ASIAN DEVELOPMENT BANK MUST RETHINK
Dr. A.B. Thapa
It appears Nepal is heading towards the implementation of the West Seti High Dam Project completing ignoring the issues related to downstream benefits sharing, displacement of a large number of Nepalese people resulting from the extensive submergence in Banke district in violation of Nepal’s Interim Constitution. Above all, peoples of Nepal and India might be un-necessarily going to be exposed to a great risk of dam failure catastrophe.
The proposed West Seti dam impounding a huge reservoir over 1500 million cum .meters in volume is going to be the highest CFRD type dam in the whole world. Nepal Government is now prepared to grant permission to a private party to construct the mammoth CFRD type West Seti high dam even without conducting from the Government side a thorough review of the entire engineering design of the project by employing a panel of competent experts.
It is said that the ADB has already agreed to provide financial assistance to implement the West Seti Project. It is explained hereinafter how our ministry remains indifferent to even the most serious water related problems. Everybody likes to hope that the Asian Development Bank will consider all issues before finally deciding to provide assistance to implement the West Seti Project.
Ministry’s Indifference to Water Problems
Two prime-ministers, one of them the Prime Minister of Nepal had signed an agreement to conduct detailed feasibility study of the Kosi dam project which is expected to be one of the largest multipurpose water resources projects in the whole world. The project is considered indispensable to save the life and property of millions in Nepal, India and also Bangladesh.
Unfortunately our Ministry of Water Resources does not seem to realize the extent of the damage to entire nation if the Kosi dam project is not handled with great care. At present one wing of the Ministry of Water Resources and Indian experts have started to conduct jointly the detailed study of the Kosi project. At this very time to the great horror of everybody another wing of the same Water Resources Ministry without the slightest hesitation is busy to devastate the proposed Kosi dam project by allowing a private developer to conduct detailed feasibility study to implement the Lower Arun Project despite the fact that the Kosi Dam Project and the Lower Arun Project are mutually exclusive.
Why West Seti Dam Could Be Unsafe?
The West Seti Project will have a 195-m high concrete face rockfill dam ( CFRD ). This type of dams are found to be very competitive in cost but until recent time they were considered risky for heights above 150 meters. This type of dam could have also been considered as one of the alternatives in selection of the high dam for the Kankai Project. The French expert called in to advise on Kankai dam appears to have dissuaded the German study team from considering the CFRD as a viable option. It was considered that it could be unsafe to build the CFRD. So finally at the end an embankment type dam with an asphaltic concrete face was selected.
The CFRD is very sensitive to settlement and deformation of the rock-fill supporting the upstream face. These deformations produce movements of the concrete slab joints by opening them and if the movements exceed certain limits then the resulting leakage is difficult to control.
There is no Precedent
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.
The proposed developer of the West Seti Project has cited as precedent in their report two CFRDs close to the West Seti dam in height. It is claimed that they are already in good service. They are the Tiensingquiao of China with a height of 180 meters and Aguamilpa of Mexico with a height of 185.5 meters. Unfortunately both these CFRDs can not be satisfactory example to justify the selection of CFRD for the West Seti Project. The Tiensigquiao dam of China might have been only recently completed. According to the original schedule the dam was expected to be completed towards the May of 1999. So nobody might yet be knowing how that dam would be going to perform. The Aguamilpa reservoir was first filled in August 1993. Since then two abnormal peak seepage values have been observed. These events were of great concern, and several hypothesis were made to explain this behaviour although none has been satisfactory. Now underwater inspections are in progress to try to identify any factor, which could explain the observed behaviour.
Past Bitter Experience
Kulekhani high dam was on the verge of collapse few years after its completion. The cause was poor geology. This writer had cautioned about the poor geology even before the commencement of the construction. The comments were published in local and foreign news media. The comments were not taken seriously. Later the imminent dam disaster was averted at great expense.
Violations of Interim Constitution
Interim Constitution requires that any water resources project that involves a neighbouring country must be approved by a 2/3 majority of the House if such project would result to widespread and long lasting adverse impact. People of Nepal and particularly those living in the Western Terai would be forced to bear the disastrous consequences if the West Seti Dam Project is implemented without resolving the worsening flood problems in the Western Terai associated with the Saryu Canal ( that includes Laxmanpur Barrage also) which is in realty a component of the West Seti Dam Project.
According to Interim Constitution a project must be approved by a 2/3 majority of the parliament if it involves on an appreciable scale sharing of benefits with the neighbouring country. It is quite surprising that our concerned Ministry has never revealed the existence of irrigation report of India’s Northern UP prepared by foreign consultants under the World Bank assistance with the direct involvement of the governments of Nepal and India. According to that irrigation study report the total net irrigation benefit accruing to India from the West Seti project would be almost twice the total net power benefit. There is a general principle of internnational law based on precedence that provides that the upper riparian country has a right to 50% share in total net downstream benefits( in our case irrigation benefit). This principle was applied in the Treaty between the USA and Canada. Recently the Government of tiny Lesotho has been provided 56% share of the total net downstream benefit by the South Africa.
