PMO Note

1. Subsequent to the Tsunami calamity, certain urgent technical issues have arisen regarding the SSCP which have been noted with alarm in responsible sections of the scientific community of the country

Tuticorin Port Trust Observations

PMO Note is the summary of an article titled " Pre- and Post Tsunami – Is the Sethusamudram Shipping Canal Project Technically feasible ? " which appeared in the Economic and Political weekly dated January -22, 2005.

The article is contributed by Dr. R. Ramesh, M.B., B.S., who is  a medical professional. His expertise in the complex phenomenon of Tsunami  and its impact  is debatable.  His readings on the subject of tsunami and the project region are limited as evident from the references cited by him.

There  have not been any observations made by any scientist on the basis of scientific evidence  except for some statements in the media attributed to Dr. Ted Murty, NRI Scientist about the need for reorientation of the channel entrance in the Bay of Bengal. This is dealt with separately.

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PMO Note

2. The Tsunami waves which were generated on December 26, 2004 by an earthquake of 9 Richter magnitude off the west coast of north Sumatra traveled westwards and eastwards.  The eastern wave was blocked by the Thai, Malaysian and Indonesian landmasses.  A portion of the undissipated energy of this eastern wave was transferred to the western wave front traveling towards Sri Lanka and the Indian east Coast.

Tuticorin Port Trust Observations

Yes.

This is also supported by animation models generated in India and also outside.

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PMO Note

3. Before touching Sri Lanka, the tsunami was traveling westward.  When it struck Sri Lanka and the east coast  of India, a clock wise  wind was created with the Palk Bay as it hub.  Had the Sethusamudram Shipping Canal been operational at the time of this tsunami, the currents in the Palk Bay and the associated turbulence would have damaged the canal considerably and would have caused a wide disposal of the dredged material placed at sea.

Tuticorin Port Trust Observations

A slide from an animation model by M/s. Indomer Coastal Hydraulic (P) Ltd., Chennai in association with M/s. Alkyon Hydraulic Consultancy and Research by the Netherlands is enclosed (slide 1) .  This clearly establishes  that Palk Bay and Palk strait were comparatively free from the turbulence caused by the Tsunami in the Bay of Bengal and Indian Ocean. This slide is also supported by the animation model of the National Institute of Advanced Industrial Science and Technology ,  Japan (Slide 2)

In the case of tsunami, significant damages have been and will be seen only along the near shore beach areas because of resistance  of near shore structures against the Tsunami passage.  The very location of the Sethusamudram channel far away from the Indian or Sri Lankan coast pre-empts this possibility.

Scientists have also expressed the view that the channel situated in mid sea can not show any resistance displayed by near shore structures except for the possibility of bed scouring  which may have the impact of increasing the depth of the channel as witnessed in Chennai Port.

Tuticorin Port, situated in the Gulf of Mannar and very close to the project region, did not experience any significant change in the bathymetry due to tsunami's impact.

If a clockwise swirl had indeed been created in the region with the Palk Bay as its hub ( as stated in the note but not supported by the animation models), such clockwise swirl would have taken the dredged materials placed at sea, proposed to be dumped in depths of about 20-30 M in the Bay of Bengal away from Palk Strait.  A quantity of around 34.5 million M3  of dredged materials is proposed to be dumped in an area of about 25 Sq.KM, which will raise the sea-bed by an average of 1.4 M only.  The clockwise swirl would have carried this deep into the Bay of Bengal, redistributing it over a very wide area making the impact of such redistribution, even if it would have taken place, insignificant in view of the wide area over which it would be redistributed and greater depths available North and Northeast  of the proposed dumping location in Bay of Bengal 

Therefore, there is no scientific basis for the apprehension that the shipping channel , if it were in place during  tsunami, would have been damaged by the currents and / or associated turbulence. `Wide dispersal of the dredged materials placed at sea' would have had insignificant effect.

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PMO Note

4. The SSCP is an off shore shipping canal project in the Palk Bay.  It aims to shorten the distance navigated by ships sailing form the west coast and bound for ports on the east coast by avoiding circum-navigation of Sri Lanka.  On the completion of the SSCP, ships would navigate through the Gulf of Mannar and Palk Bay and enter the Bay of Bengal directly

Tuticorin Port Trust Observations

Yes.

