Opinion (Spotlight Weekly)

Uniqueness Of Kosi Flood Problem

By Dr. AB Thapa

The new cycle of the Kosi flood disaster feared to commence again in near future after a pause of few decades would have nothing in common with the very recent flooding in the North Bihar which caused only limited damages to property. Moreover, the adverse impact of the recent Kosi flood damages on property did not last long. The flood affected area returned to normal as soon as the floodwaters subsided. The loss of life was also quite insignificant.

The recent flood disaster in North Bihar is particularly significant because it was more or less widespread, and it temporarily affected one of the most densely populated regions of our South Asian Sub-continent. Unfortunately the reporting of the recent floods in North Bihar could convey very wrong message to many of us to trifle with the grave threat to our region already on the brink of the devastating Kosi floods triggered off by the change in course of the Kosi . Many peoples, who do not know the difference between the physical processes underneath the imminent devastating Kosi floods and the recent floods that hit the North Bihar, could easily draw a wrong conclusion that we have to learn to live with the Kosi floods.

The Cause of Kosi Floods

Thirty million years ago the sea bottom that was to become the Himalayas began to be pushed up, and this movement is still in progress. The Himalayas continue to rise and so do their peaks including the Mount Everest. It is said that were it not for the strong erosion that simultaneously wears down the entire Himalayan region, the Mount Everest summit would now be nearly 20,000 meters above the sea level. So the Kosi rising in the Himalayas and emptying into the plain at Chatra after traversing the mountain region, brings with her every year an enormous quantity of sediments estimated at 120 million cubic meters along with 52 billion cubic meters of water. The annual volume of the Kosi sediment is about 5 times greater than that of Sutlej at Bhakra and 2 times greater than that of Nile at Aswan.

Various studies done on Kosi so far come to one common conclusion - the Kosi carries enormous load of sediments that it is unable to transport far beyond. The river, therefore, deposits huge quantity of sediments. In this process of building up an inland delta, the river shifted over 120 km from east to the west during the period from 1736 to 1954.

Embankments Would be Ineffective

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 in between the embankments 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 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 incidence 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.

Solutions to Kosi Flood Problem

Solution to the Kosi floods should be found quickly. Renowned experts and scientists who have studied the Kosi say the provision of dams in the drainage area with very big storage volume is the only lasting solution to this problem. We can draw similar lessons from China's experience.

China had both depended on and dreaded its mighty rivers. It is reported in CHINA DAILY that during the Qing Dynasty (1644 - 1911), control of the Yellow River was thought critical to dynastic stability. So a ministerial post - Governor of Yellow River Affairs - was established. The holder of this post was only second in power to the prime minister. Over the years sedimentation had raised the Yellow River bed by 5 - 10 centimeters a year. The riverbed in the lower reaches was elevated by 3 - 5 meters above the level of surrounding fields. The Yellow River had thus become a "hanging river". Until recently there were on an average two breaches of the dikes every three years, and a major change of river course once a century.

The centuries old China's Yellow river flood problem has been resolved. China built several storage dams to control the Yellow river floods. The Xiaolangdi dam is the latest. This dam on the lower Yellow River 130 km downstream from the existing Sanmenxia project in Henan province is now under construction. This project is financed with a World Bank loan of US$ 460 million, plus an IDA credit of US$ 110 million.

The flood control of the Yellow River is regarded as "a remarkable achievement". Keeping the Yellow River at bay has saved the China US$ 50 billion. It is not difficult to establish that storage dams should be built to avert the imminent Kosi flood disaster.

Confusion About Kosi Dams

Unfortunately, some people in Nepal and India have misgivings about the storage dams. They think that the storage dams should not be built to control the floods. Even journals like the "HIMAL" give credibility to such views by publishing them. The core issues often raised against the embankments and dams in Kosi drainage area do not appear to be sound. Some subscribe to the principle that the Kosi should get back its original route to the Ganga. One would certainly be at a great loss to find out the original route of the Kosi to the Ganga. The Kosi route had shifted from east to west over a distance of 120 kms in a period of about 200 years.

