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.