Re-flooding the Kosi

To date, flood-control mechanisms in India have been almost completely guided by the colonial legacy of embanking rivers, as well as by the simplistic engineering approach of dam-building. The enduring myth that freedom from floods can ever actually be achieved demonstrates a dramatic lack of understanding of how river basins function. In contrast, farmers in Assam, Bihar and Bengal had an age-old culture of living with floods. Indeed, they welcomed low-intensity flooding, having inherited a uniquely evolved technique of replenishing their farmland with layers of fertilising silt carried by the water, a method called 'overflow irrigation'.

Despite having functioned well for centuries, such traditions began to disappear during the British Raj. At that point, many rivers in Bengal were embanked in an attempt to combat the annual flooding – including the Damodar, often called the 'sorrow of Bengal' due to its frequent flooding. These bunds did ensure security against low-intensity flooding, but the long-term effects were detrimental, leading to the decay of river systems and the congestion of drainages. As recurrent breaches of the embankments and drainage congestion became commonplace, the sense of security provided by the bunds proved to be false. By 1858, the decision was made to demolish the right embankment on the Damodar, in order to ensure the safety of the left bank, through which the Grand Trunk Road and the railway were aligned. The so-called Sepoy Mutiny of 1857 probably contributed to this decision, making the British feel that railways and roads needed to be secured from floods in order that troops could quickly be deployed to areas of revolt. The whole experience was to be an eye-opener for the British engineers, who did not repeat their mistake by trying to tame the Kosi.