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Odisha has violated dam safety measures ? Part I
Odisha Water Resources Department has organised International Dam Safety Conference on 2019, February in Bhubaneswar On the other hand Water Resources Department has violated dam safety measures in Odisha. As a consensuses citizen of India, I did not get these answer, why?

Who will answer these questions, Engineer-in-Chief, Er. AK Banerjee or Secretary, Water Resources Department, Govt of Odisha, PK Jena?

How have you constructed so many large concrete dams in Odisha like Telingiri, Ret, Lower Suktel, Kanpur, Upper Indra etc in clear violations of technical specifications formulated by BIS?

By not constructing the dams with pre-cooled concrete, you have given scope for development of cracks in the body of the dams for which all dams will profusely leak in course of time?

With so much of technical violations how can you submit the report to the government that no dangers are foreseen for these dams?

Why you do not report to the CWC for suggesting remedial works which is essential for these dams?

How are you proposing to impound the reservoir before taking of the rehabilitation works?

Since DRIP is already working in Odisha will it not be proper to refer them for the rehabilitation works of all the concrete dams?

Dams, big or small, impounding reservoirs, are all very important and costly structures and these are constructed strictly in India as per the 'technical specifications' issued by Bureau of Indian Standards (BIS). Any dam break or dam safety hazard can be disastrous with loss of lives and property and financial loss for the State. No one has forgotten till now USA's dam devastation tragedy of the 70s and the recent dam disaster in Brazil. The loss of lives must be still fresh in everyone's mind. Dam safety organizations have come up in every state in India to monitor the safety aspects of all dams during construction and also later during maintenance periods. Central Water Commission (CWC) is the nodal agency in India for all Dam Safety monitoring works. 

Several large concrete spillway dams in Odisha, now under construction in advance stages, need rehabilitation before the impounding of the reservoirs since the construction is sub-standard and defective because of serious violations of various important stipulations of the Bureau of Indian Standards (BIS) vide their publications, IS:457 and IS:14591.

Notable violations are the absence of temperature control in concrete, use of very small size of aggregates requiring excess use of cement and contributing to higher heat of hydration, concrete pouring in very high atmospheric temperature even at 45 degree C, adopting smaller lifts and thereby increasing the numbers of horizontal construction joints in mass concrete works. It is feared that main body wall concrete might have cracked in all directions with wide openings during the process of cooling from a much higher temperature including the rise due to heat of hydration to a much lower ambient value, yet to be reached and will happen after formation of reservoir.

Further, the construction of body-wall of the dams are not monolithic with the central core portion being raised first by several lifts followed by face concreting after some lapse of time, thereby creating cold joints between the core and face concreting. Because of all these construction deficiencies, there may be heavy seepages through the body-walls and the durability of concrete must have been severely impaired due to such elaborate cracking. For all these reasons, the experts' comments that rehabilitation works should be ordered by CWC's team of experts before the impounding of the reservoirs.

Odisha's past experience in dam construction

Odisha state is not new in the field of construction of various types of dams. The famous Hirakud dam with a very large reservoir was constructed by the government of India in between 1947 and 1956. Since then, Odisha's department of water resources (DOWR) has constructed several major dams and reservoirs, namely, Salandi, Balimela, Rengali, Upper Kolab and Upper Indravati projects by end of twentieth century. Besides the above, Odisha has also constructed more than thirty-five spillways during the same period for the medium irrigation reservoir projects.

The then engineers never dared to construct any concrete spillway dams for the simple reason that a lot of mechanization would be needed to manufacture pre-cooled concrete and they avoided that option because of high cost and sophisticated mechanized works including cooling and ice plants.

However, in only one dam, namely Upper Kolab in Koraput, the engineers chose the concrete dam option for the spillway portion for earlier completion of the dam and reservoir during the eighties. All the non-overflow blocks were planned as masonry blocks and all ten spillway blocks were concrete blocks, constructed with pre-cooled concrete. All works were fully mechanized with pouring of concrete through cable ways.

Four blocks adjoining the spillway on either side were started with masonry construction, but completed with pre-cooled concrete pouring through cableways. In all conventional major and medium spillway projects, the core section of the main body-wall was random rubble stone masonry, but the upstream(u/s) and downstream(d/s) faces, bucket, piers and deck slab were done with conventional concrete manufactured in small batching plants. The thickness of faces varied between 1.5 to 2 metres. Pouring of pre-cooled concrete was not required in such works as these were not mass concrete works.

Changing over to concrete spillways

Reasons are not forthcoming now from the present government officials as to why all the new generation major spillway dams in the twenty-first century were converted into concrete construction without following the norms and who took such bold decisions. The authorities never thought for a moment to find out the reasons why concrete dams were not constructed earlier except Upper Kolab over a period of fifty years since the planned developments started. One reason could be that the quality of masonry construction was deteriorating fast because of dearth of good quality masons and several completed masonry dams were leaking profusely in the country, details of which were made known through a publication by the Central Board of Irrigation and Power (CBI&P). This problem could have been solved by providing a sandwiched column of rich concrete as done in Upper Indravati and Muran dams of Upper Indravati project. The other reason could be the mechanization spree arriving in the country after a policy shift by the Union government to opt for market economy and more liberalisation.

Most of the foreign companies started manufacturing construction machineries inside India for the benefit of contracting agencies and the process of mechanization became the order of the day replacing the conventional manual process not only in excavation works but also in concreting and other works. This could be the main reason for the changeover from masonry dam to concrete dam as the mechanization process became faster and cheaper compared with manual work.

If the engineers chose to construct concrete dams for whatever reasons, it was definitely a welcome decision, but they should have also satisfied the various technical needs of a 'concrete dam' project as was done in Upper Kolab project. All technical details of pre-cooled concrete were available with the engineers, but they made no use of such literature and know-how. Even otherwise, the designers and engineers had easy access to volumes of literature and data on concrete dams from the 'internet'.

The technical know-how for the concrete dams was also available from various codes issued by the BIS and these were well known to design engineers. The engineers' job was to prepare a comprehensive 'contract document' to include all technical specifications related to the pre-cooled concrete construction and placement temperature, bill of quantities (BOQ) of various items of works to be executed in pre-cooled concrete work, contract conditions, and the various specification drawings etc for enabling the invitation of tender.

Unfortunately, the contract documents prepared by the engineers were deficient in so many ways since the engineers never contemplated temperature control. The spillway drawings indicated through a note written inconspicuously that IS:457 and IS:14591 are to be followed for mass concrete works, but such instructions were ignored. It is not known if the tender conditions were vetted by the design engineers. The senior engineers who approved the tender documents should have insisted for following IS:457 & IS:14591, but it was not done. In consequence, pre-cooled concrete was never even thought of by DOWR engineers.

(To be concluded?)

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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