The Ram Sethu Canal Must Be Scrapped for Scientific Reasons

There are plenty of reasons to scrap the Sethusamudram project: we don’t know how sediments behave within the canal, how cyclones will affect it and how its marine environment will be wrecked.

The location of Palk Bay. Credit: Google Maps

The location of Palk Bay. Credit: Google Maps

Ever since the UPA government mooted the Sethusamudram Shipping Canal Project (SSCP) in 2004, it has been a target of criticism from environmental advocates as well as religious enthusiasts. The project envisages excavating the shallow sea between the Palk Bay and the Gulf of Mannar to create a narrow shipping passage, linking the east and west coasts of India and obviating the current ‘hassle’ of circumnavigating Sri Lanka to reach the eastern coast of India (and vice-versa).

The total length of the channel is estimated to be 152.2 km. Creating it will require two phases of dredging (or even blasting, depending on the nature of the substratum) the 20-km-long coral-reef platform known as ‘Adam’s Bridge’ or ‘Ram Sethu’, as some like to call it, and the 54-km long Bay of Bengal segments. The third segment falls in the Palk Bay, with a total length of 78 km and which reportedly requires no dredging as this area has a clearance depth of 12 m.

Sethusamudram, as the name suggests, is that part of the ocean being constantly bridged by natural sedimentation processes. Like the Great Barrier Reef off of the northeast coast of Australia, Ram Sethu is a continuous stretch of limestone shoals that runs from the Pamban island near Rameswaram to Mannar Island off of the northern coast of Sri Lanka. Because the ocean floor is shallow in this area, natural processes have formed coral platforms here for millions of years.

During a glaciation period 20,000 years ago, many parts of the Indian coast including, parts of Sethusamundram, may have been exposed above water. From 20,000 years ago until 6,000 years ago, seas level steadily rose around the world due to glaciers melting. As it did, the coral polyps could once again have grown higher on the newly submerged platforms. And in time, the platforms may have been used by human migrants to cross over the oceans. The Indian epic Ramayana refers to a putative land bridge in this region; believers hold it as the structure that Lord Ram and his army built to reach Lanka.

An initially assessment by the National Environmental Engineering Research Institute (NEERI) ruled out any environmental risk and certified the feasibility of the project. However, serious concerns have been raised from different quarters on the stability of the proposed canal and the environmental impact of this project. Its total cost is Rs 25,000 crore.

Government agencies entrusted with this work at that time seemed to show an extraordinary enthusiasm, brushing aside uncomfortable questions and keeping the public in the dark about the canal’s stability and adverse environmental impact. However, using an interim order in 2007, the Supreme Court had stayed the dredging of the Ram Sethu after admitting a plea that it had immense religious value for Hindus. Subsequently, the UPA government was compelled to constitute a committee in 2008 headed by R.K. Pachauri, then the director-general of The Energy and Resources Institute, to explore the possibility of an alternative route that would not affect Ram Sethu’s integrity. His committee found that the project could pose a serious threat to the ecosystem even after adopting an alternate alignment. Their report was also critical of the government’s economic claims.

Many known unknowns

The Palk Bay region is a sediment sink. The different stretches of the bay, through which the canal passes, are thought to have variable sedimentation rates. Even today, the sedimentation dynamics within the bay is not completely understood. For example, scientists don’t know the net annual quantity of sediment transported within the basin nor the pattern in which it is deposited. This raises serious concerns about how the dredging will be maintained.

Cyclonic storms are also a major risk factor in the area. Tamil Nadu’s coast in general, and the project area in particular, is considered to be very vulnerable to such storms. For example, in December 23, 1964, a storm surge washed away the Pamban Bridge and Dhanushkodi island. Cyclones can and do unleash autonomous dynamics of their own that redistribute sediment and disperse the dredged material. So how a cyclonic storm will change the sedimentary budget of the Ram Sethu region is not fully understood, consequently skewing the predicted estimates of sedimentation patterns and their rates.

In other words, the total amount of material to be dredged could be much more than projected. Second: cyclones could necessitate a reevaluation of the amount of dredged material to be dumped at various sites.

So the SSCP’s sustainability if struck by a cyclone or a tsunami is a real concern – and not just from a hazards point of view. Computer models suggest that the central portions of the Palk Bay and those located to its ease and northeast also receive waves of higher energy. This means that these areas also receive more sediments, rendering them more turbid. The models also indicate that waves enter the bay from its north and south, corresponding to how the canal is aligned. So another question arises: will attempts to deepen the canal create a new deep-water route for a future tsunami to reach India’s west coast?

Experts think the answer is ‘yes’ – that the canal’s Bay of Bengal entrance could funnel a tsunami through from the south Sri Lanka to south Kerala and also make the waves taller in the process.

A third point of concern is safety. For example, where can the dredged material be disposed safely, without harming terrestrial or marine ecosystems? Some experts also think that sediment slides could make the channel itself unstable. The emissions of ships traversing a channel as narrow as the one SSCP will build will pollute the air and water. Additionally, if a rogue ship containing oil or coal is grounded or strays from its course within the canal – or if two such ships collide – the ensuing ecological disaster will be terrible. Alternatively, if ships are going to be guided by tugs, a toll would have to be charged that would work out be more expensive than sailing around Sri Lanka.

Open to abuse?

Meanwhile, it has also been announced that the Indian Council of Historical Research will conduct a pilot project to “ascertain” if Ram Sethu was built naturally or by intelligent creatures. How is this assumption going to be scientifically validated? Victor Mallet, the author of a recent book on the Ganges, River of Life, River of Death, asks a pertinent question: “How can the Ganges be worshipped by so many Indians and simultaneously abused by the same people?” A similar might be awaiting the Ram Sethu as well.

The coral reef platforms between Thoothukudi and Rameswaram in the Gulf of Mannar are notified as a marine biosphere reserve of India. About more than 36,000 species of flora and fauna live here, flanked by mangroves and sandy shores considered conducive for turtles to nest. It is also a breeding ground for fish, lobsters, shrimps and crabs. Of the 600 recorded varieties of fish in the region, 70 are said to be commercially important. Plus the whole area is already threatened by discharge from thermal plants and brine run-off from salt pans. The shipping canal, if it becomes a reality, will be the final body blow to this sensitive environment – not to mention the livelihoods of thousands of people.

So, the project should be scrapped quickly and for reasons that can be validated scientifically. Sound scientific arguments to abandon the project are aplenty.

C.P. Rajendran is a professor of geodynamics at the Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru.