If ever there was a lesson in the unintended effects of damming rivers, the Farakka Barrage is probably it. A 4.5-kilometer irrigation dam constructed on a tributary of the River Ganges in 1974-75, it is threatening to wreak havoc on a series of downstream villages and ultimately silt up the Kolkata harbor, the condition it was partly designed to fix.

The barrage, a low-height dam, in the Guinness Book of Records as the longest in the world, is now raising the possibility that two of the Ganges’ major tributaries, the Padma and the Bhagirathi, will merge, with devastating consequences. Some 20 km downstream from the barrage, the two rivers are now fewer than 750 meters apart. Ten years ago, they were almost 3 km from each other.

If that happens, the flow of water to the port of Kolkata 257 km downstream, already faced with declining navigability, is expected to wane further.

Although the barrage was originally intended to divert water from the Ganges into the Hooghly River during the dry season and rescue the Kolkata port as well as providing dry-season irrigation, the government in Dhaka has accused India of using it to turn parts of Bangladesh into a desert, raising salinity, affecting navigation and adversely influencing the environment, agriculture and fisheries.

The ornate treasury palace of Jagat Seth, once the most fabulously rich banker in pre-British India, has been swallowed up by the changing course of the Padma. Other 18th century palaces have also been washed away. A large village, Akheriganj of Bhagabangola, has disappeared from the map with the destruction of 2,766 houses, leaving 23,394 villagers homeless. A school, a college, mosques and local government offices have disappeared, with erosion gobbling up towns and villages. The changing river channel, which forms the border between India and Bangladesh, has resulted in rising tension as more than 10,000 hectares of land

have shifted from the Bangladesh side to India.

Critics say this is a product of the so-called “engineers’ racket,” a term coined by the Indian geographer Sunil K Munshi, to describe corruption resulting from greedy civil contractors working together with irresponsible state and federal governments. And it appears that now India will seek to undo the damage with a mammoth US$120 billion plan to interlink its rivers, which originate in the Himalaya Mountains, with 30 interlinked canal systems that would deliver water to so-called Peninsular India.

Mohd Khalequzzaman, associate professor, department of geology and physics at Lock Haven University in the United States, said in an email interview that "interference with the natural flow of the Padma has already led to anthropogenic and natural upsets in Bangladesh. On the contrary, the Calcutta (Kolkata) port didn't gain much in the way of increased flow that would have been enough to flush out the silt.”

Part of the problem, according to environmentalists, is that the original silting up of the Kolkata Port came about because damming of rivers as a part of the Damodar Valley Corporation hydro project cost others their ability to flush the Hooghly River. The Farraka Barrage, intended to correct that problem, appears set to cause a bigger one.

It was hardly unexpected. The first technologist to warn vainly against decision to build the barrage was the late Kapil Bhattacharya, then chief engineer for the West Bengal government, who said that the plan to deliver 40,000 cubic feet of water per second to flush the harbor was absurd, and that the designed capacity of the barrage would seldom rise above 27,000 cu.ft/sec. He also warned that the new distribution of silt loads after the construction of the barrage would result in huge floods in West Bengal and Bihar. His prediction came true almost immediately after the barrage began functioning.

The New Delhi-based Centre for Science and Environment in a 1999 study, Floods, Floodplains and Environmental Myths, criticized the raising of levies to manage floods, which, they charge, creates problems rather than of ameliorating them. Many Himalayan rivers are have been surrounded by levies over their full course and as a result in many places the river beds are now higher than the surrounding areas. Even moderate rainfall causes inundation, particularly in West Bengal and Bihar.

Rivers in the Himalayas, an erosion-prone mountainous region, carry a lot of silt. The question is thus whether to resort to flood management or learn how to live with floods based on oral traditions. However, the engineers’ racket may have taken much of India past the point where that is possible.