Environmental Impact Assessment for
Proposed Sethusamudram Ship Channel Project


National Environmental Engineering Research Institute

Nehru Marg, Nagpur - 440 020

 August 2004




India does not have, within her own territorial waters, a continuous navigable route around the peninsula due to the presence of a shallow (1.5 to 3.5 m depth) ridge called ĎAdamís Bridge? between Pamban island on south-eastern coast of India and Talaimannar of Sri Lanka. While Rameshwaram is a major pilgrim centre on Pamban island, the tip of the island is marked by Arimunai. Consequently, the ships calling at ports on the east coast of India have to go around Sri Lanka entailing an additional distance of about 254-424 nautical miles and about 21-36 hours of ship time.


The Sethusamudram Ship Channel Project under the consideration of the Ministry of Shipping, Government of India, envisages creation of a ship navigation channel to suit different draughts (9.15 m, 10.7 m and 12.8m) through dredging/excavation in Adamís Bridge, parts of Palk Bay and Palk Strait. The navigation route will originate from the Tuticorin new harbour in the Gulf of Mannar (GOM) using available navigation depths (> 20 m) up to south east of Pamban Island, pass through a channel created in Adams Bridge within the International boundary and proceed parallel to the International Medial Line for fishing rights as the Bengal Channel. In Palk Bay area availability of depths in middle channel uk fake ray bans, capital dredging across Adams Bridge and in Palk Strait and continuous maintenance dredging along the proposed transit are the critical project related issues.


The routes selected through earlier studies particularly in Gulf of Mannar area have been rejected, keeping in view sensitivity along the coastal stretch of GOM harbouring marine national park. Instead a navigation route keeping a minimum 6-8 km distance from Van Tiu near Tuticorin and more than 20 km from Shingle in Adams Bridge approach area has been suggested.


Tuticorin Port Trust (TPT), the nodal agency identified by Ministry of Shipping, Govt. of India for the implementation of the project in pursuance of its decision to incorporate environmental considerations in the design phase of the project, retained, in March 2002, National Environmental Engineering Research Institute (NEERI) to conduct the Environmental Impact Assessment (EIA) study for the project.


This report presents briefly the project setting, describes the baseline environmental status of the project area, identifies environmental issues, predicts and evaluates impacts due to the proposed project and delineates environmental management plan to mitigate potential adverse impacts.


The EIA study has primarily drawn upon the available information on the proposed project, the hydrography, marine water quality and ecological resources in the project area, and the primary data generated during the course of study. This environmental impact assessment study with intensive data collection has resulted into fuller description and appreciation of the natural processes occurring in the study area, and delineates the environmental consequences including the ecological risk associated with the proposed project with or without proper environmental management plan.





The proposed Sethusamudram ship channel will have two legs, one near the Point Calimere called the Bay of Bengal Channel and the other across the Adams Bridge. The Bay of Bengal Channel traverses the Palk Bay wherein the sea-bed is mostly soft to hard clayey-sand in nature. Some hard strata has been reported beneth the soft sand during recent survey by the National Hydrographic Office, Dehradun. The area adjoining Admaís Bridge, Dhanushkody Peninsula on the North and the South is reported to be sandy by National Ship Design Research Centre (NSDRC), Visakhapatnam during their survey in connection with this project.


While navigational depths will be used in Gulf of Mannar from Tuticorin Port to Adamís Bridge area, a 20 km long, 300 m wide channel with 10.7 m draught with two way controlled traffic is proposed to be created as ultimate phase by dredging shallow area of Adamís Bridge upto 12 m depth. Similar excavation will be done in Palk Strait and adjoining parts of Palk Bay to achieve the required depth over a stretch of around 36 km and 18 km respectively. A control station, administrative building and Vessel Traffic Management System (VTMS) is proposed to be located at Rameswaram island between Dhanushkodi and Koil Nagar village to control navigation, besides other infrastructure including administrative requirements.



