The Catastrophic Floods in India: A Perspective on Embankments

A humanitarian crisis of epic proportions is unfolding in South Asia. The region has experienced devastating floods leading to a loss of over a 1000 lives in India, Nepal and Bangladesh. Senior research fellow at the Institute of Water Policy, Robert James Wasson, has spent years studying floods in Assam in eastern India. Here he talks about his views on the Indian government’s policy of building embankments to control floods. Annual flooding in Indian states such as Bihar and Assam is a huge problem. But this year, reports say that the flooding is particularly severe. Is there any particular reason why?

Robert James Wasson: At the moment the reasons for the severe rainfall and flooding are not clear. The only stand-out anomaly is the Indian Ocean which has been warmer than usual thereby providing more moisture to the atmosphere. It will take some time for climatologists to work out what is and has been happening, including what is called an attribution analysis whereby the role (if any) of climate change is assessed. Why is the Indian government policy for flood control heavily aligned towards building embankments?

Wasson: Embankments as a ‘solution’ for flooding have a long history in India, stretching back to the Mughals and the British. When the British established cash crops in Assam and Bihar in particular, floods represented a severe threat to revenues. Embankments were seen as the solution. Once embankments are built more cropping is possible in previously flood-prone areas and this, in turn, needs to be protected thereby leading to the construction of more embankments. The techno-fix represented by embankments fitted the time when the idea of conquering nature was in vogue. Engineers dominated the advice to the government but some engineers in British India argued against embankments because of their propensity to cause water logging and disease in stagnant water, and also because they are likely to breach. Also, there was and still is a political and business imperative at work. Politicians can point to embankments as a tangible sign of their activity, and the private sector benefits from both construction and maintenance contracts. But many lay people, environmentalists and academics have argued that embankments cause more problems than they solve, and this criticism and debate continues. But young people in flood-prone areas have no experience of life without embankments and have not maintained the traditional coping strategies of houses on stilts, for example. And during serve floods villagers camp on embankments with their animals.

“Embankments as a ‘solution’ for flooding have a long history in India, stretching back to the Mughals and the British.” Has the embankment policy been successful in flood control?

Wasson: Strangely there does not appear to have been an analysis of the Indian flood death and damage data to see if embankments have had any effect. We have analysed these data showing that between 1953 and 2011 damage (adjusted for inflation) has increased across India, but deaths (adjusted for population) have remained unchanged and, importantly, have not declined. However, adjusted deaths during the period from 1982 to 2011, when embankments were much more extensive, declined but the area affected by floods also declined thereby confounding a simple explanation of the reduced deaths. Damage data have yet to be fully explored.

In Assam, where we have done the most detailed research, neither deaths nor damage has systematically changed through time, despite extensive embankments. But many deaths and some major damage have occurred during the largest floods. This may be evidence of the ‘levee effect’ whereby the construction of levees (or embankments) leads to an unwarranted sense of enhanced safety and complacency among local people and decision makers, and people begin to live and build close to rivers. The largest floods then cause massive damage and many deaths.

“In Assam, where we have done the most detailed research, neither deaths nor damage has systematically changed through time, despite extensive embankments.” What kind of policies do we need to mitigate the damage from floods? How should the Indian government approach these policies?

Wasson: While there is some evidence for a positive effect of embankments, they do not provide protection during the largest events, but they do provide refuges for people and their animals. However, flood mitigation policies that compliment embankments are urgently needed to mitigate the impacts of the largest floods. Such policies might include floodplain zoning and possible relocation of at-risk people, enforcement of the existing building code to make sure that construction is robust, insurance, better warnings, refugees, education, and probably most importantly more local authority for flood mitigation planning and implementation so that people do not just wait for the government to act but take more responsibility for their own safety. Can you provide some historical perspective to Assam’s floods?

Wasson: Assam is prone to both large damaging floods and great earthquakes. The great earthquake of 1950 in upper Assam generated a huge number of landslides that have added sediment to the Brahmaputra River and thereby raised its bed. The floodplain has not been raised by sedimentation at the same rate as the channel bed so floods extend further across the floodplains despite embankments because the embankments are not continuous and often breach. It appears that the increase in the bed level of the Brahmaputra has stopped because the landslide sediment from the 1950 earthquake has been exhausted, an idea that needs to be thoroughly checked. If this is correct, floods may not get progressively worse, but will still be dangerous during large rainfall periods such as at the moment and as climate change takes hold. Of course when (not if) another great earthquake occurs the same set of processes will recur, along with the likely destruction of many embankments by ground shaking.  Is there any ‘permanent’ solution to Assam’s flood problem?

Wasson: Assam will always be flood-prone, and floods will get larger as the climate changes because of the Greenhouse Effect. But the institution of the policies listed above, along with better maintenance of embankments to limit breaches, will reduce deaths and damage.


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