PMO Note

5. The total length of the canal in the Palk Bay is 152.2 Km.  This is divided into three legs – the Southern leg in the Adam's Bridge area  which is 20 KM, the northern leg in the Palk Strait area which is 54.2 Km and the central portion which is 78 Km in length.  Dredging would have to be done in the southern and northern legs to dredge the shallow sea bed of the Palk Bay and Adam's Bridge to a depth of 12 metres in order to make navigation possible.  The central leg does not require dredging as it lies the adequate depth of 12 metres.

Tuticorin Port Trust Observations

The statistics furnished in the Note are based on the Techno-Economic Feasibility Report prepared by the National Environmental Engineering Research Institute, Nagpur in July 2004.  The Detailed Project Report since submitted to the Ministry  of Shipping, RT & H, has suggested some minor changes in the channel alignment on navigational considerations. The length of the proposed channel now is 167.57 Km , with the southern leg at Adam's Bridge area having a length of 34.92 Km, the northern leg in Palk strait 54.33 Km, and the intervening stretches of Palk Bay, not requiring any dredging, having a length of 78.32 Km

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PMO Note

6. This is the first effort by the India to dredge a navigation channel, which is located 30-40 Kms off shore.  It is also the longest sea bed dredging project undertaken by India.

Tuticorin Port Trust Observations

Yes.

PMO Note

7.  The problems that will be faced by SSCP are expected to be

         (i) problems due to sedimentation

        (ii) problems due to tropical cyclonic disturbances and

       (iii) issues related to dumping of the dredged materials

Tuticorin Port Trust Observations

Significant issues relating to the SSCP, which has a major dredging component, are :-

i.Sedimentation in the Channel which will determine the stability of the channel and maintenance dredging.

ii.Identification of dumping locations for dredged materials disposal with the objectives of -

a)minimising environmental impact to manageable levels and

b)ensuring that the dumped spoils do not re-enter the dredged channel.

Though the National environmental Engineering Research Institute had scientifically identified the dumping areas supported by modelling studies, further modelling studies were carried out by Tuticorin Port Trust during September 2004 – January 2005 with involvement of Alkyon Hydraulic Consultancy and Research bv the Netherlands for validation and verification of NEERI's findings, and for optimisation of distance to dumping locations.  While validating NEERI's findings   the studies  have indicated the possibility of opitimising the lead distance.  However, considering the environmental sensitivity of the project region, it has been decided to retain the dumping locations suggested by NEERI.

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PMO Note

8.  In order to tackle these problems, detailed information and knowledge needs to be gathered regarding sedimentation and cyclone disturbances in the Palk Bay

Tuticorin Port Trust Observations

Tuticorin Port Trust has carried out detailed wave modeling studies, tide and current circulation modeling studies, nautical studies and sedimentation modeling studies inter-alia analysing in-depth the sedimentation regime along the entire channel length. 

As regards tropical cyclonic disturbances, " information on the normal wave conditions is required for further studies on sedimentation and erosion and to establish the limiting conditions for navigation through the channel. Information on the extreme wave conditions is required for the design of various structures, like groynes and bank protection," (Report of Indomer Coastal Hydraulics (P) Ltd., Chennai on Hydradynamic modeling and ship Maneuvering studies for the SSCP). Wave modeling studies of international standards, involving an internationally acclaimed organisation, have been carried out to meet these requirements. 

The following findings  of the modeling studies are relevant vis-a-vis sedimentation in the channel in Palk Bay / Palk Strait which the Note primarily deals with- 

"Based on the computed  sediment transports,  it can be concluded that the incoming sediment volume (23,100 m3 ) is of the same order  of magnitude as the transported sediment along the channel  (32,500 m3).   This would imply the following - 

•At the shallow zone of Palk Strait, the channel depth will remain constant at CD (-) 12m (the incoming sediment volume from long shore transport approximately equals the outgoing sediment volume due to transports parallel to the ship channel). This implies that no maintenance dredging is required along this channel section (at Palk Strait). 

•East and west  of shallow zone, however, the transported sediment volume  will deposit due to reduced sediment transport capacities.   The deposited sediment volume equals to 32,500 m3/y."

The relevance of the findings  is two-fold:

(i)                   Detailed  field investigations/ modelling studies  have been carried out  in the project region.                   

(ii)                   There will be  very little  sedimentation in the channel in  Palk Strait, compared to other approach channels  in the country. 

