Opinion (Spotlight Weekly)

Laxmanpur Barrage And Rapti Flooding

By AB Thapa

Both India and Nepal could be enormously benefited if Nepal's water resources are properly developed. Nepal could produce electricity in abundance to export to India. Similarly Nepal could expect to receive a fair share of the downstream benefits accruing to India from the use of regulated flows. Needless to explain that the Indo-Nepal cooperation on water resources could have far reaching positive impact on economy of North India. Cheap electricity supplied from Nepal to industries in India could be a boon to enhance further their competitiveness in the domestic as well as world markets. The Northern UP, of all other region of India, would be the main beneficiary. There are three major rivers that cross the Terai region of the western half of Nepal before entering into India. They are the Gandak, Karnali and Mahakali rivers. These three rivers carry on an average annual flow in the range of 3500 cumecs. Such enormous flow of these rivers could bring under year round irrigation a vast area of lands to the north of the Ganges river in the eastern UP. Nobody has any doubt that sooner or later the water drawn from the giant hydraulic structures built in Nepal would be transforming the vast tract of lands in India to the north of the Ganges river into one of the most advanced regions in agriculture production.

Indo-Nepal cooperation on water resources would be in the interest of both the countries. The good relationship already existing between the two countries in the field of water resources should not be allowed to tarnish by no means. The problems such as the one related to Laxmanpur barrage (called Rapti barrage in India) should be quickly settled to win the confidence of the local people living on both sides of the Rapti river in Nepal. Their cooperation would be vital for the successful launching of the Karnali, West Seti and Pancheshwor storage projects. If we examined the West Rapti flood problem in its entirety, it is not difficult to find out that the present flood problem is directly the result of the plans to build the Karnali or the West Seti or Pancheshwor storage dam projects, as a result, the governments of both India and Nepal could be blamed for the dreadful plight of people living in the eastern Banke district of Nepal. Thus both the governments should resolve the submersion problem at the earliest.

West Rapti Flooding and West Seti Privatization

Nepal has embarked on a plan to launch three major storage dam projects in Western Nepal completely disregarding how the vast quantity of regulated water is going to be utilized in India. The feasibility study report of the Karnali Project carried out at an enormous cost provides in depth information on downstream uses, but we are not interested to look into them. Our concern is mostly electricity. While the fate of the Karnali and Pancheshwor projects are yet to be decided, the West Seti project was awarded to a private company SMEC to go ahead. Fortunately the last deadline to produce financial management details had expired in December 2002 and hence the license had become invalid. It was hoped that the water resources ministry headed at that time by one of the persons long since involved in water resources problem of our country would revoke the past decision to go ahead with the West Seti project until the matters related with the downstream uses remained unsettled. . because many knew that the West Seti project is directly linked with the widespread submersion of lands affecting the four districts in Western Terai near the border with India. Unfortunately it was not done so.

The Girjapur Barrage

The Girjapur barrage across the Karnali river is located 1.2 km downstream of the confluence of the channel Girwa and Kauriala and 8.8 km downstream of Katarnia Ghat railway station of North Eastern Railway in India. The site of the barrage is about 16 km from the Nepal border along the River Kaurila.

There are two irrigation canals taking off from the Girjapur barrage . On the left is the Saryu canal running to the east beyond the Banganga river and on the right is the Link Canal connected with the Sarda Sahayak canal planned to irrigate about 2 million ha of lands. At present only the right bank canal is operational because the dry season flow of the Karnali river is quite insufficient for both the canals and there are technical difficulties to utilize the monsoon flow of this river. The year round operation of the Saryu canal depends entirely on availability of the regulated flow from the proposed storage reservoirs in Nepal. The construction of the Saryu canal, that started a long time ago, is still continuing at a snail's pace perhaps due to uncertainty about the date when the West Seti project would be ready for operation. Nevertheless, it appears that the Saryu canal could be made operational at short notice after the completion of the West Seti Storage Project because most of the structures of the Saryu canal might be already ready. After that our people near the border area would be forced to live virtually in swamps throughout the year.

