Large Dams, barrages, reservoirs and canals

Dams have often been regarded as man’s response to nature’s vagaries, to mitigate flood and drought by containing water and releasing it as per demand and supply. Lately, dams are seen more as hydropower generators with flood mitigation, irrigation and drinking water supply only being additional benefits. This can be because of the increased acceptance that dams and canals, as awe inspiring as their structures might be, fail to deliver water to more than half of their commands. However, data and experience tell us that even the hydropower generation is also falling way below the promised numbers.

History and extent of dams in India

India’s first dam is the Kallanai built on the Cauvery river by King Karikalan of the Chola dynasty around 2,000 years ago. The dam, which is still functional and irrigates millions of acres, spans 329 m in length and 20 m in width. However, it was only post-independence that India’s love for big dams became more intense with the commissioning of a slew of projects including the Hirakud (1957), Gandhisagar (1960), Bhakra-Nangal (1963) and Nagarjuna Sagar (1967). Since then, the country has been continuously working on reining in its rivers for want of power, irrigation and domestic and industrial water supply needs. Almost half of the large dams in the country were built in the two decades of 1970-90. Maharashtra has the maximum number of large dams in the country (1845) followed by Madhya Pradesh (905) and Gujarat (666).

Map of major dams in India

A multi-purpose dam project includes one or more dams, infrastructure for generation of hydropower, infrastructure for housing of workers and for offices, a distribution network of canals and pipe systems, and access roads. All these have their individual and cumulative impacts on the river and the surrounding environment. Here also lies an opportunity to minimise the 'collateral damage' caused by dam projects by minimising the footprint of these adjuncts.

Dams as power generators

Hydropower is often billed as a renewable, economic and non-polluting source of energy and hence there is an increased emphasis on building dams especially in the hydrologically-rich but geologically-fragile Himalayan states. An assessment study put the hydroelectric power potential of the country at about 84,000 MW with maximum schemes envisaged on Brahmaputra basin (226) followed by Indus basin (190) and Ganga basin (142).

Possibility of revenue generation through sale of power units to other states and private players remains the main draw for state governments to invite project developers. However, reports suggest that poor financial conditions of discoms make it a poor proposition. Average generation per MW of hydro capacity in India in 2014-15 was over 20 per cent less than that in 1993-94.

Dams and canals for irrigation

Canal system of irrigation had been prevalent in India for centuries but it was the Ganga Canal that laid the foundation for large scale diversion of water to farms.

Number of dams in various statesThough the work was undertaken under the leadership of British Colonel Proby Cautley, it was the traditional acumen of local villagers that made the vast network possible. The canal was commissioned in 1855 irrigating around 5,000 villages. Today, the system irrigates nearly 9,000 km² of agricultural land in 10 districts of Uttar Pradesh and Uttarakhand.

The start of the Green Revolution in the mid 1960s put the spotlight on canal irrigation as the new hybrid crop varieties bred on heavy dose of chemical fertilizers and pesticides demanded assured irrigation. However, the increased investment and network expansion dealt little benefits. The World Commission on Dams in its year 2000 report found that the contribution of large dams to increased food grains production in India was less than 10 percent.

Loss in seepage, huge demand-supply gap, diversions under political pressures and comparatively easier and local availability of groundwater through pervasive use of borewells are the reasons for decline in efficiency trend.

Between 1996-97 and 2002-03, the area under canal irrigation declined by 2.4 million ha (13.8 per cent), the area under tank irrigation fell by 1.4 million ha (42.4 per cent), and the area irrigated by all other sources declined by 1 million ha (28 per cent). The only irrigation source that increased its share was groundwater wells, by 2.8 million ha (more than 9 per cent).

A study of 210 major and medium irrigation projects by SANDRP used the data supplied by the Ministry of Agriculture to show that after investing Rs 130,000 crore, these delivered 2.4 million ha less irrigation during 1990-1 to 2006-7. This means, the governments have to invest twice as fast in canal irrigation projects every year just to keep their command areas from shrinking

The study said that around Rs 1,00,000 crore was wasted in the name of improving irrigation. Feasibility studies were fudged in the case of most of the projects with huge investments, over-optimistic predictions were made and very little money was earmarked for basic maintenance such as desiltation. In some cases, political interests ensured that water was diverted to unviable areas at the cost of needier regions.

