One might be shocked to hear it, but there is no such river called the Kosi. The correct name of the river is Sapta Kosi, meaning it is the combined flow of seven rivers. The westernmost of these rivers is the Doodh Kosi, ("milk" Kosi), which flows into Nepalese territory from China's Tibet region through a V-shaped pass through the Himalayas, .and on the border of these two countries has been constructed a bridge, called the "Miteri Sango" (Friendship Bridge) over which passes the Lhasa to Kathmandu road, called the "Arniko Marg" in Nepal .(Arniko is said to be an architect who had invented the so called "pagoda system" of temple building peculiar to the Kathmandu Valley and had gone to China for undertaking construction works there.

Dudh Kosi joins the "Soon Kosi" (the gold Kosi) apparently because gold files were found on its banks at some time in the past. The Soon Kosi is joined by the Indravati at a picturesque place Dolalghat. The river continues with the name Soon Kosi. The direction of the flow is generally from the north-west to the south-east.

Almost directly north of the present barrage on the river – the Hanumannagar Barrage –the river Arun comes from Tibet to join the Sun Kosi. At about the place this union takes place, the Tamur River comes from the east to join the combined flow. The Tamur originates in Tibet the combined flow of all these rivers is called the Sapta Kosi.

The summer snow melt and the incessant monsoon rainfall in the area covering most parts of eastern Nepal – east of the Kathmandu Valley makes the Sapta Kosi a very formidable river in terms of water discharge – the maximum of 8,50,00 lakh cusecs (cubic foot per second) ,was recorded in 1954 and hence when the construction of the Hanumannagar barrage was taken up, the maximum flow designed was 9,50,000 lakh cusecs. The mean annual run-off was estimated at 41 million acre foot (maf)

Since these tributaries originate in the Himalayas, the flow of water in them are always swift and they carry enormous energy. This is not the case with the rivers in India sauch as the Bhagirathi (the Ganga) and the Yamuna .Because of the swift currents caused by steep fall in height, these rivers carry enormous volume of earth and stone technically called coarse silt. Because of the excessive volume of this coarse silt, the flow is blocked often and the river (the Sapta Kosi in particular) changes course to find newer exist routes for the huge volume of water flowing towards the Ganga.

According to a booklet "Taming the Kosi" published by the Kosi Project Administration of the Government of Bihar in April 1959, within the last fifty years (before 1959) the river has meandered about 70 miles ( 112 kilometres approximately) westwards. The booklet says :"This meander is attributed to the excessive coarse silt content in the flood water which gets deposited ,blocking the flow of channels and forcing the river to cut new channels in the adjoining soft ground." The Kosi, therefore, is recognised as one of the most turbulent rivers in the world. The name Hoang Ho, the river of sorrow of China, naturally comes to mind and the Kosi, therefore is treated as Bihars river of sorrow.

The river's eastern tributary the Tamur comes from the east and it debauches to the plains near Barahkshetra the annual floods in the river used to cause devastation and human misery almost e very year in about 8000 square miles (128,000 square kilometers) in Bihar and Nepal. Hundreds of villages have been destroyed by the westward shift of the river during the centuries.

The booklet mentioned that the problem had attracted attention as early as 1896 but no solution was considered possible. Intensive investigation was however, launched from 1947 and in due course the proposals to construct a 750-feet high dam at Barahkshetra and a 90-fet low detention dam at Belka "were formulated and abandoned".

It adds:"The flood in 1953 spot-lighted the urgency of the matter and Prime Minister Jawaharlal Nehru .who was visibly moved after a personal inspection of the affected area, declared that a tangible scheme must be undertaken in hand immediately to alleviate public suffering due to annual flood devastations."

The Government of India ,particularly the Central Water and Power Commission (CWPC –now bifurcated into Central Water Commission and Central Electricity Authority) took up investigations in detail and prepared the scheme, described later, with consultations between the CWPC and the Ministry of Irrigation and Power, then headed by Mr. Gulzarilal Nanda. Well known irrigation engineer Mr. Kunwar Sain was heading the CWPC.

The scheme was drawn up and since Nepal was involved in a big way, the Governments of India and Nepal had signed an agreement on April 24, 1954 for operating the proposal.

A Kosi Control Board was set up at Patna and a liaison office was opened at Kathmandu for interacting with Nepalese authorities. The Control Board had a representative from the Union Government too. Around 1956 or so it was Mr.T.P.Singh ICS was in charge of Kosi Project (later he was made in charge of the Gandak Project too in 1960).The task of expediting the project and maintaining constant liaison at the diplomatic level too was his responsibility.

The scheme was to first to build a barrage across the river at Hanumannagar (not Bhimnagar, although that place is located in the vicinity) and construction of levees or embankments on, both sides of the river. The barrage is located only a few kilometers downstream of Barahkshetra. The purpose of the barrage was to (i) tie up the lines of embankments below and above it, (ii) arrest coarse silt and flatten the gradient and (iii) provide water for irrigation. The barrage was to be built at a place where the river is four miles (6.4 kilometers) wide.

There was –and still is, one hopes – on, either side of the barrage there would be guide bundhs each roughly a mile (1.6 km) long with an average height of 18 feet, top width 30 feet and base width 120 feet for the purpose of training and guiding the main course of the river downwards through the main spillway.

Along with the construction of the barrage and associate works, the Government of India undertaken the construction of - according to informal agreements between the two governments – the Trishuli Hydro-electric Project of 21,000 MW capacity north of Kathmandu and the Chatra canal taking off from the Kosi north of the Project.

The Hanumananagr Barrage was inaugurated on April 25, 1965 by King Mahendra of Nepal. It appears that the embankment mentioned earlier has given way at a place called Kusaha in Nepal which caused the diversion of the river waters away from the route through the barrage. This resulted in considerable loss in that area. However, the area affected in Bihar is simply mind boggling as a result of the Kosi waters diverting from their normal routes and taking a new course, which this tempestuous river has been doing from decades or even centuries .

When the barrage was being built in Nepal, the people of Bihar under the leadership of the Bharat Sewak Samaj had undertaken construction of 75 miles of earthen, embankments from the two sides of the barrage towards the south covering the nearby districts of Supaul.Saharsa, Araria, Madhepura etc. The result was that 309 villages falling with this embankment s with a width of three to ten kilometers had to be evacuated but the people could come back during the dry season to undertake agriculture. The idea was to confine the river within these two embankments so that it flows down to the Ganga meeting the sacred river at a place called Kursela without undergoing any change of course.

This year's rains and the breach in the embankment in Nepal have dashed all these dreams and the Kosi again has returned to her old and destructive habit of changing its course. So far, at least 25 lakhs people have been displaced and hundreds- nay thousands of boats of all types is trying desperately to shift the affected population to safe places.

EMAIL THIS NEWS COMMENTS POSTED BY Sankara Pillai, Navi Mumbai on September 5, 2008, 10:05 am
Thanks for a well researched article Arbinda;How does this compare with what is occasionally touted as a disaster in waiting- A century old dam built at Mullaperiyar on the border of Kerala and TN. Does it have the same potential to over-run 3-4 districts in kerala, if it gives way. How would the cusec release compare? Can we laearn from this post mortem to do some ante-mortem preventive measures?

Sankara Pillai