India - The unbearable lightness of big dams

After repeated floods, will the government evaluate the performance of the big dams and embankments and decommission those that are non-functional, without making it a prestige issue?

Dinesh Kumar Mishra Jamshedpur

Gujarat and Maharashtra are the two most dammed states in the country. Dams are known for providing irrigation, produce power and hold floods apart from fulfilling the needs of the industry. Until three years ago, the dams in Maharashtra and Gujarat were cursed for not holding enough water to meet the drought situation there. They are being cursed even now but for a different reason. They did not hold enough water that could prevent flooding the downstream areas. Dams, in fact, are only fair weather friends when it comes to dealing with water and they do not deal with anything else. Any aberration in rainfall, whether excess or short, leads virtually to their non-performance. This is the lesson from the past two years in these states. The situation in Madhya Pradesh is no better.

The official response is common to the non-performance of these dams: there should be more dams built to increase water storage. Nobody asks what the dams would store if the rainfall is deficient. There are expectations from the dams that they would store enough flood waters in case of excess rainfall. But do they?

Heavy downpour in the catchment areas of the river causes floods. The dams are expected to hold this flow to prevent flooding the countryside. This is possible if the dams are kept empty to the extent possible. The demands of irrigation and power production would require the dams to be full as far as possible. Thus, the choice is very limited. Flood control always takes a back seat. Reservoirs are normally kept full by September end or early October. In case of heavy rain in such periods, all the incoming water will have to be passed over the dams. Hence, the releases from the dams will be to the detriment of the people living downstream.

What happened in Surat and at places in Maharashtra this year was unique. The flooding was caused in early August, much before the end of the rainy season. Incessant heavy rainfall was observed in the upper catchment areas of the Tapti river but no action was taken to release water till it got filled to the brim. Indeed, the dams are inching towards making floods an urban phenomenon too while floods are basically known as a rural phenomenon.

Damodar floods (1968 and 1978) are cases in point when it rained very heavily in the first week of October. West Bengal suffered its worst-ever floods because of the dams of the Damodar Valley Corporation (DVC). Floods in the downstream area of the Hirakud dam in Orissa (1982 and 2001), were caused by excessive releases from the dam. There was panic release of water from the Bhakra reservoir in September 1988 which flooded Ludhiana, Jalandhar, Amritsar and Bhatinda affecting over 4.3 million people. The Bhakra-Beas Management Board issued a routine explanation that the devastation would have been more intense if the water was not released. The chairman of the board was killed in a terrorist attack soon after.

Similarly, in Banda in Uttar Pradesh, in 1992, the floods that occurred on September 12/13 ruined the lives of millions of people in 600 villages. Torrential rains continued for four days and the water levels kept on building up in the Ken river. The officers responsible for the functioning of the Rangawan, Gangau and Bariyarpur dams were not aware of the tragedy. When the reservoir level rose alarmingly, all the gates of these dams were opened simultaneously and the entire Banda town and the district suffered immensely.

There were floods in Surat, just before the infamous plague in 1994. This was caused by the releases of the Ukai reservoir on the Tapti. The same tragic drama was enacted, once again, in 1998. The flood waters this year rose to alarming heights in Surat town and people had to go without food, water and electricity for five days. The local people used to believe that the floods were due to natural causes; now they know that they are caused by malfunctioning of reservoirs. Ask any resident of Surat, after this year’s terrible experience, and he will tell you that in case of failure of the Ukai dam, 50-60-ft-deep surge of water would ravage the town.

In an interview in Dainik Hindustan (August 19, 1995, Patna), the Minister of Water Resources, Ramashray Prasad Singh, Government of Bihar, had mentioned about the utility of dams in flood control and praised the performance of the Chandan and Badua dams in central Bihar. The Chandan dam was swept away in the floods of September 26, 1995, killing hundreds of people in the districts of Banka and Bhagalpur. These districts have found a permanent place on the flood map of the state now.

