Since my last blog, there have been a few issues that I wanted to write about namely the controversy around the Australian theatre play Ganesh Vs Third Reich, the MMCRA – the mother of all defence contracts, then Australia’s Uranium export policy. There was only one reason why I did not write on any of those topics – laziness. The Mullaperiyar dam issue between Kerala and Tamil Nadu is decades old and has generated a lot of political hear and sensational press in the last couple of months. This is an issue where it is impossible to finalise a win-win situation and a loss for either side would be political suicide. I am from Tamil Nadu which is my home state and it will be fair to say that I will be biased. But, I promise to be logical and factual and present an analysis which will be primarily based on artefacts available on the internet. I will be providing no references and I welcome you all to challenge the logic and data presented. The main intent of this post is to try and squash some of the myths generated in the media. One of the reasons for this post is the mediocrity of analysis presented by the media.
The Mullaperiyar dam is a gravity lime mortar dam that was built in the late 19th century across the Mullaperiyar River. The dam site is 881m above mean sea level and sits firmly on Kerala land and is controlled by Tamil Nadu. Tamil Nadu pays a nominal fee for the land covered by the water body & the dam site, the personnel on the dam and a few other sundries. The contract between the then parties, the British Government and the Travancore state is obviously over a century old and after independence the executors of the contract are Tamil Nadu (for the British Govt) and Kerala (for the Travancore state)
Undoubtedly Tamil Nadu is the primary beneficiary of the dam is Tamil Nadu, which is used to irrigate the drought prone Sivaganga, Theni, Madurai and Ramanthapuram districts, benefitting millions of farmers on those areas. The Mullaperiyar river which once naturally flowed from Tamil Nadu, into Kerala and then finally into the Arabian Sea has been dammed and redirected back into Tamil Nadu and flows to Vaigiai dam, 100 KMS away via a tunnel. That feature is itself an engineering marvel.
Downstream from the Mullaperiyar dam in Idukki district, is another Dam built by the Kerala government in the 1970’s primarily for hydel power generation. The Idukki dam is about 700m above mean sea level and is one of the highest in Asia. Any overflow from Mullaperiyar flows into the Idukki Dam. The capacity of the Idukki dam is 2,000 Million Cubic Metres and that of Mullaperiyar is 443 Million Cubic Metres. So, in theory Idukki dam can hold 4 times the water that Mullaperiyar can and more. The Kerala Government, via a Supreme Court order, citing safety reasons have managed to set the maximum water level at 136m though the full reservoir level is 156m. Tamil Nadu has wanted this level to be increased to 142m, without much luck. So, effectively the capacity of Mullaperiyar is much less the 443 M cu.m.
Based on a Google maps analysis, between Mullaperiyar and Idukki along the flow of the periyar river there are 4 towns Vandiperiyar, (836m, 70,000 people), Devikulam (1800m, 350), Upputhura (915m, 21,000) and Alady (no information available). Notice that Devikulam and Upputhura will not be affected due to their mean sea levels being higher than Mullaperiyar Dam.
The biggest opposition from the Kerala Government is around the dam safety. The century old dam is in a quake prone zone, has far outlived its time, the dam is leaky and will not be able to handle the pressure and stress of large tremors thus endangering the lives of the people downstream.
If there is a tremor (I would think atleast 6 of the Ritcher Scale) and if that causes the Mullaperiyar Dam to completely fail, the water will flow down to Idukki dam. It is quite possible that the people in some of the towns mentioned above will directly be in the path of fury (less than 100,000). So, I completely accept these people will be in harm’s way. Idukki dam is only about 50 Kms away and it is most likely that any tremor affecting Mullaperiyar is likely to affect Idukki as well. This is the first scenario where Mullaperiyar fails and Idukki dam is unaffected. This scenario is plausible only if you assume Idukki is able to handle the stress of the tremor. Being built only 40 years ago, with technology much better than in 1880’s, I would like to think Idukki will be able to handle that.
What intrigues me is that most of the media commentary quotes that 3.5 million people in the districts of Idukki, Eranakulam, Kottayam, Alapuzha and Thrissur will be endangered. Now, this scenario is under the assumption that there is a chain effect, where Mullaperiyar fails, the water flows into Idukki and Idukki also fails unable to take the pressure and this in turn affects the Idukki downstream towns and villages. Now remember, Idukki can take more than 4 times the capacity of Mullaperiyar, and due to the reduced maximum reservoir level imposed by the Supreme Court, I would probably estimate 5 to 6 times. So, I do not see this scenario happening. In the event of a tremor, mechanisms can be put in place to release water from Idukki so that it has the capacity to take the overflow from Mullaperiyar. So, Idukki Dam is safe then the 3.5 million people are also safe.
One could argue that it is not necessarily the pressure applied by the large mass of passive water extending over hundreds of square kilometeres in Iduki dam, but also the sheer force of the water gushing from Mullaperiyar that will hit the dam. This is unfounded and not based on logic. The Cheruthony Dam, the Kulamavu Dam and the Idukki Dam which form the Idukki reservoir are at extreme ends of the reservoir from the view point of where water enters the Idukki reservoir. Look at the map below and you will understand what I am talking about.
There is a third scenario where Idukki dam and Mullaperiyar dam fail because of a major earthquake. If such is the case, let us pray God be with these people. Even then I will question if at all 3.5 million will be affected.
The Kerala Government obviously has the safety of its people as the number one priority. Atleast that is what is what they have been projecting. But, there must be some underlying reasons why they are motivated to bring the Mullaperiyar dam. They are persistent in their quest to bring the Mullaperiyar down. They have even offered to use its own funds to build a dam a few kilometres downstream from Mullaperiyar and provide Tamil Nadu with the same amount of water they are entitled to. On the face of it this looks good, but with this option Tamil Nadu will lose control of the dam and the livelihood of the farmers in the drought prone districts of Tamil Nadu will be at the whims and fancies of the Kerala Government, which would control the new dam. Tamil Nadu has reason to be worried, because in spite of a Supreme Court ruling to provide a quantum of water to Tamil Nadu from the Cauvery, Karnataka has time and again failed to maintain the order. Why will Kerala not follow the same path?
I agree with the argument that the Mullaperiyar Dam might not be structurally sound. But, I cannot find any basis to the propaganda that the dam has outlived its 50 years of envisaged life. Who builds a dam that lasts for 50 years? The Grand Anaicut across the river Cauvery, in Trichy was built in the 2nd Century and has still stood the test of time. While this is not an apple for apple comparison, the point is that with proper maintenance and with the use of modern technology dams can be maintained well. In the last 10 odd years the Tamil Nadu government has completed large scale maintenance work based on advice from technical experts. This includes strengthening the base of the dam and inserting vertical steel columns in the dam and many other things.
I have run out of time and will update when I get a chance. As suggested before I am no expert. Any discrepancy in data or logic please comment and I will consider your suggestions.
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