Dams and flood control

The efficiency of dams to withhold floods has always been put to question. Critics have also termed dams as harbinger of floods claiming that the essential scientific assessment for consistent release of water to avoid build up is rarely done.

Absence of a standard operating procedure for releasing water from the dam gates was evident in 2014 when 24 students picnicking in a river were swept away due to sudden release of water from Larji dam in Himachal Pradesh

Similarly, area downstream of Hirakud dam in Odisha has witnessed 14 floods in recent past with nine caused by sudden release of water from the dam. A major reason is that the dam has not changed its flood control strategy for 23 years while the rainfall pattern has undergone major changes in local areas. Lack of a coordination mechanism between neighbouring states about water flow also leads to emergency situations like one in 2011 when sudden release of water flow from upstream dams in Chhattisgarh led to breaching of danger mark in Hirakud.

In Gujarat, sudden release of large quantities of water from Ukai dam led to the biggest flood of 34 years in Tapi river submerging over 80 per cent of Surat, killing 150 persons and stranding over 20 lakh. Similar examples have been reported from other states.

Problem with 'training rivers'

Dams cause a disruption in the flow of a river by transforming it into a series of pools separated by dry stretches. The environmental impacts can be felt on the landscape, water resources, forest cover, and biodiversity. The Himalayas are almost equally distributed between zones 4 and 5. While a series of dams are being constructed in a seismically vulnerable and ecologically fragile zone, not only is optimisation of the planned development not considered, but the cumulative effects of the dams also are not considered. On a local level, blasting increases the possibility of landslides, and causes air and noise pollution. Quarrying on hill slopes and in the riverbed causes pollution and destabilisation of the slopes.

The large scale construction that is an inescapable part of hydropower development leads to deforestation. It has been observed that construction leads to the inadvertent loss of much more forest than has been accounted for. The presence of a dam on a river also impacts the ecosystem by bringing about a drastic change in the species composition. Invasive species tend to appear and flourish while suppressing endemic species and even causing some to become extinct. 

An affidavit filed by Ministry of Environment and Forest in the Supreme Court admitted the role of hydropower projects in Uttrakhand disaster in 2013. It said that “the maximum damage sites in the disaster affected areas (were) located either upstream or immediately downstream” from hydropower projects.

According to a paper by the United Nations Environment Programme, dams and their associated reservoirs permanently impact on freshwater biodiversity by several processes. Climate change has also been linked with dams. Studies show that large dams cause anoxic decomposition which leads to the formation of methane gas. This ‘greenhouse gas’ produced by dams may contribute to global warming to an appreciable extent. According to a study, dams contribute about 24 per cent of the total methane emissions in the world. Of these emissions, India contributes slightly under 28 per cent.

Submergence and displacement

Though the benefits of a dam are often exaggerated, the estimates related to land submergence and possible displacement of people are invariably kept low to paint a positive picture.

From Hirakud to Bhakra Nangal to Tehri and many more, scores of affected families were not rehabilitated at all. Those rehabilitated also complained about lack of livelihood opportunities and poor living conditions. Narmada Valley project, around which a big people's movement was built, remains the most controversial irrigation and hydropower plan. Envisaging around 30 irrigation and hydroelectric multipurpose dams, the project's environmental and social costs vis-a-vis the benefits have been cause of much debate and litigations. Sardar Sarovar dam, the largest structure on Narmada river, is believed to have displaced over 3 lakh families and is expected to displace additional 2.5 lakh families if its height is further increased by recently-approved 17 metre.

The World Commission on Dams in its report says: “While dams have delivered many benefits and made a significant contribution to human development, in too many cases the price paid to secure those benefits, especially in social and environmental terms, has been too high and, more importantly, could have been avoided.”

Political issues around dams

Shortage of water is increasingly being felt resulting in conflicts across the world. For the same reason India is facing disputes both within and outside its boundaries. While Punjab, Haryana and Rajasthan are fighting over water sharing from Bhakra Nangal, Kerala and Tamil Nadu went to court on diversion of water from Mullaperiyar dam.

