Opinion (Spotlight Weekly)

FORTHCOMING STUDIES OF KOSI DAMS

Dr. AB Thapa

An agreement was signed in 1997 between Nepal and India to conduct detailed studies of the Sun-Kosi Dam Project, Kosi Dam Project, and Kosi Navigation Canal Project linking Nepal with the seaport. It should be explained here that out of the above three projects the latter two would be enormously large projects.

Originally, India had proposed Nepal to build only the Kosi Dam Project. We explained to India that we wanted to develop inland navigation as an integral part of the Kosi Dam Project by providing a navigation canal between Chatra and the Ganges. Like the landlocked Switzerland using the Rhine canal for navigation to get access to the seaport, we, too, liked to conduct the detailed study of the navigation canal to directly link Nepal with the seaport. Both the countries agreed to conduct detailed study of the Kosi Navigation Canal. A 120 km stretch of the proposed Kosi Navigation canal would be in Indian territory. Similarly we convinced India that the implementation of the Kosi Dam Project would be indefinitely delayed if the detailed study as well the construction of the Sun-Kosi Project is not completed well ahead of the commencement of the Kosi Dam Project construction. The Sun-Kosi Dam Project and the Kosi Dam Project would be mutually exclusive if the latter is implemented first. As a result, India agreed to provide financial assistance to conduct the detailed study of the Sun-Kosi Dam Project also side by side with the Kosi Dam Project that would enable Nepal to implement the relatively small Sun-Kosi Dam Project in time.

Why India Agreed

Both India and Nepal are independent countries. So it is not unusual that interests of both of our countries would not be the same on many issues. On several matters our interests could even be diametrically opposites of one another. It is not that we are often seen blaming each other for the failutre to taken into account the genuine interests of each others.

In the past water resources had proven to be highly contenious issue in relationship between Nepal and India. The Kankai High Dam Project proposed to be constructed constructed with the technical and financial assistance of the German Government was the first major casualty of the conflicting interests of India and Nepal on water resources development. Many of us might wonder why India is now so anxious to help Nepal to implement projects like the Sun-Kosi Dam Project, Kosi Navigation Canal Project and Kosi Dam Project on our terms while that country was so hard on us with respect to other water resources projects, and, as a result, Nepal was denied foreign assistances desperately needed to implement several of its irrigation projects. There is a simple answer. There can be a total convergence of the interests of Nepal and India on implementation of the Kosi dams projects. Timely implementation of the Kosi dams is vital for the safety of life and property of millions of peoples in both India and Nepal. In the absence of timely intervention in resolution of the Kosi dams problems the vast stretch of the Kosi flood plains to the north of the Ganges could virtually turn into graveyard for tens of thousands of innocent peoples of India and Nepal. What is the cause of the Kosi danger? Many of us might be interested to know about it.

Cause of Kosi Danger

The Kosi River known as the river of sorrow of the Bihar shifted from east to west over 12O km in the last 200 years. In the past about 8000 sq. km. of lands had been laid waste as a result of the sand deposit. In course of shifting, many towns and villages were wiped out, and heavy losses of property, cattle, and human life were inflicted. Fortunately the embankments built few decades ago temporarily helped to check the lateral shifting of the Kosi. But at present the detention basin upstream of the barrage at Hanumannagar is almost full of sediments. Soon the embankments would be ineffective to control the Kosi floods.

The Kosi River is now on the verge of shifting to the east far away from its present course. The peoples of Nepal and India are heading for a natural disaster of an unprecedented scale. But it appears that only very few in Nepal and India have. realized the extent of this danger. It would be unfortunate if the Kosi swing to the east takes the life and property of millions in South Asia by surprise while the governments of Nepal and India would merely be silent spectator.

What Do Experts Say?

The Kosi River brings every year an enormous quantity of sediments from its catchments in the mountains. Sir Claude Inglis an expert on Kosi had attributed the shift of the Kosi River channel to excessive sand load carried by the river. Leopold and Maddock considering Kosi behavior had stated that a braided stream will tend to shift laterally at a rate dependent on the rate of accumulation of material being deposited. As one course becomes higher than possible adjacent paths, the river would shift.

