Opinion (Spotlight Weekly)

Kosi High Dam And 1997 Study Agreement

By Dr. AB Thapa

I was fully convinced well in advance of the year 1996 when I was appointed to lead a Nepalese team constituted to negotiate with India about the Kosi Study Agreement that the proposed Kosi Dam could become the highest in the world. I had explained about it in my study report entitled “ Planning Kosi High Dam Project” brought out several years before the 1997 Indo-Nepal Kosi Study meeting.

Many of us might be astonished to learn that the installed capacity of the Kosi Dam Hydropower Station could reach 16 million KW or even more if the evaluation criteria used in the determination of the installed capacity of the Karnali Project (Chisapani) is applied to the Kosi High Dam Project too. According to the detailed feasibility study the installed capacity of the Karnali Project (Chisapani) is only 10.8 million KW. Similarly the annual power generation of the Karnali Project ( Chisapani) is about 20 billion KWh, whereas in case of the Kosi High Dam Project, such annual generation could be about 30 billion KWh. As of now the biggest hydropower station already in operation in the whole world is the 12.6 million KW Itaipu Hydropower Station jointly built by the Governments of Paraguay and Brazil. The 18 million KW Three Gorges Project Hydropower Station in China is still under construction. Thus among the hydropower projects so far in operation throughout the world the Kosi High Dam Project could exceed all others in terms of both the dam height as well as the total installed capacity of the power station, as a result we would not be able to benefit from the previous experience of building anywhere in the world a hydropower project of a similar colossal size.

Research & Development

Needless to say that we would be encountering enormous difficulties in planning and implementation of the Kosi High Dam Project since it is going to be one of the biggest projects in the whole world. . In resolution of several such problems, the Research & Development works would be virtually indispensable. In several instances the results of the Research & Development would be required even to work out the plan to conduct the detailed study of this mammoth project. Thus there would be a need to spend a fairly long period to complete such research and development works. Realizing such bottlenecks that would have further delayed the completion of the detailed study, I had even signed in my capacity as the Executive Secretary, Water Energy Commission an agreement in 1997 with the Kathmandu University to facilitate the R&D necessary to conduct the detailed study of the Kosi High Dam Project and its navigation canal component. Competent employees of the Ministry of Water Resources willing to perform the R&D works were to be engaged It was agreed with the Kathmandu University that on successful completion of the R&D the researchers were to be awarded the M.Sc. or the Ph.D. degrees. The proposed on the job training was expected to be an integral part of a running foreign assistance program and thus the finance for supporting this task was fully assured. . Soon I retired from the government service and, unfortunately, there was nobody thereafter to push ahead this program. .

Key Issues Raised in 1997 Meeting

There was not much discussion about the size of the Kosi High Dam Project in the 1997 Indo-Nepal Kosi Study Meeting. Nevertheless, both sides knew perfectly well that the Kosi High Dam Project is going to be one of the biggest in the whole world. The following three key issues were raised in the meeting. They were the Kosi flood control, Sun-Kosi Dam Project and Kosi navigation canal. India agreed to accept our proposal on all three issues.

Until few years back the Indian Government was seen to be drifting away from the facts that it is absolutely indispensable to provide storage dams in the basin to prevent the Kosi flood disasters. The Indian Government was saying that the Kosi flood control problem has already been resolved after the completion of the construction of embankments on both sides of the Kosi River. . So right at the outset of the meeting held in Kathmandu to finalize the Kosi Study Agreement, I had to give a brief presentation on Kosi flood problems. The presentation was quite helpful in explaining our viewpoint on Kosi development. Later on in course of discussions the leader of the Indian team expressed off the record that from now on they are fully convinced of the fact that the biggest benefit to accrue from the Kosi development would be the flood control

The study to construct the Kosi High Dam is now firmly tied up with the provision of a 165 km long navigation canal out of it a 120 km long section of such navigation canal would be in Indian territory. The proposed navigation canal would be linking Nepal with the seaport through Ganges, Bhagirathi and Hoogly rivers

The Kosi Study Agreement 1997 has shown beyond doubt that the commencement of the construction of the Kosi High Dam would be contingent upon the prior implementation of the Sun-Kosi High Dam Project on technical grounds. The Sun-Kosi High Dam Project, regarded to be benefiting almost exclusively Nepal, prominently figured in the talks to finalize the 1997 Kosi Study Agreement. Indian side had wanted somehow to exclude the Sun-Kosi Dam Project from the Kosi development study. They did not want to get bogged down into the relatively big Sun-Kosi Dam Project Ultimately the Indian side was convinced that it is no more possible to sideline the prior implementation of the Sun-Kosi Dam Project despite the fact that it would be a project to serve almost exclusively Nepal. They realized the fact that the construction of the Kosi dam would be further delayed if the construction of the Sun-Kosi Dam Project is not completed in time. As a result, the Indian side even agreed to provide financial assistance to carry out expeditiously the detailed study of the Sun-Kosi Dam Project also.

