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Environmental Impact Assessment for Proposed Sethusamudram Ship Channel Project Sponsor Tuticorin Port Trust, Tuticorin National Environmental Engineering Research Institute Nehru Marg, Nagpur - 440 020 August 2004

EIA Full Report of Neeri on Sethusamudram Ship Channel Project

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Page 1: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Environmental Impact Assessment for Proposed Sethusamudram Ship Channel Project

Sponsor

Tuticorin Port Trust, Tuticorin

National Environmental Engineering Research Institute Nehru Marg, Nagpur - 440 020

August 2004

Page 2: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

National Environmental Engineering Research Institute

Nehru Marg, Nagpur - 440 020

August 2004

Sponsor

Tuticorin Port Trust, Tuticorin

Environmental Impact Assessment for Proposed Sethusamudram Ship Channel Project

I N D I A

Tamil Nadu

Rameshwaram

Point Calemer

Mandapam Keelakkarai

Valinokkam

Terkmukkaiyur

Vembar

VaiparTuticorin

S R

I

L A

N K

A

I N D I A

GULF OF MANNAR

BAY OF BENGAL

PALK BAY

Palk Strait

Mandapam

Page 3: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Contents

Item Page No. List of Figures vi List of Tables xi List of Plates xv List of Drawings xvi

1. Introduction 1.1-1. 25

1.1 Preamble 1.1 1.2 Earlier Studies Involving Creation of Canal 1.3 1.3 Project Region 1.7 1.4 Geomorphology of Study Region 1.9 1.5 Environmental Impact Assessment (EIA) 1.14

1.5.1 Objectives of EIA Study 1.15 1.5.2 Scope of the Study 1.15 1.5.3 Plan of Work 1.16 1.5.4 Components included in the Study 1.17

1.5.4.1 Coastal Waster Environment 1.17 1.5.4.2 Marine Environment 1.17 1.5.4.3 Land Environment 1.18 1.5.4.4 Biological Environment 1.18 1.5.4.5 Socio-Economic and Health Environment 1.19 1.5.4.6 Ecological Risks 1.19

1.5.5 Environmental Management Plan 1.20

1.6 Techno-economic Viability 1.20

1.6.1 Traffic Potential 1.20 1.6.2 Alignment of Canal 1.20 1.6.3 Dredging and Disposal Areas 1.21 1.6.4 Cost Estimates and Economic Viability 1.21

1.7 Permits and Approvals 1.21

Figures 1.1-1.3 1.22-1.24 Table 2.1 1.25

2. Proposed Project and Oceanographic Environmental Setting 2.1-2. 104

2.1 Proposed Project 2.1

Page 4: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

2.2 Oceanographic Status in Project area along Route Alignment 2.2

Page 5: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Item Page No.

2.2.1 Waves 2.2

2.2.1.1 Wave Measurement 2.3 2.2.1.2 Wave Refraction 2.4 2.2.1.3 Wave Period 2.5

2.2.2 Tides and Currents 2.5

2.2.2.1 Longshore Currents 2.5 2.2.2.2 Currents Studies 2.7

2.2.3 Sediment Transport 2.12

2.2.3.1 Longshore Sediment Transport 2.13 2.2.3.2 Spit Configuration 2.22

2.2.4 Geological Strata along Navigational Channel in 2.23 Adams Bridge Area 2.2.5 Bathymetry and Shallow Seismic Survey in 2.25 Gulf of Mannar and Palk Bay Area

2.2.5.1 Bathymetry and Shallow Seismic Survey in Area Identified for Channel in Adam's Bridge 2.26

2.2.5.2 Bathymetry Survey of Area of 4 km. X 4 km. 2.36 2.2.5.3 Bathymetry and Seismic Survey along the

Channel in Palk Bay Area 2.37

2.2.6 Selection of Route in Adam's Bridge Area 2.38 2.2.7 Navigation Route in Palk Bay and Palk Strait 2.38 2.2.8 Computation of Dredged Material 2.38

2.3 Environmental Setting in Project Area 2.39

Figures 2.1-2.51 2.44-2.98 Tables 2.1 - 2.6 2.99-2.104

3. Marine Environment 3.1-3.167

3.1 Physico-chemical Characteristics 3.1 3.2 Biological Characteristics 3.3 3.3 Biodiversity of Islands in Study Region 3.32

3.3.1 Mandapam Group 3.32

3.3.1.1 Shingle Island 3.35 3.3.1.2 Krusadai Island 3.35 3.3.1.3 Pullivasal and Poomarichan Island 3.36

Page 6: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

3.3.1.4 Manoli and Manoliputti Islands 3.38 3.3.1.5 Musal Island 3.39

Item Page No.