Environmental Regulations


At the National level, the environmental clearance to the project is subject to compliance with the stipulated safeguards under the provisions of Environment (Protection) Act, 1986; Forest (Conservation) Act, 1980; The Water (Prevention and Control of Pollution) Act, 1974; The Water (Prevention and Control of Pollution) Rules, 1975; The Water (Prevention and Control Pollution) Cess Act, 1977. The Water (Prevention and Control of Pollution) Act, 1981; and other rules and regulations in force. Land use on the coastline will be subject to regulation as per the Coastal Regulation Zone (CRZ) Notification issued by the Ministry of Environment and Forests (MoEF), Government of India in 1991 and subsequent amendments under the Environmental Protection Act. This notification is administered by the State Department of Environment and Forests.


The Wildlife (Protection) Act of India (1972) provides legal protection to many marine animals including reef associated organisms. Chapter IV of this Act dealing with Sanctuaries, National Parks etc. is equally applicable to marine reserves, marine national parks and biosphere reserves.


The Gulf of Mannar Marine Biosphere Reserve (GOMMBR) has been notified in 1989 through an executive communication from the Secretary to the Government of India, Ministry of Environment and Forests to the Chief Secretary, Government of Tamil Nadu.


During the operational phase of the project, the most important instrument to be complied relates to the International Convention for the Prevention of Pollution from Ships 1973 as modified by the Protocol of 1978 (MARPOL 73/78) for which India is a signatory.




Key Findings


Environmental Status


Marine Environment 

The Palk Bay and the Gulf of Mannar covering an area of 10,500 sq. km in which the proposed ship channel is to be created are biologically rich and rated among the highly productive seas of the world. Its diversity is considered globally significant. In the Gulf of Mannar, between the coast line and the proposed alignment, there are 21 islands which have been declared as National Marine Parks by the Tamil Nadu Forest Department and the MoEF, Government of India. While the proposed channel alignment in the Tuticorin Port area shall be about 6 km from Van Tiu the nearest island, in Adamís Bridge area it will be about 20 km from Shingle Island which is a part of National Marine Park.


The data on physico-chemical characteristics and marine biological resources was collected from various sampling stations in Gulf of Mannar and Palk Bay. Primary data on physico-chemical characteristics of marine water shows no significant variation in alkalinity (102-106 mg/l) and pH (8.0-8.2) along the proposed channel alignment. The DO values varied from 3.2 to 5.7 mg/l and the silicates from 0.003 mg/l to 0.017 mg/l. No significant variation in salinity is observed between surface and bottom samples. An inverse relationship between salinity and silicates has been observed. The nitrate concentrations vary from 0.78 mg/l to 1.1 mg/l. Data from secondary sources in coastal areas of Palk Bay near Palk strait shows pH ~ 8.2, D.O. 5.8-6.5 mg/l and Total nitrogen content of 0.4 mg/l.


Sediment samples collected along the proposed channel alignment show the presence of organic carbon, total nitrogen, total phosphorous and sulphates in concentrations adequate for biological growth. Almost all the sediment samples show presence of oil & grease. The concentrations of heavy metals are high in some of the sediments in the Palk Bay as compared to other locations.


Biological Resources 

The gross primary productivity along the proposed channel alignment vary from 142 to 472 mgC/m3/day indicating that the Gulf of Mannar and the Palk Bay are biologically productive regions. The zooplankton are dominated by copepod. Macrobenthos represented by 78 varieties exhibit fairly good diversity. The meiofauna comprised larval polychaetes, nematodes and worms.


The corals along the proposed channel alignment in Adamís Bridge do not exist though major groups of biological resources like sea fan, sponges, pearl oysters, chanks and holothuroids at various sampling points have been recorded. In general, the density of economically/ecologically important species along the proposed alignment is not significant.


All the three groups of prochordata organisms, considered as the connecting link between invertebrates and vertebrates, viz., hemichordata, cephalochordata and urochordata comprising 1, 6 and 59 species respectively have been recorded around the islands of the Gulf of Mannar.


