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Odisha has violated dam safety measures - Part II
Review of works of the concrete spillways: At the time of reporting it reveals that 'under construction' dams which were in progress during 2017, Er. Sarat Kumar Mohanty as an 'Independent Director' of the Government owned 'Odisha Construction Company', OCC in short, who were executing all the concrete spillway works for the government. The names and other details of five spillway dams reviewed by him are Lower Indra in Khariar district on Indra river, a tributary of 'Tel' in Mahanadi basin, Kanupur spillway in Keonjhar district across river 'Baitarani, Telengiri spillway across Telengiri river, a tributary of Indravati in Godavari basin in Koraput district, Ret spillway on 'Ret' river, a tributary of 'Tel' in the Mahanadi basin in Kalahandi district and Lower Suktel spillway on Suktel river, a tributary of river 'Tel' in Mahanadi basin in Bolangir district. All the spillways are fairly large in volume involving three to four lakh cum of concrete of different grades. He was flabber

The most serious violation is that no temperature control was adopted in any of the dams with huge mass concrete pouring and concrete was placed on the dam at the atmospheric temperature.

Er. Sarat Kumar Mohanty, retired Eng-in-Chief wrote to the Managing Director of OCC that the matter must be discussed soon in the Board of Directors of OCC Ltd, as OCC is executing sub-standard works, but when this was not done even after five months, Er. Mohanty tendered his resignation complaining to the Chairman, OCC that BIS specifications are not followed and sub-standard works are rampant in all spillway concrete dams. His resignation was accepted without a word from the Chairman about his complaints.

Through RTI, collected lots of information from the field staff of most projects through RTI applications and was confirmed beyond doubts about the sorry state of affairs and about violation of BIS norms. Whereas the contract document should have included the pre-cooled concrete in the bill of quantities & specifications, clearly indicating the placement temperature and procedure, height of lift etc, there were none of those stipulations. The only exception is the 'Lower Suktel' project where the placement temperature was mentioned as 120 Centigrade in normal times and 70 in winter. The field engineers ignored these stipulations.

The most notable design deficiency observed was the use of 40mm maximum size of aggregates for the mass concrete work of M15 grade which was too small and it was no surprise that the cement consumption was as high as 275 kg per cum and this must have contributed substantially to much higher heat of hydration. Another violation was the lift height in most dams, which was limited to less than half metre. This has substantially increased the numbers of horizontal joints, which are potential sources of seepage. It is not known how well were the surface preparation of joints before receiving the next pour of concrete and these are usually grey areas. The construction methodology adopted was also defective to raise the core of the dam first by several lifts with the help of shutters at both faces above the level of u/s and d/s face concrete.

When face concreting was done at a later date, cold smooth joints were created which are undesirable and these joints also are the potential path of seepage through the body of the dam. It is most essential that pouring of one lift of concrete involving different strengths and zones of concrete should have been laid in one operation starting from d/s shutter and closing only at the u/s shutter in one spell of work. For all major spillway dams involving huge quantities, the designers should have stipulated some instrumentation, but nothing was provided. Installation of thermometers could have measured the actual heat rise due to heat of hydration, but there were none.

The pity is that the spillway sites are frequently inspected by several top engineers, but none of them could observe the deficiencies in the constructions. Senior engineers of 'Design wing' have made frequent visits to work sites, but none of them objected to the violations of IS: 457 and IS: 14591 which was stipulated by them in the construction drawings. One conclusion can be drawn from the author's reviews is that there has been a complete system failure, but it could not be established if it was out of ignorance and knowledge paralysis or because of some administrative decisions to opt for Concrete dams.

The scribe was shocked to find that thousands of crores of rupees are being spent for irrigation projects, but sub-standard works are being executed by the engineers for various reasons. When the authorities refused to make a review, the then engineer-in-chief, Er. Sarat Kumar Mohanty, wrote to the top most hierarchy of the government, ie, the Chief Minister for taking note of the dam safety violations and urge the DOWR to immediately refer the matter to the Central Water Commission (CWC), the country's nodal body for all water related subjects including dams and reservoirs, for advice in regard to remedial measures.

