Monday, September 8, 2008


Like their attacks on USA, if terrorists attack Tehri Dam, Indian National Security and Economy will be in shambles. TEHRI DAM A BOON OR A CURSE FOR INDIA Prof.T.Shivaji Rao, Director, Centre for Environmental Studies, GITAM Institute of Technology, VISAKHAPATNAM-530 045.

PROF.T.SHIVAJI RAO abstracted this material from his book TEHRI DAM IS A TIME BOMB Director, Centre for Environmental Studies, GITAM Institute of Technology, Visakhapatnam-530 045.Formerly Principal, College of Engineering, Andhra University, Waltair, P.W.D Engineer at Nagarjuna Sagar dam. As an International Expert he was invited by the Royal Swedish Academy of Sciences in 1976. He delivered key-note addresses at two international conferences at Khatmandu, Nepal in 1979 and 1997. He is the recipient of Best State Teacher Award for 1986-87 and the Swami Pranavananda .National Award for 1991 of the University Grants Commission on Ecology and Environmental Sciences. He was a member of the A.P.State Pollution Control Board and Chairman of its Technical Committee and was member of the Environmental Appraisal committees of the Union Ministry of Environmental and Forests for Industries and River Valley projects (and during this period had an opportunity to review the Environmental Impact of Tehri Dam as a member of the Bhumbla Committee and recently as a member of the high-power committee on seismic safety of Tehri dam appointed by the Government of India in April 2001, the author studied all the relevant reports on seismic safety of Tehri dam).
As a member of the Environmental Appraisal Committee of the Union Ministry of Environment in 1989-90 I am glad to state that our committee headed by Dr.Bhumbla studied in depth the safety aspects of the Tehri dam from geological, seismic, siltation design and disaster management and economic aspects and rejected the project.
The project was intended to generate 600MW hydro-power was estimated at about Rs. 200 crores in 1972 when the Uttar Pradesh Chief Minister influenced the Planning Commission to give clearance to the project. The 260 meter height earth and rock-fill dam at Tehri across Bhagirathi has a storage capacity of 3500 million cu. m. of water with an underground power house of 1000MW under stage-I and another 1000MW with reversible pump turbines under Stage-II (Pump storage plant). It has another 103.5 meter high concrete dam with a gross storage of 86 million cu.m. of water as a balancing reservoir with a surface power house of 400MW at Koteswar, 22km downstream of Tehri dam site. 4238 million units of energy will be produced per year. Tehri reservoir water is proposed to irrigate an additional area of 2.7 lakh ha. in non-monsoon period in Upper and Lower Ganga canal command area and it stabilises irrigation in the existing 6 lakh ha. Tehri power station will be run as a peaking station with the construction of Koteswar dam. If Hydel power is not available for meeting peaking requirement this would have to be met by diesel or gas-based power plants whose generation cost would be double that of hydro-power. The dam was underdesigned by using low seismicity for Tehri region. Since the dam is located in between the two crashing tectonic plates of India and Tibet known for devastating earthquakes, the risks involved like dam failure result in wiping out of existence several millions of people including saints and sadhu’s of Devprayag, Rishikesh, Hardwar and other places. The devastating floods caused by the inevitable collapse of the Earth and Rockfill dam at Tehri and the concrete dam at Koteswar, 22kms down, will destroy lakhs of villages and hundreds of towns and cities all long the river Ganges in U.P., Bihar and Bengal.
Again as a member of the expert committee headed by Hon’ble Union Minister Dr.M.M.Joshi to study the seismic safety of Tehri dam, I have presented evidence from several angles to show that the Tehri dam project is under-designed and highly hazardous due to the anticipated maximum credible accident of magnitude 8.5 on Richter scale which is forecast by International experts to occur at Tehri within the next 10 to 20 years as reported in the latest US Science magazines and News Week.