There was a devastating flood in the Narmada basin in September 1999. It spread over more than 300 villages of six districts submerging one-third of Hoshangabad town. The flood coincided with the parliamentary elections, which had to be postponed. The release of water from three of the six dams constructed under the gigantic Narmada dam project, namely the Bargi, the Barna and the Tawa, was responsible for the flood. If the water had not been released, the reservoir level would have risen and submerged the villages of the displaced people upstream. By opening the gates, the authorities doomed the downstream areas but no one apparently takes the responsibility for these transparent operational failures.

Every dam-related disaster leads to predictable statements by politicians across the spectrum that had the dams not existed the situation would have been far worse. Engineers don’t give public statements but speak the same language; they almost always brand the disaster as a natural calamity. This is how they defended the 1978 floods in Burdwan in the downstream areas in the Rashtriya Barh Ayog Report (1980). As far as the flood victims are concerned, they know that these are man-made and, in most cases, they can identify the men who made it.

It has not been raining too much in Bihar for the past two years and except for the Bagmati basin that keeps the flood issue alive, a drought-like situation continues in north Bihar — the permanent abode of floods. Two years of continuous drought is not enough to term it as a consequence of climatic change, since similar or even worse conditions existed in 1967, 1972, 1981 and 1992. However, whenever there have been floods in Bihar, most politicians and engineers generally chant in a chorus that the floods were caused by heavy rainfall in the upper reaches (implying Nepal) and unless the discharge in the rivers were controlled, floods just can’t be controlled.

Obviously, dams are prescribed to be built if the discharge in a river has to be controlled and one often hears about the Barahkshetra dam on the Kosi, Chisa Pani dam on the Kamla and the Nunthar dam on the Bagmati. Of these, the Kosi dam was first proposed in 1937 and negotiations are on with Nepal ever since. It is an endless wait for the people to get a respite from the floods while the carrots of this dam have been dangled before them for about 70 years now. Besides, whether this dam, if ever built, would be able to tame the river, is seriously under doubt.

The Second Irrigation Commission (1994) of Bihar suggests that the Kosi has a catchment area of 59,550 sq km at site No: 13 where the Kosi High Dam is proposed to be built. Below this site, the Kosi has an additional catchment area of 2,266 sq km up to Bhimnagar barrage and 11,410sq km between Bhimnagar and Kursela where the river joins the Ganga. This brings the total catchment area below the dam to 13,676 sq km, which is only slightly less than that of the catchment area of the Bagmati and nearly double that of the Kamala. Those who have seen the Bagmati and the Kamala in spate can well imagine the quantity of water passing through these rivers. This much of water will always flow below the proposed dam site and try to enter the Kosi, which the existing embankments on the river would prevent from entering it, as is happening at the moment. Hence, there will be just no change in the water-logging condition outside the embankments. And, since all the water cannot be held behind the dam in the rainy season, the release from the dam will always keep the population within the embankments on their toes, as usual.

As far as the dam on the Kamala near Chisa Pani is concerned, it was first proposed in 1956, but, according to the Second Irrigation Commission of Bihar (1994), this proposed 66.14-metre-high dam can accommodate a peak discharge of 5,377 cusecs (1,89,270 cusecs) but there is no flood cushion provided in this proposed dam and flood control, if any, is proposed to be achieved through flow regulation alone. It is interesting to note whether the politicians and engineers are aware of this fact as both claim that once the Chisa Pani dam is constructed, the flood problem of the Kamala basin will be solved.  No details about the dam proposed on the Bagmati are available.

Will the politicians in Bihar ever question the functioning of the Gujarat and Maharashtra dams before they demand the revival of the dams for flood control on their rivers? Will the engineers do some introspection so that the performance of these dams can be improved? Will the government revisit the National Flood Policy of 1954 and seriously consider constituting a ‘Drainage Commission’ for the country as most floods are being caused by drainage congestion? Will the government evaluate the performance of the dams and embankments and decommission those structures that are found non-functional, without making it a prestige issue?

The writer is Convenor, Barh Mukti Abhiyan, Jamshedpur, Jharkhand