Friday, June 10, 2005

Sethusamudram Shipping Canal would destroy the coastline stability of Sri Lanka and India.


Will the Sri Lankan expert committee wake up at least now?


Sri Lankan President Mrs. Chandrika Kumaratunga visited India recently. One of the issues taken up for discussion between her team and Government of India (GoI) was the issue of Sethusamudram Shipping Canal Project. The experts who had accompanied her are said to have raised the issue of the negative impact of the Sethusamudram Canal on the Sri Lankan Coastline. To their queries, it is said, that the Indian authorities had provided clinching scientific evidences, which prove that Sethu Canal will not be damaging to the coastlines of either Sri Lanka or India. These evidences, it is said, had allayed the fears raised by the Sri Lankan experts. A discussion between the experts of the two countries is scheduled again in July.

One of the most important studies, shared by the Indian authorities with their Sri Lankan counterparts, is the ‘Hydro Dynamic Modelling and Ship Manoeuvring Studies for SSCP’ conducted by a Chennai based company called Indomer Coastal Hydraulics.

The Indian authorities are reported to have said that this study had concluded: “Tide/wind induced flow during various seasons, the wave propagation, (and) the sediment transport pattern remain similar with the same magnitude and direction after opening the channel for the region falling 500 metres away from the channel... Such findings imply that the dredging of the channel will not have any impact on adjacent coastlines on the Sri Lankan coast and further on any of the offshore islands or on the sand spits present across the Adam's Bridge. Hence the project will be safe to implement and it will not have any negative impact on the stability of the coastlines in Sri Lanka and India." (Ref. 1) (Note 1)

It is said, that the experts from Sri Lanka did not have any data to counter this particular conclusion. However, it was reported that GoI was prepared to consider any scientific evidence that GoSL may present in the future that go on to prove its apprehensions correct and was prepared to make the necessary technical modifications in the project. (Ref. 2)

Hydro Dynamic Modelling for SSCP by Indomer Coastal Hydraulics is a scientifically incomplete study.

Indomer Coastal Hydraulics (P) Ltd., is owned by Dr.Ponnambalam Chandramohan, an oceanographic expert and a former research scientist at National Institute of Oceanography, Goa, whose prime research interests lay in wave and sediment dynamics with respect to the stability of the Indian coastline. (Ref. 3).

Dr.Chandramohan’s prime works with respect to Palk Bay include: 1) the 1990 work completed with Sanil Kumar and Nayak ‘Wave Atlas for the Indian Coast based on Ship Observations, 1968- 1986’, 2) ‘Beach dynamics at Pudhuvalasai in Palk Bay’ studied in the year 1997 along with B.K.Jena and A.S.Murty, 3) ‘ Longshore Transport Based on Directional Waves Along North Tamil Nadu Coast, India’ written in 1997, and published in 2000 along with B.K.Jena and V.Sanil Kumar, 4) ‘Longshore currents and sediment transport along Kannirajapuram Coast, Tamilnadu, India’ published in 2000 with Sanil Kumar, V, Ashok Kumar, K. , Gowthaman, R. and Pednekar, P., 5) ‘ Littoral drift sources and sinks along the Indian coast’ published along with B. K. Jena and V. Sanil Kumar in the year 2001.

The 2001 study had actually calculated the annual amount of sediment getting deposited in Palk Bay. The paper had noted, “Any attempt to handle the coastal problems, either to arrest erosion or prevent deposition, requires a thorough understanding of the factors and processes involved in the coastal geomorphological system: the pattern of changes, the sources for the sediments supplied to the littoral region, the sinks acting as large-scale depository basin of the sediments and the volume and direction of sediment movement in the littoral zones.” It had further noted: “ Occurrence of cyclonic storm during north-east monsoon is common in the Nagapattinam–Poompuhar region, which causes an erosion along this region. The sediments are transported southerly and deposited in the Palk Bay. Low wave action inside the bay and protection from the southerly waves encourages the deposition of sediment.” It had also noted the presence of specific regions in Palk Bay, wherein the sediment deposition is far higher than other regions of the Bay.

