14 Sep 2016 13:24 IST

Should the Farakka barrage be removed?

Its design has obstructed sediment flow, perhaps causing floods in Bihar

The Farakka Barrage, which has so far been the point of contention for India-Bangladesh transboundary water relations, is now emerging as an inter-state water dispute.

The Bihar chief minister has recently called for removal of the Farakka Barrage, holding it responsible for the floods in Bihar and UP. The validity of the claim needs to be analysed in light of ecological engineering and the emerging hydro-politics of the region.

Sediment not factored in

The barrage, located in the Indian state of West Bengal, roughly 16.5 kilometres from the border with Bangladesh, was planned to enhance the flow of the Bhagirathi-Hooghly branch to resuscitate the port at Kolkata (then Calcutta), located downstream.

Right from its proposal phase, the Government of Bangladesh had been critical of the project. It was apprehended that by enhancing the flow into Bhagirathi-Hooghly, the barrage would reduce the dry season flow of the Ganges/Padma into Bangladesh. In fact, the voices within Indian technocracy who opposed the project, like Kapil Bhattacharya, were singled out and marginalised.

There is ample literature to suggest that Farakka barrage is responsible for reducing flow, causing salinity ingression, and drying up of the Sundarbans delta.

In that sense, the barrage stands as a classic example of the the reductionist engineering paradigm (promoted by the British colonial legacy) that looked at short-term economic benefits, ignored long-term sustainability concerns, and created the ‘metabolic rift’ between humans and Nature.

This “half-baked” reductionism continued to dominate the Indian water engineering scenario even after Independence, and has created situations of enhanced damages, livelihoods losses and eventually conflicts at both international and inter-state levels.

With the existing paradigm being devoid of the knowledge of the complex eco-hydrology and the fluvial geomorphology of Himalayan rivers like the Ganges and Brahmaputra, the possible negative impacts of the construction of the Farakka Barrage were not perceived at the design stage. The British constructionist regime neither understood peak and lean flows, nor the sediment dynamics associated with them.

This is the most significant knowledge gap linking up upstream floods with the Farakka Barrage.

Flooding in UP and Bihar is an annual phenomenon and is an integral component of the global eco-hydrological cycle.

It is reductionist engineering that has perceived flood as “unmixed bane”. British engineering knowledge hardly understood that when floodwater recedes, rich silt and sediments that are left behind have made the Gangetic plains the “rice bowl of South Asia”.

The tradition of ignoring this critical ecosystem service continues to this day.

Understanding floodplains

However, the recent call for Farakka Barrage removal is motivated by the perspective of “man-made floods”.

This contention seems to have been based on the backwater effect hypothesis, caused by sedimentation in the Farakka, and consequent cascading of the sediments upstream of the barrage. With the sediments acting as obstructions, the water takes a diversion towards Malda district in West Bengal causing bank erosion and flooding. This has caused considerable disruption and displacement in West Bengal as well. However, the Farakka Barrage and the accumulating sediment in the upstream seem to have incapacitated the river's capacity to carry and flush out the sediments to the sea. “Sediment flushing” is an ecosystem service of the natural flow regime.

But, the obstructions seem to have resulted in the water flowing back and causing upstream floods. The recent floods in Bihar may have been linked with the Farakka barrage from this point of view.

On the other hand, the Bengal Delta is geo-morphologically dynamic and is built on the huge sediment load carried by the Himalayan Rivers, namely, the Ganges and the Brahmaputra.

The barrage seems to have punctured the “soil formation” service of the ecosystem further downstream. However, even the avowed purpose of resuscitating the Kolkata port has not been satisfied .

But removing the Farakka barrage is not going to solve the problem either. The unintended benefit of the barrage is amelioration of the water problem downstream in the densely populated areas of West Bengal.

The increasing urban water demand of the burgeoning Kolkata metropolis seems to have been met because of the Farakka, which has not only enhanced the surface water flow in the channel, but has also ensured groundwater recharge.

Removal no solution

Removal of the Farakka will negatively affect the ecosystem services in this part of the State. Therefore, the basic problem is the flawed design of the barrage, which did not consider the sediment variable. China has developed its own rules of ecologically informed engineering while designing its dam on Yangtze.

The design helps in flood control, and also uses the peak flow to use the sediments effectively for downstream floodplain cultivation.

Such ecologically informed engineering is the need of the hour. While pursuing integrated basin management, such ideas can be executed.

River basin commissions with powers above the federal states should be set up to avoid escalation of inter-state river conflicts.

But above all, outmoded engineering paradigms should be dispensed with. A new technological and institutional arrangement in managing our rivers is called for.

Whether a beginning can be made with the Farakka barrage needs to be considered. The Centre and States could revisit the drawing board.

(The writer is a senior fellow at Observer Research Foundation Kolkata, and senior economic advisor at World Wide Fund for Nature, New Delhi, India. The views are personal. The article was first published in BusinessLine.)

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