Climate change and upstream damming are causing the Brahmaputra to flood without rain, rhyme or reason
The boat lurched dangerously. A sudden change in the water current slapped us around for a few minutes, and the river began rising rapidly, unexpectedly. There were no clouds in the sky, no signs of an impending storm, no radio reports of rains upcountry. In fact the weather forecast promised a clear and sunny day in the entire region when we began our journey upriver in the morning.
“These days the Brahmaputra needs no rain, rhyme or reason to swell suddenly like this,” says Jadav Payeng, aka Mulai, a Mishing cowherd now famous as the Forestman of Assam. “As if the deadly floods caused by the monsoon downpour between June and September every year are not enough, since the last few years we have seen floods in the Brahmaputra, with or without rains -- in summer, monsoon, winter. It is like someone is controlling the water flow but is not very good at it. I am certain the dam-building activity upstream is responsible, either dams in Arunachal Pradesh or Tibet, with Indian or Chinese control. Whoever is responsible is blind. They don't know what they are doing to the thousands-of-years-old civilisation and still undiscovered biodiversity wealth downstream.”
He exchanges a quick, decisive glance with the other oarsmen and changes the course of the boat to drift back to the northern bank where we will wait on higher land till this bout of unseasonal flood passes. Jadav Payeng has lived on the river all his life; he criss-crosses it every day to go to his home island Aruna Sapori, where he single-handedly planted a 1,360-acre forest over 30 years, now named the Mulai Kathoni after him. He has observed the cycle of floods and erosion of the tempestuous Brahmaputra from close quarters. His forest, like so many others along the river, has been sustained by these seasonal, life-giving floods of the river and its many tributaries.
Jadav Payeng is not the first to blame the upstream damming activities for the unseasonal floods, increased erosion and general mayhem caused by the river's unpredictable flows. I heard the lament repeatedly, from the wizened old boatmen near Guwahati, the subsistence farmers near Nagaon, the rangers of Kaziranga National Park and the residents of the flood-ravaged Majuli island.
The Brahmaputra begins its journey as the Tsangpo, the highest river in the world, from a spring called Tamchok Khambab, at an elevation of 5,150 metres in Kanglungkang glacier, south-east of Mansarovar lake in Southern Tibet. The Tsangpo flows 1,625 km in Tibet, 918 km in India (278 km in Arunachal Pradesh as the Siang river and 640 km in Assam as the Brahmaputra) and 363 km in Bangladesh as the Jumna before it joins a tributary of the Ganga and disappears into the Bay of Bengal. The Brahmaputra receives as many as 22 major tributaries in Tibet, 33 in India and three in Bangladesh. Many of the north bank tributaries are of Himalayan origin, fed by glaciers in their upper reaches, eg the Subansiri, the Jia Bharali (Kameng), and the Manas. The Dibang and Lohit are two large tributaries emerging from the extreme eastern flank of the Himalayas, while the Jiadhal, the Ranganadi, the Puthimari and the Pagladiya are some of the major tributaries with sources in the sub-Himalayas.
This unique geo-environmental setting in the eastern Himalayas is a fragile geological base characterised by an active seismo-tectonic instability zone and a potent monsoon regime. More recently, it has been in the news because of the drastic rise in rate of glacial melt. All of these are cited as the primary reasons for the excessive flooding, landslides, erosion, siltation and braiding of the Brahmaputra. Experts also point out the inadequate capacity of the river channel due to its inherent braided nature which causes spilling of floodwater over the banks as well as drainage congestion at the outfall of tributaries during the high stage of the main river. Intense land use pressure and high population growth especially in the floodplain belt and ad hoc or temporary flood control measures are other factors that cause and intensify destruction by floods in the Brahmaputra basin.
For Assam, the floods of June 2012 have been recorded as the worst in the last 10 years. According to Oxfam India, nearly 2.4 million people have been affected and half-a-million displaced. Scientists may be reluctant to cite climate change as the direct cause of the 2012 flood, but they are unanimous that the frequency of such incidents will increase drastically in the future.