It would be important to note here the conclusions regarding the impact of cyclones on Palk Bay as presented by 3 important research papers in which Dr.P.Chandramohan himself happens to be a co-author of two of the Papers. Among these three articles, two deal with the direction of the annual gross sediment movement from Nagapattinam coast and the third analyses the same from the Kannirajapuram coast. Let us quote their observations: “It is … observed that the occurrence of cyclonic storm during northeast monsoon which is common in the region would considerably increase the southerly drift and may cause the littoral drift material to deposit in the sink at Palk Bay. Such loss of material is one of the prime reasons for the erosion of the shoreline between Nagapattinam and Poompuhar”. “9 cyclonic disturbances have been reported or recorded in this (Kannirajapuram) region during 1891 to 1970.Out of this 7 have occurred in the months between October and December and one each in the months of January and March...The annual gross transport was found to be 0.15X106m3/year and the annual net transport was 0.12X106m3/year (toward northeast).” (Note 2)

The question now is, did the Indomer’s ‘Hydro Dynamic Modelling and Ship Manoeuvring Studies for SSCP’ take into consideration all the above factors noted in Chandramohan et al.’s 2001 paper? The answer is a definitive ‘No’. The reasons for this conclusion are two: 1) There’s no dedicated research available yet, on the interactions of cyclones that cross the region once in 4 years (Note 3 a) and their influence on the sedimentation regime of Palk Bay and nothing is known about the quantum of sediments contributed by these storms to Palk Bay, 2) Till this date, quantification of the sources for the sediments coming into Palk Bay have been done only for about 00.614% of the total quantum of sediments calculated so far. (Note 3 b)

Hence, we come to the conclusion that the results of Indomer’s “‘Hydro Dynamic Modelling and Ship Manoeuvring Studies for SSCP” could only be considered as partial and incomplete. We also note here that this model should be improved upon with further future dedicated researches on sedimentation pattern in Palk Bay during the times of Cyclones and Tsunamis.

Claiming a partial mathematical model as a scientifically complete one and proceeding with the dredging work for the Sethusamudram Shipping Canal based on its scientific strength might throw environmentally dangerous and costly surprises for both Sri Lanka and India in future.

Indomer-Alkyon’s tsunami simulation model reveals that Sethu Canal will be dangerous to both Indian and Sri Lankan Coastlines.

Indomer in collaboration with Alkyon Hydraulics of Netherlands has created a simulation model of the 2004 December 26th tsunami. (Ref. 4) (Note 5). Analysis of this simulation model yields some interesting results that happen to directly oppose the claim by the SSCP proponents that ‘the project will be safe to implement and it will not have any negative impact on the stability of the coastlines in Sri Lanka and India."

This simulation model reveals, like the simulation models created by Prof. Steven N. Ward, of the Institute of Geophysics and Planetary Physics, University of California, Santa Cruz, USA and the one by Prof. Aditya Riyadi, of Pusat Penelitian Kelautan Institut Teknologi, Bandung, Indonesia (Note 5) that ‘the northeastern, central, eastern portions of Palk Bay received waves of higher energy and thus these areas remained more turbulent during the Tsunami. This means, the extent of sedimentation and thus the extent of damage to the marine ecosystem in this part of the Bay should have been much higher than the other areas of the Bay’. Incidentally, all these areas fall well within Sri Lanka’s territorial waters.

This simulation model points to us that the areas through which the most turbulent waves have entered Palk Bay both from North and South are the areas where the Sethusamudram Shipping Canal is to be located. It is this point that has been of concern for international tsunami experts like Dr. T.S.Murty. When he said Kerala would face destruction, what he actually meant was that drastic consequences were in store for the entire shoreline extending from Dhanushkodi to Ernakulam, and from the Delft Island to Colombo. (Note 6)

The steeply placed Palk Bay has actually shielded the above said shoreline from the harsh impact of the Tsunami waves approaching it from Bay of Bengal located in the northeast; but the deepwater route of the SSCP is about to destroy this protective shield.

SSCP has two acute bends in its course. These bends would obstruct the waves gushing through the canal, and thus there would be excessive sedimentation in the upper and lower courses of the canal. The impact of the high-energy waves on the bends would destroy these bends, thus paving way for the waves to enter the central portion of Palk Bay. Sediments carried by these waves would make the central portion of the Bay much shallower. Prior to the Tsunami, it was said that this 78 km stretch of Palk Bay would have had an adequate depth of 12 meters. Post-Tsunami, there has been no study on the changed depth of this region.

