NEPAL COULD BE DECEIVED: West Seti Project
By Dr. AB Thapa
After a prolonged silence, again voices are heard in the corridors of power to give fresh impetus to implement the controversial West Seti Project. Unfortunately, even until now almost all of us in the government, media, various NGOs or other concerned institutions are still unaware of various critical issues related to implementation of the West Seti Project. We would be greatly harming the vital interest of our country if we failed to address the following three issues before taking the final decision to implement the West Seti Project. Those issues are recovery of downstream irrigation benefits, realignment of the Saryu Canal built in Indian territory, which is going to be virtually the extension of the West Seti Project, to prevent from flooding of the Banke district, and through checking of the engineering design of the West Seti dam, which appears to be riddled with a great deal of uncertainties.
The West Seti High Dam Project
The West Seti high dam project is among the very few schemes in Nepal which have been extensively studied. It has two major components. They are the irrigation and power. A study at feasibility level on power was carried out by SOGREAH of France, whereas the Karnali Multipurpose Project study fully covers the irrigation component of this project. Feasibility level study of the Karnali Multipurpose Project had been done thrice in the past. One of the main objectives of the latest feasibility study was to involve India in the studies to determine the magnitude of the irrigation benefits accruable to that country from the regulated flow of the Karnali River and obviously it also denotes the regulated flow of the West Seti River which is a tributary of the Karnali River.
It has been proposed to build a 187 meters high gravel filled dam across the West Seti river in the feasibility study carried out by the SOGREAH. The total storage capacity of the reservoir will be 1,600 million cubic meters. The power station will be underground type. The power station will produce 2202 GWh firm energy annually. The total annual energy production will be 2,402 GWh. After the regulation of the West Seti run-off the present dry season flow at the dam site of about 45 cubic meters per second will be increased to about 135 cubic meters per second. Thus the net augmentation of the dry season flow could be about 90 cubic meters per second which is about 40% dry season flow of the Karnali river.
Downstream Irrigation Benefit
There will be a significantly large downstream irrigation benefit accruable to India after the completion of the West Seti Storage Dam Project. Such benefit has been quite thoroughly evaluated in the Karnali Multipurpose Project study. Agricultural production over a vast area adjoining the Karnali river in the Indian territory is at present greatly constrained by the scarcity of water needed for irrigation particularly in dry seasons. The regulated West Seti flow could be used for increasing the cropping intensities of the Sarda Sahayak irrigation system or the Saryu irrigation system already in operation in the Utter Pradesh province of India. It is not necessary to build a new barrage for the diversion. The West Seti regulated flow could be diverted for irrigation from the existing Girjapur barrage into the Sarda Sahayak canal or the Saryu canal. Additional canal network also would not be needed for the delivery of water. The existing capacity of the canal system would be adequate.
According to the study carried out by the SOGREAH, if the year 2003 is taken as the reference year and the 1989 price level is adopted at a discount rate of 10%, the total discounted power benefit of the West Seti project would be 912 million US Dollars against a discounted cost of the project estimated at 456 million US Dollars. Thus the total net discounted power benefit of the project could be 456 million US Dollars. Based on the feasibility study of the Karnali High Dam project the total net discounted irrigation benefit of the West Seti project at 1989 price level for the reference year 2003 could be as high as 720 million US Dollars. It implies that the net irrigation benefit of the West Seti project could be greater than the net power benefit. Now a very big question arises. Should we ignore the West Seti downstream benefit? Will we be morally right to do so?
Sharing West Seti Downstream Benefits
India must be approached to share with Nepal a certain percentage of downstream benefits to accrue to that country from the use of the regulated flow of the West Seti. It is a practice followed by the USA and Canada while implementing the Columbia river dams in Canada. At present Canada is receiving 50% of the net downstream benefits from the USA in perpetuity for the use of the regulated flow of the Columbia river in the USA. It should be noted that Canada had declined to take a decision to implement the Columbia river projects until the USA agreed to sign a treaty on downstream benefit sharing.
Why Nepal is hesitating to raise downstream benefit issues in bilateral summit meetings? The USA President and the Canadian Prime Minister were themselves directly involved in the process of resolving various issues of the Columbia River Treaty. We should learn from the experience of the USA and Canada.
India Willing to Pay for Water
Few years back two important news had appeared in the Indian news media. It was reported that the Government of India had appointed a three-member task force headed by the former power minister Suresh Prabhu. The task force was expected to address the issue to obtain the consent of Nepal (also Bhutan ) through a revenue sharing pact to divert water of the major rivers for irrigation across the India. Until that time India was seen to be hesitating to accept the idea of buying water stored in the reservoirs proposed to be built in Nepal.
Nepal has not yet taken up the downstream benefit matters very seriously despite the fact that India already appears to be taking interest to find a way to share benefits accruable from the water delivered from Nepal for distribution across India. Thus, we would be doing a great injustice to the people of our country if it is decided to implement the West Seti Project totally ignoring its downstream benefit component.
Saryu Canal Operation Depends on West Seti Project
There are two irrigation canals taking off from the Girjapur barrage built across the Karnali river in Indian territory . 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 fully 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.
Submergence of Nepal’s Western Terai
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 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.
At the Question of Dam Safety
The West Seti dam project appears to be ridden with serious technical problems that concern the safety of its most important structure, the high dam itself. The WECS had few years back sent its opinion to the Water Resources Ministry stating that the type of the high dam proposed for the West Seti by the private developer could be risky. Some of the evidences put forward by the developers to justify their selection do not appear to tally with the information contained in the recently published scientific documents.
The proposed West Seti Dam is going to be highest in the World among the CFRD. Needless to say that there is a need for great caution in adopting very high CFRD. According to J. Barry Cooks, Consultant USA ( Development in High CFRDs, Hydropower & Dams, Issue Four 1997), this type of dams are of empirical design and based on precedent design and experience. Unfortunately only very recently relatively high CFRDs have been introduced
WECS had suggested to constitute a panel of few renowned international experts recognized to be the authority on their respective discipline to seek their opinion. Any further action in the direction of taking the decision to award the project to the private developer should be deferred until the panel gives its absolutely positive opinion. It is not known who had approved the technical design of the West Seti project on behalf of the government to vouch for the correctness.
The incidence of the Kulekhani high dam should not be allowed to be once more repeated. At that time the Kulekhani dam could be saved which was on the verge of collapse resulting into one of the biggest man made disasters in the world In case of the West Seti reservoir the magnitude of such disaster would be far greater because the volume of the West Seti reservoir might be about 15 times greater than the volume of the Kulekhani reservoir.
(Dr. Thapa writes on water resources)