3.3.2 Marine Organisms Observed around the Mandapam Group of Island 3.40

3.3.3 Trend of Fish Catch in Mandapam Region 3.42 3.3.4 Keezhakarai Group 3.42

3.3.4.1 Mulli Island 3.43 3.3.4.2 Valai and Talairi Islands 3.44 3.3.4.3 Appa Island 3.45 3.3.4.4 Anaipar Island 3.46

3.3.5 Marine organisms recorded around Keezhakarai Group Islands 3.47

3.3.6 Vembar Group 3.48

3.3.6.1 Nallathanni Island 3.49 3.3.6.2 Pulivinichalli Island 3.49 3.3.6.3 Upputhanni Island 3.50

3.3.7 Marine Organisms around Vember Group of Islands 3.51 3.3.8 Tuticorin Group 3.52

3.5.8.1 Karaichalli Island 3.53 3.3.8.2 Vilanguchalli Island 3.53 3.5.8.3 Kasuwar Island 3.54

3.3.9 Marine Organisms 3.55

3.4 Palk Bay/Palk Strait 3.56

3.4.1 Marine Water Quality 3.56 3.4.2 Biological Productivity 3.56

3.4.2.1 Primary Productivity 3.57 3.4.2.2 Secondary Productivity 3.59 3.4.2.3 Tertiary Productivity 3.61

3.4.2.4 Benthos 3.61

3.4.3 Sponges and Corals 3.62 3.4.4 Fishing in Palk Bay 3.64 3.4.5 Marine Mammals 3.64 3.4.6 Distribution of Palk Bay Reef 3.65 3.4.7 Review of the Coral Reef Ecosystem of Palk Bay 3.66 3.4.8 Present Status of Palk Bay 3.69 3.4.9 Wildlife Sanctuary Adjoining Palk Strait 3.70

Page 7: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

3.5 Gulf of Mannar 3.72 3.6 Issues Related to Coral Reefs 3.73

3.6.1 Natural Stresses to Coral Reefs 3.74 3.6.2 Impacts of Human Activity on Coral Reefs 3.75

Item Page No.

3.6.2.1 Sedimentation 3.76 3.6.2.2 Runoff/Chemical Pollution/ Water Quality 3.77 3.6.2.3 Sewage 3.78 3.6.2.4 Temperature Stress and Bleaching 3.79 3.6.2.5 Coral diseases 3.80 3.6.2.6 Destructive fishing practices 3.80

3.7 Impacts in Palk Bay and Gulf of Mannar 3.82 3.8 Conservation 3.83 3.9 Future Direction 3.84 3.10 Strategies for Coral Reef Ecosystems in India 3.85

3.10.1 Analyzing the Short Comings in Coral Reef Conservation in India 3.85

3.10.2 Understand the Coral Reef Problems 3.85 3.10.3 Determine the True Economic Value of Coral Reefs in India 3.85

3.10.4 Coral Reef Conservation Education 3.87 3.10.5 Focus Management of Coral Reef around the Stakeholder 3.87 3.10.6 Incorporate More Coral Reefs in Marine Protected Areas 3.87 3.10.7 Control Managing Practices 3.88 3.10.8 Promote Sustainable Uses 3.89

3.10.9 Monitor the Effectiveness of Coral Reef Management in India 3.89

Figures 3.1-3.18 3.92-3.109 Tables 3.1-3.46 3.110-3.167

4. Land Environment 4.1 - 4.15

4.1 Objectives 4.1 4.2 Data Used 4.2 4.3 Hardware and Software Used 4.3 4.4 Selection of Study Sites 4.3 4.5 Methodology 4.4 4.6 Data Interpretation 4.6 4.7 Identification of Dumping Sites for Dredged Materials 4.8

Plates 4.1-4.4 4.10-4.13 Tables 4.1-4.2 4.14-4.15

Page 8: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

5. Socio-economic Environment 5.1 - 5.19

5.1 Socio-economics of the Fishing Community 5.1 5.2 Sample Survey 5.3 5.3 Existing Status 5.6

Tables 5.1 - 5.3 5.13-5.19

Item Page No.

