'Unplanned release of water': Bengal floods revive concerns on role of dams

By Bharat Dogra* 
Recently, on September 20, Chief Minister of West Bengal Mamata Banerjee wrote a letter to the Prime Minister Narendra Modi in which she stated that at least seven districts in Bengal are facing floods because of the “unprecedented, unplanned and unilateral” release of around 500,000 cusecs of water from the DVC’s Maithon and Panchet dams. 

The letter stated that such a huge quantum of discharge from the DVC system had never happened in the past. This letter says that this is the biggest flood since 2009, affecting 1000 square kilometers of area and nearly five million people. It said: 

“I am compelled to call it a man-made flood, a situation engineered by sheer neglect and turning a blind eye to sustained requests from the stakeholder and long-suffering state government like us to address the technical, mechanical and engineering issues concerning the DVC system... It remains a fact that the sharp increase in the combined dam release was made without waiting for the water levels to reach the maximum flood management levels at the two reservoirs mentioned above, and without having advance consultation with the state government.” 

After emphasizing the need for dredging and de-silting reservoirs, she added:

“It is also alarming that DVC appears to have shifted focus from its primary objective of flood control in the Damodar river, as mandated by law, to power generation, disregarding the social obligation. This shift has sacrificed the interests of the downstream state of West Bengal.” 

However it needs to be added that the Central Government has stated that all norms were followed while releasing water from the DVC dams. On September 22 the controversy deepened when the Bengal power secretary Santanu Basu resigned as state representative from Damodar Valley Corporation while another engineer also quit a key panel to protest against “unplanned and uncalibrated” water release.
Earlier in 2021 also the Chief Minister of West Bengal Mamata Banerjee had written a detailed letter to Prime Minister Narendra Modi regarding the man-made floods created in her state due to excessive, uncontrolled and unplanned water discharge from DVC Dams. In particular she had criticized the discharge of about 10 lakh acre-feet of water between September 30 and October 2, 2021 which caused serious devastation in lower Damodar region before the festival season.
In this letter written in October 2021 she had reminded that she had not yet received a reply to her earlier letter sent on August 4 in which she had “highlighted the structural factors that give birth to grave man-made flood situation in southern Bengal, repeatedly, pitifully and tragically.”
Earlier in 2021 the Chief Minister of Bihar Nitish Kumar had also raised questions about Farakka Barrage aggravating flood sitiuation in some parts of the state and elsewhere too.
These statements of two Chief Ministers should be seen together with what has been reported from several other parts of the country regarding excessive dam water releases leading to very destructive floods and dams and barrages contributing to floods in other ways as well. Another interesting aspect is how the points made by the two Chief Ministers, although made in different contexts, turn out to be related to each other.
A disturbing aspect of many flood situations in recent years has been that these were caused by sudden and heavy discharge of water from dams. The highly destructive floods in Surat in 2006, for example, were caused by heavy release of water from Ukai dam. 

Around the same time the South Asia Network of Dams, Rivers and People reported, "Mismanagement and negligent operations of the largest reservoirs on Tapi, Narmada, Krishna, Godavari, Mahi and Sabarmati rivers have caused man-made disasters in Gujarat, Maharshtra, Madhya Pradesh, Karnataka and Andhra Pradesh. The big dams that were expected to reduce the floods have actually been responsible for the flood disaster visiting these states now, the states that also happen to have the largest number of big dams."

Looking at other such reports of recent decades we find that water releases from dams of the Damodar river system, the Bhakra-Beas system, Hirakund dam and several other dams have caused very destructive flash floods. Such floods are different from the gradual rise in river water seen in normal floods and the destructive capacity of such floods is much higher than normal floods.
Theoretically and on paper of course, dams with storage reservoirs are supposed to protect from floods by holding back excessive rain water, but excessive silting, poor management and distorted priorities as well construction of hazardous, undesirable projects can at times instead lead instead to aggravation of floods. 

