Safety and stability of Sethusamudram Project
Prof.G Victor Rajamanickam is one of the India's eminent coastal geo-morphologists and mineralogists.
Interview with Prof G Victor Rajamanickam
Prof.G Victor Rajamanickam is one of the India's eminent coastal geo-morphologists and mineralogists. And he is an authority in the studies of Tamil Nadu's coastal geomorphology. He has authored innumerable research papers and made substantial contribution in the study of coastal mineral deposits and sedimentation dynamics.
During 1990 and 2000, Prof Rajamanickam had organized two international seminars on changes in sea level and their effects on the coast. Top coastal mineralogists in India including Dr V J Loveson, Prof N Chandrasekar, Dr N Angusamy and Dr Anbarasu have been his students.
Prof Rajamanickam, till recently, was heading the School of Earth Sciences at the Tamil University, Thanjavur. He currently heads the Department of Disaster Management at the SASTRA Deemed University, Thanjavur.
Prof Rajamanickam has evinced keen interest in the Sethusamudram Shipping Channel since the early eighties. Having analysed the high sedimentation in the Palk Bay in the late eighties, he wrote extensively on the need to dig a channel in order to save Palk Bay from becoming a lagoon. More recently, in October 2004, he was invited to deliver a special lecture, Sethusamudram - the lifeline of Tamil Nadu, at a national seminar on Ecological Balance and Sethusamudram Canal, organized by the Department of Oceanography and Coastal Area Studies of Alagappa University.
As for the ongoing SSC project, it is pertinent to note here that the entire section on the Geomorphology of Palk Bay and Gulf of Mannar in the Environmental Impact Assessment (EIA) Report prepared by the Nagpur-based National Environment Engineering Research Institute (NEERI) has been based on the original research findings and writings of Prof Rajamanickam and his student, Dr V.J.Loveson.
Following is the transcript of the taped interview given by Prof Rajamickam to the editor of the web portal www.sethusamudram.in
at Thanjavur on August 10, 2005.
This interview assumes its immense importance on two counts: firstly, in the context of the very first meeting of the High Level Environmental Monitoring Committee for the ongoing Channel Project, held at Chennai on August 9, 2005; secondly, in the context of the stir proposed by fishermen to blockade the project's dredging ship on August 12, 2005, at Palk Strait, to highlight their point that this dredging activity would endanger their entire livelihood.
Question: Professor, can you please tell us briefly about the significant and unique features of the dynamics of the Tamil Nadu coast?
Prof Rajamanickam: Regarding the Tamil Nadu Coast general status, the peculiar transformation of sediment transportation toward landward migration (which is also the phenomenon faced by the peninsular India as a whole) is an important phenomenon to be observed by every one. So, as long as the landward migration is there, there is no need to be anxious about the issues of erosion or deposition in this coast.
The erosion and deposition noted in this coast are due to local geo-morphology and tectonics. Cliff and river mouth convergence are also existent. Convergence creates certain amount of erosion.
However, we have to underline here that the erosion that this coast is facing today is mainly due to the anthropogenic activity of the Madras harbour and the Tuticorin harbour extensions. Tuticorin harbour extension has transformed the coastal stretch between it and Kanyakumari from a coast of sediment deposition into a coast of erosion.
Besides this, we should also note that there is some amount of effect on these coastal processes by the Achankovil Shear Zone, near which the Kudankulam Nuclear Power Plant is fast coming up. This shear zone is always expected to cause upward unevenness, tectonic pressure, which might in turn cause any amount of coastal sinking or uplift.
The recent recurrent entry of Sea, in my opinion, is due to a tectonic lowering or tectonic sinking, which must have acted in line with Andaman fault.
Question: When the Tsunami struck the Indian coast on December 26, your team was already involved in Placer Deposit Studies in the Cuddalore-Vedaranyam coast for one and a half years. Immediately following the Tsunami, your team led by Dr Loveson, one of your old students, identified that the Tsunami deposits were very rich in titanium. Can you please describe this finding in detail?
Prof Rajamanickam: Yes. The coast between Nagapattinam to Nagore, Nagore to Poompuhar, Colachal and Madras were the places where the strong impact from the Tsunami was noticed. These were also the places where a high order of ilmenites was found soon after the Tsunami.
For example in the Nagore coast, the pre-Tsunami heavy mineral content of 14 per cent jumped to 70 per cent of ilmenites after the Tsunami. Such is the spectacular difference between the pre and post-Tsunami estimates. Whatever Zircon, Garnets, Amphebole, Pyroxenes were washed away by the Tsunami from these beaches were replaced and filled with high, denser minerals like ilmenites and magnatites - ilmenites the maximum.
