Opinion (Spotlight Weekly)

In The Aftermath Of Kosi Floods

By A.B. THAPA

Big floods could have disastrous consequences for the economy of the affected countries. It is not uncommon that news of major floods anywhere make headlines everywhere. A short time ago, floods caused havoc in Eastern Europe. Similarly, in China, the swollen Yangtze river was posing a serious threat to the people living in the adjoining areas. The news had been given extensive coverage in our newspapers also.

The recent flood disaster in Eastern Europe is particularly significant because it was widespread, and it affected one of the most developed regions of the world. Nonetheless, the people in the affected areas were mostly concerned about immediate safety. They knew that the loss of life was not going to be too significant and the damage to property, however big they might be, would be temporary. After some time, hardly any trace of the damage would be left behind. Thus the people are able with great ease to cope with the suffering from this type of floods.

Unfortunately, news of the floods in Eastern Europe could convey a very wrong message to countries of our region already on the brink of the Kosi flood disaster. Many people, who do not know the difference between the physical processes underneath the Kosi floods and the recent floods that hit the Eastern Europe, could easily draw a wrong conclusion that we, too, 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 plains at Chatra after traversing the mountain region, brings with it 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 five times greater than that of Sutlej at Bhakra and two 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 full very soon. 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 one. 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 disaster in China's Yellow River in 1938, about half a million people were killed. Such shifting of the Kosi to the east would be a massive disaster for the whole region. Generally, flood damage is temporary, but the impact of the Kosi flood would be widespread and permanent. Shilling Feld, an expert on Kosi, warned a long time ago that the eastward movement of the river would be in one big swing accompanied with a 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 river 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.

China's centuries-old Yellow River problem has been resolved. The country built several storage dams to control the 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. 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 the Sunkosi high dam should be built immediately to avert the imminent Kosi flood disaster.

Learning to Live with the Floods

Unfortunately, some people in Nepal and India have misgivings about storage dams. They think such dams should not be built to control floods. 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.

In almost all the cases when there is surplus water in the river, flooding results. This is a well-known phenomenon in hydraulic engineering. The recent floods in Eastern Europe come under this category. The Yantze River floods are also of similar nature. Some people try to attribute future Kosi floods also to this type of hydraulic phenomenon. Unfortunately, the Kosi flood, feared to wipe out vast areas of densely populated lands in our region, is altogether different in nature. Unlike the disaster in Eastern Europe, the damage from the Kosi floods would be virtually irreversible.