6. Assessment of Environmental Impacts 6.1-6.77

6.1 General 6.1 6.2 Impact Networks 6.1 6.3 Impacts due to Land Based Facilities 6.2 6.4 Impacts due to Dredging 6.3

6.4.1 Dredged Material Disposal 6.7

6.4.1.1 Disposal on Land 6.7 6.4.1.2 Disposal in Sea 6.8

6.5 Impacts due to Road and Rail Traffic 6.12 6.6 Impacts on Productivity and Ecology in GOM/Palk Bay 6.12 6.7 Impacts on Hydrodynamic Conditions 6.15

6.7.1 Tidal Current Distributions – Before and After Dredging 6.16 6.7.2 The Salient Conclusions 6.18

6.7.2.1 Gulf of Mannar 6.18 6.7.2.2 Palk Bay 6.18

6.8 Socio-economic Impact 6.19 6.9 Analysis of Alternatives for Route Alignment 6.19

Figures 6.1-6.30 6.23-6.58 Tables 6.1 - 6.11 6.59-6.76

7. Environmental Management Plan 7.1-7.9

7.1 Construction Phase 7.1

7.1.1 Acquisition of Land for Onshore Facilities 7.1 7.1.2 Dredging Activity 7.1

7.2 Operational Phase 7.3

7.2.1 Route Alignment 7.3 7.2.2 Discharges from Ships 7.3 7.2.3 Maintenance Dredging 7.5

Page 9: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

7.3 Summary of Environmental Management Plan 7.6

7.3.1 Construction Phase 7.6 7.3.2 Operational Phase 7.7

8. Bibliography 8.1-8.7

List of Figures

Figure No. Title Page No.

1.1 Shipping Routes in East Coast of India 1.22

1.2 The Gulf of Mannar and Palk Bay/Palk Strait Area 1.23

1.3 The Study Area 1.24

2.1 Measured Significant Wave Height 2.44

2.2 Measured Maximum Wave Height 2.44

2.3 Wave Refraction Between Tuticorin and Arimunai (NE Monsoon) 2.45

2.4 Wave Refraction Between Tuticorin and Arimunai (SW Monsoon) 2.46

2.5 Wave Refraction Between Tuticorin and Arimunai (SW Monsoon) 2.47

2.6 Wave Refraction Between Arimunai and Vedaraniyam 2.48 (NE Monso

2.7 Variation of Currents Off Arimunai in SW Monsoon 2.49

2.8 Components of Currents Near Surface off Arimunai (Stn. C1) during Southwest Monsoon 2.50

2.9 Components of Currents near Bottom Off Arimunai (Stn. C1) during Southwest Monsoon 2.51

2.10 Variation of Currents off Uthalai (GM)in SW Monsoon 2.52

2.11 Components of Currents near Surface off Rameswaram Island South (Stn. C2) (GM) during Southwest Monsoon 2.53

2.12 Components of Currents near Bottom off Rameswaram Island South (Stn. C2) (GM) during Southwest Monsoon 2.54

2.13 Variation of Currents off Pamban Pass in SW Monsoon 2.55

Page 10: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

2.14 Components of Currents near Surface off Pamban Pass (Stn. C3) during Southwest Monsoon 2.56

2.15 Variation of Currents off Tharuvai in SW Monsoon 2.57

2.16 Components of Currents near Bottom off Tharuvai (Stn. C4) during Southwest Monsoon 2.58

2.17 Variation of Currents off Arimunai in NE Monsoon 2.59

2.18 Components of Currents near Surface off Arimunai (Stn. C1) during Northeast Monsoon 2.60

Figure No. Title Page No.

