Effects of Large Dams on Nature

Large Dams and Effects on Nature

Dams serve the purpose of tapping the water resources for irrigation, hydro-electric projects and drinking water to the population. The purpose turned into ambition in order to construct the largest dams involving concrete and high end technology. With the increasing demands for water, many of the hilly terrains are now finding proposals in the offing for the construction of large dams in various states. Unfortunately, the planning and implementation of these large scale dams has proved faulty to the core. The dam construction projects promise many things: supply of drinking water, flood prevention, increasing soil fertility apart from providing employment to the local people. Large dams have come to define the national prestige and honour, provide the parameters for development and relieve the conditions of mass poverty and hunger. The promises seem most feasible to the farmers as they are the producers of the food grains of the nation. Thus the planners think it as a step towards food security. India too started the construction of these large dams primarily as an answer to the looming questions of food insecurity to the vast masses.Hirakud, Damodar, Bhakra- Nangal, Tungabhadra and Tehri are some of the large dams in India. Large dams have negative impacts on the land, population and environmental resources. There is a massive destruction of agricultural land, prevalence of salt encrusted areas, displacement of people from their original habitat areas, acute harm to the land through earthquakes, floods and erosion of soil in case of flash floods. Large dams have major ecological consequences that are more damaging than one can imagine. They have negative effects on the fragile hills and mountains, and due to deforestation, there is a rise in the temperature levels that further triggers the atmospheric imbalance. The displacement adds to the woes of the people as the resettlers use vast natural resources to rebuild their lives elsewhere thus placing enormous stress on the limited available resources. The costs of resettlement and rehabilitation are high that often leaves many of the settlers penniless due to the apathy of the state.

In India the construction of two large dams in the Tehri Garhwal District and Narmada region have evoked mass scale protests for both socio-economic and ecological consequences. The dam constructions were opposed on the grounds of massive exploitation of natural resources on the river basin, and also owing to the threat of submergence of vast areas of forest and agricultural land. The region is a geologically seismic zone, prone to earthquakes that are likely to damage the structure of the dam. Around 150,000 acres of forest land are under the threat of submergence and the total area of forest land that would be affected by likely floods constitutes 350,000 hectares, approximately around 11% of the river basin’s forests.

The Tehri dam project also faces the same fate with the threats of flood and earthquakes looming large over the areas. The dam construction area situated between the rivers Bhagirathi and Bhilangana near the Tehri town is a high seismic area. The region has already witnessed earthquakes of high magnitude, measuring upto 7 points on the richter scale. The rivers in the region follow a weathered track and weak metamorphic formations occur in its foundations.

	The rocks in the exterior zone are not only frail but also heavily splintered. In case of an untoward natural calamity, these become deformed and give in to the pressures of the calamities. According to one of the estimates of the INTACH, in case of such eventuality, the dam is likely to submerge Tehri town and 23 villages in its vicinity, 72 other villages will be partially submerged and some 5200 hectares of land, 1600 hectares of it being cultivated land, will be lost to the reservoir. Finally, about 85,600 persons will be displaced because of the dam. This estimate is rather an old one and any new estimate would place the total figures to more than three times the estimated loss. The dam constructions facilitate road constructions, widening of the roads, and heavy movement of traffic, people and goods as well. The improvement of infrastructure also leads to making these areas holiday spots, thus increasing other construction activities and movement of people apart from encouraging the usage of plastic and other non-biodegradable substances. With one negative aspect giving way to others, the purpose of dams i.e. to supply drinking water is lost and is replaced with commercialisation of water resources and would lead to monopolisation of water resources, increasing participation of Multi National Corporations and finally leading to the injudicious use of natural, especially, water resources. The main contention is the displacement of vast masses of the regions concerned who would be rendered homeless. Alongwith the predictable human loss, there would be irreversible ecological damage, which if not taken care of, would wreak havoc with the humankind in the long run. (CNF)


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