The increase in the frequency of floods and intensity of erosion is not only threatening the lives of the people in the state of Assam but has led to permanent loss of land, livelihood and, as in the case of my last destination, the fast-disappearing river island of Majuli, the very culture and identity of its people.
Ironically, the construction of multipurpose dams was originally proposed as a practical method for controlling floods and generating electricity in the Brahmaputra valley. According to the Central Electricity Authority (CEA) study of the Brahmaputra basin in 2001, 168 hydropower projects with an estimated capacity of 63,328 MW have been identified for construction in the northeast region, which earned it the title ‘future powerhouse of India’ at the Northeast Business Summit in Mumbai in July 2002. Soon after, in 2003, the ministry of power launched the 50,000 MW Hydro Initiative largely focusing on the Brahmaputra basin. Till October 2010, the government of Arunachal Pradesh has already allotted 132 projects to companies in the private and public sector for a total installed capacity of 40,140.5 MW, with around 120 of these projects involving private players.
Now activists allege that flood control was merely a pretext for stealing natural resources and spawning a multi-million-dollar hydro-development scam in the northeast. The idea that multipurpose dams can help flood control along with hydropower generation has already proven unviable and dangerous. India's Hirakud dam was built in the name of flood control, yet extreme floods in the Mahanadi delta between 1960 and 1980 were three times more frequent than before Hirakud was built. Panic release of water from Hirakud has been blamed for much of the devastation. In 1978 nearly 65,000 people were made homeless by floods exacerbated by forced discharges from Bhakra dam. There are several instances of floods worsening because waters were held back while the reservoir filled, and then suddenly released to prevent the dam being over-topped. The risk increases twice over now that private companies have bagged the contracts: they will prioritise profits from electricity generation over flood control.
Meanwhile, confirming long-held fears of the local people, the Chinese State Council, or cabinet, has now publicly approved plans for the construction of three new hydropower projects in the middle reaches of the Brahmaputra, or Yarlung Zangbo as it is known in China. The projects were listed in an energy development plan for 2011-15 announced in January 2013. Work has already begun on a 510 MW dam in Zangmu in the Tibet Autonomous Region.
China has assured India that the new hydropower dams it is planning to build on the Brahmaputra will not affect flood control and environmental efforts across the border in the Indian northeast. But there is a real and palpable fear amongst the local population about the Chinese damming of the Brahmaputra and what this could mean for the river and its people.
*** The water finally receded, and we crossed the river, more than two hours later than planned but without further incident. I continued on my journey upstream and northeast, via Jorhat to Dibrugarh. The river is at its widest, almost 16 km, near Dibrugarh, a mishmash of sandbars, islands, floating forest debris, all on a gigantic scale.
The next day I left for my destination, the Dibru Saikhowa Biosphere Reserve and National Park, located close to the border of Assam and Arunachal Pradesh, at the confluence of three rivers, the Siang aka Brahmaputra, Lohit and Dibang, all of which are being dammed for hydropower projects.
The Biosphere Reserve is spread over 765 sq km and its core zone of 340 sq km is the Dibru Saikhowa National Park, a complex of wetlands, grasslands, littoral swamps and semi-evergreen forests, including the largest salix swamp forest in Northeast India, an Important Bird Area (IBA) with more than 310 avian species already identified. Of the 15 critically-endangered bird species of India, five – the white-bellied heron, white-rumped vulture, slender-billed vulture, red-headed vulture and Bengal florican are found here. Among globally endangered species, the DS complex hosts white-winged duck and Nordmann’s greenshank. The swamp francolin, black-breasted parrotbill, Jerdon’s babbler, Rufous-vented prinia and marsh babbler are found in the grasslands. The fauna list includes the Asian elephant, tiger, leopard, sloth bear, slow loris, pig-tailed macaque, Rhesus macaque, Assamese macaque, capped langur, barking deer, hog deer, flying squirrel, Gangetic river dolphin, monitor lizards, various turtles including Assam roofed turtle, and snakes including cobra and python.
