the staple diet of local populations; embankment blocks their movement downstream as well as intercept the cycle of breeding among them. In places like Jharkhand and Chhattisgarh, the cutting down of forests has forced the wild animals to wander into villages in search of food, often attacking and killing the locals. Dams convert rivers into reservoirs, which has environmental implications on its entire drainage area – upstream, downstream and the command area of the reservoir. Embankment restricts the river water to flow downstream.
The upstream in the process collects the sediment, which increases the water level and can cause floods in the area drowning people and property. The river downstream, denied of its regular quota of water and sediment is, according to McCully, ‘hungry’ and eats away the plains along its course. The plains are also denied of the rich alluvial content of the river, which affects the fertility, quality and the productivity of the soil.
The river downstream also experiences sudden fluctuations, with water being thrown out periodically from the command area to reduce the pressure of water. Often this may destroy vegetation along its way as well as settlements that take over the land vacated by the river after the construction of the dam. The reservoir by holding large quantity of water encourages high rate of water evaporation. This leads to the increase in the salinity of water, which can have a long-term effect on the quality of water.