On the other hand, Pakistan claimed that design of Baglihar project in Jammu and Kashmir violated the Indus Water Treaty whereas India is wary of China's plan to tame Brahmaputra waters through a series of dams. Similar are the concerns of Bangladesh which lies further downstream over India's attempt to build dams.

Way forward

It is evident that instead of focusing on building new dams, we need to attend to underperformance of existing projects. Decentralised solar, wind energy and small hydroelectricity projects with local communities as their managers as well as consumers can offer sustainable alternatives to big dams. This will not only mitigate ecological and social impacts of power generation but also reduce cost of power generation and distribution.

For irrigation purposes, revival of traditional community-managed networks like kuhls of Himachal Pradesh, phad irrigation of Maharashtra and recharging of underground aquifers through rainwater

The World Commission on Dams lists seven steps as a remedy to issues arising from dams. These include gaining wide public acceptance, exploration of alternatives to dams, optimal usage of existing structures, protection and restoration of ecosystems at river basin level, recognising entitlements of the affected people, compliance with applicable regulations and regional co-operation on trans-boundary rivers.

A few of the western countries, having realised the futility of large dams, are trying to help rivers reclaim their territory. Dams that no longer serve a useful purpose, are too expensive to maintain safely, or have harmful impacts are facing the axe especially in United States where the rate of decommissioning of large dams has overtaken the rate of construction since 1998.

The provision of adequate environmental flow releases from dams is an important means of achieving a compromise between overt exploitation of our rivers and a non-practical cessation of all use. Attempts have been made towards the assessment of these flows for the Ganga, and an ongoing project aims to achieve implementation of these flows in the Ramganga. The successful process of e-flows in India may indicate that it is going to be mainstreamed into water resource management policy.

 

Featured Articles
December 4, 2022 What is the status of inland fisheries in India? Read these situational analysis reports to know about inland fisheries, the life of the fisherfolk, governance and tenure in inland fisheries and threats to the sustainability of inland fisheries.
Fishing in an irrigation canal in Kerala (Image Source: Martin Pilkinton via Wikimedia Commons)
November 23, 2022 Inspite of the realisation that minimum flows are essential for rivers to maintain their health and biodiversity, water released from various dams in India continues to disregard minimum environmental flow requirements.
Cauvery river at Hogenakal, Karnataka. (Source: IWP Flickr Photos via Claire Arni and Oriole Henri)
March 25, 2022 Dammed and bound, will the beautiful river Teesta survive India's insatiable demand for electricity?
Heaven on earth: A view of the Teesta from the coronation bridge (Image Source: Paramanu Sarkar via Wikimedia Commons)
November 21, 2021 Upstream hydrological modifications altered the basin hydrology, says study
Kathiya Gaon, Tehri, Uttaranchal (Image: India Water Portal)
October 25, 2021 Will it be possible to achieve tradeoffs between meeting water needs of people and retaining river waters to sustain the rare and beautiful, but endangered Indus River Dolphin in the Beas river?
Beas river at Kullu, Himachal Pradesh (Image Source: Wikimedia Commons)
July 26, 2021 Do dams worsen floods? These videos by Jeevitnadi Living River Foundation highlight the role of dams in controlling floods and the emerging challenges to flood management in India.
Hirakud, India's oldest dam (Image source: India Water Portal on Flickr)
Himachal Pradesh state policy on disaster management (2011)
This document presents the disaster management policy for the state of Himachal Pradesh. Posted on 25 Sep, 2011 04:28 PM

Main hazards that the state is prone to consist of earthquakes, landslides, flash floods, snow storms and avalanches, droughts, dam failures, fires – domestic and wild, accidents – road, rail, air, stampedes, boat capsizing, biological, industrial and hazardous chemicals etc.

Indicators of climate change in the middle Himalaya - A rapid inventory - Current Science
The responses or coping strategies initiated by mountain communities to deal with these changes were noted in the study. Posted on 22 Sep, 2011 01:22 PM

This article published in the journal Current Science presents the findings of a study that aimed at developing a rapid inventory on the impact of the recent climatic changes on the ecosystem, flora and fauna of the Himalayan region with a special emphasis on livelihoods.  