The general philosophy followed  worldwide in designing an off shore  structure is that predictions about the ocean  environment have to be made first,  ideally  based on the history of the environment for  'hundreds of years of  data' (A.K.Malhotra – "Ocean Science and Technology" p 32, 1980)".   "In actual fact, the data for a particular location usually cover  a much shorter period and, therefore,  are a poor basis for predicting the future from the oceanographer – statistician's point  of view.   Despite this, valid operating  and design values can be obtained by one of several methods" (A.K.Malhotra).  This  is normally done through predictive  modelling, as carried out by Tuticorin Port for SSCP.

The issues relating to cyclonical disturbances are discussed in Section 12.

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PMO Note

9.  Palk Bay is one of the major permanent sediment sinks of India. In a study entitled " Littoral Drift Sources and Sinks along the Indian Coastal by Chandramohan and others in 2001, the sea depth reduction due to sedimentation in the Palk Bay  has been estimated to be 1 cm per year Marine and riverine sources contribute to these sediments.  In a publication entitled " Rapid Land Building Activity along Vedaranyam Coast  and its Possible Implications" brought out by Ramasamy and others in 1998, the sediment building activities due to sea currents in the Vedanarayanam-Jaffna peninsular stretch of Palk Bay has been estimated to be 29 metres per year.  Similarly in another study on the Sethusamudram Canal published by Rajamanickem in 2004, the sedimentation rate has been estimated to be 24 cms per year in the Manamelkudi area of Palk Bay

Tuticorin Port Trust Observations

The Note refers to findings reproduced in some research papers which are based on micro-regional studies or application of mathematical formulae.

 The study  of Rajamanickam  has  been mentioned.   Rajamanickam says in his paper – "Sethusamudram Canal:  The life line of Tamilnadu" (National Seminar  on Ecological  balance and Sethusamudram Canal, 1-3rd October, 2004,  Department of Oceanography and Coastal Area Studies, Alagappa University), that "it is interesting to see that the maritime surveys  conducted between 1960 and 1986 reveal the change of contour to the tune of 6m shallowness in the Palk Strait.    That shows that around 24 cm per year is being  silted off  in the Strait."   The Note  only quotes  this part of his observation  but fails to add that he has actively supported the construction of the navigation channel to remedy his natural phenomenon.   In  his paper, Rajamanickam visualizes   "the merger of this two  (spit from Thalaimannar side in Sri Lanka and spit from  Manalmelkudi in India) within the next 50 years.  Once these  spits join, the Palk  Strait will become into two lagoon of the north and south.   The flushing of waters from Gulf  of Mannar to  Bay  of Bengal  will be stopped".  He has  further opined -"Because  of such ocean circulation, Tamil Nadu is getting monsoonal rainfall.   The  day siltation initiated, one must have observed the drifting of cyclones and low depressions to Nellore and Orissa. 

Slowly the quantum of rainfall in Tamil Nadu and the order of cyclones in delta region have been in the decreasing order.  If the flushing is completely stopped, the monsoonal winds and ocean circulations may not be directed through this Strait.  If such action takes place, Tamil Nadu may not get proper rainfall and subsequently the granary of rice, the Cauvery deltas will become a desert by the turn of this century.

The moment, Sethusamudram Canal is brought in force, that Canal may become the draining canal first for all the silts dumped  along  the coast of Palk in the past. There is every  possibility to retrieve back the clear water and comparatively  deeper shelf in  many areas.   Such  increase  of depth and clarity of water may enable the delicious fish varieties  to get more populated and fishermen in this region can do the fishing right in front  of the hamlets as in the case of 19th century.   The per capita income of the fishing community of nearly 40,000 people may go up many times.  The delta region may get   good rainfall and may plan to go for cultivation without the dependence of Mettur  water.   In the beginning, the Sethusamudram Canal may face frequent dredging due to the sliding of the silts dumped earlier.  In few years  this will be settled.   The fear  complex  developed among the fishing community  is baseless.  Instead  of loosing  their  fishing  and trawling,  they will get more catch due to the  International navigation as in the case of Panama.

Therefore, scientific  evidence is being cited against the project when the scientist who has produced such evidence  goes on to say in the same research paper that  the scientific  evidence leads him to believe that an environmental and ecological disaster is waiting to happen unless the Sethusamudram Ship Channel is urgently created to provide a draining canal for the silt in Palk Bay/Palk Strait.

For a dredging project  involving  creation of a navigation channel,  sedimentation in the project setting and in the channel as a result of sedimentation regime in the area  need to be studied.  In the case of SSCP,, sedimentation transport rate along the channel  and long shore sediment transport across the channel need estimation for computation of annual maintenance dredging requirements.  Such  estimation  has been done in the past (earlier studies) through modelling and  radio-active  tracer analysis.   Tuticorin Port Trust has carried out sedimentation modelling in the project area involving a world-renowned organisation which has clearly established that sedimentation transport rate along and across the channel is insignificant.