I had already indicated that since Tehri dam plans to store water over a depth of 850ft. (260meters) any bombing by the agents of enemy countries or militants or terrorists, the dam being made of earth, sand and gravel will easily collapse, killing millions of Indians and destroying holy temples and sacred towns and cities as stated already. Crops, buildings and properties estimated at more than several lakh crores of rupees will be destroyed. In view of the latest terrorist attack on the World Trade Centre and Pentagaon buildings in USA a similar attack by terrorists, militants or enemies on Tehri dam should be anticipated because it will be an inexpensive bid for them to easily destroy the life and culture of the whole of Aryavartha.
Infact Dr.Narendrapuri, Professor of Structural Engineering, Roorkee University presented an animated picture before Dr.M.M.Joshi and our committee members as to how the Westerns bombed one of the dams when flash floods caused large scale destruction of human and animal populations and properties on the down stream side of the broken dam.
As it is the Tehri dam is under-designed and very unsafe. But some of the proponents of the dam who have vested interests in the project are misleading the secretaries to the Government who inturn are misleading the Prime Minister to take unscientific and hazardous decisions to continue work on the Tehri project even though it is highly detrimental to the life and culture of people of India in general and the Gangetic states in particular. Tehri dam is an easy target for terrorists to ruin the economy of India and thereby threaten the national security, promote the growth of poverty, unemployment and violence in this holy land of Buddha, Mahavir and Mahatma Gandhi.
Surprisingly the Union Ministry of Power in its letter dated 10-4-2001 on the constitution of the expert committee to examine the seismic safety of Tehri dam in the light of the Bhuj Earthquake under the chairmanship of Dr.M.M.Joshi states that the Tehri dam is safe to withstand the maximum credible earthquake as per the experts. There is lot of misunderstanding among the experts as to what exactly is meant by the seismic safety of Tehri dam because most of the experts who pronounced judgements on the issue have taken academic degrees in the collateral but not the relevant seismic and environmental safety fields of study and hence their decisions are bound to be imperfect, unscientific and harmful to national interests. WHO IS AN EXPERT? HOW SHOULD AN EXPERT OPINION BE EVALUATED? According to law an expert opinion becomes relevant for right decision, if only it conforms to certain fundamental norms. According to sec.45 of the Evidence Act, a person specially skilled, is considered as an expert. When the court has to form an opinion upon a point of science, art or engineering, the opinions upon that point of such persons who are specially skilled in such science, art or engineering are relevant facts. But an expert in order to become a competent witness need not acquire special knowledge or skill professionally because it is enough if he made a special study of the subject or acquired special experience therein.
Before the testimony of a person becomes acceptable his competency as an expert must be proved, may be by showing that he possesses the required qualification or that he has acquired skill therein by experience. An expert should be subjected to cross examination because like any other witness, the expert is fallible and the real value of his evidence consists in the rightful inferences which he draws from what he himself has observed and not from what he merely surmises. Facts which are not otherwise relevant become relevant, if they support or overthrow the opinion of experts when such opinions are relevant.
Where the opinion of an expert is to be acceptable, the grounds or reasoning upon which such opinion is based may also be inquired into. Opinion is no evidence, without assigning the reason for such opinion. The correctness of the opinion can better be estimated in many instances when the reason upon which is it is based are known. If the reasons are frivolous or inconclusive, the opinion is worth nothing. While the value of non-expert witness depends upon the credibility of the witness (i.e. his inclination and capacity of telling the truth), the value of opinion of an expert depends largely on the cogency of the reasons on which it is based, and the competency of the expert to form a reliable opinion. An expert opinion cannot be the basis for decision-making, unless the expert opinion is also corroborated by other evidence.
For instance the National Standing Committee for seismic Design Parameters (NCSDP) of the Central Water Commission has recommended a seismic coefficient of 0.15 for the design of the Tehri dam. This is a very low value which makes the design unsafe. Infact Mr.B.B.L.Goyal, Chief Engineer of Tehri dam in a Technical paper(Technical session IX, CBIP, July, 1989) stated that Watana dam in Alaska and Karun dam in Iran in a similar tectonic setting were designed for seismic co-efficients of 0.5g on circum-pacific earthquake belt while Tehri dam was designed for only 0.15g. Infact Hensha dam, 120ft. high, in California was designed for a seismic co-efficients of 0.3g. Japanese codes specify the coefficient for embankment dams as 0.3g. Hence Tehri dam was under-designed because NCSDP experts furnished wrong design criteria, perhaps because several members were experts in collateral fields other than seismology and environmental safety.
