Are Big Dams Temples of Modern India?

B. Vijayasarathy

There is lot of controversy and conflict regarding the construction of Narmada dam. Will construction of big dams like Narmada really contribute to the sustainable development of this country? When you say no to this question you will be branded as anti- development activist. People involved in degrading the environment in the name of development say that environmentalists are against development. We will analyze the merits and demerits of construction of big dams.

India is now ranked the world’s third largest builder of dams. The Indian government has spent nearly 80,000 crores on dam projects.

More than 92% of the dams built in India solely serve the purpose of irrigation, 2.2% hydroelectric power generation, less than 1% water supply and less than 3.5% serve irrigation, water supply and hydropower generation. According to the Central Water Commission, we have 3600 dams that qualify as big dams (height 33 meters and above); 3300 of them were built after Independence and a thousand more are under construction. With the construction of big dams, the irrigation potential has increased from 22.6 million hectares (mha) in the pre- Independence period, to about 89.56 mha at the end of the Eighth Plan. This has greatly contributed to the increase in food grain production from 51 million tonnes (mt.) in 1950-51 to 198 mt. in 1996- 97 at a compound annual growth rate of around 3 per cent. The proportion of this increase attributable to large dams is under dispute. The government claims 30%, while independent agencies put it at 10%.

The supporters of dams argue that the rainfall is not evenly distributed in space and time, resulting in flooding in certain areas and drought conditions in certain parts of the country. Most rivers in India are monsoon-fed. About 80- 85 per cent of the flow takes place during the rainy months – usually between June and September – and 70% of river water is discharged into the sea without utilization. The purpose of a dam is  to  impound and store rainwater  in  its  reservoir  and  then  use it judiciously for  the  rest  of  the  year. Therefore, it becomes necessary to build dams with large storage capacity to control floods and droughts and also provide water for use by domestic, agricultural, industrial and power generation sectors for the rest of the year. This will in turn see to the development of the nation. But the reality is distressing. There are more drought and flood-prone areas today than there were in 1947.  One fifth of our population – 200 million people – do not have safe drinking water and two-thirds – 600 million – lack basic sanitation, 40% of our people live below the poverty line and only 3% pursue higher education. What kind of development is this?

Impact of big dams

 Ecologically big dams are a disaster.

  • They cause floods: Numerous cases of floods have been recorded because dam operators held back water while the reservoir was filling, and when the water kept pouring in, they had to open their spillways at maximum capacity to prevent damage to the dam from being damaged.
  • They cause water logging and salinity: Water logging and salinity are two major environmental problems generated by the construction of dams with serious economic consequences. According to ‘secret’ government studies, more than 52 per cent of the Sardar Sarovar command area, which comes under the controversial Narmada Sagar dam, is prone to water logging and salinity. In India about 10 million hectares of cultivated land are affected by water logging and 25 million hectares by salinity problems. Water logging, salinity, soil quality and agriculture production are inter- related to one another.
  • Sedimentation has reduced the life of many dams: All rivers carry sediment with them. This sediment settles in the bottom of the reservoir slowly reducing the storage capacity of the dam, thereby defeating the basic purpose for which it was built. Sediments play a dual role – both negative. Apart from rapidly filling their reservoirs, they also cause abrasion of turbines and other dam components thereby reducing the generating efficiency of the power. In India, government statistics on 11 of the country’s reservoirs with capacities greater than 1 km3 show that all are filling with sediment faster than expected. The increases over assumed rates range from 130 per cent (Bhakra) to 1,650 per cent (Nizamsagar in Andhra Pradesh). A 1990 World Bank paper on watershed development concluded that in India, ‘erosion and [reservoir] sedimentation are not only severe and costly, but also accelerating’. Removing sediment from the dams is expensive process.