Layout of the Saryu Canal

The Saryu canal project consists of a canal network that connects the head regulaters of the barrages across the Saryu (Babai river) , West Rapti and Rohini ( Banganga river). A link channel 48.4 km long taking off from the left bank of the Girjapur barrage outfalls into the Saryu river just upstream of a barrage across it. A link canal 56 km long taking off from the left bank of the Saryu river outfalls into the West Rapti river just upstream of the Laxmanpur barrage. Beyond that a 125 km long canal taking off from the left bank of the West Rapti river extends up to the Banganga river.

A Very Similar Kosi Canal

India had proposed Nepal to build a canal similar to the Saryu canal to deliver Kosi water drawn near Chatra to irrigate lands as far as Birjung in the west. Instead of such Indian proposal, Nepal indicated its decision to implement the Sun-Kosi diversion project. The Indian proposal was dropped. The following is the excerpt from the Indian proposal.

"The Project, therefore, envisages the construction of a new barrage at Chatra which would be 8 km downstream of the proposed Kosi High Dam, with two high level canals, one on each bank in Nepal. These canals are expected to serve one of the most fertile areas of the terrain in Nepal. Preliminary assessment on the basis of data available shows that it may be possible to cover a gross command of 11.05 lakh ha on the right bank and 4.17 lakh ha on the left bank ( both in Nepal and India). Another major advantage of providing Kosi waters to the high level canals in Nepal would be that, dependence on smaller rivers which are crossed by these canals would not be necessary and it may be possible to develop these rivers in an integrated manner along with Kosi water which would provide irrigation needs both in Nepal and India and at the same time release waters below Chatra for intensifying irrigation in India."

How the Submersion is Caused

The total length of the Saryu canal running almost parallel to Indo-Nepal border is about 230 km. In the original design the barrage across the Saryu river was at a location about 328 meters to the south of the railway bridge at Nanpara. Later, the design was modified and the location of the barrage was shifted 10 km to the north from the original site. The longitudinal gradient of the Saryu canal has been reduced to a minimum. It is only one meter on a stretch of 9 km. The adoption of such extremely mild slope permitted the alignment of the canal to be pushed as far as possible to the north very close to Indo-Nepal border specially in its middle and lower reaches.

Normally siphons are provided to deliver canal water across a river. A much higher average slope of the canal is required for the operation of this type of cross drainage structure, which has to operate under pressurized condition. A free flow hydraulic regime needs to be maintained at the river crossing if the average gradient of the canal is to be reduced. For reducing the average slope of the Saryu canal an altogether a different type of structures has been devised, which at first glance drives anybody crazy. Barrages have been built across the rivers to elevate the river water to such a level that would allow free passage of canal water across the river into the canal taking off from the other side of the river The contentious Laxmanpur barrage is one of such structures devised to deliver the water from the Girjapur barrage across the West Rapti river. It need not be mentioned that the barrage would help to draw West Rapti water also into the Saryu canal.

It would be necessary to maintain all the time pond water upstream of the barrage above certain fixed level to keep the Saryu canal running at desired capacity. Thus the pond would always be full, with the result that a sizeable area of lands in Nepalese territory could remain perpetually submerged. When the river is in flood, the water would be spreading out onto the lands that were never before regarded prone to flooding.

The Saryu canal is expected to cross innumerable small rivers and drains on its way. Embankments and dikes are needed to train these drains and small rivers for the protection of the Saryu canal. These river training structures could also result in widespread flooding inside Nepal where the canal route is close to the border.

In Conclusion

It is becoming increasingly clear that it was a big mistake to shift the original alignment of the Saryu canal 10 km to the north, as a result, the submersion problem of Nepalese lands is sure to worsen further in the years to come when the project becomes fully operational. The way the the Saryu canal water would be delivered to the canal on the other side of the river after level crossing also raises fear that the upstream bed of the Rapti river {also Babai and Banganga} would be very rapidly rising as a result of aggradations. It would further aggravate the submersion problems.

A through study should be carried out based on confirmed data to determine exactly the impact of the Saryu canal on Nepalese territory. It would also be necessary to determine how far to the south the Saryu canal must be shifted once it is established that the proximity of the canal alignment to the border is the cause of the present flooding in Nepal.

Nepal should not commit a blunder by sticking to the decision to implement the West Seti project before resolving the present flood problems in the Western Terai.