In addition to this, the Indian Department of Ocean Development’s (DOD) report on Tsunami damage, published in late March 2005, has documented that the sedimentation rate at the coral reefs around the Pamban Island had increased two-fold during the tsunami. (Ref. 5) A team of scientists from led by Dr.V.J.Loveson of the Council for Industrial and Scientific Research (CISR) New Delhi, studying placer deposits in the area, says an estimated 40 million tonnes of Titanium alone has been deposited in the entire stretch of 500 kilometer coastline hit by the Tsunami. (Ref.6) The Zoological Survey of India’s report talks about the consequences of excessive dumping of silt by the Tsunami on the Palk Bay Bay ecosystem. (Ref 7) Independent surveys conducted at Kodiakkarai, in Tamil Nadu, in January have revealed that the sea is now half its depth than what it was prior to the Tsunami. (Ref. 8)

All these studies reveal that the amount of material to be dredged would be far higher than the one estimated by NEERI in early 2004. The post tsunami simulation modeling studies have revealed that during cyclones and tsunamis, the canal has the potential to transport the sediments into Palk Bay at a far higher quantity and rate than it is during the cyclone – tsunami free periods.

It is in this context, the project proponents claim that the Sri Lankan experts on oceanography possess no data to counter the scientific validity of their argument.

Will the Sri Lankan experts present at least now, the tsunami simulation modeling results of the very agency that has done the mathematical modeling for SSCP to their Indian counterparts? Will they then ask GoSL to demand GoI to defer the project for at least now and take up the necessary scientific studies to make the project environmentally viable and friendly?

The Sri Lankan expert committee should act NOW! Waiting up till July, when the bilateral expert committee meeting is scheduled next, would not have any meaning since the dredging work would have already commenced (in the third week of June)!


‘Sethu channel will not affect coastline: study’, The Hindu, 9 June 2005
The tsunami simulation model can be downloaded from Choose to download the simulation model with the file size of 15. 28 MB, as this gives a better picture clarity and coverage than the files with 8.28 and 1.89 MB sizes.
DoD’s report on Tsunami damage is available at the following link:
The Times of India, JANUARY 14, 2005
The Hindu, 22 April 2005, “Marine ecology of Bay of Bengal irrevocably altered by tsunami”
Personal Communication, Dr.Senthil Kumaran, Coimbatore, Unpublished Report,


1. It is interesting to note that the Indomer’s mathematical modeling study does not find a mention in the Environmental Impact Assessment (EIA) for SSCP done by NEERI. This EIA was published in May 2004. Indomer’s website records that this study was taken up in the year 2004. At the same time, the website does not claim that its mathematical modeling has considered the issue of December 26 tsunami with respect to its effect on SSCP. (Ref. 3) Hence, it is safe to assume that this is a study commissioned by the project authorities after the publication of the NEERI EIA but completed before December 26th 2004.
2. The research articles on Nagapattinam and Kannirajapuram Coast can be downloaded from the following link:
3. a) The data on cyclones in this region is available at R.Ramesh ‘R.Ramesh, “Sethusamudram Shipping Canal Project and the unconsidered high risk factors: Can it withstand them?” pp- 42 -52
b) The annual sediment load = 58.8000 X 106 m3
The net annual quantum of sediment transported by long shore currents from the Nagapttinam coast into the Palk Bay = 00.0950 X 106 m3
The total net annual quantum of sediment transported by tides and long shore currents
into the Palk Bay fro Gulf of Mannar through Pamban Pass and Adam’s Bridge = 00.2657 X 106 m3
The net annual quantum of sediment for which the source is not yet pinpointed
(58.8000 X 106 m3 –(00.0950 X 106 m3 + 00.2657 X 106 m3 ) = 58.4393 X 106 m3
So, we are yet to have studies that pinpoint the source for 99.386% of the net annual quantum of sediment entering into the Palk Bay. Studies on the quantum of sediment transported in the Palk Bay during cyclonic disturbances are non-existent.
For a detailed discussion on this see R.Ramesh, “Sethusamudram Shipping Canal Project and the unconsidered high risk factors: Can it withstand them?” (16 Nov 2004) pp –57 -63
The monograph can be downloaded from the following link:
4. The recreated zoomed version of the Indomer-Alkyon simulation model that shows just the Palk Bay region can be downloaded from the following link:
5. All these simulation models are available at
6. Article on the analysis of Dr.Tad S.Murty’s view is available at