This was referred to the DOWR and then to the Engineer-in-Chief (EIC) for a report. After inordinate delays and a lapse of nearly six months in search of a reply, a joint report of the Engineer-in-Chief and other Chief Engineers (CE) was sent to the DOWR mentioning therein that all is well and no danger to the ongoing spillways is foreseen. They have also opined to go ahead with the impounding of the reservoirs as per their construction schedule. According to the report, if some problems will be encountered in future after impounding of reservoirs, they would be approaching CWC for suggesting remedial measures. The author was accordingly informed through a communication enclosing the joint report of EIC and four CEs. There was no comment on the report from DOWR either in regard to violations of BIS codes or about the defective design and construction works. The special secretary of DOWR, who happens to be an engineer in the rank of EIC, made no comments on the joint report.

Analyzing the joint report

The experts have studied the joint report minutely and felt that the main issues are surreptitiously avoided and not replied. They stated in their report that all design works are being done based on various codes and guidelines, but actually it is a lie. The report makes mention about BIS codes, IS: 457 and IS: 11155, but it has deliberately omitted the most vital code, IS: 14591, which deals with the temperature control measures.

The report is silent on why the designers chose the maximum size of aggregates for mass concrete as 40mm when IS: 457 stipulated 100mm to 150mm size vide Para 4.1. It is not difficult to understand why the reference to IS:14591 was deliberately omitted in the joint report sinceIS:14591 provides vide the 'Foreword', paras 5.4.1, 5.4.2 about the necessity of pre-cooled concrete, cement content of the mix and the height of lift etc, which were all violated. The report makes mention of several old completed spillways taking credit that all these are working well, but they should have better known that all those spillways were not concrete spillways, but composite dams with masonry core and concrete facing. After making a thorough study, the author wrote to Odisha government to reject the sub-standard report as it is deceptive in view of suppressing crucial facts. Even though the group of engineers gave a safety clearance that no dangers to the ongoing dams are foreseen in writing, they never explained why they have violated the various stipulations of the BIS codes during construction.

The author is more than convinced that all these spillways must be declared as unsafe from the point of view of dam safety and the experts should immediately start probing to know the internal cracking pattern so that immediate rehabilitation measures can be taken up. If the same are taken up before the impounding of the reservoirs it would be ideal, otherwise all proposed rectification works at the u/s face must be completed before impounding so that underwater works are avoided.  If Odisha's DOWR still feels that all their dams are safe and will not have any problems, it is for the Apex body CWC to take a view to arrive at a conclusion. Out of the five numbers spillway dams reviewed, the rate of construction was slow to moderate in two dams, namely Lower Indra and Kanupur taking more than ten years. The cooling process may have been completed substantially in these dams. The main problems in these two dams will be the large nos of construction joints which are the potential seepage paths. The rate of construction was moderate to high in the rest three dams and mass concreting works are nearing completion in these dams. The process of cooling in these dams are likely to continue for at least five to seven more years after which it will be reduced. The competent authorities should take a decision regarding impounding of reservoirs.

This is an exceptional situation when a responsible citizen of the country is levelling serious charges against the government of Odisha state that they are spending thousands of crores of rupees in constructing several concrete dam spillways to form reservoirs for irrigation projects, but all works executed by them are sub-standard since they have violated several important stipulations of relevant BIS codes. He has alleged that several cracks of various openings must have developed inside the body of the concrete dams and there will be profuse leakages. He suggests taking up remedial measures through CWC experts before impounding of reservoirs, DOWR engineers of Odisha government, however, have opined that all is well and no dangers to the dams are foreseen. The present 'International Dam safety conference-2019' will be the best platform to discuss and interact over all related issues.

With references: BIS relevant codes, IS: 457, IS: 14591. Joint report of EIC and four CEs on the dam safety issues sent to the author.Proceedings of the Meetings of Board of Directors of OCC Ltd. Technical details of some Spillway dams collected through RTI Act from field officers.

Editorial NOTE: This article is categorized under Opinion Section. The views expressed in this article are solely those of the author and do not necessarily represent the views of merinews.com. In case you have a opposing view, please click here to share the same in the comments section.
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