2.19 Components of Currents near Bottom off Arimunai (Stn. C1) during Northeast Monsoon 2.61

2.20 Variation of Currents Uthalai (GM) in NE Monsoon 2.62

2.21 Components of Currents near Surface off Rameswaram Island South (Stn. C2) (GM) during Northeast Monsoon 2.63

2.22 Components of Currents near Bottom off Rameswaram Island South (Stn. C2) (GM) during Northeast Monsoon 2.64

2.23 Variation of Currents off Pamban Pass in NE Monsoon 2.65

2.24 Components of Currents near Surface off Pamban Pass (Stn. C3) during Northeast Monsoon 2.66

2.25 Variation of Currents off Tharuvai in NE Monsoon 2.67

2.26 Components of Currents near Surface off Tharuvai (Stn. C4) during Northeast Monsoon 2.68

2.27 Components of Currents near Bottom off Tharuvai (Stn. C4) during Northeast Monsoon 2.69

2.28 Variation of Currents off Arimunai in FW Period 2.70

2.29 Components of Currents near Surface off Arippumunai (Stn. C1) during Fair Weather 2.71

2.30 Components of Currents near Bottom off Arrippumunai (Stn. C1) during Fair Weather 2.72

2.31 Variation of Currents off Uthalai (GM) in FW Period 2.73

2.32 Components of Currents Near Surface off Rameswaram Island South (Stn. C2) (GM) during Fair Weather 2.74

Page 11: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

2.33 Components of Currents near Bottom off Rameswaram Island South (Stn. C2) (GM) during Fair Weather 2.75

2.34 Variation of Currents off Pamban Pass in FW Period 2.76

2.35 Components of Currents near Surface off Pamban Pass (Stn. C3) during Fair Weather 2.77

2.36 Monthly Sediment Transport Rate 2.78

2.37 Monthly Sediment Transport Rate 2.79

2.38 Monthly Sediment Transport Rate 2.80

2.39 Annual Net Sediment Transport Rate 2.81

Figure No. Title Page No.

2.40 Annual Gross Sediment Transport Rate 2.82

2.41 Location of Boreholes 2.83

2.42a Grain Size Distribution at BH1 at Surface and 2.5 m 2.84

2.42b Grain Size Distribution at BH1 at 5.0 m and 7.5 m 2.85

2.42c Grain Size Distribution at BH1 at 9.0 m and 12 m 2.86

2.43a Grain Size Distribution at BH2 at Surface and 2.5 m 2.87

2.43b Grain Size Distribution at BH2 at 5 m and 6.5 m 2.88

2.43c Grain Size Distribution at BH2 at 11 m 2.89

2.44a Grain Size Distribution at BH3 at Surface and 0.7 m to 8.5 m 2.90

2.44b Grain Size Distribution at BH3 at 8.5 m to 10 m and 10.5 to 12.7 m 2.91

2.45 Bathymetry Map of Gulf of Mannar (1975) 2.92

2.46 Bathymetry map of Tuticorin Coastal Region (1999) 2.93

2.47 Location of Proposed Site 2.94

2.48 Bathymetry Study Over 100 Line km Across the 20 km x 4 km line 2.95

2.49 Area Showing Bathymetry More than 12 m and Hard Strata in Palk Bay Area 2.96

2.50 Area Showing Bathymetry more than 10 m with Hard Strata at about 16 m depth in Palk Bay Area 2.97

2.51 Bathymetry along the Proposed Channel 2.98

Page 12: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

3.1 Data Locations 3.92

3.2 Variation in Salinity 3.93

3.3 Variation in Salinity and Silicate 3.94

3.4 Particle Size Distribution of Sediments (1-10 Sampling Stations) 3.95

3.5 Trophic Relations of Marine in Study Area of Sethu Samudram Ship Canal Project 3.96

3.6 Maximum Diversity Index values of Phytoplankton in 21 Islands of Gulf of Mannar 3.97

3.7 Maximum Diversity Index values of Zooplanktons in 21 Islands of Gulf of Mannar 3.98

Page 13: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Figure No. Title Page No.

3.8 Location of Corals in the Gulf of Mannar and the Palk Bay 3.99

3.9 Coral Reef and Seagrass Areas around the Islands of Gulf of Mannar 3.100

3.10 Maximum Diversity Index values of Corals in 21 Islands of Gulf of Mannar 3.101

3.11 Locations of Pearl Banks in the Gulf of Mannar 3.102

3.12 Chank Habitats in the Gulf of Mannar and the Palk Bay 3.103

3.13 Habitats of Sea Cow (Dugong-dugong) in the Gulf of Mannar and the Palk Bay 3.104

3.14 Habitats of Sea Weed, Sea Grass and Holothuria in the Gulf of Mannar and the Palk Bay 3.105

3.15 Maximum Diversity Index values of Seagrass in 21 Islands of Gulf of Mannar 3.106

3.16 Maximum Diversity Index values of Mangroves in 21 Islands of Gulf of Mannar 3.107

3.17 Locations of Mangroves in Gulf of Mannar and the Palk Bay 3.108

3.18 Maximum Diversity Index values of Corals, Mangroves and Seagrass in 21 islands of Gulf of Mannar 3.109

6 .1 Environmental Impact Network - Construction Phase 6.23

6.2 Environmental Impact Network - Post-Construction/ Operation Phase 6.24

6.3 Study Area for Route Alignment in Adam’s Bridge Area 6.25

6.4 Borehole Data in Adam’s Bridge Area 6.26

6.5 Bathymetry Along Line 1 6.27

6.6 Bathymetry Along Line 2 6.28

6.7 Bathymetry Along Line 3 6.29

6.8 Bathymetry Along Line 4 6.30

6.9 Bathymetry Along Line 5 6.31

6.10 Quantity Dredged Material along Various Tracks in Adam’s Bridge 6.32

6.11 The Alignment of the Proposed Channel 6.33

Page 14: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

6.12 Bathymetry along the Proposed Channel 6.34

Figure No. Title Page No. 6.13 Cross Section of Proposed Channel 6.35

6.14 3D Plume of Disposed Silt 6.36

6.15 Near Field 6.37

6.16 Far Field 6.38

6.17 Central Line Dilution 6.39

6.18 Geographical Domain Considered for Modelling 6.40

6.19 Locations for Current Measurements 6.41

6.20 Tidal Stream Observations 6.42

6.21 Tidal Stream Observation 6.46

6.22 Tidal Observations 6.50

6.23 Proposed Ship Navigation Alignment Considered for Modelling 6.51

6.24 Calibration Tide Heights 6.52

6.25 Calibration Currents 6.53

6.26 Spatial Current Predicted by the Model - Before Dredging 6.54

6.27 Spatial Current Predicted by the Model - After Dredging 6.55

6.28 Locations of Coral Reefs in the Modelling Domain (Adjoining Mandapam and Pambam Islands) 6.56

6.29 Locations of Coral Reefs in the Modelling Domain (Dhanushkodi Portion of Pambam Island) 6.57

6.30 Plan Showing Various Alignments of Sethusamudram Ship Canal Project and the Group of Islands (Marine Parks) in Gulf of Mannar 6.58

Page 15: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

List of Tables

Table No. Title Page No.

1.1 Texture, Mineralogy and Elemental Composition of Sediments in Palk Strait 1.25

2.1 Monthly Variation of Breaking Wave Height (m) 2.99

2.2 Monthly Variation of Wave Period (s) 2.100

2.3 Predominant Wave Characteristics Buoy Data Off Vembar from Wave Rider 2.101

2.4 Monthly Variation of Longshore Current (m/s) 2.102

2.5 Longshore Sediment Transport Rate 2.103

2.6 List of Islands in the Gulf of Mannar 2.104

3.1 Particulars of Sampling Locations along the Proposed Canal Alignment 3.110

3.2 Physico-chemical Quality of Marine Water 3.111

3.3 Marine Water Quality (Inorganic, Nutrient and Heavy Metals) 3.112

3.4 Sediment Quality 3.113

3.5 Gross Primary Productivity 3.115

3.6 Number of Species Recorded in the Gulf of Mannar Marine Biosphere Reserve during Different Periods 3.116

3.7 Status Report of Biota of Gulf of Mannar 3.117

3.8 Distribution of Phytoplankton in Gulf of Mannar (Number of Species Recorded During October '98, August '99) 3.124

3.9 Maximum Diversity Index Values of Phytoplankton in 21 Islands of Gulf of Mannar 3.125

3.10 Enumeration and Diversity of Phytoplankton 3.126

3.11 List of Phytoplankton Recorded 3.127

3.12 Distribution of Zooplankton in Gulf of Mannar (Number of Species Recorded During October '98, August '99) 3.128

3.13 Shannon Weaver Diversity Indice of Zooplankton Recorded at various Coastal Waters in India 3.129

3.14 Enumeration and Diversity of Zooplankton 3.130

Page 16: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

3.15 List of Zoolplankton at Different Locations 3.131

Table No. Title Page No.

3.16 Maximum diversity index values of Zooplankton in 21 island

3.17 Distribution of Benthic Organisms in Gulf of Mannar 3.133

3.18 Enumeration and Diversity of Macrobenthos 3.134

3.19 List of Macrobenthos Recorded 3.135

3.20 Density and Biomass of Meiofauna in Sediment Samples 3.138

3.21 Distribution Pattern of Corals, Live Corals (Percentage) and Seagrases 3.139

3.22 Maximum diversity index values of Corals in 21 island

3.23 List of Fishlanding Centres within Sethusamudram Ship Canal Zone 3.141

3.24 Shannon Weaver Diversity Index (H' value) for the Ornamental Fishes Recorded Around each Island in the Gulf of Mannar 3.143

3.25 Commercially Important Species Contributing to Fishery in the Gulf of

3.26 Major Fishing Gears used in the Gulf of Mannar and the Palk Bay 3.145

3.27 Marine Fish landings in the Gulf of Mannar during 1992-96 (In Tonnes) 3.146

3.28 Composition of Different Groups in Marine Fish Landings in the Gulf of Mannar (Catch in Tonnes) 3.147

3.29 Composition of Trawl Catches in the Gulf of Mannar 3.149

3.30 Composition of the Trawl Catches at Pamban, Rameswaram and Tuticorin 3.150

3.31 Pearl Oyster Paars in the Gulf of Mannar and the Palk Bay 3.151

3.32 Distribution of Seagrass in the Islands of Gulf of Mannar 3.152

3.33 Maximum diversity index values of Seagrass in 21 island

3.34 Maximum diversity index values of Mangroves in 21 island

3.35 Mangrove Species in Coasts of Palk Bay and Gulf of Mannar 3.155

3.36 Distribution of Mangrove Vegetation in the Islands of Gulf of Mannar 3.156

Page 17: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table No. Title Page No.

3.37 Annual Primary Productivity (Gross) in Certain Marine Environments as Grams Carbon per square meter Sea Surface 3.157

3.38 Coral Fauna around the Mandapam Group of Islands 3.158

3.39 Summary of Underwater Observations on Shelter and Food of Various Coral Reef Associated Fauna in the Mandapam Group of Islands 3.159

3.40 Marine Water Quality in Palk Bay (Latitude 9O44’) 3.160

3.41 Distribution of Zooplankton in Palk Bay near the Proposed Channel 3.161

3.42 Distribution of Decapods in Palk Bay 3.162

3.43 Distribution of Desmospongiae and Corals in Palk Bay 3.163

3.44 Distribution (kg/hr) of Various Fishery Resources along Palk Bay SE Coast of India during 1985-90 3.165

3.45 Abundance of Demersal Finfish Resources (kg/hr) in SE Coast of India EEZ 3.166

3.46 Perches Abundance in kg along S.E. Coast (Palk Bay) 3.167

4.1 Land use/Land cover Status in Pamban Island, Based on the Satellite data of May, 2002 4.14

4.2 Land use/Land cover Classification System 4.15

5.1 Summary of Coastal Villages/Towns in the Study Area 5.13

5.2 Details of Coastal Towns/Villages in the Study Area (Palk Bay) 5.14

5.3 Details of Coastal Towns Villages in the Study Area 5.18

6.1 Bathymetry along Line: 1 6.59

6.2 Bathymetry along Line: 2 6.60

6.3 Bathymetry along Line: 3 6.61

6.4 Bathymetry along Line: 4 6.62

6.5 Bathymetry along Line: 5 6.63

6.6 Dredging Requirement for 10 m Depth (9.15 m draught) and 300 m Width Channel 6.64

6.7 Dredging Requirement of 12 m Depth (10.7 m draught) and 300 m Width Channel 6.65

Page 18: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

6.8 The Quantity of Dredged Material for 14 m Deep 500 Wide Channel 6.66

Table No. Title Page No.

6.9 Expected Number of Transits through Sethusamudram Channel 6.67

6.10 Inputs to Model for Dredged Material Disposal (12 m deep channel) 6.68

6.11 Maximum and Minimum Tidal Current (Speed) at Locations in Palk Bay and Gulf of Mannar 6.69

6.12 Speed and Direction of Currents for Patch-I - Before Dredging 6.70

6.13 Speed and Direction of Currents for Patch-II - Before Dredging 6.72

6.14 Speed and Direction of Currents for Patch-III - Before Dredging 6.74

6.15 Speed and Direction of Currents for Patch-IV - Before Dredging 6.76

Page 19: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

List of Plates

Plate No. Title Page No.

4.1 Merged FCC (IRS 1D PAN Sharpened LISS III) depicting

Pamban Island 4.10 4.2 Merged Imagery (LISS III + PAN) depicting Western Surrounds of Sethusamudram Ship (Navigational) Canal route in Indian Water 4.11 4.3 Land Use/Land Cover Status in Pamban Island based on IRS 1D 4.12 (LISS III + PAN), May, 2002 4.4 Merged Data (PAN + LISS III) depicting degraded land, selected for dumping dredged material in Pamban Island 4.13

