Possible ecological consequences from the Sethu Samudram Canal Project, India
Marine Pollution Bulletin
Volume 56, Issue 2, February 2008, Pages 170-186 doi:10.1016/j.marpolbul.2007.10.018
D.V. Subba Rao a, , , K. Srinivasa Rao b, C.S.P. Iyerc and P. Chittibabud
aBedford Institute of Oceanography, Habitat Ecology Division, Department of Fisheries and Oceans, P.O. Box 1006, Dartmouth, NS, Canada B2Y 4A2
b815 Rainier Court, Allen 75002, Texas, USA
cIndian Institute of Information Technology & Management Kerala, Thiruvananthapuram, Kerala, India
dBaird and Associates Coastal Engineers, Suite 500, 1145 Hunt Club Road, Ottawa, Ontario, Canada K1V 0Y3
Available online 20 December 2007.
The Sethu Samudram Canal Project (SSCP), considered as a harbinger of economic growth in India, is a mega engineering project being developed to provide a 260 km long, 300 m wide and 12 m deep shipping channel between the Arabian Sea and the Bay of Bengal. This project impacts the unique biota and biodiversity of a 10,500 km2 Marine Biosphere Reserve. This man-made link facilitates exchange of water masses between the less saline Bay of Bengal and the more saline Arabian Sea. Initial construction, subsequent dredging for channel maintenance, and the associated ship traffic would result in irreversible changes to the already over-exploited and stressed environment. Additionally, the channel would form a deep ocean route for future tsunamis. However, to provide assurance to the public, particularly the 50,000 fishing folk, in 47 villages in this area, it would be crucial that a long-term environmental monitoring program is instituted. A thorough evaluation of the impending environmental impacts, similar to those addressed by a Before/After and Control/Impact (BACI model) is recommended.
Keywords: Mega-engineering shipping channel; Environmental impacts; Tsunamis; India–Sri Lanka region/
Corresponding author. Present address: 12 The Horseshoe, Manor Park, Dartmouth, Nova Scotia, Canada, B2Y 4E5. Tel./fax: +1 902 463 7804.
Comments on the SSCP by Dr. CSP Iyer, Indian Institute of Information Technology and Management, Kerala, Thiruvananthapuram, Kerala, India (20 March 2008)
1. The NEERI on the project was submitted in May 2004 and it was titled rapid EIA. In August 2004 the final version appeared which incorporated bathymetry survey of NHO. This version was without the words rapid EIA normally for project of this magnitude a comprehensive EIA covering all the seasons of primary data is required. However this has not been carried out. Their EIA notification 1994 also requires risk assessment report, disaster management plan and an environmental management plan. They needy EIA list briefly they impacts an risk without any contification.
2. Under the wild life protection Act 1972 it is necessary to get a clearance under this Act since corrals along with rate species as sea horses, sea cows etc., are in this area.
3. It is well known that the area under study is a high sedimentation place. It was therefore necessary to collect primary data in the region. However primary data is collected only at Adams Bridge. No studies have been conducted in Palk Bay and Palk Strait. In the absence of such a data it is very difficult to come to realistic figures of Capital dredging and more importantly that of maintenance dredging. In this context it is suggested that since part of the channel is already dredged, we can make use of this channel to make realistic estimates of the sedimentation during the period of the on coming south-west monsoon.
4. Regarding the dumping of the dredged spoil, there is no idea given as to dumping sites it is necessary to evaluate this and carry out radio active tracer studies to optimize the dumping areas.
5. The environmental studies carried out by center for advance study in Marine Biology, Annamalai university and Suaganthi, Devadasan Marine research institute Tuticorin as given in appendix 6.1 of chapter 6 of the report by the committee of the eminent persons merely mentions that there is no influence on physical or chemical or biological parameters due dredging it is also mentioned that there is no impact on quarrels reefs for a scientist to appreciate it one should have figures in terms of the parameters measured to arrive at such conclusions.
6. Any dredging activity would lead to destruction of Benthic and other sedentary organisms on the ocean flow. This would lead to significant alteration in the seabed and make the Benthic recovery protracted process. In this connection, it may be mentioned that changes in bathymetry will change local flow patterns of sediment flex and effect sediment of Benthic organisms equilibrium of quarrels would be reached only after a period 5 to 10 years.
7. A brought comparison of Bay of Bengal prevails existence of large distances in physical, chemical and biological characteristics. The Balk Bay waters resemble more those of the Bay of Bengal with respect to their lower senility. The Gulf of mannar on the other hand has higher senility as it is connected to the Arabian Sea are these different characteristics of the Palk Bay and Gulf of mannar has contributed to the unique of the nature of the Bio diversity in this region one more important factor is the difference in depths of the Palk bay compared to the Gulf of Mannar is very significant from the Adams Bridge to the Gulf of mannar site there is a steep drop in depth to the tune of nearly 1000 meters where as on the Northern side of the Adams Bridge the drop in that is only of the order of 5 to 10 meters. Once the channel is made cutting a cross Adams bridge they difference the depths in between the water masses will lead to an ecological catastrophe.
8. The fish heel and the fish stocks are lower in the Bay of Bengal than in the Arabian Sea. Once the Adam’s bridge is cut-open the fish spanning ground will be affected.
9. The existence of quarrels in this Gulf of mannar is due to the unique nature of the water characteristic and the bathymetry of the gulf of mannar. Once the channel is made effect on corals would have to be assessed.
10. The present alignment of the channel has been made 20kms away from the nearest island has been chosen and the justification for has not been made clear. Is it because we will be almost touching he International boundary line between India and Sri Lanka.