Tackling Brahmaputra: the river of sorrow
STRAP: Every year, Brahmaputra and its tributaries run amok, wreaking havoc in the Northeast – Assam is the worst hit. Is there any permanent solution in this blight..
Manish Tiwari
Guwahati, December 25
THIS YEAR again, the Dhemaji district of Assam, situated about 430 km from here on the Arunachal border, was devastated by the Brahmaputra and its tributaries. At several places, railway tracks and roads were washed away, embankments breached, houses inundated and crops worth crores of rupees destroyed. The rail link is yet to restored, while condition of roads are, as usual, pathetic.
While some families have been living on embankments constructed a few decades ago to control floods, others have been forced to desert their villages and migrate elsewhere. “For us, problems posed by floods have become a part of life. By now, we have learnt to live with the floods,” remarked Amal Kumbang of Bhaluka Guri village in Dhemaji district.
Frequent floods have been the bane of almost all the districts of Assam, causing not only widespread devastation but also hurting the fragile agro-economic base of the region. Some other states such as Arunachal Pradesh, Manipur, Meghalaya and Tripura are also facing floods due to the mighty Brahmaputra and other rivers in the region.
Of all the Northeastern states, Assam is the worst affected. Floods in Assam occur twice a year leave ugly scars on the minds of its residents. Since 1954, around 3.5 lakh hectares of cultivable land has been eroded in the state due to floods, 2,534 villages inundated, around one lakh families affected and thousands of crores worth of property and crops destroyed.
Till a few years ago, only some districts of Assam such as Dibrugarh, Dhemaji, North Lakhimpur, Nagaon, Nalbari, Barpeta and Goalpara faced acute flood problems. Over the years, almost all districts in the state have been affected. The Assam Brahmaputra Valley alone has a total flood-prone area of over 3.2 million hectares, with nearly 40 per cent of its land susceptible to damage by floods.
TALE OF DESTRUCTION
Statistics reveal that Assam experienced major floods in 1954, 1962, 1966, 1972, 1977, 1984, 1986, 1988, 1998, 2002 and 2004. Experts say that most floods are triggered by heavy rainfall in the catchment area of the Brahmaputra as the monsoons in the region brings along a lot of rainwater.
However, the problem has been greatly accentuated over the years by manmade interferences such as construction of embankments, increased human settlement in flood-prone areas, encroachment of wetland areas that otherwise retain a lot of rainwater and stop it from flowing into the Brahmaputra, massive deforestation, heavy sedimentation and tremendous congestion around the riverbanks.
Partha J. Das, a research scholar at the Department of Environmental Sciences, Guwahati University, has done extensive study on flood-related problems in the Northeast. He said that the intensity, frequency and damage due to floods increased progressively in the aftermath of the earthquake in 1950. The tremor led to rise in the Brahmaputra bed level by nearly three metres. This in turn caused increased floods and erosion potential in the river, pointed out Das, who is also an activist with a Guwahati-based NGO Aaranyak.
The earthquakes of 1897 and 1950 were among the most severe in recorded history, which led to extensive landslides, resulting in natural damming of rivers, flash floods due to bursting of landslide-induced temporary dams and rise in riverbeds levels due to silt.
In one of the articles co-authored by Prof D. C. Goswami, a well-known water resources expert and authority on the Brahmaputra river system, and Partha J. Das in Ecologist Asia, said that the floods of 1988 and 1998 were the worst in recent history. The 1988 flood broke all previous records of damage, and affected 3.82 million hectares, nearly 12 million people, five lakh households and 1.43 million hectares of cropland. Besides, it claimed lives of 226 humans, and innumerable cattle and wildlife. The total damage was estimated at Rs 1,512 crore.
Similarly, the 1998 floods affected all 27 districts in the Assam Valley, causing upheavals in the lives of 4.7 million people in 5,300 villages. The floods damaged 0.97 million hectares of cropland, washed away or damaged 30,400 houses and claimed 156 human lives.
