West Rapti Again Floods Banke District

By DR. AB THAPA

Newspapers have again started to report that as in the previous years a large area of the Banke district has already been submerged by the West Rapti flood water. People are abandoning their houses to find temporary shelter elsewhere. It is quite unfortunate that the nation is not paying due attention to resolve this problem that has led to a serious humanitarian crisis.

The Tip of The Iceberg

Last year it had been reported in one of the local English dailies dated July 21, 2005 on clarification of the Indian Embassy what is causing recent flooding in Banke district. “The Embassy reiterates that Laxmanpur Barrage, which is located 8 kilometers downstream of the India-Nepal border, is not yet operational, and the gates are never lowered and remain open at all times. There is, therefore, no question of Laxmanpur Barrage obstructing the flow of water in the Rapti River” It was further stated “ The Embassy understands that heavy rains in recent days had led to water logging in this region, including in adjoining areas in India …” It is clear based on the reporting of the Indian Embassy that the present widespread excessive flooding in Banke district could be primarily due to narrowing of the Rapti River course after the construction of the guide bunds upstream of the barrage. Thus the present Banke district flooding problem might be only the tip of the iceberg. A vast area of the Banke district would remain all the time submerged during the wet seasons as soon as the Laxmanpur Barrage would be operational. It is explained hereinafter that the construction of Laxmanpur Barrage is an integral part of an overall plan to utilize the regulated flow of the Karnali and West Seti rivers for irrigation in India. Such plan would be dependant on Nepal ’s decision to implement the Karnali or the West Seti Storage dam projects. Nepal might have to convince India to amend the design of the Saryu Canal if we want to resolve the Western Terai submersion problem.

Saryu Canal

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 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.

The Saryu Canal Project consists of a canal network that connects the head regulators 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 the barrage across it. Similarly 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 right up to the Banganga River.

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. The river flow would not be obstructed if such siphons are built. 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 drastically 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 already 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 West Seti water drawn from the Girjapur Barrage across the West Rapti River.. It need not be mentioned that the Girjapur Barrage would help in future to draw the regulated Karnali River water also into the Saryu Canal to extend the coverage of lands under year round irrigation.

It would be necessary to maintain all the time pond water upstream of the barrages 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 would also result in flooding inside Nepal where the canal route is close to the border.

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 Birgunj 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 canal proposed by India would have led to submergence of a vast area of Nepal ’s Eastern Terai . 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.”

Nepal ’s Self-deceptive Water Policy

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 only 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 with final design works

It might appear utterly unbelievable that Nepal might be going to drown a very large number of her own citizens living in the Western Terai . Unfortunately it is a bitter reality. At present we are about to take final decision to grant permission to a private developer to build the West Seti Storage Dam Project to generate electricity completely disregarding the fact that the regulated flow of the West Seti River would play havoc in the Western Terai to the east of the Karnali River. It has already been explained that the 230 km long Saryu Canal taking off from the Girjapur Barrage already built in India across the Karnali River is going to be the extension of the West Seti Storage Dam Project. The middle and lower reaches of the Saryu Canal run very close to our border. Extremely objectionable type of river crossing structures have recently been built completing ignoring the fact that they would result in perpetual widespread submergence affecting a vast area of Nepal’s Western Terai. Already serious flooding problems have been experienced even though those structures are not yet in operation. The flooding situation would be extremely grave once those structures would be in use after the Saryu Canal starts to operate. Our government, various water related agencies and NGOs have already been cautioned about this grave danger through media.

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 Saryu Canal has been designed to provide river crossings raises fear that the upstream bed of the Rapti River{ also Babai and Banganga} would be very rapidly rising. It would even further aggravate the submersion problems.

A through study should be carried out based on confirmed data to determine exactly the adverse 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 Saryu 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.

(Dr. Thapa writes on water resources)