Wednesday, January 11, 2012


Prof.T.Shivaji Rao, 
Center for Environmental Studies, 
GITAM University, Visakhapatnam.[                                           damBREAK by I.I.T.    experts] 
For assessing the safety of Mullaperiyar dam 3 goals of public safety must be satisfied as per the modern state-of-art used for design of the dams. 
[1] The first goal is based on the selection of site with  limited population and properties likely to be affected in case of an accident, geological foundations , seismic potential and seismicity of the area which does not pose a  seismic threat to safety of the Dam
[2] The second goal pertains to structural safety of the dam based on maximum credible earthquake including,Dam’s structural Design safety , hydrological safety and spillway design flood. 
[3] The third safety goal for the dam pertains to the environmental safety that comprises the risk analysis, dam break analysis, emergency response, disaster management including the feasibility studies of emergency evacuation plans and cost benefit analysis. 
The detailed Emergency evacuation procedures and dam break analysis including disaster management plans have not been prepared and hence the authorities are not in a position to assess the advantages and disadvantages of this dam and the alternatives as remedial measures. In the case of the 116 year old Mullaperiyar dam all these safety goals were violated and hence the Government  is paving the way for enabling a man-made disaster occur at Mullaperiyar. 
The controversy about the Mullaperiyar dam is based upon the contention of the Kerala state that the dam is in a deteriorating state and its imminent collapse causes avoidable killing of 35 lakhs of Keralites due to a wall of flood.  In order to avert this disaster waiting in the wings Kerala insists on construction of a new dam to provide security of life for the Keralites while assuring uninterrupted irrigation water to Tamilnadu as per the agreement between the states. 
But Tamilnadu is suspecting the intentions of Kerala in planning for a new dam which may be placed under the control of Kerala that may soon curtail the existing Periyar water diversion into Tamilnadu.  Thus Tamilnadu is rejecting the demand of Kerala for a new dam on the pretext that the aged Mullaperiyar dam is almost as strong as a new dam due to the remedial strengthening measures implemented by it. 
 But if the existing dam were to burst for several reasons even Tamilnadu cannot get Periyar water and consequently lakhs of Tamilnadu agriculture fields will become barren lands that may lead to avoidable suicides of thousands of farmers and farm workers.  Tamilnadu is ignoring the fact that their costly strengthening measures produces only a composite dam and not an integrated and strong dam.  The dam cannot withstand the stresses resulting from peak ground accelerations due to a 6.5 magnitude earthquake at a shallow focal depth in close proximity of the dam.  Even a strong Koyna dam cracked in some parts in 1969 due to an earthquake of 6.5 magnitude and caused serious damage
 Violation of  Hydrological Safety  in the design of Mullaperiyar dam by Government Experts:
Moreover the dam has also been under-designed for hydrological safety because the historical maximum flood is 86 lakh cusecs and the design flood for spillway discharge is 1.22 lakh cubic ft. per second (cusecs) .  In United States safety of dam is reviewed  every 5 years to decommission hazardous dams and to strengthen the useful one by implementing remedial measures for strengthening them.    In case of Mullaperiyar dam the extreme flood magnitude in terms of safety works out to 2.44 lakh cusecs based on the mathematical formulations and the envelope curves connecting extreme floods with catchment areas published by the International Commission on Large Dams (ICOLD) under the guidance of  experts like Prof.L.Berga, Chairman, ICOLD and Lempererie, Chairman of French National Committee on Large Dams.
According to the old standards,the irrigation engineers used to consider the historical flood and compute the design flood as one and half the historical flood.The actual flood in 1943 was8,453 cumecs and hence the PMF should have been taken as 12,680 cumecs..Surprisingly,the Chairman of CWC recommended PMF of 7,249 cumecs which is an under-design and this was again reduced to 6,003 cumecs and thus the hydraulic safety of the dam was deliberately violated  by the Central Water Commission[CWC]
Moreover the impact of climate change is causing both the intensity and duration of cyclones that magnify the floods.  Particularly in thickly forested river basins.  For instance the October  2009 are extreme flood of 26 lakh cusecs at Srisailam dam on Krishna river constituted 2.7 times the historical flood and twice the maximum spillway design flood.  Since Mullaperiyar dam is thus under-designed both from seismological and hydrological safety aspects this dam is inevitably bound to collapse irrespective of the pronouncements of the engineering experts who could not stop the collapse of more than 40 dam bursts in India including the masonry dams of Tigra in Madhya Pradesh, Kundali in Maharashtra, Chickhole in Karnataka and Kadhakwasla in Maharahstra.
With regard to Violation of Seismic safety,Roy Mathew reported in The Hindu ni 2007,as follows::[]
Violation of seismic safety standards in the design of Mullaperiyar dam by Government Experts :
while assessing the safety of the  [Mullaperiyar]dam, the expert committee of the CWC had taken the design horizontal seismic co-efficient as 0.12 g instead of 0.18 g. The value 0.18 g is the least recommended value for zone III as per IS 1893-1984 where Kerala is situated. In this context it may be noted that the standing committee set up by the Union Government for advising the seismic coefficient for the river valley projects recommended a value of 0.24 g.”
With regard to structural weakness of the Mullaperiyar dam its strength is estimated at 1/3rd the strength of the roofing concrete used for the residential buildings.  The concrete used for Iddukki dam is about 6 times stronger than the lime Surkhi concrete used for Mullaperiyar dam.  The area of the dam site is close to a number of major faults which are active and other with the potential to become active soon.  Earthquakes occurred in this region with magnitude 5 on 12-12-2000 and 4.8 magnitude on 7-1-2001 .  Roorkee experts have identified 22 major faults in a radius of 300km around the dam site and the Tekkadi-Kodaivannualur fault is identified as the fault that will create a most devastating impact on Mullaperiyar dam site which may experience an earthquake of 6.5 magnitude on Richter within 16km from the dam site and a peak ground acceleration (PGA) of 0.21g may be experienced from the dam site but it may be recollected that such an earthquake of 6.5magnitude produced PGA of 0.64 at Koyna dam in 1967.  According to the experts the inherent weaknesses developed by the aged dam causes its collapse even if an earthquake of about 5.0 magnitude on the Ricther scale occurs at an about 15km distance from the dam site.