Page 20: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

List of Drawings

Drawing No. Title 2.1 General Bathymetry in Palk Bay

2.2 Bathymetry and Shallow Seismic Survey - South of Adam’s Bridge Line 1

2.3 Bathymetry and Shallow Seismic Survey - South of Adam’s Bridge Line 2

2.4 Bathymetry and Shallow Seismic Survey - South of Adam’s Bridge Line 3

2.5 Bathymetry and Shallow Seismic Survey - South of Adam’s Bridge Line 4

2.6 Bathymetry and Shallow Seismic Survey - South of Adam’s Bridge Line 5

2.7 Bathymetry and Shallow Seismic Survey - North of Adam’s Bridge Line 1

2.8 Bathymetry and Shallow Seismic Survey - North of Adam’s Bridge Line 2

2.9 Bathymetry and Shallow Seismic Survey - North of Adam’s Bridge Line 3

2.10 Bathymetry and Shallow Seismic Survey - North of Adam’s Bridge Line 4

2.11 Bathymetry and Shallow Seismic Survey - North of Adam’s Bridge Line 5

2.12 Bathymetry Survey in Palk Bay along Proposed Channel Alignment

Page 21: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

1. Introduction

1.1 Preamble Shipping plays a vital role in the development of the Indian Economy as the

country has been gifted with a peninsular coastline of about 6,000 km, which is

studded with 12 major and over 150 intermediary and minor ports. It also has a

strategic location as one of the world's main sea routes and thus has a history of

maritime trade with countries across the globe.

It is, however, unfortunate that despite having such a coastline India does not

have, within her own territorial waters, a continuous navigable sea route around the

peninsula from the Gulf of Mannar to Palk Bay and vice-versa due to the presence of

shallow (about 3 m) sand-stone reef called 'Adam's Bridge' at Pamban near

Rameswaram between the south-eastern coast of India and Talaimann on the western

coast of Sri Lanka. Consequently, the entire coastal traffic from the east coast of the

country to the west and vice-versa has to go around Sri Lanka entailing an additional

distance of more than 254-424 nautical miles and 21-36 hours of sailing time. The

shipping routes and savings are shown in Fig. 1.1.

The Gulf of Mannar, an inlet to the Indian Ocean between south-eastern India

and western Sri Lanka, is bounded on the north-east by the island of Rameswaram,

Adam's Bridge and Mannar. The Gulf is about 130-275 km wide and 160 km in length.

The Palk Bay on the north of Gulf of Mannar is about

64-137 km wide and 137 km long and includes many islands of Sri Lanka.

Furthermore, Adam's Bridge is a chain of shoals, nearly seven in all, located between

India and Sri Lanka separating Palk Bay and Gulf of Mannar. It is about 30 km long

and the sea across this portion is shallow with a depth of about

3-3.5 m only during high tides.

Various committees that have deliberated the subject have observed that a

shorter route through the Palk Bay is an important necessity to save time and foreign

exchange spent on import of fuel for Indian ships, also the country can stand to gain

revenue in foreign currency due to toll collections from International ships.

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The creation of a channel called "Sethusamudram Ship Channel ", now under

consideration of the Ministry of Shipping, Government of India, envisages construction

of channel in stages and of varying lengths to suit different drafts ranging from 9.15 m

to 12.8 m through dredging / excavation across the Adam's Bridge. It is proposed to

study different alignments for the proposed channel in the light of representations from

the public, the fisherman, the pilgrims and above all its techno-economic viability. The

channel will originate from Tuticorin Harbour, extend north-east upto south of Pamban

island, cut through Adams Bridge and proceed parallel to medial line of fishing

between Sri Lanka and India before joining the Bay of Bengal channel. The width of

channel will vary between 200 and 500 m and will require dredging to arrive at desired

depth in the Adams Bridge and Palk Bay area. In GOM navigation depths will be used

hence no dredging is required. The area engulfing the Adam’s Bridge known as

‘Sethusamudram’ has been derived from the Kings of Jaffna who were called

'Sethukavalar,' meaning protectors of Adam's Bridge and the Southern sea that

surrounds the region. The Gulf of Mannar and Palk Bay/Palk Strait separated by

Adam's Bridge are shown in Fig. 1.2.

The proposed channel on commissioning will bring plenty of prosperity and

industrial growth in the Indian hinterland lying along the proposed ship channel and

the very presence of the short route would increase the turn-arounds of the coastal

and international vessels. There are many other benefits which are difficult to quantify

like (a) surge in the development of coastal trade,

(b) development of Industries in Ramanathapuram and Tuticorin Districts,

(c) amelioration of distress due to droughts visiting annually Ramanathapuram and

Tuticorin Districts.

