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)
Bangledesh's perspectives on Tipaimukh dam
This article by Md. Khalequzzaman deals with Bangladesh's position on the Tipaimukh dam. Posted on 18 Jan, 2012 11:33 PM

The Indian government and two other Indian authorities have signed an agreement on October 22, 2011 regarding construction of the Tipaimukh Dam.

Hydropower in the Northeast: Potential and harnessing analysis - A critique
This paper was commissioned as an input to the study “Development and Growth in Northeast India: The Natural Resources, Water, and Environment Nexus” by the World Bank. Posted on 15 Jan, 2012 11:41 PM

The main objectives of the hydropower study are as follows: 

  • An analysis of the hydropower potential in the Northeast and key elements of the strategy that should be followed for optimal realization of this potential 
  • An overview of the hydropower development options in the Northeast with regard to the water resources in the different river basins, including consideration of flood control and irrigationmap of the north-eastern states

Map of the north-east states

SANDRP invites applications for a Researcher, Delhi
Posted on 15 Jan, 2012 09:29 AM

SANDRP

South Asia Network on Dams, Rivers and People (SANDRP), an informal network working on issues related to rivers, large dams and their impacts,sustainability and governance is looking for a Researcher.

The unquiet river: An overview of select decisions of the courts on the river Yamuna
This report by Ritwick Dutta presents an overview of the legislation on the river Yamuna. Posted on 14 Jan, 2012 06:40 PM

The river has attained the distinction of being perhaps the river attracting the most judicial attention in india, after the Ganga. This report analyses the various laws and judicial decisions pertaining to the Yamuna and their effects on the river.Cover page of 'The unquiet river'

River Yamuna - Dying by default or by design: A public lecture on river Yamuna
This presentation by Peace Institute Charitable Trust is part of a lecture organised by Toxics Link as part of the Yamuna Jiye Abhiyaan and held at the India International centre in September 2007. Posted on 14 Jan, 2012 05:24 PM

It aims to inform, enlighten and suggest solutions to bring back the river Yamuna to a healthy and resilient state. 

slide showing factories on the banks of the Yamuna

India, Pakistan and water - Lecture by Ramaswamy Iyer at MIDS
This lecture by Ramaswamy Iyer delivered at the Madras Institute of Development Studies (MIDS) highlights the conflicts over water sharing in India and Pakistan. Posted on 12 Jan, 2012 10:57 PM

It traces the roots of the conflicts to the strained relations between India and Pakistan following the partition and the framing of the Indus Water Treaty in 1960.

Floods in Orissa: No lessons learnt – An article in EPW
This article on floods in Orissa shows how no lessons have been learnt yet. Posted on 06 Jan, 2012 02:26 PM

This article by Kishore C Samal in the Economic and Political Weekly (EPW) discusses how in the natural disater prone state of Orissa the authorities have not been able to draw up an effective disaster management plan and politicians continue to play politics with relief works. It argues that for dealing with these disasters and the relief and rehabilitation work that follows what is needed is the participation of the local community and functionaries of panchayati raj institutions, and coordination with national and international bodies.

Big dams and protests in India: A study of Hirakud dam – An article in EPW
This article by Arun Kumar Nayak in the Economic and Political Weekly (EPW) examines the movement against the construction of the Hirakud dam in Orissa. Posted on 06 Jan, 2012 12:29 PM

It is evident that the domestic resistance to the project was variously compromised by nationalist rhetoric, imperatives of state development and absence of transnational support. The Hirakud dam project has failed on all of its objectives – flood management, hydropower production, irrigation and navigation. Its socio-economic impact has been devastating.

Living rivers, dying rivers: Bagmati river in Nepal
The fifth lecture in the ten-part series titled "Living Rivers, Dying Rivers" was delivered by Dr. Ajaya Dixit and Dr. Dipak Gyawali. Posted on 05 Jan, 2012 06:07 PM

Bagmati river in Kathmandu: From holy river to unthinkable flowing filth

Bagmati river, Nepal (Source:Bagmati Action Plan 2009-2014)

Ajaya Dixit initiated his presentation with a general account of how rivers shape the landscape and how riverine ecosystems have nurtured society and kept civilisations vibrant, cultured and creative. Dixit went on to discuss the basin characteristics of the Bagmati, a tributary of the Kosi that rises in the Shivapuri hills, north of the Kathmandu valley. Around fifteen percent of the basin area (3700 sqkm) lies in Nepal, while the remaining is in India. The average annual rainfall in the basin is 1400 mm and is more than 2000 mm in the hills. Bagmati is a seasonal river with rainfall and springs as its main source. Its mean flow is 15.6 cubic metre/second and low flow is 0.15 cubic metre/second in April.

Kathmandu lies in the Upper Bagmati basin and studies suggest that an ancient lake called the Paleo-Kathmandu lay within the Kathmandu valley as a lacustrine formation. Early settlers lived in lower slopes and used springs and river in the upper reaches. When they moved to the valley floor, they built dongia dharas, which are stone water spouts fed by the unconfined aquifers and delivered water through surface channels. Even today, dongia dharas dated back to 1500 years exist. The state built canals (raj kulo) tapped the upper stretches of the rivers close to the mountains. Rivers and irrigation helped recharge aquifers and ponds.

However, rising urbanisation has damaged these ancient artifacts. Over the last sixty years Kathmandu has expanded massively and its population has increased from 0.41 million in 1951 to 2.6 million in 2011. The city has a huge transient population aside from this, reducing it to a concrete nightmare. Seismologists suggest that Kathmandu is a rubble city in the making. Though the Bagmati river flow has not changed significantly in the last seventy years, the character of the river has been transformed significantly during the period 1970 to 1990. The river has been canalised while the dumping of the city’s garbage into it continues. Dixit identified a plethora of problems faced by the river such as upstream water diversion for drinking water needs, disposal of untreated liquid waste, disposal of solid waste, river jacketing for roads and commercial activities, sand mining and physical encroachment.

The state of the river is an outcome of the current approach to waste management particularly liquid waste management. Three types of waste water namely yellow water flux, grey water and yellow black flux are being generated and flowing water is being used as a vehicle to dispose these. The idea of a water based disposal system e.g. flush toilet embedded in Victorian engineering has led to a technological lock-in with the result that the notion of a natural hydrological cycle has undergone a fundamental transformation.

All the same, the bulk of the load in the river is biological though there are some factories releasing effluents. In the last 20 years some of them have been closed or relocated and the river now stands a chance of being salvaged.

  

 

Bagmati River at Pashupatinath Temple (Source:Wikipedia)
A plan for resolving Mullaperiyar conflict in Kerala - Forum for Policy Dialogue on Water Conflicts in India
An open letter to the Prime Minister on resolving Mullaperiyar conflict in Kerala is presented below - Posted on 31 Dec, 2011 12:56 PM

Guest Post: Forum for Policy Dialogue on Water Conflicts in India

The Forum for Policy Dialogue on Water Conflicts in India has been closely following the Mullaperiyar issue for the last several years. The polarisation of views around the Mullaperiyar has hardened over the years. The Tamil Nadu government insists that the Mullaperiyar dam is safe and that the water level must be maintained at the maximum level as per the agreement. The Kerala government insists that a new dam, downstream of the present dam, must be built because the present dam is unsafe. The recent tremors with their epicentres near the dam and the already diminishing trust and rising fears and apprehensions on both sides have created a grave situation needing immediate intervention and your initiative in getting the two parties together is a welcome move.