Sethusamudram: to strike a balance

WITH 36 years of marine fisheries research work and particularly being part of Gulf of Mannar and Palk Bay scientific research programmes for 15 years, I felt motivated to highlight the implications of the Sethusamudram Ship Canal Project (SSCP) to natural resources of the area and evaluate strengths and weaknesses of the SSCP from a biological angle for a pragmatic view of project execution.

On the face of it (The Hindu, November 2) the present project appears far better and appropriate than the earlier proposal, which was to make a land canal near Uchippuli (Ramnad district) or cut the Rameswaram island itself.

The area is strategic in terms of geography, history, mythology, politics, commerce, navigation, meteorology, biology and culture. Typical reversal of the Northeast monsoon (October-December) and the Southwest monsoon (June-September) with strong gales, at times reaching up to 100 km per hour, accompanied by storms and cyclones affect the area. Fishing operations shift from the Palk Bay to the Gulf of Mannar and vice versa depending on the calmness of the sea, thus ensuring year round occupation to coastal communities. A series of sensitive islands with coral reefs in the Gulf of Mannar, the diverse marine habitats and complex physical, chemical, biological characteristics of the water make the area a classical and rich biosphere.

About 3,600 species ranging from diatoms to whales that include an array of phyla composing of sponges, corals, crustaceans, molluscs, echinoderms, fishes, turtles and mammals abound in the area. The endangered sea cow and turtles constantly use the region as their habitats. The world famous pearl oyster beds are located in the Gulf of Mannar.

However human interference in the past has been very intense leading to extensive destruction and fragmentation of marine habitats and living resources, which are the mainstay of the people. This has been controlled to a great extent by the establishment of the Gulf of Mannar Marine Bioreserve (GOMMBRE) in 1989.

About one lakh people are estimated to live in 127 fishing villages along the course of SSC, of which 87 villages are in the Palk Bay area and 40 in the Gulf of Mannar area. They mainly depend on fishing, collection of seaweeds and shells for ancillary industries.

The economic benefits of the project are claimed to be immense. The canal provides a shorter route linking all the ports along the east coast and round the peninsula to the west coast. This reduces cost of fuel and time for navigation. Maritime trade and commerce will improve. Fishing harbours could be developed and fishing activities get extended to oceanic areas for reaping better and valuable harvests.

Great potential for employment opportunities is foreseen. National defence and security of the area can be strengthened. Due to development of efficient ocean transportation, foreign exchange earnings would increase. Consequently, the dependence on foreign shores for transhipment of Indian cargo will decrease.

The amount of silt and turbidity resulting from dredging can have far reaching direct and indirect effects on the flora and fauna of the area. The very route of navigation can alter water quality. The traffic (6 to 9 trips a day) will cause enough disturbances in the otherwise placid waters. The accompanying pollution by way of oil spills, discharge of bilge water, marine litter, grease, rust and metallic wastes, generation of flotsam, jetsam and other human wastes would be highly deleterious to living resources of the sea.

Diminished sunlight due to turbidity directly affects primary productivity and thereby the flora and fauna. Silt and sediments besides smothering and burying benthic fauna, especially the coral reefs, affects plankton, dissolved oxygen content of water and impairs respiration of animals by choking. Destruction of seagrass and seaweed beds can spell doom to sea cow, turtles and a wide variety of fishes that depend on this habitat, in the long term.

Underwater currents will erode shorelines, reefs and paars. Alteration of the prevailing currents (0.7 m/s) may transport sediments, silt and sand to unknown locations. This may entail continuous dredging to remove silt/sand (0.5 million cubic metres/year) the cost of which could be prohibitive. The disposal of dredged debris, sediments, sand and silt would pose a serious challenge. Dumping this in the sea would surely harm marine wealth. How much of international shipping would make use of this route to the advantage of the country is only a guess at the moment.

The grave concerns expressed above have to be addressed dispassionately to obviate the damage to ecology of the region. The following suggestions are offered to strike a balance to avoid peril to the bounty of nature.

The sustainable use of ocean should be the prime concern.

The SSC route should take a course first at right angles to Tuticorin port (8.48 N Lat., 78.11 E Long.) and then almost perpendicular to Adam's Bridge (9.05 N Lat., 79.35 E Long.) in the north to minimise the damage to living resources.

Prohibit any type of discharge by ships in the canal and adjacent areas.

Environment-friendly methods of dredging have to be employed and monitored.

The dredged material and debris may be dumped at Dhanushkodi to reclaim the lost land with suitable measures for rehabilitation of fishermen and others inhabiting the site.

Continuous monitoring of environmental parameters during and after the construction of the canal, and for about three years during operational phase by experts should be an integral part of the project. Utilisation of sea-truth data rather than mathematical modelling or trace studies will be an apt method of approach.

Coastal biodiversity, the marine reserve and the ocean environment should be protected.

The overall economics of the entire project, the savings in time, fuel and funds and the notional damage to sensitive coral reef ecosystem/living resources need critical analysis.


Former Director, Central Marine Fisheries Research Institute, Cochin

Recommended for you