Opinion (Spotlight Weekly)

Sunkosi Project For Development Of Nepal And India

By A.B. THAPA

We are surrounded by the wrong information that the Sunkosi diversion project benefits only Nepal, whereas the Kosi dam project would be providing benefits totally to India. In reality, both projects are indispensable for the safety of life and property of millions of peoples in our both countries. The direct economic benefits accruing to Nepal from Kosi project hydropower could also be extremely large, if this project is handled prudently. In one of the concept papers present recently in the Water and Energy Commission Secretariat, it was explained that Nepal could make a net earning of about half a billion US dollars per annum at present price of the electricity immediately after the Kosi hydropower station comes under operation. The net annual benefit would increase to about $1.5 billion after the repayment of loan within a period of 10 to 12 years. The Kosi dam is expected to be one of the highest in the world and the size of this project could also be exceptionally large so we should not be astonished by the enormity of the Kosi power benefits. Similarly the Kosi navigation canal linked with the seaport as a part of the Kosi project could work miracles for our landlocked country, though the benefits to North Bihar region of India from such navigation canal would be no less significant.

Contrary to general belief of the peoples in Nepal and India, the Sun-Kosi dam project would also be greatly benefiting India. The electricity produced at the Sun-Kosi project in large scale could be exported to the adjoining region of Bihar on the fringe of the India's North-Eastern power grid at reasonable price. This would help to a great extent to resolve the problem of present power shortage over a large area on the northern periphery of Bihar. However, the most significant benefit to Bihar would still be the irrigation. It is intended to irrigate about 300000 ha of lands of the Eastern Nepal by diverting the regulated flow of the Sun-Kosi river into the Terai. The Sun-Kosi water would be made available throughout the year for irrigation in Nepal. Perhaps almost another 300,000 ha in Bihar also could automatically come under irrigation even if the Sun-Kosi project is planned to irrigate exclusively Nepalese territory. The reasons for it are given below:

Return Flow From Nepal

The feasibility study of the Karnali (Chisapani) High Dam project carried out under the aegis of the World Bank provides a great deal of very valuable information on irrigation planning. They can be applied for planning irrigation from the Sun-Kosi Dam project. It can be said based on the Karnali feasibility study that India would be getting for free about 65 percent of the water diverted from the Sun-Kosi reservoir for irrigation in Nepal's Eastern Terai as return flow.

About 35 percent of the diverted flow could be assumed to evaporate or be transpired by crops, thus 65 percent must return via surface and groundwater. Of the 65 percent returning, 15 percent could enter into deep subsurface aquifer, leaving 50 percent for return as surface water and shallow groundwater. The return flow from the Nepal Terai would drain back into innumerable small streams flowing from our country into India. They can easily be tapped in the Indian territory for irrigation. The canals provided to divert such surface return flow for irrigation could also be used to deliver underground return flow. It would be necessary to provide tubewells for abstracting such underground water.

Summer Season Paddy

The volume of the Sun-Kosi reservoir would be relatively small so it would not be possible to fully regulate the annual flow of this river. Thus, we would be interested to produce as much as possible electricity per month during the monsoon period to make maximum use of the surplus river water. Fortunately it is also the season when the paddy crop that requires the application of water for irrigation at a very high rate is grown. Normally the total monsoon rainfall is more than adequate to support paddy crops. Nevertheless, acute water shortages are experienced because there are always big variations in internal distribution of the rainfalls within this period. Barring few exceptional years there are almost always prolonged dry stress periods at some stages of the paddy cultivation, whether it is at the beginning period, or the middle or at the end. So short period irrigation becomes virtually indispensable even for the cultivation of the monsoon season paddy crop. Thus, the surplus rainy season flow of the Sun-Kosi river diverted into Terai for the generation of the secondary energy would be at the same time irrigating large area of lands under paddy cultivation in Northern Bihar.

Winter Crops

During winter season, the ambient temperature is too low in our Terai as well as in North Bihar for the cultivation of crops like the paddy that requires application of maximum amount of water for irrigation. Usually crops like the wheat are grown that are less susceptible to low temperature. In case of wheat, the water requirement is less than half of the paddy. The water diverted into Terai from the Sun-Kosi reservoir during winter season for the generation of electricity would thus be far in excess of our need for irrigation in Eastern Terai, and, as a result, such excess water would be freely available in Northern Bihar for bringing vast area of lands under irrigated agriculture.

Variation In Cropping Pattern

There can be a great deal of variations in cropping patterns adopted by the farmers in Nepal Terai and Bihar. It might happen due to some differences in meteorological conditions. As a result, even for the same type of crops the maximum stress period for irrigation could advance ahead or go behind within a certain time range. The spreading of the peak water requirement for irrigation over a longer period would certainly help to increase the area of lands going to be irrigated in North-Bihar by the surplus Sun-Kosi water flowing out from Nepal across the border into India.

Dry Season

Dry months of the spring season just before the onset of the monsoon can be very critical for the generation of electricity and also for the irrigation over North Bihar dependant on water supply from the Sun-Kosi. During this period the Sun-Kosi river discharge would be as usual at its lowest whereas the proposed Sun-Kosi storage reservoir would be virtually empty. Fortunately, this is harvesting season when the demand for irrigation is generally very limited. Thus despite some constraint in availability of the Sun-Kosi water expected to be experienced for a short period in dry months before the onset of the monsoon there would hardly be any other threat to extensive irrigation development in the Northern Bihar. Even such short period constraint in availability of the water posing some threat particularly to early paddy cultivation could be greatly relaxed by adopting the practice of double or triple transplantation which helps to a great extent to reduce the demand for irrigation in initial months.

We should not spare our efforts to study positive impact of our major water resources projects extending beyond the border of our country. Such positive impact would indeed strengthen our position to seek greater cooperation from our neighbouring countries in implementation of this type of projects. In case of the Sun-Kosi dam project the people living just across the border in North Bihar going to be benefited for free from this project are sure to join us in pressing their state and central governments to agree to bear reasonable cost of the Sun-Kosi dam for flood control benefit to India and perhaps also to provide us loan assistance for the construction including the purchase of electricity at reasonable price after the completion of the project.