One may take this as a blessing in disguise. Now, titanium is going to give higher revenue to the Government as its cost is increasing everyday - like oil.
We have confirmed the availability of titanium not only in the surface but also its presence in the sub-surface. At Nagore, for example, we had noted that the Tsunami had caused an erosion of two meters; however, titanium sand had replaced this two-meter sand. We have recorded this using the GPR also.
Question: How do you think that the recent Tsunami interacted with the already existing coastal sedimentation regime between Chennai and Palk Bay, and also Palk Bay and Kanyakumari?
Prof Rajamanickam: The Tsunami had completely disturbed the Shelf sediment right from River Krishna down to Kanyakumari. It had disturbed the seabed even up to 200 meters. From the Shelf break, the Tsunami had churned the sediments and brought the material to the coast and had pushed them further upland and while receding had taken back all the fine heavy minerals, fine silts, clays back to the Shelf. So, the Shelf sediments now have a completely new texture after the Tsunami.
If one studies the present sediments, one would be surprised to find the seabed to be a different one now. It is in this regard I feel that we have to undertake a resurvey of our seabed and understand the nature of the sediment present in it. Hence I feel an understanding of the pre-Tsunami sedimentation condition alone cannot work possibly for any modeling.
Question: After the recent Tsunami, the Centre for Marine and Coastal Studies of the Madurai-Kamaraj University (MKU) found that the sedimentation rate in some places of Palk Bay has increased almost by 64 per cent. (The sedimentation rate recorded earlier was 32.5 mg/d in November 2004; it had increased to 53.4 mg/d during the Tsunami). Do you think that the entire Palk Bay would have experienced such an increase in sedimentation rate or would it be that only a few selected areas in Palk Bay known already for higher sedimentation rates had experienced this?
Prof Rajamanickam: The finding of suspension load or sedimentation of 53.4 mg/d is possible because the churning impact of the Tsunami from the deeper depths reminds us that it might take some time - may be even years - to settle back all the churned out clay and silt surfaced by the waves.
Earlier, our own study on the quantification of the sediments at Sethubavachatram had revealed the immense amount of sedimentation that is going on in the Bay.
Question: Do you think that the entire Palk Bay would have experienced such an increase in turbidity?
Prof Rajamanickam: Yes. It would be a general phenomenon throughout the Bay because Palk Bay had also faced the Tsunami. Refracted Tsunami waves had entered Palk Bay.
So, churning (of the sea bed by the Tsunami) must have prevailed there also. It should be remembered here that Palk Bay seabed is only a temporary seabed - I mean, not a consolidated one. It is a seabed made up of dumped sediments. So, the entire dumped sediments to the tune of nearly about 6 to 7 meters should have been churned up by the refracted Tsunami waves. This I feel will take a longer time to settle down in Palk Bay particularly.
Question: Between May 2003 and February 2004, NEERI had studied the bathymetry of Adam's Bridge area. During January-February 2004, NHO had surveyed the entire alignment of the Sethu Channel (north of Adam's Bridge). L&T-Ramboll, the firm which that prepared the SSC's Detailed Project Report (DPR), in its February 2005 report, had suggested changes in the Channel's length and alignment.
The Channel length in the Adam's Bridge area has been increased by about 14.92 km, and the same in Palk Strait by about 0.13 km and the undredged central portion by about 0.32 km. -- thus increasing the total length of the Channel by about 15.37 km. This is about 9.17 per cent increase in the original length proposed by NEERI. The total dredging cost proposed in NEERI's Technical Feasibility Report was Rs. 1595.35 crores. An increase in the length of the channel by 9.17 per cent would increase the cost of dredging by about 146.34 crores.
All these are of course pre-tusnami estimates. In the light of the post-Tsunami sedimentation increase at Palk Bay as reported by the MKU study, are we to expect an increase in the quantum of sediments that has to dredged? In your professional opinion, do you think there would be cost escalation for the project, in this aspect?
Prof.G.V.Rajamanickam: Definitely. Now the dredging level will go high because at least half to one meter of sediment must have been deposited at the Palk Strait by the Tsunami. When you cross through the Palk Strait, the previous bathymetry of 10 meters would only be 9 meters now. So, to reach a maximum of 12 meters bathymetry, you would have to remove one more meter of the sediment. This would definitely lead to cost escalation of the project. The total quantum of sediment to be removed now would be more than the pre-Tsunami estimates. There is no question about it.
A re-survey of the present depth and also the nature of the sediments that the Tsunami had brought in is a must today. Tsunami has brought in a new stratum of sediments. If the pre-Tsunami dredgers approach this now, they would find a quite contrasting change in the nature of the present sediments. Hence, it is always advisable for having a quick look in the seabed now existing after the Tsunami.