There are 87 fish landing stations between the south of Point Calimere and Pumban in the Palk Bay, and 40 stations in the Gulf of Mannar between Pamban and Tuticorin. Out of over 600 varieties of fishes recorded in this area, 200 are commercially important. During 1992-1996, the fish production has increased gradually from 55,325 tonnes in 1992 to 2,05,700 tonnes in 2001.



Non-conventional fishing in the region is represented by pearl, chank, sea weeds, ornamental shells and holothurians. There has been a declining trend in the production of these organisms as evidenced by the revenue received by MPEDA.


Rare and endangered species of sea turtle, dolphin, sea cow and whale are recorded in the Gulf of Mannar and the Palk Bay. The sea cow inhabitates the shallow shore regions where grasses occur, while other endangered animals mostly prefer deep sea.


Several species of green algae (32), brown algae (35), red algae (59), blue green algae (3) and sea grasses are recorded in the Gulf of Mannar and the Palk Bay. A few of the 21 islands are reported to possess patches of mangroves predominated by Avicennia sp. And Rhizophora sp.


Most of the habitats of the sensitive biota, viz., corals, pearl oysters, chanks, sea cow, holothuroids and marine algae are along the coast and around the 21 islands, and mostly away from the proposed canal alignment.


Point calimore wild life sanctuary sprawling over 17.26 sq. km. Area comprising tidal swamp, dry evergreen forests and mangroves is located in coastal areas of Palk strait in Nagapattinam District. The sanctuary is bestowed with population of varied wildlife such as Chital, Wild Bear, Bannet, Macaque, Black Buck, Flamingoes, Teals, Gulls Tems, Plovers and Stilts, Dolphins and Turtles are seen close to shore area.


Land Environment 

Based on an analysis and interpretation of IRS IC LISS-III satellite data, merged with PAN data, degraded area in Pamban island has been delineated for anticipated disposal of dredged material to the extent possible with prior approval under CRZ regulations. A large stretch about 753 hectare, of such land between Rameshwaram and Dhanushkody is available.

There are no archaeologically significant structures along the proposed channel alignment. However, there are apprehensions of encountering cultural/ archaeological artifacts during the excavation of the channel though borehole data generated by the National Ship Design Research Centre (NSDRC) does not support such a situation.


Socio-economic Environment  


Along the coast in the Gulf of Mannar and the Palk Bay there are 138 villages and towns belonging to 5 districts. The socio-economic profile of the fishermen in the villages of Gulf of Mannar coast is low, and more than 40% of families are in debt. The local people are of concern that the creation of channel would result in the reduction of their income due to fishery.


Oceanographic Status


The hydrodynamic studies of the seabed in Adamís Bridge and its adjoining area have been carried out in May 2003 and February 2004 by retaining the services of National Ship Design Research Centre (NSRDC), Vishakhapatnam. The hydrographic charts bearing nos. 1584, 1586, 1587, 2069, 2197 and 96 have been referred while conducting the surveys.


There are two circulations of water masses observed in the Bay of Bengal, the clockwise circulation in south-west monsoon and the counter clockwise circulation in the north-east monsoon. The tidal variations are between 0.05 to 0.7 m. The current velocities in the Palk Bay and the Gulf of Mannar are as mild as 0.2 - 0.4 m/s except on few days during south-west monsoon when it rises upto 0.7 m/s. Water currents follow the directions of predominant winds. The analysis of current data shows no potential threats to siltation of channel. It is observed that during southwest monsoon the sediments move from Gulf of Mannar to Palk Bay and during fair weather the direction reverses. In annual cycle, a net exchange of 6000 m3 of sediment is found to move from Palk Bay to Gulf of Mannar through Pamban pass and 25000 m3 of sediment moves from Gulf of Mannar to Palk Bay through Arimunai.


Geological strata in Adamís Bridge area shows soft and hard sand upto 12 m with particle size varying from 65 to 600 mm. The bathymetry varies from 0.6 to 6.3 m. Depth in Palk strait averages to about 8 m.


