On August 18, the eastern afflux bund of the Kosi river breached in Nepal, reviving the buried embankment debate once again. The river carries an annual sediment load of about 92,800 acre feet. If a bund of one metre by one metre cross section is built by this much of silt and sand, it will go three times round the equator. That is the problem with the Kosi and its meandering nature which has haunted people for ages.

It was embanked once in the 12th century by King Lakshman-II and only traces of it are still seen in Supaul district. The British administrators took this as a warning that the river cannot be contained within the embankments. The political masters of independent India were in a hurry to be seen doing something for the people and they embanked the river in the late 1950s. Let’s look at what an embankment does to a heavily silt laden river.

Primary function

Embankments prevent a river from overflowing its banks during floods but they also prevent the entry of floodwater. This leads to a major problem as the embanked river is no longer able to fulfil its primary function — draining out excess water. With the tributaries prevented from discharging into the river and accumulated rainwater finding no way out, the surrounding areas quickly become flooded. The situation is aggravated by seepage from under the embankments. The areas outside the levees remain waterlogged for months after the rainy season.

Theoretically, sluice gates located at these junctions should solve the problem but, in practice, such gates quickly become useless; as the bed level of the main river rises above the surrounding land, operating the gates lets water out instead of allowing outside water in. When the sluice gates have failed, the only option left is to also embank the tributary. This results in water being locked up between the embankments. Moreover, no embankment has yet been built or can be built in future that will not breach. When a breach occurs, there is a deluge.

A paper published by the government of Bihar calls anyone subscribing to these views as one with a colonial bent of mind. Proponents of embankments have tried to rationalise the jacketing of rivers thus: forcing the same quantity of water through a narrow area increases the water velocity thereby increasing its eroding capacity. The increased velocity of water dredges the river bottom and transports the sediment out preventing the rise of riverbed levels, increasing the carrying capacity of the river and reducing the extent of flooding. These were the arguments of engineers in independent India when they resorted to massive embanking of rivers in the Ganga and the Brahmaputra basin.

The inevitable happened on August 18, 2008 and the river came out of its shackles. Ideological bankruptcy and callous indifference towards the welfare of the people are the sole reason for this human tragedy. This has happened earlier too and this is the eighth incident of its kind but the first above the Kosi barrage that was built to regulate the flow of the river.

The government fooled the people by saying that they have a technology to plug the breach within two to three days. When that time was over, it came with an excuse that materials are being moved on to the site and the work would start soon. When nothing happened, the chief minister said that the gap may not be plugged before April. He was stating a historical truth as none of the seven breaches that had occurred earlier were plugged before the Holi festival in March.  

That being the reality, the flood victims of Bihar will stay in open till that time and half the rainy season and the whole of winter stares at them. One does not know how long the enthusiasm of the government and NGOs would last to extend care to the hapless victims of official apathy.

It will be interesting to know the cost of the repair of the embankment that would have prevented this catastrophe and what would be the cost of plugging it now and who will foot the bill. The blame and mud slinging is going on in full swing and the victims are looking towards the rain lord to spare them for the time being.

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