By violating the Hydrological and Seismic safety standards,the CWC made Mullaperiyar Dam highy  under-designed and hence it is bound to collapse .
 According to the Environmental Protection Act the dam safety studies including disaster scenarios, emergency response systems, emergency evacuation schemes and cost-benefit analysis reports have not been prepared consequently the people and the Governmental decision making bodies  have been disabled to come to a scientific decision on the safety of the Mullaperiyar dam and that it is why the Tamilnadu Government fails to read the writing on the wall and thereby indirectly promoting a man-made catastrophe like the Bhopal disaster inspite of the forewarnings by several experts.  If the Mullaperiyar dam collapses sooner than later it will cause not only loss of lifes of lakhs of people but also causes an economic disaster paving the way for economic bankruptcy of the states and the nation.  Since Mullaperiyar dam is a prescription for disaster it must be prevented by the whole national by exerting pressure on the Prime Minister to resolve the problem by building a new dam even without dismantling the existing dam by forming a corporation on the lines of  the one used for building Tehri and Sardar Sarovar Project
There is a danger to the life of people of kerala due to an impending Dam Burst because the Supreme Court orders may or may not be implemented by the states under the guise of seeking clarifications ferom the Courts and in the meantime precious time will be lost and the Dasm may bursgt and kill 35 lakhs of,kerala state must immediately call for an international tender to find out if foreign experts can furnish alternate  small scale Dams that can absorb the flash floods caused by Mullaperiyar Dam Burst,after verifying the flood a bsorbing capacity of Idukki Dam and other Dams

1 comment:

About Me

My photo
Born in 1932 at Mudinepalli, near Gudivada, Krishna Dist. Andhra Pradesh, received Bachelors degree in Civil Engg., from Viswesaraiah Engineering College, Banglore (1956) and Masters Degree in Environmental Engineering from Rice university, Houston, Texas, (USA) (1962), Ph.D (Hony). Former Head of the Department of Civil Engineering and principal of College of Engineering, Andhra university.Formerly Hony.Professor in Andhra University,Manonmanian Sundarnar University,JNT University. Fellow of the Institution of Engineers,India Recipient of the University Grants Commissions National Award "Swami Pranavananda Award on Ecology and Environmental Sciences" for the year 1991. Recipient of Sivananda Eminent Citizen Award for 2002 by Sanathana Dharma Charitable Trust, Andhra Pradesh state. Presently Working as Director, centre for Environmental Studies, GITAM University,