It is also a must to assess the expenditure column and the time it is going to take for dredging in this changed scenario.
Question: L&T-Ramboll's DPR has identified the dumping sites for the dredged materials. These sites are said have a depth of 30 to 40 meters and they lie just adjacent to the northern and southern mouths of the Channel.
In an interview to this web portal in July 2005, Canada-based Tsunami expert Prof Tad S Murty has said: " I did some analytical analysis of whether cyclones (and storm surges) and tsunamis can move the dredged material from Palk Bay into the channel. (I have come to the conclusion that) tsunamis can move a significant amount of the dredged material into the channel". Professor, do you think this is as a possibility?
Prof Rajamanickam: See… after having witnessed the Tsunami's impact and its ability to disturb the seabed even in the outer shelf - one should be very careful in choosing the dumping sites.
Further, as I described to you earlier, we have landward migration of the sediments in this part of the coast. The presently chosen depths of 30 to 40 meters as the dumping sites, any monsoon will be able to disturb, leave alone cyclones or a tsunami.
So, unless and otherwise the project people take these dumping sites farther away to deeper areas, I feel, there would not be any solution at all. Whatever you dump, the next monsoon it will be brought back. So, your dredging would be perennial. There won't be any solution, reduction in the dredging.
In the recent workshop on Ecological Monitoring of the Sethu Channel held at Madurai I had projected this opinion.
We should take the dredge materials to deeper areas at least with 50 meters depth. If it is going to be more than 50 meters still better. Also, the project people should not think of dumping at one single point; they should rather spread it over. That is the ideal action to control the landward migration of the dumped materials back.
Question: Professor, here is a small problem! Taking the dredged materials farther away is going to further escalate the project cost…
Prof Rajamanickam: No. I don't think this would increase the cost much when you consider the nature of the slope of the Eastern Shelf. This has a very high slope. So planning to take the dredged materials farther away by about 200 to 300 meters, you would be reaching areas with 20 meters higher depths. When you compare this with the Western Shelf - there, to reach areas with 5 meters higher depths you will have to travel a few kilometers. The Shelf nature is like that.
So, there is no need to be worried about cost escalation when your work is in the Eastern Shelf.
Question: The Indian Shipping Ministry has set up a Monitoring Committee to assess the impact of the dredging activity on the environment and advise the project authorities. The Committee consists of marine biologists and microbiologists besides experts from the fields of fisheries, agriculture. However, it had not considered including sedimentologists, geo-morphologists or meteorologists.
The work on the Channel is progressing with an a priori understanding of the sedimentation situation of the pre-Tsunami period. The project authorities have not attempted a post Tsunami survey of the sedimentation situation before starting their dredging work.
The pre-Tsunami a priori understanding of the Project authorities on the sedimentation and meteorology dynamics of the area had not considered many of the most important sedimentation and meteorological studies done for the area from 1990 to the present.
What do you think would be the consequence to the future of the Project and the coasts around from such a supposedly negligent attitude? Can you suggest a plan to remedy this urgent situation?
Prof Rajamanickam: I have already emphasized, at the recent workshop at Madurai, that the lack of Earth System scientists - I mean, geo-morphologists, sedimentologists, mineralogists, oceanographers, climatologists - team will definitely bring problems to the maintenance of Palk Strait in the future. Theirs is the most important work, as this would occupy 90% of the total necessity in the monitoring work of the possible impact of dredging and maintenance of the project area. The present monitoring team, which comprises scientists from Marine Biology, Fisheries etc., will be able to do only 10% of the total required monitoring work.
Unless Earth System Science teams strongly enter - right from the initial stages to the continued monitoring of Palk Strait - this whole activity will be a failure sooner or later.
It is with this concern in mind myself and Prof T J Pandyan have suggested in the Madurai workshop the Geo-technology team of Manonmaniyam Sundaranar University to be brought into the monitoring committee.
Question: What about including private organizations in oceanography like Indomer Coastal Hydraulics, Chennai etc., into the monitoring committee?
Prof Rajamanickam: Ironically, it is my personal opinion that the private industries - if you give them the pertinent direction - like telling them we want these, these, and these - they will sincerely execute the job.
So, inducting private oceanographers or private parties or researchers is no harm; but they should be given a clear-cut instruction that these are the works that have to done meticulously. If there is any failure on this, the project people should tell them point blank that they will be responsible and will be penalized even. Such an attitude will make them to work properly.
See… Private research companies have already conducted the Biological Survey, Environment and Hydrographic Survey etc., for the Sethu Project. So, why not include them also in the monitoring work?
As for the present, there is absolutely no tool to check whether all the important factors like hydrography, bathymetry, current dynamics, total suspension load, climate changes, sea level alterations etc., that have the ability to affect the Project and the Bay are being monitored in the first place. So, who is going to do that?