Although officials point out that at times such heavy release of water becomes unavoidable, critics allege that frequently due to the pressure to maximize hydropower as much as possible, enough attention is not given to flood-control. As a result there is not enough capacity in the dam reservoir to absorb floods and very heavy discharges have to be made resulting in flash floods. Such situations are more likely to arise towards the end of the monsoon season or an extended monsoon season when flood-control gets less attention.
In 1988 such an extremely serious flood situation emerged in Punjab due to excessive discharge of water from Bhakra-Pong dams built on Sutlej river. Commenting on these floods which caused immense damage including loss of lives, Prof GS Dhillon, Dept. of Civil Engineering at Punjab Agriculture University wrote around this time:

"Bhakra and Pong, mighty dams that they are, still could not protect Punjab from flood rather discharges from their overfilled reservoirs added to the problem ... This has led the people to lose their faith in large dams operated for the purpose of power and irrigation mainly and people feel that the flood control aspect has been neglected by the authorities in charge of operation and maintenance of these dams. If that is not the case, how can flood storage space of the Bhakra dam above EI 1685 be converted into storage in the interest of irrigation and power. It is rumored that the authorities panicked and released the volume stored above EI 1685, they forgot the headworks downstream have limited capacity.”
On the other hand, senior officials of the Bhakra-Beas Management Board stated that they had saved the dam under very adverse conditions. In his talk with newspersons the late Gen BN Kumar, Chairman of the BBMB, made the following statements soon after the disaster:
"We all in Punjab and many others elsewhere were 0.03 inch away from one of the worst catastrophes in living memory during the last week of September when the Bhakra dam's concrete structure registered a 0.99 inch tilt against its danger mark of 1.04 inches. We have saved the Bhakra dam as its survival was essential, else it would have been all over... We measure the tilt of the dam by a piano-wire -- like pensulum, through a hole which runs from top to bottom of the dam. The tilt during these four days (September 24 to September 27, 1988 was between 0.95 inches to 0.99 inches against its designed non-seismic tilt of 1.03 inches. In fact Punjab and other parts were 0.04 inches away from disaster."
Asked what would have happened if Bhakra dam had given away, Gen. Kumar closed his eyes and raised his hands saying, "It is unthinkable, and the very thought is horrifying -- we would not be here to review the flood disaster."
This clearly shows how big risks are faced at times in dam management and how these are related to water flows and discharges. Floods also cause immense harm and cannot be seperated from dam safety. As Mamata Banerjee wrote particularly in the context of Bengal in her 2021 letter,  “Unless the Government of India addresses the basic underlying structural and managerial issues, both on a short term and a long term basis, the disasters will continue unmitigated in our lower riparian state.”
However the question is not just of excessive release of dam water. If we look at extremely destructive floods in Uttarakhand in recent times, these were aggravated greatly by construction of dam projects in several ways such as obstructing the natural flow of river, making many areas more vulnerable with blasting work, careless disposal of vast debris and rubble in rivers and in other ways. 

A major problem here is that the dam projects leave mounds of muck and when floods carry the debris and boulders then their fury and capacity to destroy increases greatly. The linkages of dams to hydel projects including under-construction ones here has been well documented in a report prepared at the directions of the Supreme Court by a committee chaired by Dr Ravi Chopra.
Of course the biggest damage takes place in the case of dam collapse, such as the collapse of the Machu dam in 1979 which proved so destructive for Morvi town in Gujarat and nearby villages. There have been around 50 dam collapses during the last 65 years in India, including Kaddam, Chikahole, Dantwada, Aran and Khadakwasla. Here again Uttarakhand ( as well some downstream reaches of the Ganga in other states) is placed in the more vulnerable situation due to the construction of highly hazardous Tehri dam project constructed against expert advice in the Himalayan reach of the Ganga river. 

In this context again it was an officially constituted River Valley Projects Appraisal Committee of the Ministry of Environment, which had warned of the most terrible consquences for the downstream thickly populated cities like Rishikesh and Haridwar if something happens to this gigantic structure. At the same time this committee as well as other committees and experts have argued in detail about the extremely hazardous characteristics of this project.
As the Ganga flows on its long journey the Farakka Barrage Project in W.Bengal has become the other most controversial project in the context of dams and floods. Chief Minister of Bihar Nitish Kumar has spoken regarding the highly adverse impact of Farakka barrage on making Bihar more prone to floods. Other experts have pointed out that Murshidabad and Malda regions in W. Bengal have also become more prone to floods and erosion as a result of this barrage which was completed in 1975.
Nitish Kumar has stated that the Farakka project by increasing the silt load in the Ganga river has made it difficult for flood waters to be cleared quickly. In fact he has gone a step ahead and called for removing or decommissioning the project. Several activists and social movements including the Ganga Mukti Andolan in particular have supported this demand.