    Fig
  • There is mounting evidence linking big dams to earthquakes: Most of the strongest reservoir- induced seismic activities are observed in dams over 100 mts. The scientific explanation of how dams cause earthquakes is related to the extra water pressure created in the micro cracks and fissures in the ground under and near a reservoir. When the pressure of the water in the rocks increases, it acts to lubricate faults, which are already under tectonic strain, but are prevented from slipping by the friction of the rock surfaces. There have been 17 cases of earthquake tremors induced by large reservoirs in India
  • Safety of big dams: A World Bank report in 1991 notes that because of financial factors, local pressure and political interference, substandard materials are used in the construction of dams to make large illicit profits. The construction quality in India is deficient for a number of dams, posing serious potential risk to downstream populations.
  • Spread of water borne diseases: Malaria has spread due to the large water bodies which act as breeding sites.
  • They induce conflicts between the people: Sharing the reservoir water has given rise to interstate conflicts e.g. Cauvery river dispute between Karnataka and Tamilnadu, Alamatti dam dispute between Karnataka and Andhra Pradesh.
  • Threat to aquatic life: Dams have either eliminated or endangered one-fifth of the world’s freshwater fish. E.g. Hilsa fish and river Dolphin
  • Change in traditional cropping pattern of command area: This may lead to abandoning of dryland crops and farming of water intensive cash crops, resulting in water logging and salinity in the area.
  • Displacement of people: More than forty million people, the majority of whom are tribals, have been displayed.
  • Destruction of forests: Over 500,000 ha. (5000 sq.km) of forestland have been destroyed in more than 1500 major river valley projects.
  • Violation of conditions: Data emerging from the records of the Government of India, collected by the offices of the Ministry of Environment and Forests, suggests that in a shocking 90% of cases, dam project authorities had not complied with the conditions under which their projects had been cleared. e.g. Telugu Ganga project in Andhra Pradesh.
  • Cost-benefit analysis: The Public Accounts Committee (PAC) in India stated that a scrutiny of 32 major projects in post independence India have shown cost overruns of 500 percent more than estimated. Not only have the cost overruns been under estimated, benefits have also been exaggerated. The social and environmental costs have not been taken into consideration in the cost-benefit analysis. It is accepted universally that it is difficult to measure these in purely financial or economic terms. Studies have shown that most of these projects have had higher costs than benefits.

Despite the disturbing evidence of the role of big dams, the government has not commissioned a single post-project evaluation of its 4300 dams    to gauge the truth but continues to build more big dams. For whose sake are the policy makers still persisting with the big dams even though the cost benefit ratio of big dams is inferior to what was required? In the developed countries, dams are being de-commissioned or blown up because that they do more harm than good. So they are exported to the Third World in the name of Development Aid, along with their other wastes like obsolete weapons and banned pesticides, drugs, etc. In the name of development, the World Bank will readily fund big dams like Narmada Sagar.

According to the Central Soil and Water Conservation Research and Training Institute (CSWCRTI), analysis showed that ten tiny dams with catchment area of 1 ha will collect much more water than one large dam with a catchments area of 10 hectares.

This is because of the fact that water collected over large reservoirs will have to run over a large area before it is collected and a large part will get lost through leakages, evaporation, and infiltration into the soil, etc. One study of CSWCRTI reveals that increasing the size of the catchment area from 1 hectare to 2 hectare reduces water yield/hectare by as much as 20%. The small check dams conserve more water and are more beneficial than big dams. These check dams will not create problems like water logging, salinisation, sedimentation, earthquakes, deforestation, floods, etc. Let us take Alwar district in Rajasthan. Mr. Rajendra Singh got the Raman Magsaysay award in 2001 in recognition of his work on greening of Alwar district, Rajasthan, by constructing check dams with active involvement of local population. Rainwater harvesting and check dams are the solution in drought-proofing this country, not big dams.

According to Arundhati Roy, “Big Dams haven’t really lived up to their role as the monuments of Modern Civilisation, emblems of man’s ascendancy over nature. Monuments are supposed to be timeless, but dams have an all-too-finite lifetime. They last only as long as it takes Nature    to fill them with silt”.

Let us join hands with those noble people who are protesting against big dams to protect themselves and to protect us from the disasters of big dams for the betterment of our country.

Reference

  1. “The Greater Common Good”, Frontline, June 4, 1999 by Arundhati Roy.
  2. Making water everybody’s business, Anil Agarwal, Sunita Narain & Indira Khurana.
  3. Operation monitoring and decommissioning of large dams in India, Dr. V.P. Jauhari.

Source: Eco News, Vol 9, No 3, October to December, 2003.

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