The total loss was estimated at Rs 1,000 crore. In 2002, the total loss due to floods was estimated at Rs 2,000 crore. There is no sign of respite for the people in the area since flood problem is aggravating year after year. In 2004, floods damaged public and private property worth Rs 1000 crore.
In a memorandum submitted to United Progressive Alliance (UPA) chairperson Sonia Gandhi in August this year by an all-party delegation of Assam Legislative Assembly, the state has demanded an immediate flood relief of Rs 1,000 crore.
Meghalaya Principal Secretary (Revenue) W.M.S. Pariat pointed out that even some parts of his state, especially West Garo hills district, also faced serious flood problems this year. The continuous downpour in catchment areas of the Brahmaputra and reverse flow of water from it into Jinjiram and Rongai rivers, which were already in spate, affected the plains and caused damage to flood protection works in places like Chbinang, Phulbari, Bhaitbari, Rajabala and Hallidayganj (all in West Garo Hills). Embankments were breached, roads damaged and crops worth Rs 78 crore destroyed due to floods this year.
In a memorandum submitted to the Union government recently, the Meghalaya government sought a financial assistance of Rs 210 crore from the Centre for restoration work. Arunachal Pradesh has also demanded similar grants from the Government of India.
BRAHMAPUTRA AS MIGHTY RIVER
Brahmaputra is truly an international river as it has a drainage area of 5,80,000 square kilometres. Of this, nearly 50.5 per cent lies in China, 33.6 per pent in India, 8.1 per cent in Bangladesh and 7.8 per cent in Bhutan.
The river traverses 1,625 km in China, 918 km in India and 337 km in Bangladesh before reaching the Bay of Bengal. The Brahmaputra basin in India lies in the states of Arunachal Pradesh (41.9 per cent), Assam (36.3 per cent), Meghalaya (6.1 per cent), Nagaland (5.6 per cent) and Sikkim (3.8 per cent).
Two rivers, the Dibang (also known as Siang) and the Lohit, join the upper course of Brahmaputra. While flowing 2,880 kilometres through China, Tibet, India and Bangladesh, the river is joined by nearly 22 major tributaries in Tibet, 33 in India and three in Bangladesh. Some of the major rivers and tributaries that join the Brahmaputra include Subansiri, Jia Bharali, Manas, Debang, Lohit, Jiadhal, Ranganadi, Puthimari and Pagladiya.
FLOOD CONTROL MEASURES
For decades, successive governments at the Centre and the state have made efforts to tame the Brahmaputra, one of the mightiest and longest rivers in the world, by constructing thousands of kilometres of embankments on the river and its tributaries. But as the length of the embankments increased, so did the miseries of the people.
The embankments did help control flood problem for a few years. But the network mostly constructed during 1950, 1960 and 1970 is no more adequate to control Brahmaputra. Rather, they have contributed to the aggravation of the situation.
“We have constructed so many embankments. Yet, engineering solutions have failed to provide any relief to the people of the Northeast. The flood situation has only aggravated in the absence of a holistic approach to tackle the situation,” opines Prof. Goswami.
Of the total 15,675 kilometres of embankments along the lengths of various rivers in the country, nearly 5,027 km of embankments are on the Brahmaputra and its tributaries alone. These structures, constructed to provide immediate relief to the people facing floods, have outlived their utility and are not much of a use today, he added.
The situation in the Barak Valley is also no better. The overflowing Barak, Sonai, Kushiyara and Kathakal rivers have been causing widespread devastation to the districts of Cachar, Karimganj and Hailakandi in the Barak Valley.
Experts maintain that the government's decision to tame a mighty river like the Brahmaputra was a farfetched one. The government did try to manage the problem in the short run by building embankments, but it did not look for long-term solution. The river is one of the heavily sediment-prone rivers in the world, only next to the Yellow river of China.
