In August 2008, Bihar experienced its worst floods in nearly five decades. Kosi River Breached its embankment at Kusaha in Nepal’s Sunsari district, killing more than 400 and displacing thousands. At the peak of the floods in Bihar, 33 lakh people were affected.
Actually, Kosi river breaks the walls of its embankment every few yearsPutting lives and livelihoods at risk, and naming it the ‘River of Sorrow’.
In the eastern Gangetic plains and surrounding flood plains, rivers have swelled during the monsoon for centuries, causing devastating floods. Kosi originates in Tibet and Nepal and later joins Ganga in Bihar. often called “seven Kosi” Due to its seven tributaries, it is a delicate and dynamic river that naturally sheds large amounts of sediment. Over the years, the river has changed its course by several kilometres, leading to floods.
committee report
According to a report by the People’s Commission, an independent commission on the Kosi Basin, the river has moved 120 km westward in the last 250 years due to heavy natural sedimentation process. Experts suggest that the construction of barrages in Nepal in the 1950s and subsequent embankments in Bihar have significantly altered the natural flow of the river.
Levees are artificial structures made of earth, stone or concrete, designed to control the flow of water in flood-prone areas. These structures are built to withstand the effects of gravity, water pressure and other external forces and are expected to remain stable over time. While these are often promoted as an ideal solution to protect settlements and enhance agriculture, experts have long warned about their limitations.
GR Garg Committee report came in 1951 The Central Waterways, Irrigation and Navigation Commission warned against such projects. Its appointment was made after Assam decided to build embankments in the hope of preventing floods during the monsoon. The report found that the river’s two main functions, providing land (by erosion and deposition) and draining its basin, are hindered by embankments. It further cautioned that these structures are useful only when the river carries less silt; Otherwise they may cause more harm than good.
However, instead of heeding these warnings, the Assam government proceeded to build embankments along the Brahmaputra River. While the idea was simple – to prevent flooding – its effects were adverse. Particularly in Assam, rivers deposited thick silt and sand on their banks, affecting agriculture. Local communities lived in constant fear of violations. The accumulation of silt reduced the depth of the river and made navigation more difficult.
flood control
“Northern rivers bring a lot of silt. So if you build embankments on them, the river gets higher because of silt accumulation,” said E. Somanathan, head of the Center for Research on Economics of Climate Change, Food, Energy and Environment. “And because silt increases every monsoon, the embanked river becomes dangerous after a few years, even though it may have provided some protection initially.”
This is why such incidents involving Kosi are not isolated: the river breached its embankment in 1963, 1968, 1971, 1980, 1984, 1987 and 1991, before breaching it again in 2008 and 2024.
Almost exactly a year ago, when the Mahuli tributary of the Kosi River entered India and hit the Kosi Barrage, the amount of silt in the river increased, causing devastating floods. Every year, the amount of silt endangers local people and submerges vast tracts of agricultural land.
Frequent breaches raise an important question: should embankments be considered flood-control structures?
Impressive and rich rivers
“Whether embankments are necessary or not depends on the purpose,” said Rahul Yaduka, a postdoctoral scholar working on the WATCON project at The School of Oriental and African Studies in London. “If development is the goal, embankments will serve the purpose because you control the river. But people have always been living with floods for centuries.”
When the British noticed that the Kosi river was changing its course, they found it difficult to control it and decided to build an embankment to control the flow. But the exercise resulted in water-logging outside the embankment, causing flooding for people living between the embankments,” Dr Yaduka said.
On the other hand, Bindi W., director of the Center for Himalayan Studies at Delhi University. Pandey argued that embankments could play an important role in rivers in the western Himalayan region because they are less flood-prone and geologically more stable. However, he cautioned against building embankments on rivers in the eastern Himalayan region as they were vulnerable to breach, geologically weak and more prone to landslides.
“West-flowing rivers are affluent, meaning that as the river flows through different states, rainfall decreases. Whereas east-flowing rivers are affluent, meaning the amount of rainfall increases over time,” Professor Pandey said. He said construction in such geographically vulnerable areas should be coupled with constant monitoring and a transparent rehabilitation process for displaced people.
His argument was based on Dr. Somanathan’s warning: that embankments may provide short-term protection but often open the door to long-term vulnerability.
‘Not a viable option’
Dr. Somanathan said, “The US has destroyed embankments and allowed floods to occur. When we build more infrastructure that alters the course of the river, siltation in the river bed keeps increasing, but without embankments floods are very rare. If an embankment is built, we need to keep increasing its height. But that requires finance.”
The alternative he proposed is ‘learning to live with floods’.
“When we do this, we are allowing the river to function as a natural drainage system,” Dr. Somanathan said. Kosi Nav Nirman Manch Andolan member Mahendra Yadav also sticks to the concept of ‘living with floods’, but believes that this can happen only if people in between the Kosi embankment are trained with early warning systems and provided rehabilitation outside. “The solution that can be offered to people is to rehabilitate them outside the embankment because if the embankment is blocking them, they cannot get out even with early warning systems.”
“For India, embankments are not a viable option because we do not have the infrastructure to maintain it,” Dr. Somanathan said. But since embankments are a reality for many rivers in northern India, Dr. Yaduka suggested that one “needs to identify ways to improve and stabilize them. Along with this, paleochannels (abandoned ancient river or stream channels) should be revived so that water can be distributed.”
Mr Yadav also suggests improving palaeochannels, which trap water well within their basins, thereby preventing floods.
big promises
Ahead of the Bihar elections this year, the National Democratic Alliance (NDA) had promised “Baad Se Bhagyodaya” in its election manifesto for the people of Bihar. According to the ‘Sankalp Patra’ jointly released by the BJP and the NDA, the alliance assured residents that if elected to power, the newly formed government would launch river-linking projects, embankments and canals under the “flood to fortune” model to boost agriculture and fisheries.
Although this promise carries with it an undertone of political optimism, the state’s geography is complex and requires a deep understanding of long-standing ecological realities, including sedimentation and siltation. The river-linking project under consideration is the Kosi-Mechi project, which aims to extend the EKMC (East Kosi Main Canal) to the Mechi River, a tributary of the Mahananda River, to provide irrigation to the water-scarce area along the Mahananda basin, primarily during the Kharif season. However, in reality, if it rains near the Kosi catchment, the monsoon reaches the Mahananda in a day or two and there is almost no need for water during the monsoon.
“But if the problem (floods) were to be solved by embankments, there should not have been floods at all, but that is not the case. If the river-linking project is completed, 5,247 cusecs of excess water will be diverted towards the Mechi river. But in last year’s floods, the Kosi river carried around 6 lakh cusecs of water. So, we are not reducing flood waters by building embankments or interlinking rivers,” Mr Yadav explained.
Apart from this, money has to be spent every year on raising the embankment, but this is not a permanent solution, he said. “In fact, it is a luxury option. Even if the money is spent, does it really last? And more importantly, who is benefiting from it? Locals stranded in the embankment face the wrath of no rehabilitation facilities.”
Mr Yadav said, “Due to the embankment the flood has increased almost four times.” He said that desilting should be done through scientific methods.
Dr. Somanathan argued convincingly that embankments disturb ecological integrity, groundwater and biodiversity, and hoped that the discussion would shift from flood-control to flood-resilience.
For families who lose their homes each year as the river swells, the embankment is both a threat and a promise, a line drawn against nature that never lasts long. But as the Kosi story shows, every time the embankment is raised, the river immediately regains its jurisdiction.
