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 heat and sensational press, albeit any analysis in the last couple of months. This is one of those political issues where it is impossible to finalise a win-win situation. In the case of both parties Tamil Nadu and Kerala a loss for either side would be political suicide. To the benefit of the readers, might I inform that 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 and may be slightly based on conjecture. 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, which has been driven by dramatisation and sensationalism.
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, which is used to irrigate the drought prone Sivaganga, Theni, Madurai and Ramanthapuram districts, benefitting millions of farmers. The Mullaperiyar river which once naturally flowed from Tamil Nadu, into Kerala and then finally into the Arabian Sea has been dammed by the Mullaperiyar Dam and redirected back into Tamil Nadu. This water then flows to Vaigiai dam, 100 KMS away via a tunnel. That feature is itself an engineering marvel and is ripe for comment in another article.
Downstream from the Mullaperiyar dam, in Idukki district, is another Dam built by the Kerala government in the 1970’s. This dam was built primarily for hydel power generation. The Idukki dam is about 700m above mean sea level and is one of the highest (167.68m) 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 and a bit more than what Mullaperiyar can. The Tamil Nadu Government maintains the water level at only 136m, in spite of a Supreme Court order allowing it to maintain the water level to 142m. Note, that the Full Reservoir Level of Mullaperiyar is 152m. So, effectively the capacity of Mullaperiyar is much less the 443 M cu.m. I don’t know the exact figures by I am assuming the reduced capacity to be 400 cu.m, which would mean that Idukki could hold 5 times the water that Mullaperiyar can.
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 on 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. I would like to play this analysis to cite a few scenarios and actually see what might be the effect of those scenarios.
The first scenario: There is an earthquake in the region big enough to affect Mullaperiyar Dam and it completely fails. However, Idukki is able to handle the stress and is not affected. Remember Idukki was built only 40 years ago, with technology much better than in 1880’s. Now also consider that in the event of Mullaperiyar carrying the full 400 cu.m, Idukki should be able to easily carry that capacity. An IIT Rourkee report said that if a dam break occurs when the water level in Mullaperiyar is at 136 feet, the water level in Idukki reservoir, which is 36 kilometres away, would rise by 20.85 meters.
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 (Scenario 2) 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. This in turn affects the Idukki downstream towns and villages. Now remember, Idukki can take close to 5 times the capacity of Mullaperiyar. Even assuming that Idukki dam is full, it is possible to open the sluice gates of Idukki as it takes just over 2 hours for the water from Mullaperiyar to reach Idukki. By the way in its history of 40 years Idukki dam has never held more than 50% its capcacity. So, I do not see this scenario happening. So, if 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 a major earthquake causes both Idukki and Mullaperiyar to fail. If such is the case, let us pray that 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, and very rightly so. 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. They have promised to ensure that Tamil Nadu with get the same entitlement of water as with Mullaperiyar.
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. Even before that getting environment clearance for a project of this scale will be nothing short of impossible. Tamil Nadu has reason to be worried, because in spite of a Supreme Court ruling to provide a quantum of water regularly 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.
The Central Water Commission had advised that the dam can be strengthened using various measures in three phases — emergency, medium-term and long-term. Tamil Nadu has completed the short term and medium term phases and is unable to complete the long term measure due to Kerala’s stubbornness. Some of the excuses have been manufactured and will sound quite pleasing to the gullible.
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.
So, in my view the Mullaperiyar Dam is structurally safe and with proper governance processes can be put in place to ensure the least amount of people are effected in the event of a catastrophe.