With the construction of around 5,027 km of embankments on the Brahmaputra and its tributaries in the past 50 years, a large amount of sediment has been confined between the embankments on both sides of the river system. Deposited on the riverbed, the silt had led to rise in the riverbed level. Before the embankments were constructed, the silt would spread over a large part of the basin during floods, leading to less rise in riverbed level.
With the construction of embankments, water remains confined and gushes out at the time of breaches and causes devastation in the area. Due to floods, heavy deposits of sediments on cropland are now turning land useless for cultivation.
“In the past 50 years, engineering solutions have done more damage than benefits to the region. In many cases, they have, in fact, worsened the situation,” Das remarked. The whole Brahmaputra Valley is situated on the foothills of the Himalayas, the soil of which is very loose and fragile in nature. A large number of people have settled near the Brahmaputra, who are now facing the consequences.
“I feel it is the Brahmputra that has become a victim and not the people. More than the people, rivers need to be rehabilitated,” said Prof Goswami. The rivers in the region have been wronged due to manmade interventions like embankments, deforestation, encroachments of wetlands and catchment areas. “The rivers are wreaking vengeance for our follies and wrong decisions. If we deny the right to the rivers, this is what will happen,” he added.
N. Panigrahy, a scientist at Centre for Flood Management Studies (CFMS) under National Institute of Hydrology, Roorkee (an institution of Union Ministry of Water Resources), claimed that the CFMS had hardly conducted any concrete study on flood management so far. For the last four years, the Centre has been focusing on flood-related issues. But due to lack of funds and manpower, no worthwhile research has been carried out, he added.
However, A. K. Mitra, Additional Chief Engineer, Water Resources Department, Assam, asserted that the flood problem in the state had to be seen in an entirely different perspective. “I completely disagree with those who are against construction of embankments. These were required to be built as part of short-term measures. However, the government should have focused on medium and long term measures as well, but it failed.”
WETLAND DESTRUCTION
There are around 3,500 wetlands or beels in Assam, which have trememdous potential of retaining floodwater. These wetlands are rich with flora and fauna. In fact, large number wetlands are situated in the Brahmaputra basin. Nearly 180 wetlands in the Northeast have been found be more than 100 hecatres or above.
Unfortunately, a large number of these wetlands have been destroyed over the years due to siltation, encroachment, bad land use practices and construction of roads and embankments, says Partha Das. Due to this, the rainwater which used to be accumulated in the wetlands now directly reach the Brahmaputra river and its tributaries, leading to excessive water flowing through the river.
This is one of the reasons why the flood problems have further aggravated in the region. A concerted approach on the part of government officials and local people can help revive most of these wetlands, Das adds.
THE IMPACT OF DAMS
THE NORTHEASTERN region has been identified as the richest source of hydropower generation. At present, there are 55 hydel projects in various stages of implementation.
Of the total 226 potential sites identified by the Union Power Ministry for large muti-purpose dams on various rivers of the Northeast, most are on the Brahmaputra and its tributaries. The hydropower potential of the Brahmaputra is about 41 per cent of the country’s total power generation potential. However, only three percent of this potential has been tapped by the country so far, says Dulal C. Goswami, a well known expert on the Brahmaputra river.
The Cabinet Committee on Economic Affairs (CCEA) has already approved last year the Rs 6,285-crore Lower Subansiri hydroelectric project, one of the tributaries of Brahmaputra river, in Arunachal Pradesh. The project was pushed hard by the Union government during Prime Minister Atal Behari Vajpayee's tenure. The 116-metre high dam project would submerge 3436 hectares of forests.
While environmentalists have raised serious doubts over the viability and sustainability of the projects and their environmental impact in the region, the government officials felt that the dams would not only help tap a vast hydro power potential in the Northeast, but also help control the floods.
In nutshell, the government officials, experts and environmentalists still remain divided as to whether the dams would actually help control floods in the region. Some experts pointed out that in view of an inadequate database, proper studies about environmental impact of dams, and lack of systematic data over an adequate timespan, these projects should not be implemented in a hurry. Environmental Impact Assessments (EIAs) are required to be conducted before building these dams, they maintained.