The hydrographic survey of Palk Bay and Palk strait area has been carried out during Jan. 25 - Feb. 18, 2004 by the Naval Hydrographic Department of National Hydrographic Office (NHO). According to the findings of NHO, the seabed in this region comprises of sand and mud with few broken shells. The depth contours in the sea are in agreement with those depicted on the existing navigational chart no. 358. While navigable depth (more than 12 m) will be used in about 78 km stretch in Palk Bay, a sizable stretch (about 54 km) will require to be dredged in Palk Strait and adjoining area. Sub bottom profile studies indicate that though the upper layer of sediment is made up of mud and sand, there is some hard strata under the soft sediment. This hard strata if discovered to be rock, if would require blasting at the time of dredging to achieve the desired draught.


The tides in the area are not similar. Both semi-diurnal and diurnal tides are observed at the tidal station set up. The range of spring tides vary between 0.4 to 0.7 m. The current in the area is N-S direction with speeds varying from 0.08 to 0.8 m/s and may reach 1.8 m/s (4 kt) in spring. No wrecks and obstruction have been observed during the survey.




Impacts due to the Project


Impacts on Landbased Facilities


The project envisages construction of shore facilities to cater the needs of channel in Adamís Bridge area, viz. service jetties, slipways, buoy yard, repair workshop as also staff and administration buildings for facilitating regulated traffic in the vicinity of Adamís bridge area. The locations of land-based structures, and the extent of area required for their construction is required to be identified on Pamban island in consultation with local authorities. Most of the land east of Rameshwaram is barren and covered by sand and scant vegetation. There are few hamlets at Arimunai and Dhanushkodi who are engaged in fishing. These fisherman will be displaced in the event the land based facilities are planned in this area. Temporary displacement of these fisherman is envisaged. A BSF check post will also be temporarily affected. Land on Pamban island has also been identified for disposal of dredged material (silt / clay / sand). The land cover, landuse as also the ownership of sites required for the project related activities will be firmed up once the modus-operendi of traffic regulation in channel is finalized. Hence, the extent of land acquisition, the need for resettlement and rehabilitation of affected population, if any, can not be assessed at this juncture. However, given the fact that channel will cut across the Adamís Bridge area, the impacts on land based facilities would be negligible in comparison to that envisaged in earlier studies where land locked canal cutting through Pamban Island was proposed.

During the construction of the ship channel, it is anticipated that considerable sea-borne activity in the form of logistic and support services would take place. This would have significant adverse impact on the traditional fishing activities by the licensed fisher folk and consequently on their income levels.


Impacts on Productivity and Ecology in GOM/Palk Bay


As the proposed alignment in Gulf of Mannar is more than 20 km away from the existing 21 islands in National Marine Parks in the Gulf of Mannar, the marine biological resources around these islands will not be affected to any significant level.


The existing level of primary productivity in the project area will remain practically unaltered during the construction and operation phases of the channel. There would not be any significant change in water quality including turbidity due to the proposed deployment of cutter suction/trailor suction hopper dredgers for capital and maintenance dredging.


Due to dredging the bottom flora and fauna on an area about 6 sq. km along the channel alignment in Adams Bridge and about 16-17 sq.km in Palk Bay/Palk Strait area will be lost permanently. This loss, however, will be very insignificant compared to the total area of 10,500 sq. km of the Gulf of Mannar Marine Biosphere Reserve.


In Adamís Bridge area about 38 million m3 of dredge spoil comprising about 7-8 million m3 clay silt will be generated for achieving 12 m depth for 300 m wide channel including allowances for slope and tolerance. It is proposed that spoil containing a mixture of clay and sand will be disposed on degraded areas of Pamban island for reclaiming the land subject to approval of Forest and Environment Department (TN) for use of area falling under CRZ as dumping of wastes in CRZ area is not permissible activity. Balance 30 million m3 spoil containing mainly sand (particle size 125 mm to 600 mm) will be discharged in sea 25 km away from the dredging area keeping safe distance from medial line at depths varying from 30-40 m to minimise the impact. In the event of restricting the channel to 10 m depth to suit vessels with 9.15 m draught, the quantity of dredged spoil will reduce by 13.5 million m3 and material required to be disposed in sea will be 16-17 million m3 instead of 30 million m3 as envisaged for 12 m depth. This would further minimize impacts on sea bed due to disposal of dredged spoil.