Clear the air on Sindhol - WIO urges Government of Odisha
Before asking public on Sindhol project, they do have a right to know the project details, demands Water Initiatives Odisha. Posted on 17 Sep, 2011 01:47 PM
  • Is the government really serious about the Project?  Water Initiatives Odisha(WIO) apprehends this to be a political game rather than a hydro power project, at least for now.
  • We urge upon the government to first clear the air on the project design and other related issues before moving any further.
  • The project is uncalled for without making a comprehensive analysis of water and energy scenario of the state; and if it displaces people and submerges agriculture land and forests

Disaster management in India – A report by Ministry of Home Affairs
This report by the Ministry of Home Affairs on disaster management in India is the outcome of an in-house compilation and analysis of information relating to disasters and their management. Posted on 09 Sep, 2011 05:28 PM

The perception about disaster and its management has undergone a change following the enactment of the Disaster Management Act, 2005. The definition of disaster is now all encompassing, which includes not only the events emanating from natural and man-made causes, but even those events which are caused by accident or negligence.

Basanti and the Kosi: How one woman revitalized a watershed in Uttarakhand
Chicu writes about the river and a woman's tireless effort to protect it. Posted on 07 Sep, 2011 03:22 PM

Guest post by: Chicu

Adaptive water resource management in the Lower Bhavani project command area in Tamil Nadu – A research report by IWMI
This study by IWMI explores the theory and practice of adaptive management based on a detailed field study in the Lower Bhavani project command area. Posted on 25 Aug, 2011 11:07 PM

Bhavani

To what extent farmers and water resource managers already practice adaptive management and whether it is practiced in an optimal manner or could there be areas for improvement based on recent advancements in the theory of adaptive management are some of the questions that are particularly appropriate in the light of rapid changes in river basin water use and also in relation to basin closure.

This paper draws on the development and use of water resources in the Lower Bhavani Project (LBP), with the LBP reservoir and the 84,000 hectare (ha) LBP command area. The project diverts water from the Bhavani River, a tributary of the Cauvery River in Tamil Nadu.

Restructuring of the Central Water Commission – Ministry of Water Resources invites comments on its proposal till September 30, 2011
The Ministry of Water Resources has invited comments from various stakeholders on restructuring of the Central Water Commission. Posted on 25 Aug, 2011 12:24 PM

CWC

The restructuring is being proposed primarily to adopt river basins as the fundamental block for integrated planning, development and management of water resources in the country. 

Boundary concepts for interdisciplinary analysis of irrigation water management – A working paper by Peter Mollinga
This paper by Peter Mollinga, University of Bonn reviews the boundary concept that has emerged in interdisciplinary irrigation studies in South Asia, particularly India. Posted on 24 Aug, 2011 07:16 PM

The focus is concepts that capture the hybridity of irrigation systems as complex systems, and cross the boundaries of the natural and social sciences. 

Blue harvest – Inland fisheries as an ecosystem service – A report by UNEP
The report highlights the integrative ecosystem approach to inland fisheries. Posted on 24 Aug, 2011 11:34 AM

CoverThis report by United Nations Environment Programme (UNEP) reviews the importance of inland fisheries as an ecosystem service, the pressures upon them, and management approaches to sustain them and thus helps inform future approaches to conservation and management of freshwater ecosystems.

There is an urgent need for major investment in policy and management approaches that address the direct and indirect drivers of aquatic ecosystem degradation and loss of inland fisheries taking into account their role in sustainable development and human well being. The UNEP Ecosystem Management Programme (UNEP-EMP) provides an effective framework for pursuing this challenge.

Hydrology of the Upper Ganga river – A report by the International Water Management Institute
This report by International Water Management Institute deals with the hydrology of the Upper Ganga river - the upper main branch of the river. Posted on 21 Aug, 2011 10:43 PM

To provide the background hydrological information for the assessment of environmental flow requirements at four selected ‘Environmental Flow’ sites, a hydrological model was set up to simulate the catchment in the present state (with water regulation  infrastructure) and to generate the natural flows (without water regulation infrastructure).

×