Indian Concept of Kosi High Dam

The Kosi had shifted from east to west over 120 km within the last 200 years, as a result, about 10,000 sq. km was laid bare with sand deposit. The idea of building the Kosi High Dam was conceived in the past primarily to resolve the worsening Kosi flood problem. A request was made to build Kosi embankments in Bihar’s Post War Plan. However, India’s Central Government felt that a comprehensive study of the entire range of possibilities should be made before embarking on building embankments.

Central Government advanced the idea of building the storage dams in the Kosi basin for controlling the floods. India started the study to build the Kosi High Dam in 1946. India had even circulated a preliminary report of the Kosi High Dam Project. The Kosi High Dam Project according to the study conducted by the Government of India consists of a 269 meters high and 710 meters long concrete gravity dam about 2 km upstream of the Barahachhetra. The installed capacity of the hydropower station would be 3,000 MW. The project includes a diversion barrage 969.9 meters long near Chatra, 8 km downstream of the dam. There will be canal system with three power houses with a capacity of 300 MW.

Kosi Reservoir Volume Insufficient

The nature of the topography of the Kosi reservoir area is completely different from that of the Karnali storage reservoir (Chisapani). The proposed heights of the Kosi as well as the Karnali dams are virtually identical. The Kosi dam height is 269 m similarly the Karnali dam height is also 270 m. Despite the fact that the height of both the dams are almost the same, there is a vast difference in volume of the storage reservoirs. The gross storage volume of the Karnali storage reservoir is about 39 billion cu. m out of it the dead storage, regulating storage and flood control storage would be 11 billion cu. m, 16 billion cu. m, and 12 billion cu. m respectively. The total gross storage volume of the proposed Kosi storage reservoir would be only 13.45 billion cu. m out of it the dead storage, regulating storage and the flood control storage would be 4.08 billion cu. m, 7 billion cu. m, and 2.37 billion cu. m respectively.

Recent studies of the Himalayan region provide a whole bunch of information very useful for planning high dams. Such information were extensively used for detailed planning of the Karnali High Dam. The Karnali studies carried out at an enormous cost by a consortium of renowned consulting firms of several countries under the aegis of the World Bank in close consultation with the governments of Nepal and India have greatly helped to realize that compared to the earlier perceptions the magnitude of the problems to be actually encountered in dam planning in the Himalayan belt would be far more serious and also complicated. This has been amply reflected in finalization of the design of the Karnali High Dam. As a result, it can be said that the proposed Kosi dam height is too small to be effective to control the Kosi floods for a relatively long period. We certainly would not go far wrong if the gross storage volume calculated for the determination of the Karnali high dam is applied in approximately determining the height of the Kosi dam also since in every respect the Kosi is a bigger river than the Karnali.

A Panel of Experts

The river Kosi is bigger than the Karnali in terms of the total annual water flow, annual volume of the sediments being carried into the Terai from the mountains and the drainage area. Thus, if it is presumed on the above grounds that the total storage volume of the Kosi reservoir by comparison with the Karnali reservoir should at least be equal, the total volume of the Kosi storage reservoir would have to be 39 billion cu. m. Needless to explain that the dam height should be further raised to increase the storage volume of the reservoir. If the Kosi dam height is raised from 269 m to 300 m, the total storage volume would still be only about 19 billion cu. m. Perhaps the dam height should be in between 335 m and 350 m if the total storage volume of the Kosi reservoir is to be about 39 billion cu. m. At present the highest dam in the world is the Ragun dam in the former Soviet Union. This dam is still under construction though it was expected to be completed many years before.

The Kosi Dam can be expected to be the highest in the whole world. Planning as well as the implementation of the dam of this scale is going to be a very big challenge. There is an urgent need to constitute a panel of few renowned experts at the very early stage to help us prepare program to conduct the detailed feasibility study.

(Dr. Thapa writes on water resources)