After a surprisingly easy and very fruitful Gangetic river dolphin-spotting tour along the banks, I met Joynil Abdin, Secretary General of Dibru Saikhowa Conservation Society. We watched the river, muddy-brown and debris-laden, rushing at great speed from the courtyard of his eco-resort near Guijan ghat. Joynil aka Benu is a self- proclaimed poacher turned conservationist. Having grown up on the banks of the river and hunted in these forests in his younger days, he is as perturbed as Jadav Payeng about the future of his land.
"The most urgent threat facing us today is the downstream impacts of the 1750 MW Demwe Lower project in the Dibru Saikhowa Biosphere Reserve. There will be a fluctuation in water levels of 3-4 metres in different parts of the Dibru Saikhowa National Park due to simultaneous operation of the dams on the Siang, Dibang and Lohit rivers. Natural flow regimes are the heartbeat of a river and such drastic changes will have a major impact downstream. IIT-Guwahati as part of its study on the Lower Subansiri project has found that such massive diurnal (daily) flow fluctuations in winter (involving starving the river for long periods, followed by flooding it in a short burst) will increase erosion of river banks and reduce groundwater levels. This is a man-made disaster that will permanently wipe out one of the finest conservation areas of Northeast India." Joynil informed me that Dibru Saikhowa is, very much like Majuli, being eaten up by the Brahmaputra and large parts of the sanctuary are now underwater.
His biggest grouse is against the government for foisting the dam projects without proper information-sharing or adequate consultations with downstream communities. His story is the same as scores of others, only the names of people and locations change. The damming of the river and drastic alteration of flow patterns will impact the livelihoods of millions of river-dependent people, who are mainly engaged in fisheries and agriculture. There are several biodiversity hotspots and important sites of cultural-spiritual significance that will be negatively impacted due to drastically altered flow patterns.
Scanning local and regional newspapers and news channels it was evident that over the last few years the Brahmaputra valley has witnessed severe opposition against hydropower dams from downstream communities, predominantly the indigenous people, the worst-affected in terms of the impact on their livelihoods, economy, biodiversity, society and culture. Opposition to the Lower Subansiri hydro-electric project is the fiercest and construction has been halted for over 10 months now.
Whatever the fate of the dams in the northeast, now regularly referred to as temples of doom, it is important to remember that intense precipitation, faster glacial melt, ongoing deforestation, constant degradation and urbanisation of watersheds is increasing the speed at which water runs off the land and into rivers, worsening the severity of extreme floods. A recent study done by IIT-Guwahati based on recent climate change models, has predicted that the Brahmaputra valley will experience "longer floods and more flood events outside the monsoon period; not only will peak flow increase but so will incidents of pre-monsoon floods."
It is a fact that dam designers work on the assumption that historic hydrological variables such as average annual river flow, annual variability of flow, and seasonal distribution of flow are a reliable guide for the future but as is now abundantly clear, the past climate is no longer a sufficient guide to the future. As climate change takes hold, there's already a significant change in annual rainfall patterns and worse, the rate of snow pack melting has speeded up dangerously and instances of unseasonal flooding have increased drastically. The ruins of hundreds of embankments built as first line of defence in the 1980s and ’90s are a testament to that reality.
The writing is already on the wall. We are seeing the effects of climate change and to build worthwhile flood defences it is important to be able to accurately predict the climate of the next 50 to 100 years. Until then it is imperative that a moratorium be imposed on all dam-building activities while investments should be diverted for disaster risk reduction and rapid relief capacity-building in the Brahmaputra basin. That is the only way, river people like Jadav Payeng and Joynil Abdin will tell you, because the Brahmaputra cannot be dammed; the more you try to stem its flow, the more volatile it will become.
Infochange News & Features, August 2013