In Palk Bay area, about 44 million m3 of dredged spoil will be generated due to excavation activity in Palk strait and Palk Bay to achieve 12 m depth for 300 m channel including allowances for slope and tolerance. The NHO data indicate hard strata beneth soft sand hence spoil may contain silt, sand and hard material. The dredging may also require blasting if hard strata is encountered. In the event of blasting, adverse impact on sea bottom fauna is envisaged. The spoil is proposed to be discharged in Bay of Bengal at suitable depth (25-40 m) to minimize impacts on coastal areas of Palk Bay. An option of using silt/clay for beach nourishment is also recommended. In the event of restricting the channel depth to 10 m the requirement of dredging in Palk Bay/Palk strait will drastically reduce to about 14.8 million m3 as against 44 million m3 envisaged for 12 m depth. This would minimize environmental impacts as well cost of dredging and disposal.


It would be ideal to explore the possibility of dredging the channel to 10 m depth in first phase to cater to vessels of 9.15 m draught and monitor environmental status during construction and operation phases. The proposal of 12.0 m depth can subsequently be taken up in second phase provided adverse impacts on environment are not observed.


Hydrodynamic modelling studies using Depth Integrated Velocity and Solute Transport (DIVAST) model have shown that, even for the highest spring tidal water conditions, there will be no significant change in the magnitude and direction of current velocities along the proposed alignment due to the construction of the channel in Adamís bridge area.


During the construction and operation phases of the channel, the potential sources of marine pollution are spillage of oil and grease, marine litter, jetsam and floatsam including plastic bags, discarded articles of human use from the sea-borne vessels which will have to be controlled.


The channel may facilitate the movement of fishes and other biota from the Bay of Bengal to the Indian Ocean and vice versa. By this way, the entry of

oceanic and alien species into the Palk Bay and the Gulf of Mannar, as also the dispersal of endemic species outside the Palk Bay and the Gulf of Mannar could occur.


Socio-economic Impact


The channel will establish a continuous navigable sea route around peninsular coast within the Indian territorial waters, reduce shipping distance by about 254-424 nautical miles and voyage time of about 21-36 hrs as also the attendant operating costs. The channel will become a valuable asset from national defence and security point of view enabling easier and quicker access between the coasts.

Due to the construction of infrastructure in the island, the land access, now available to the local fisher folk to Dhanushkody area for traditional fishing will be hindered unless alternative arrangements are made. The dredging and shipping operations will have to be so regulated as to cause minimum disturbance to the normal fishing activities.

The project will provide employment opportunities and avenues of additional income through establishment of small ancillary industries. The project will also trigger development of coastal trade between the ports south and north of Rameswaram consequently reducing the load and congestion on railways and roadways.

The project will help in saving considerable foreign exchange through reduction in oil import bill and generate revenue income from dues levied on ships transiting the channel which will add to the national economy.



Environmental Management Plan


Construction Phase

  • No dredging will be done in Gulf of Mannar except in Adamís Bridge area

  • Alignment of navigation route at Adamís Bridge in Gulf of Mannar will be minimum 20 km away from marine national park

  • Land acquired for mobilization and monitoring of activity will be returned to users after completion of dredging activity

  • A proper rehabilitation plan for the fisherman at Dhanushkody will be drawn during construction phase

  • Dredged spoil comprising clay and sand upto 2 m of dredging depth will be used for  reclaiming degraded land in Pamban island subject to approval of FED for CRZ. Balance dredged spoil will be disposed in sea at a depth 30-40 m, 20-25 km away from islands in National Marine Park in Gulf of Mannar. Dredged spoil generated in Palk Strait / Palk Bay area will be disposed in open sea in Bay of Bengal at
    25-40 m depth, 30-60 km away from dredging area