Destructive floods in Uttarakhand in recent times were aggravated greatly by construction of dam projects

A former irrigation minister of West Bengal Devavrata Bandyopadhyaya had said some years back that the people of Malda and Murshidabad are doomed by this project. He had said this in the context of increasing erosion of land and the increasing tendency of the river water to erode land as the river bed is clogged by too much silt.

Kapil Bhattacharya, former Chief Engineer of W. Bengal, was firmly opposed to the Farakka Project but his objections were pushed aside rudely and he was badly victimized while the controversial project went ahead. After losing his job, Kapil Bhattacharya later emerged as a prominent human rights activist and was active in this movement till his death.
Bangladesh has all along been opposed to the Farakka project due to the adverse impacts on water availability. This project has also adversely affected the relations of two friendly countries.
Clearly a big mess has been created in which everyone ultimately appears to be unhappy and feels cheated. In fact the messy story starts not with the Farakka project but with the dams built on the Damodar and Rupnarayan rivers, two tributaries of the main Hooghly river (the part of the Ganga moving towards West Bengal; the other part Padma goes towards Bangladesh). 

As Kapil Bhattacharya had stated, these dams did not take into account flood tides and tide-borne silt. A lot of silt and sand accumulates in the lower reach of Hooghly river which was earlier flushed into the sea by the normal floods of Damodar and Rupnarayan rivers. But this natural process was disrupted by the DVC dams. 

The silt deposits accumulated, reducing the water carrying capacity of the Hooghly and causing destructive floods. The navigability of the river was threatened, endangering the future of Calcutta Port. It was at this stage that Farakka Barrage was taken up on the plea that this will divert more water to the Hooghly and save the Calcutta Port. But the real story turned out to be quite different.
Bangladesh was soon complaining that after the diversion the lesser flow to the Padma river led to sand accumulation in its lower reach which could even change the river flow and hence bring floods in new areas, while also causing water shortages in most other areas in the lean season. There were also reports of salt water intrusion in coastal areas and adverse impact on fisheries. 

West Bengal and Bihar both experienced worsening of flood situation. Land erosion in Malda and Murshidabad became very acute. Ths was much along the lines Kapil Bhttacharya had predicted. Fish catch over a wide area declined too, leading to protests by fisherfolk.
Once adverse impacts of DVC dams started to appear Kapil Bhattachrya suggested that one way out is to give up the irrigation component of DVC and instead use this water to flush the lower Hooghly. The irrigation loss could have been made up by many small-scale irrigation and water-conservation projects taken up at only a fraction of the cost of the huge Farakka Project. In this way the need for taking up Farakka Project could have been avoided. 

But the government did not follow this advice and, pushed partly by the big construction lobby, went ahead with Farakka to correct the problems created by DVC dams. This turned out to be a classic case of a corrective measure for one problem turning out to be even worse than the original problem. This also shows how the problems of floods aggravated by dams raised by Mamata and Nitish in the context of two different projects are actually related and parts of the same sorry mess.
What then is the way out? Mamata Banerjee had written in her 2021 letter to the PM, “This annual problem requires immediate short-term and long-term measures so that the sufferings of the people are mitigated.and the national loss in terms of loss of life and property is avoided.” She had further urged, “I request that the Government of India should get into some serious actions without further delay.”
What should such actions be, keeping into consideration also the wider national and regional context? Clearly dam management should improve significantly so that flood protection objectives are never subordinated or sacrificed in the quest for other attractive objectives like maximizing electricity generation. Siltation rates should be properly assessed and not under-estimated as is often done to get projects cleared. 

Catchments should be well-protected. Unfortunately all this is easier stated than achieved. The reality has been that of violations of all these suggested good practices. Environmental ruin of crucial catchment areas has if anything aggravated further in recent times.

Overall much better and more honest appraisal of dam projects is really needed. All the real hazards and problems should be propery accessed and instead of taking a simplistic approach, the longer-term impcts and chain impacts should be properly considered so that projects more likely to increased floods risk are avoided at the outset. If very harmful projects got wrongly approved and constructed in the past, the possibility of decommissioning dams should also be considered. 

This has become even more essential in times of climate change when possibilities of more torrential rain concentrated in shorter time spans have increased significantly.
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*Honorary convener, Campaign to Save Earth Now. Books: “Planet in Peril”, “Protecting Earth for Children”, “Man Over Machine” and “A Day in 2071”