It is encouraging to note that at present people in Nepal are gradually showing their concern about the Kosi dams by publishing their opinion in local newspapers. Mr. D.R. Prasai has rightly pointed out in his recent article published in one of the local newspapers that we should not rush to decide to implement the Kosi dam projects without correctly establishing who stand to benefit from such projects. Nepal could not support those projects proposed to be built at the cost of Nepal’s vital interest. Unfortunately, until now even the basic information about the proposed parameters of the Kosi dam projects has hardly been disseminated. As a result, people in Nepal are made totally confused.

There is a great confusion that the Kosi high dam at Chatra would submerge the holy Barahachhetra temple, though this problem had been resolved a longtime ago. Now the proposed site of the Kosi dam is few kilometers upstream Barahachhetra temple near Tribeni which is immediately after the confluence of the three rivers ( Sun-Kosi, Arun and Tamar).

Sun-Kosi Dam Project

The Sun-Kosi High Dam Project, forerunner of the Kosi High Dam Project, should be implemented in time to save the life and property of millions in Nepal and India. It has already been explained that at present the Kosi river is on the verge of shifting to the east far away from its present course devastating vast region of Sunsari and Morang districts. This project is vital for the safety of the people in India also, as a result, India has already agreed to provide financial assistance to conduct detailed study of this project. After the completion of the detailed study, India would be bound to help our country in our efforts to make financial arrangements for the timely implementation of this project. Needles to say that the surplus Sun-Kosi power could be easily sold to India at a fair price since it is in the interest of our both countries to implement this project as soon as possible.

Nepal could complete the study as well as the implementation of the Sun-Kosi dam project within the next 12 years. About 300,000 ha lands in Nepal Terai would come under year round irrigation. This project would be able to generate annually about 4,000 GWh firm power which is about two times greater than the total present electricity generation in Nepal. The generation cost of the electricity could be only about US $ 1/100 ( one US Cent) per unit if this project is prudently implemented. The Sun-Kosi dam project is not merely an environmentally friendly project. This project is indispensable for the preservation of environment, as a result, this project would not have to bear the brunt of the criticism from the anti-dam lobby.

The Kosi Dam Highest in the World

A study of the Kosi dam was taken up by India in 1946. The concrete dam proposed at that time with a height of 269 m was to be the highest in the world. The great Hoover dam in the United States with a height of mere 221 m was then the highest. Even to this date there is only one concrete dam higher than 269 m. This is the 285 m high Grand Dixene dam in Switzerland.

At present abundant information are available on planning storage reservoirs in Himalayan region for flood control. The most suitable example for the Kosi planning could be the Karnali feasibility study. If the Karnali reservoir planning criterion is applied then the height of the Kosi dam would be almost close to the height of the Rogun dam presently under construction in the former Soviet Union. At present the 335 m high Rogun dam is the highest in the world.

The Kosi high dam project is going to be one of the largest projects undertaken so far in the world. So it will be a very big engineering challenge. We should beware of unintentional give-away in Kosi development. The optimum Kosi development should not be compromised. A less than optimum dam could preclude optimum development of the Kosi river for all time.

We Should Keep A Watchful Eye

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

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 Thus India has endorsed our proposal to conduct feasibility study to build the Kosi navigation canal linking Nepal with the seaport through Ganges. Needless to say that the proposed Kosi High Dam Project tied up with the provision of a 165 km long navigation canal would be an exceptionally big project and thus it would take a long time to complete its feasibility study. Let us not forget that it took China about 20 years to complete the detailed study of the Three Gorges Project. It is too early to think about the implementation of this mammoth project yet our general public and the press should keep a watchful eye on the conduct of the proposed feasibility studies. They should not shy away from expressing their views even though on occasions it might make them look very absurd

(Dr. Thapa writes on water resources)