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PMO Note

10.  Those findings indicate that there are specific regions in Palk Bay where the annual sea depth deduction is 25-75 times higher than the average value proposed by Chandramohan etc. for the entire Bay.  The two legs of the SSCP where dredging is required happen to cross two such micro regions with high sedimentation rates.

Tuticorin Port Trust Observations

The legs of the SSCP where dredging will take place pass through two micro regions with high sedimentation rates – Adam's Bridge and Palk Strait.  This prompted Tuticorin Port Trust to commission further  modeling studies to verify and validate NEERI's findings.  The  modeling studies have led to reliable  estimation of sediment transportation rate along and across the channel in these regions.

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PMO Note

11. The Environmental Impact Assessment (EIA) for Sethusamudram Shipping Canal Project carried out by the National Environmental Engineering Research Institute (NEERI) has not taken into account the sediment contribution from the rivers flowing into Palk Bay.  This study does not pinpoint the sediment source for about 99.4 % of the total sedimentation volume.

Tuticorin Port Trust Observations

While undertaking the EIA Study NEERI  have generated primary data  in addition to relying upon secondary data.  Primary data has also been used by them for validation of Secondary data. They had also carried out mathematical/ simulation studies.  Tuticorin Port Trust, in its endeavour to verify and validate NEERI's findings,  had commissioned further modelling/ simulation studies.  

P.Chandramohan  et al (Littoral drifts sources  and sinks along  the Indian Coast, Current Science, Vol.81, No.3, 10  August 2001) in their study had  estimated 0.3 x 1010 m3 sediment    deposition in Palk Bay region, in an area of 117 km  x 105 km  over a period  of 51 years.    M/s.Indomer Coastal Hydraulics  (P) Ltd. (of which Dr.P.Chandramohan is the Managing Director) have estimated sediment  deposit  of 32, 500  m3/y in Palk Strait part of SSCP, which will have  a length of 54 kms. A comparison of the estimates is shown below:

1.Sedimentation capacity in the channel,

   proportionate to estimate to

   Chandramohan et at   .

                      54x0.3x1010   =   77,569 m3

                      117x105x51   

          2.Sedimentation computed by

                    TPT modelling study

      Along the channel-

                          Incoming sediment volume    =23,100 m3                                                                         Outgoing sediment volume    =32,500 m3

      Across  the channel-                 

                           Deposited sediment volume  =32,500 m3                                                                                                              --------------------------                                    

                    Total                                             =88,100m3

                                                             ==================

Therefore, the findings  from the modelling studies compare  favourably with results of  research studies available  for the area.   The imputation that the studies do not pin-point the sediment source for about 99.4% of the total sedimentation volume  appears to be based on the following

         (i)Total sediment  load computed:                         

                             58.8 x 106m3

           by Chandramohan  et al for entire Palk Bay     

                         (117 x105 sq.km.)

        (ii)Less net annual sediment transport :

                        0.2657 x 106m3

            Computed by NEERI  for Adam's Bridge area

                    (which has a length of 17 kms)

       (iii) Less estimation made by Sanil Kumar et al for net littoral sediment

            transportation:

                            0.095 x 106 m3 into Palk Bay from Nagapattinam  coast.        

               Unaccounted,  according  to the Note

                           58.4393 x 106m3

The primary source of the sediments deposited on the beaches is the weathering of the land; the sediments are  then transported  through rivers to the  ocean' (Chandramohan et al, 2001).   It is  also estimated that 'The quantities  of materials contributed  by head land erosion  and aeolian transport are both less than 2 per cent of river transport' (Chandramohan et al, 2001).  

Therefore, when the sedimentation  due to littoral drift from the north (Nagapattinam) estimated by Sanil Kumar et al (2002) and the total  sedimentation load for Palk Bay region computed by  Chandramohan et al (2001 – Sanil Kumar  was also  part of this research  group) are accepted as valid, the source of the difference is very clear-sediment contribution from the rivers.  This is supported by the following excerpts- `Vaigai, Vaishali and Valryar rivers are the major sediment sources entering the palk bay region'. (Malik, T.C., Indian Journal of Marine Science, 1983-12,203-208). `Large amounts of sediments from the pediments are removed constantly by rainfall and carried by minor rivers and dumped into the Palk bay'.(Loveson et al, Sea Level Variation and its impact on Coastal Environment, ed Rajamanickam, 1990, PP159-178).

