The recent inundations by the waters of the Kosi in Bihar and the resultant widespread human suffering have been declared a "natural disaster". Relief contributions are pouring in and the prime minister has sanctioned large amounts from his official funds. Political leaders have got busy blaming one another for relief not reaching the marooned, all the while looking for small political gains. As the waters would recede, and people would start returning to their original habitat, there is no doubt we will get back to business as usual, thinking that the natural disaster has been successfully taken care of.
In future, it is certain, similar events would recur, may be in a different setting each time. The monsoon inundation by the numerous tributaries of the Ganga or the Brahmaputra originating in the eastern Himalaya will cause more human tragedies. It may be the Teesta, Sankosh, Manas, or Subansiri or some other river. A different variety of annual inundation would spread over large areas in Bangladesh too.
Is our political leadership aware of the immense risks associated with the 'business as usual' approach to the flooding by the Himalayan rivers? The public, which has paid thousands of crores of rupees towards the relief of the Kosi victims, deserve a comprehensive report on the ecological background of the Kosi tragedy. Before we forget the Kosi episode and get busy with some other, is it not important for people to know what went wrong or where nature became irregular?
The two-and-a-half monsoon months bring about 80 per cent of India's annual rainfall. It is well known that such rainfall is intense in the Himalayan watersheds. The heavy monsoon precipitation on a young and still growing high mountain would fill the flow of water with a load of sediment and high mechanical energy. It is a process that has been happening over millions of years. When a river in high flow, loaded with energy and sediments, comes down from the uplands to the plains, it will need space and time to stabilize itself. Shifting of its course is only natural at this stage. This is part of the basic knowledge of Himalayan hydrology and geomorphology. Within the period of recorded mapping — which is about 240 years — the Kosi has moved westwards by about 180 kilometres. The Teesta, the Brahmaputra and the Bhagirathi-Hooghly have also shifted their courses. What then, was unusual about the Kosi inundation? Was it something unexpected in river science and engineering?
The ecological complexity of the Himalayan rivers is nothing new, but the knowledge of their hydrology and geomorphology is old, though it has remained underdeveloped. Owing to unexplained governmental reservations on disclosing detailed data on these rivers, related river research has not been taken up in the public domain. It will not be an unfair to say that the management of these rivers is going on without much contact with the advances in interdisciplinary knowledge on river systems made in the recent decades.
Thus, instead of a national discussion on the ecological reasons behind a human tragedy involving millions of people, we accept the sugar-coated explanation of "natural disaster". The Union railway minister, Lalu Prasad, touched upon the possibility of human failures in the Kosi calamity, but he quickly got busy putting the blame on his former comrade and current rival, the chief minister of Bihar, Nitish Kumar. He forgot that the Kosi has defied embankments ever since they were erected in 1954. Thus, most of the breaches preceded the reign of Nitish Kumar. India will profit greatly if politicians recognize that before we intervene in the lives of the powerful Himalayan rivers, a great deal of ecological and scientific knowledge needs to be acquired.
The annual per capita water availability in India has gone below 1,000 cubic metre — the situation would be described by experts as scarcity. Himalayan rivers are the largest sources of water for India. As a result of global climate change, there may be significant changes in the water endowment pattern. Continuing with our ad hoc, 'business as usual' approach based on outdated knowledge is just a convenient way of wriggling out of a systematic ecological research by hiding under the 'natural disaster' excuse.
In a globalizing and interconnected world, ecological links play significant roles. Ecosystem-based management has become the global practice. The Himalayan rivers connect Bangladesh, Bhutan, China, India and Nepal ecologically. The pressure of population and demand for more land for agriculture, industry and habitation have pushed men deep into the floodplains and caused considerable ecological damages. During the monsoons, a river needs the lost ground to discharge its high flows. If engineering interventions in the Himalayan rivers are guided by the recent holistic knowledge base, we would see that monsoon inundations are not always hostile acts of nature. Recent advances in the study of the ecosystem of Himalayan rivers show that the annual inundations are useful, as they recharge groundwater, transport and conserve fish biodiversity, and replenish farmlands with fine silt. Only in the event of extreme precipitations, the inundation would be longer, deeper and disastrous.
The Kosi floods that ravaged 16 districts of Bihar were caused by the collapse of man-made embankments. It was not the natural geomorphological shift of the flow of the river. It is well-known that while rivers normally flow below the land around it and act as drainage, in the case of the Kosi after it was embanked, the river bed often lay several metres above the land outside the embankments. This may have facilitated the draining of the river into the land, and not the other way round.
The failure of the embankments has prompted many to demand a high dam on the Kosi. Even though the comprehensive assessment of dams around the world is increasingly discouraging such options, India is still opting for expensive and risk-prone large dams without any open scientific assessment. Even if a dam is built, its ability to control floods would depend on whether heavy rainfall is occurring downstream or upstream. Heavy rain downstream of the Kosi dam site is likely to cause floods too. There is no dearth of examples in India where opening the sluices of dams to protect them from overtopping caused floods.
India and Nepal had signed the Kosi agreement in 1954. Following the recent disaster, there have been calls for a re-look at it. However, where can a re-look with a vision of traditional engineering lead us? It is necessary for both Nepal and India — and probably Bangladesh and Bhutan too — to gather holistic ecological knowledge on the Himalayan rivers and create an informed approach for their sustainable management. If the 'problem rivers' from the Himalaya are to be converted to 'prospect rivers', we have to avoid the 'problem engineering' of the past and make use of modern ecological engineering.
Time is running out for India to take the difficult but inevitable path of using ecological sciences, instead of taking the unscientific escape route of describing extreme but predictable ecological processes as 'natural disasters'. The cost of delay will be very high, in terms of frequent recurrence of the widespread devastation and human misery as we have seen in the case of the Kosi.