Data published in the American Society of Civil Engineering in March, 1966 indicate that in the period between 1938 and 1957 every year on an average about 100 million cubic meters of sediments used to be deposited on the Kosi River bed. The maximum such deposition was around Nirmali in India not far away from the Hanumannagar. There was very big change in sediment deposition pattern immediately after the completion of the Kosi barrage in 1963. The results of the Kosi River channel study for post barrage period have been published by V.C. Galgali, Central Water and Power Research Station, Pune (India), and Gohain & Prakash of Roorke University. All the past studies confirm that the Kosi River bed just upstream of the barrage has significantly aggraded due to sediment deposition. On account of ponding, sediment deposition had occurred, flattening the bed gradient. The bed slope of the river in the pond area was abut 0.61 m per km in the year 1956 prior to construction of the barrage, which became flatter to about 0.42 m per km in the year 1969, ie in six years of the functioning of the barrage. Studies were made to determine the sediment deposition based on post flood 1963 and 1970 surveys These studies indicated that about 35 million cu.m. sediments had deposited in the pond length of about 10 km upstream of the barrage, giving an average depth of about 0.4 m in about 8 years with a rate of bed level rise at about 0.05 m per annum.

Soon Kosi Disaster Could Strike

Embankments built a few decades ago temporarily helped to check the lateral shifting of the Kosi. The detention basin upstream of the Kosi barrage near Hanumannagar is going to be very soon full. After that the embankments would be ineffective to prevent the lateral shifting of the Kosi. It is predicted that the Kosi would again take its 1732 course. The farthest position of the new course of the Kosi is expected to be about 120 km away from its present course. The swing of the Kosi river to the east could be sudden and almost unexpected because nobody yet exactly knows when it is going to happen. The people would be completely taken by surprise. So the loss of life could be very high. In a similar type of 1938 flood incident of the Yellow River in China the number of people killed alone was about half a million. It does not need to be further explained that such shifting of the Kosi to the east would be a biggest disaster for the whole region. Generally the flood damages are temporary in nature but the Kosi flood damages would be widespread and also permanent in nature. Mr. Shilling Feld . an expert on Kosi, has warned a longtime ago that the eastward movement of the Kosi will be in one big swing accompanied with great loss of life and property.

Resolving Kosi Flood Problem

Provision of dams in the drainage area with very big storage volume is the only lasting solution to the Kosi flood problem. It is the opinion of the renowned experts and scientists involved on the Kosi study in the past. We can draw such lesson from the past experience of China also. It can be concluded that there are not any substitutes for the large storage dams to control the Kosi floods. Thus our only recourse is storage dam. The storage dams should be provided in time. Unfortunately some peoples in Nepal and India have misgivings about the Kosi dams. Such misgivings are unfounded and they are often the result of present global disenchantment with the high dams particularly for the generation of hydroelectricity. In case of the Kosi dams this type of notion is completely misplaced. The life and property of too many peoples in Nepal and India would be at great risk if the Kosi dams are not built in time.

The 1997 Kosi Dams Study Agreement between Nepal and India emanated from the understandings that the Kosi River poses a grave threat to peoples of both India and Nepal. Now, there is a great need for wider participation of various agencies, institutions, individual experts particularly those perts

Very recently preparatory works have begun after a long delay aiming at commencing in near future the Indo-Nepal joint study of distinctly three projects on the basis of the 1997 Kosi Study Agreement. They are the Sun-Kosi Dam Project, Kosi Dam Project and Navigation Canal Project to connect Chatra with the Ganges. The complexity and scale of latter two projects would pose serious difficulties even to properly start the proposed studies. Nepal certainly needs external help to guide periodically its survey team and the supervising technical personnel involved in the Kosi study within the Ministry for the following reasons.

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 other drainage areas. Thus, if it is conservatively 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 about 39 billion cu. m. The Kosi dam height should be in a range from 335 m to 350 m if the total storage volume of the Kosi reservoir is to be fixed at 39 billion cu. m. At present the highest dam in the world is the Ragun dam in the former Soviet Union. This dam is 335 m high and it 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.

Detailed planning of the 165 km long Kosi navigation canal is also going to be a great engineering task. The shape and dimensions of this navigation canal are expected to be similar to those of the Farakka navigation channel. Let us not forget that even countries like the France is now seeking technical advice from Germany to improve its existing navigation canals.

Thus, there is an urgent need to constitute a panel of few renowned foreign experts to help us prepare the program to conduct the detailed feasibility studies of all above mentioned three projects particularly the latter two or else the feasibility studies would prove to be futile exercise. Later on the members of the panel should be visiting Nepal at certain intervals to help us in finding ways to sort out critical technical problems impeding the smooth progress of the detailed feasibility studies.

(Dr. Thapa writes on water resources)