Dr.V.K.Gaur, Director of NGRI an International expert in seismology suggested that the peak ground acceleration at Tehri may be taken as 1.0g but the experts of the Department of Earthquake Engineering of Roorkee University who were predominantly Civil Engineers insisted that Tehri will experience an earthquake of magnitude 7 on Richter scale and hence PGA for design purposes may be taken as 0.25g. This clearly shows that Roorkee University experts gave wrong technical data for design of the Tehri dam.
The Roorkee experts have gone out of the way to deride the estimate on seismicity of Tehri made by Dr.V..K.Gaur on 16-10-1986 in a technical meeting held under the chairmanship of M.A.Chitale, Chairman, CWC to study the feasibility of construction of Tehri dam for seismic considerations. Even during this meeting 25 experts representing Central Water Commission(CWC), Geological Survey of India(GSI), National Geological Research Institute(NGRI) and Roorkee University etc., came to an erroneous conclusion that Tehri will not experience an Earthquake of more than 7.0 to 7.2 magnitude and that the peak ground acceleration (PGA) of 0.25g recommended by the Roorkee experts will be adequate for the design of Tehri dam to ensure its safety. In the light of this unscientific affirmation on seismicity and PGA values recommended for the design of Tehri dam, the participants cannot be considered as relevant experts and the organisations represented by these experts become suspect.
When the Tehri project authorities presented Environmental Action Plans before the 13-member environmental expert committee of the Union Ministry of Environment for Environmental clearance in November 1989, the project authorities stated that the dam was designed by Roorkee experts for an Earthquake of magnitude 7 and a PGA of 0.5g and an effective PGA of 0.25g deduced by using Mc.Guire equation based on distance-magnitude relation. After consulting several experts and making an indepth study and visit to Tehri in January 1990, the committee concluded that seismicity at Tehri will 8.5 magnitude on the Richter scale as against magnitude 7 assumed by Roorkee experts and that in the event of dam failure many holy places like Rishikesh and Hardwar will be washed away and hence rejected the Tehri project.
Since Bhumbla committee report was not liked by the vested interests behind the project, it was rejected by the secretaries to the Union Government for Power, Water Resources, Mines and Environment who appointed another High Level committee of experts headed by Dhondial with representatives from Roorkee University, CWC, NGRI and Dr.V.K.Gaur, an eminent seismologist in April 1990 this committee accepted that seismicity of Tehri must be placed at 8.5 magnitude as recommended by Bhumbla committee in February 1990. It means that the design parameters recommended by all the previous expert committees are incorrect and the size and slopes of the dam designed on such incorrect data are bound to cause the collapse of the dam soon due to one reason or the other.
Although Dhondial committee revised seismicity of Tehri from 7 to 8.5 magnitude that involved 300 fold increase in the energy release of the earthquake, they failed to make a corresponding revision in the design of the dam. Except for Dr.V.K.Gaur, all the members of Dhondial committee belong to institutions which fed unscientific and incorrect design data for Tehri dam and perhaps it became a prestige issue for them to retain the previous size and slopes of the dam and for this purpose they discarded the Mc.Guire Equation used upto February 1990 and changed to Brune’s formulation for retaining by manipulations the PGA at 0.5g and effective PGA at 0.25g. It means the Dhondial committee wants people to believe that the impact of shooting against wall structure remains the same whether you use a police constable’s gun or a Bofors gun. Brune himself stated that Dhondial committee misused his formulation by using an under-estimated quality factor Q of 50 instead of 500 for Tehri site and consequently the PGA must be revised from 0.5g to over 1.0g. But the Dhondial committee refused to heed such scientific advice and hence Dr.V.K.Gaur, one of the committee members, submitted a note of dissent. The latest scientific work proves that Dhondial committee was wrong in choosing a low value for Q at Tehri.