The studies  carried out by the Project authorities  are  for  the  purpose  of delineating the  project setting in order  to identify the environmental consequences of the proposed project,  assess their impact, evaluate  the  environmental viability of the project and devise an Environmental Management Plan to  minimise the environmental impacts. The findings  of these studies are substantiated  and supported by research studies of the region in which the project is situated.

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PMO Note

12. Out of the 61 cyclones that have crossed the Tamilnadu coast in the period 1891-1995, 6 have directly crossed the Palk Bay.  The Met Department  considers the coastal stretch between Nagapattinam and Pamban as a high risk zone for tropical cyclones.  A study entitled " Identification of Costs Vulnerable for Severe Tropical Cyclones – Statistical Evaluation" published in 2004 has named this coastal stretch as the most vulnerable to severe tropical cyclones among the many coastal regions of the Bay of Bengal.  Studies on the pattern of movement of sediments during the cyclonic storms are not available at present.  However, it is known that these storms have a tendency to transport sediments into Palk Bay from the Nagapattinam coast and from Gulf of Mannar

Tuticorin Port Trust Observations

'The most damaging oceanographic episode that coastal residents can face is a cyclone with a combination of wind, waves, surge and rain' (Antonio Mascarenhas, Current Science, Vol.86, No.3, 10 February 2004). An important prerequisite for sustainable  development, therefore, is resilience towards natural hazards and elimination of disasters.

In terms  of landfall, among the severe cyclones over a century, according to Mascarenhas, '55 crossed  the coast of Tamilnadu, 69 hit Andhra Pradesh, 58 affected  Orissa, 33 struck West Bengal.'    Impacts of  tropical cyclones have been and continue to be the  most disruptive recurring events for the east coast of India.   From available records, Mascarenhas concludes -

(i)  Andhra Coast is the most vulnerable to several tropical cyclones.   About 32% of the cyclones forming  in the Bay of Bengal  make landfall along this coastal state every year.

(ii) Orissa  follows with 27%, Tamilnadu with 26% and West Bengal with 15%.

(iii) The Andhra Coast has been subjected to storms, with a highly significant increase in the mean frequency of severe storms incident on Andhra Coast after 1975 as compared  to earlier periods.     

(iv) Orissa  is affected by the highest frequency of severe cyclones in October and November every year, with the highest probability (56%) of at least  one cyclone crossing  the coast and 1% probability of  four cyclones crossing Orissa every year.

(v) In terms of storm surges, the West Bengal coast is highly vulnerable to attack by storm surges with heights ranging from 2-12m.

The coast of Orissa  has witnessed maximum surge heights of 7 m. The Andhra Pradesh  and Tamilnadu Coasts are  vulnerable  where observed surge heights are in the range of 1 to 6 m.

(vi)                   Andhra and Orissa  are the most vulnerable to coastal inundations.

To summarise his findings,

(a)  In terms  of incidence of severe tropical cyclones, Andhra       and       Orissa are more vulnerable than the Tamilnadu coast.

(b)  In terms  of storm surges, West Bengal and Orissa       coasts are highly vulnerable, while the Tamilnadu Coast is vulnerable.

(c)      Andhra and Orissa are the most vulnerable  to coastal       inundations.

  Therefore,  absolute figures relating to Tamilnadu Coast   need to be compared with the rest of the east coast.   The statistics furnished  in para 11 of the Note  that `against the incidence of 61 cyclones on the Tamilnadu coast during the period 1891-1995, only 6 had directly crossed the Palk Bay' is also relevant in this context as in simple arithmetical language it conveys that the Palk Bay is less vulnerable to incidence of cyclones than the rest of the Tamilnadu Coast.    The Sethusamudram Ship Canal Project  was originally conceived by the British  as early as in 1860 with the objective of  providing  sheltered  passage  to merchant and navy ships,  sparing them from the vagaries of nature and to provide safe anchorage during  the tropical cyclones normally encountered off the Tamilnadu  Coast during the North East monsoon  (October – December).

The Note cites  the incidence of cyclones in the project area as the reason  for reviewing  the need for the project when the major ports of Visakhapatnam, Paradip and Haldia  are situated in coastal areas more vulnerable to such incidence.    So is Kakinada where a  major port facility  is coming up.

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PMO Note

13. There are two previous records of tsunami destruction in this area.  The first record is of an earthquake,