  • Safe distance (about 4 km) from international medial line will be maintained

  • During dredging activities, the equipments, vessels, barges required for dredging and transportation of dredged spoil will be maintained in secured area and spillage of oil or any toxic material including paints, anticorrosive agents etc. will not be allowed to spill in sea/coastal waters

  • Movement of barges for transporting dredged spoil to land area will not interfere with movement of fishing boats in both Gulf of Mannar and Palk Bay region adjoining the Adamís Bridge

  • It is also recommended that existing jetties at Rameswaram which only cater to fishing activities presently should be augmented to cater to the requirement of handling dredging activities in Adam Bridge and Palk Bay area

  • Transportation of heavy machinery and construction material in the vicinity of Adam's Bridge will be by sea route using the available navigational depths

  • During transportation of heavy equipments and machinery by road, care will be taken to avoid traffic hazard, traffic congestion and if required roads will be augmented to meet the conditions of hazard free transportation.

Operational Phase

  • All the ships originating from Tutitcorin Port will comply to International Maritime Standards and follow MARPOL convention (MARPOL 73/78)

  • Discharge of bilge, ballast, treated sewage, solid wastes, oily wastes and spillage of cargo will not be allowed in the Gulf of Mannar and Palk Bay area

  • The traffic of crude oil tankers will be allowed in this route with strict vigilance so as to avoid any possibilities of spillage in this region

  • It will be ensured that ships navigating in this region should not use such paints and anticorrosive agents on ship bottom which can cause damage to marine organisms

  • A pilot should be trained or environmental watcher will board the ship to watch marine animals viz. turtle, dolphins, sea cow etc. in the region and navigate the ship safely avoiding any damage to this fauna.

  • It will be ensured that all the ships berthing at TPT as well as all those using the route without touching TPT will have proper treatment facilities for sewage however discharge of treated sewage will not be permitted in GOM and Palk Bay / Palk strait area

  • Ships bypassing TPT and transiting the channel will be inspected for its navigational safety measures before it is allowed to enter proposed navigation route

  • An oil spill contingency plan will be drawn by Tuticorin Port Trust with preparedness to prevent spread of spillage in Gulf of Mannar and Palk Bay area and its immediate recovery by deploying equipments and ships

  • To benefit large fishing communities in the coastal area of Ramnathpuram and Rameshwaram, a corridor both in terms of space and time be provided to fisherman to use the channel in Adamís Bridge area for moving across Palk Bay to GOM and vice versa for fishing activity

  • The jetties at Rameswaram are in dilapidated conditions. A programme to construct a few Jetties at Pamban island to augment fishing activity in the region be supported by TPT

  • The traffic of ships carrying crude oil will be handled with strict vigilance so as to avoid possibility of spillage

  • The oil spill contingency plan in operation at TPT will be extended to navigation activities in new channel

  • A pilot will board the vessel either from Rameswaram or appropriate place to navigate ship through GOM area up to Bengal Channel in Palk Bay

  • The channel will be properly marked by navigational light buoys

  • Accidents by collision of ships with fishing boats will be totally prevented by slowing down the cruise speed and also alerting the fisherman by cautionary measures. During implementation and operational phases of the project, TPT will take action to avoid the collisions of ships with fishing boats or damage to fishing nets with cooperation from fishing communities, Navy, Coast Guards and other Govt. authorities

  • Suitable timings apart from ship transit will be given for fishermen to continue with their fishing activities

  • Maintenance dredging of about 0.55 million m3 per year is envisaged in the channel based on data available for sediment transport across Palk Bay and Gulf of Mannar

  • The dredged material will be mostly silt and clay and will not be disposed in sea. Instead it will be used to reclaim degraded areas on Pamban island, Ramnad and Mandapam coastal stretches

  • To cater to increase in trade envisaged due to this project and to transfer benefit to local fisherman, a minor port facility can be created at Rameswaram in consultation with state authorities