Dhondial committee report containing the conflicting views of civil engineers and seismolgists regarding PGA and effective PGA values was considered by a committee of secretaries to the Government on 10-8-1990 and it was decided to refer the matter “to an independent seismological expert of international repute” for a final decision. Unfortunately the Department of Mines committed a grave blunder in referring this issue to Prof.Jai Krishna who was a civil Engineer with specialisation in structural, (earthquake engineering) and also perhaps a consultant to the project for a number of years. He was neither an independent expert nor a seismologist of international repute as he had a vested interest in the project. Unfortunately the Government placed undue reliance on his unscientific views.
Dr.Jai Krishna considered the Dhondial committee report and accepted the revised seismicity of Tehri as 8.5 magnitude. He estimated PGA at Tehri as 0.446g on the basis of Brune formulation and placed effective PGA at 0.25g. Based on the actual records compiled by Schnabel and Seed, Jai Krishna prepared a graph to place an upper bound on PGA for Earthquakes beyond 6.7 magnitude. Further he assumed that effective PGA will be about half of actually recorded PGA. These unscientific assumptions were made for manipulating the design parameters for Tehri dam. Infact the US experts used PGA values from 0.55g to 0.89g for design of about 15 dams in USA, Casitas Embankment dam of California, 335ft, high was designed to withstand an earthquake of magnitude 6.5 and PGA of 0.55g, Auburn dam of california, 233m high was designed to withstand an earthquake of magnitude 6.5 and PGA of 0.64g on the basis of two formulations of expert groups, one by Campbell and Bozorgina and the other by Abrahamson and Silva. Actual PGA records from Northridge, Tabas, Gazli, Kobe and Taiwan Earthquakes indicate PGA values of more than 0.8g and hence prove that the contention of Jai Krishna on the upperbound for PGA is very wrong. While the US experts discarded the concept of an upper bound PGA for ground motions irrespective of the magnitude of the earthquake above 6.7 Dr.Jai Krishna stuck to this discarded concept as it serves his vested interests. Thus Dhondial Expert committee report and Jai Krishna’s report on design parameters for Tehri dam are completely misleading and detrimental to national interests.
RUSSIAN EXPERTS HAVE PREDICTED COLLAPSE OF THE TEHRI DAM: Several Russian experts stated that Tehri dam as designed is bound to collapse for several reasons.
Mr.Fink, Soviet expert stated in November 1986 that Tehri dam has been designed to withstand an earthquake of intensity 8 on the MSK or MM scale and raised it to 9 intensity which is equivalent to about 7 magnitude on the Richter scale. But the Government of India blindly believed the value of 7 magnitude fixed by all the expert committees constituted before January 1990 but revised seismicity to magnitude 8.5 recommended by the Bhumbla committee in February 1990. It means the seismicity of Tehri has been increased to intensity 11 to 12 on MSK or MM scale and according to Soviet norms the sub-structure foundations will fail and consequently the dam will collapse.
Mr.Davidov stated in January 1990 that Tehri dam was designed to withstand an intensity of 9 on the MSK or MM scale and it means as already stated above the dam fails due to an earthquake magnitude of 8.5 as accepted by the government.(Times of India, dt.8-2-1990)
Mr.Michalov another Soviet expert at Tehri dam stated in October 1991 that Tehri dam has been designed to withstand intensity 9 on MSK or MM scale and that 10 points intensity would not occur at Tehri. It again implies that the dam has sated above will collapse due to an event of magnitude 8.5, equivalent to intensity 12 on MM scale at Tehri. (Hindustan Times, dt.31-10-1991)
The Soviet experts who prepared the report entitled Tehri dam project on the Bhagirathi river in 1989 under contract No:53032/67652, Appendix-9 stated under Table No.2.3 and Table No.2.4 that for the third version pertaining to PGA (horizontal) of 0.64g and PGA (Vertical) of 1.28g the dam will fail. Infact Fig.2.19 of the report clearly shows the sketch of the dam failures pattern for version No.3. Hence the Soviet experts also predicted the impending collapse of the dam since 1986.
