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.
North Bihar is the proverbial land of rivers, with the Kosi often described as the most notorious of all. This dubious fame is intertwined with the river basin's 'fluvial geomorphology', or how the river's flow has shaped the terrain of the watershed. Here, too, farmers had long understood that the floods were, in many ways, blessings in disguise. But the first human intervention into the lower Kosi basin introduced an alien development model, as it was instituted by the British. During the mid-18th century, a road- and rail-focused urban/industrial model of development was imposed onto an inappropriate geographical setting, leading to a spectrum of detrimental environmental changes. The roads and railways were outfitted with inadequate culverts, which inevitably intercepted crucial drainage points. In turn, this led to an expansion of floodable areas, outbreaks of malaria from mosquitoes that bred in the stagnant water, and a general decline in crop production in the impacted lands. Here was yet another instance of humanity's ineffectual, and perhaps disastrous, meddling with hydro forces larger than itself.
Quick changes
The Raj ended in 1947. But the focus on purely Western-style hydraulic engineering solutions survived, used to augment lean-season flows, combat flooding, resuscitate the navigational channel and ensure adequate irrigation. These attempted solutions continued to imperil the ecological security and delicate hydrological balance of the densely populated Gangetic plain. Over the course of the past six decades, this has led to the loss of livelihoods for many poor, rural families. In West Bengal, official documents state that erosion has increased since the Farakka Barrage was completed in 1975, rendering homeless at least a half-million people.