Single one measurement of wave and currents and one turbidity measurement will not give you the solution that is required to safeguard the project or its environment.
That is why I was telling in the Madurai Workshop the other day that continuous current monitoring studies, current observations should be done in four places - In the Gulf (of Mannar) 2 places, in the Palk Strait one in the north and one in the south - that is one north of Manamelkudi and the other south of it.
Indomer can of course do wave, current and other studies; but they should be given clear-cut directions. Then there should be some professionally well competent x or y to monitor whether they have completed their work properly.
Question: How about the universities with earth science expertise taking part in the monitoring work?
Prof Rajamanickam: I strongly feel that universities should take a larger role in the monitoring work right from now on - because Sethusamudram Corporation needs manpower; and unless and otherwise the Universities are involved right now, they cannot develop to their requirement, as there would not be any exposure. This would be in the betterment of the Sethusamudram Corporation both in the short and long term alike.
Question: As a veteran geo-morphologist who had spent almost 20 years studying this coastal stretch, what is the right advice you would like to give to the Sethusamudram Corporation?
Prof Rajamanickam: The monitoring system, I mean the High Level Monitoring Committee that the Government had appointed recently, sadly does not have a hydrographer, sedimentologist, geo-morphologist, geologist, coastal tectonics expert, or experts from atmospheric sciences. So, what will this present monitoring committee do?
The fields I have just mentioned are the dominant sciences that are to ensure the safety and the stability of the Sethusamudram Project and its environment. So, I really do not know how this present monitoring committee, which lacks all these expertise, is going to do its required job of ensuring safety and stability to the channel and its environment!
I sincerely feel that the Government should go for experts from these fields of interest, in addition to the experts who are there in the high level monitoring committee. Then only you will have the proper input to see whether the Sethusamudram Channel is functioning well.
Otherwise Sethusamudram Channel will remain imbalanced. It will not give the benefit or the impact for which it had been visualized for the past 150 years.
- Asian Tribune -
1. Here are some of the important articles with respect to Palk Bay:
a)Loveson,VJ, and Rajamanickam,G.V.,(1987) "Coastal Geomorphology of Southern Tamil Nadu", in Proc.Remote Sensing in Land Transformation and Management, Hyderabad, p.115-129
b) Loveson,VJ, and Rajamanickam,G.V.,(1988) "Progradation as evidenced around a submerged ancient port, Periapatnam, Tamil Nadu", in Ind.Jr.Landscape and Ekistics Studies, 12, pp.94-96
c) Loveson,VJ, and Rajamanickam,G.V.,(1988 a) "Evidences for the phenomena of emergence along Southern Tamil NAdu Coast through Remote Sensing techniques" in Tamil Civilization, 5(4), pp.80-90
d) Loveson,VJ., Victor Rajamanickam,G., Anbarasu,K., (1990) "Remote Sensing applications in the study of sea level variation along the Tamilnadu coast, India" in G.Victor Rajamanickam ed., 'Sea level variation and its impact on coastal environment", Tamil University, Thanjavur, pp.176-196
e) Victor Rajamanickam,G., Loveson,V.J., (1990) "Results of Radiocarbon Dating from some beach terraces around Rameshwaram island, Tamil Nadu" in G.Victor Rajamanickam ed., 'Sea level variation and its impact on coastal environment", Tamil University, Thanjavur
f) Loveson,VJ., Victor Rajamanickam,G., Chandrasekar,N., (1990), "Environmental impact of micro-deltas and swamps along the coast of Palk Bay, Tamil Nadu, India", in G.Victor Rajamanickam ed., 'Sea level variation and its impact on coastal environment", Tamil University, Thanjavur
g) Loveson,VJ., Angusamy,N and Rajamanickam,G.V., (1996) "Usefulness of identifying different geomorphic blocks along the coast of southern Tamil Nadu", in Ind.Jr.Geomorphology, 1, pp.97-110
h) Loveson,VJ., Victor Rajamanickam.G., "Evidence of Quarternary Sea Level Changes and Shoreline Displacement on the Southeastern Coromandal Coast of India" in Proc. Of the International Seminar on Quaternary Sea Level Variation, Shoreline Displacement and Coastal Environment, New Delhi, 2000
# Palk Bay and Adam's Bridge - Geomorphology and Sedimentation - An Anthology This compilation contains important excerpts from the above mentioned works of Prof.G.V.Rajamanickam.
a) 'Sea level variation and its impact on coastal environment", Tamil University, Thanjavur, 1990,
b) International Seminar on Quaternary Sea Level Variation, Shoreline Displacement and Coastal Environment, New Delhi, 2000