It is shocking to read the results of the stability analysis for Tehri dam applying accelerogram of Gazli earthquake by the Hydro Project Institute, Moscow in 1992. Surprisingly the Soviet consultants certified “The Tehri dam is seismically stable under the loading of the Gazli earthquake accelerogram for a duration of 12 seconds and this report is evidently wrong, if we consider the earlier Soviet report of 1989 on the subject.”
Out of 5 members of the Group of Experts appointed to study seismic safety of Tehri in 1996 by the Government of India 4 experts virtually rejected the project while one expert who was Vice –Chancellor of Roorkee University which was given project consultancy supported the dam by violating the stipulation of the conditional Environmental clearance given by the Union Government and also the safety norms propounded by International Committee on Large Dams. The Group of Experts (Gaur committee of 1996)considered the safety aspects of the project. They felt that for determining seismic safety of the dam it should be ensured as per International Standards (ICOLD-57, Bulletin 46) that (a) the dam does not suffer significant damage, when subjected to OBE; and (b) damage to the dam is limited and no catastrophic failure occurs leading to uncontrolled release of water when subjected to MCE. The group further emphasized that the seismic risks of dam for earthquakes has two components (i) structural systems and components inclusive of the dam body and (ii) Socio-economic components
But unfortunately the group was allowed to make only a half hearted exercise on the seismic aspects of Tehri dam because it has made a casual study of the first component and the equally important socio-economic component was not studied. The Group made recommendation which is like the judgement pronounced in the Shakespearian drama “Merchant of Venice” where Shylock will be asked to take his pound of flesh from the body of the accused without a drop of blood. Hence the Expert Group cannot be considered to have made a comprehensive and unconditional recommendation in favour of continuing the Tehri dam because 4 out of the 5 experts have expressed a different opinion citing the Russian studies which categorically said that the Tehri dam will collapse for the earthquake impact with PGA equal to ax= 0.64g and ah=1.28g. The extract of the opinion of the 4 experts is as follows.
“Based on a review of the reports made available to the Group and further studies conducted by DEQ-UOR on the behaviour of the idealised two dimensional model of the dam to the ground acceleration corresponding MCE, the Group came to the conclusion that the present design of the dam is expected to be structurally safe to withstand the MCE during the economic performance life of the dam-reservoir system.
However, a number of crucial questions could not be settled, notably the slope stability on account of the difficulties reported in Annexure-13, and the response of the dam to MCE in the longitudinal direction. Keeping in view, therefore, of the sensitivity of non-linear behaviour to possible variations in the values of seismic parameters such as PGA, duration, frequency content and material properties, still larger displacements cannot be ruled out. Infact as per the Soviet Report (Tehri Dam Project on the Bhagirathi river, India, Contract No.53032/67652, 9,G.P.73-74) to which attention was drawn by one member of the Group, the idealised section of a 200m high dam fails for the earthquake impact with PGA equal to az =0.64g; ah=1.28g. Whereas there are differences in the sections analysed in the above report and the current design of the Tehri dam attention is drawn to the fact that for some fortuitous combination of inputs combined with particular reservoir-dam conditions the performance of the dam to hold water at a future date may get affected. It is therefore, further recommended that as a matter of abundant caution, the following work be carried out. (i) 3-D non-linear analysis of the dam to evaluate its performance against the MCE. (ii) A simulated dam break analysis to ensure that in the unlikely event of an uncontrolled release of water, the consequences are minimum.”
The U.S. Bureau of Reclamation in the publication on design standards for dams presented seismic design and analysis of Casitas Embankment dam on Coyoto Creek about 6.5 miles North West of Ventura, California. The dam is 335 ft. high with a crest length of 2000ft. and crest length of 200ft. and crest width of 40ft. The foundation has sands, clay and gravels overline bedrock.
Unfortunately when the Gaur group of experts committee report was sent to the Central Water Commission it referred this reports to the National Standing Committee on seismic design parameters to review the report with respect to: a.) the parameters proposed for seismic safety of the Tehri dam and b) the need or otherwise to carrying out a 3-dimensional non-linear analysis of the dam against MCE. Perhaps the NCSDP was composed of general experts in civil Engineering who could influence the views of other specialists in different fields of science and hence they come to the wrong conclusions on 24-11-1998. They concluded that firstly there is no need to get the 3-dimensional non-linear analysis for Tehri dam and secondly the dam burst scenario and the disaster management for the project even though this condition was stipulated by the Union Ministry of Environment and Forests in its conditional clearance. If there was any genuine expert in Civil Engineering he would have certainly argued that for dams in narrow canyons with length to height ratio being lessthan3, the response of the structures is 3-dimensional. Mejia and Seed made a comparative study of 2-dimensional and 3 dimensional dynamic analysis of the Oroville dam with length to height ratio of 7 and another hypothetical dam with length to height ratio of 2. Oroville dam was considered for earthquake parameters of magnitude 6.5 peak acceleration of 0.6g and frequency of 2.5 hertz while the second dam was considered for a magnitude of 5.7 peak acceleration 0.9g and frequency of 6.5 hertz. The effects of Canyon geometry on the dynamic response of the dam is stiffening of the system, causing higher natural frequencies of vibration for dam in narrow valleys. The study confirmed that the fundamental natural frequencies of the 3-dimensional dam model (L/H=2) were about 50% higher than those computed for the plane-strain analysis for the said earthquakes. For the Oroville dam (L/H=7). The 3-dimensional natural frequencies were 12% and 23% higher than those for the 2-dimensional model. Hence for dams with steeper canyons than the Oroville dam, it is necessary to perform 3-dimensional analysis to obtain satisfactory results for design purposes. Since Tehri dam has a steeper (L/H=2) canyons than the Oroville dam (L/H=7) 3 dimensional analysis must be made to obtain satisfactory results for design purposes. (Page 225 and 226 of Embankment dams by H.D. Sharma, Oxford and IBH, 1991). Since Dr.Nigam is reported to have opposed for 3-D Non-linear Analysis of Tehri dam and for the dambreak analysis and such views are against the standard international norms for dam safety his views must be rejected consequently the report of the group of experts must be considered as a rejection of the Tehri project.
Although the Union Ministry of Environment made it a condition for the Tehri Hydro Development Corporation to prepare a disaster management plan in consultation with the potential victims of the area it was not accordingly prepared. Hence the members of the NCSDP who refused to accept the recommendations of the Gaur group of Experts report cannot be treated as good experts as they have violated the principles of professional ethics and environmental regulations of the Union Government. NCSDP rejection of the report of Gaur committee is untenable.
GOVERNMENT SECRETARIES MISLEAD PRIME MINISTER AND THE NATION: It is much more unfortunate that most of the ecologically illiterate Secretaries to the Government who are not experts in seismology or Civil Engineering must have without raising any relevant scientific or technical questions blindly accepted the report of the so called expert committee “NCSDP” committee of the Central Water Commission. Having taken a wrong decision to accept NCSDP report, naturally the committee of senior secretaries to the Government must have misled the Prime Minister to take a blatantly wrong decision to continue work on the Tehri project which is most detrimental to public interests as already stated by the former Prime Minister Mrs.Indira Gandhi in 1979-80 itself.
Hence Tehri dam becomes a handy bomb for the terrorists to destroy North India and cause economic disaster for the whole nation. Thus Tehri dam should be scrapped or in order to save infructuous expenditure so far incurred, the dam must be treated as a run-off the river scheme to store minimum water so that even if the dam were to collapse it will not cause unbearable loss of life and properties in the downstream areas of the Ganga basin.


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