• The project will further enable direct movement of Indian naval fleet between

the east and west coast of the country instead of going around Sri Lanka.

• The project opens up minor ports all along Tamil Nadu coastline upto the

major port of Tuticorin and further west upto Colachal.

The Tuticorin Port Trust, the nodal agency identified by the Ministry of

Shipping for the implementation of the proposal has retained in July 2002 the National

Environmental Engineering Research Institute (NEERI), Nagpur to conduct

Page 23: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Environmental Impact Assessment studies followed by the Techno-Economic Viability

for the proposed "Sethusamudram Ship Channel Project".

1.2 Earlier Studies Involving Creation of Canal One of the pioneering efforts undertaken to study the construction of the

canal was the Commander Taylor's proposal of 1860. Although a series of proposals

on the subject were forwarded thereafter during the British regime in the country, due

consideration could never be given to the proposal and the Sethusamudram Ship

Canal remained a dream for the Indian maritime community.

After Independence, the Government of India continued to pursue the idea of

constructing the Sethusamudram Ship Canal and among the many committees

constituted for studying the feasibility of the project, the 'Ramaswamy Mudaliar

Committee' constituted in 1955, was the first. In addition to studying the feasibility of

the Sethusamudram Ship Canal project, the committee also studied the increase in

potentiality of the port of Tuticorin, if it were to be developed into a deep-sea port

alongwith the canal. Although Tuticorin port was in existence for a long time, it did not

have berthing facilities for ships and those had to be attended at the anchorage, which

was about 5 to 6 miles off the coast.

The committee was of the view that the two projects namely the

Sethusamudram Ship Canal and Tuticorin Harbour were closely inter-related and

should be taken up and executed as part of the same project. After evaluating the

costs and benefits, the project was found to be feasible and viable and the committee,

therefore, proposed an initial capital outlay of Rs. 998 lakhs for the integrated

Sethusamudram-cum-Tuticorin Port Scheme. Thereafter, series of studies were

undertaken for the project, and many of those recommended for increase in draught

from the original 26 ft. proposed by the Ramaswamy Mudaliar Committee. These

studies also led to revision of the Project cost, as also to the expected savings in

navigable distance resulting from the canal which ranged from 260 to 425 kilometres.

Finally, the Tuticorin Harbour project was sanctioned in 1963 and the Government of

India continued to study the various aspects of the Sethusamudram Ship Canal

Project.

Over a last century, several proposals were formulated by various

committees to create a continuous navigable route all around the peninsula within the

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territorial waters of India. The latest study of the project was undertaken by the

Lakshminarayanan Committee constituted by the Ministry of Shipping and Transport

(Port wing) in 1981. The Committee, after a critical review of the earlier proposals,

some of which envisaged the canal project by cutting across the main land,

investigated another alignment known as the 'K' alignment across the Rameswaram

island near Kodandaramasamy temple, and established the technical feasibility and

economic viability of the alignment. This alignment was also in keeping with the

representations of the public, the fishermen and the pilgrims of Ramanathapuram area

who preferred the island being cut east of Rameswaram town. The Committee fixed

the alignment across the land and along the northern and southern approaches in the

sea, conducted drilling operations in sea and on land, collected tidal, current, wind and

other meteorological data, and submitted to the Government of India in 1983 a project

feasibility report with an estimated project cost of Rs. 282 crores including foreign

exchange component of Rs. 3 crores. As per economic analysis by the Committee, the

project would have generated surplus from twentieth year of its operations building up

cumulative surplus of Rs. 453 crores at the end of twenty fifth year. However, no

follow-up action on this report was initiated due to financial constraints.

In its pursuit to make the Sethusamudram Ship Canal project a reality

the Government of Tamilnadu in 1996 got, through Pallavan Transport Consultancy

Services (PTCS) Limited, the Lakshaminarayanan Committee proposal updated for its

economic viability with a view to seeking approval from Government of India for the

project. Fresh particulars of cost and traffic were collected and incorporated in the

report so as to reflect conditions as of 1996.

Apart from the construction of proposed canal, which constituted the major

component of project, creation of number of other infrastructural facilities as listed

below were envisaged :

• Construction of a "lock"

• Construction of rubble mound type breakwaters on either sides of the

canal

• Navigational aids

- Lighted beacons/buoys - Racons

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- Satellite based differential global system - Improvements to Pamban light house

• Flotilla - Harbour tugs - Pilot, mooring, survey-cum-lighting launches - Despatch vessels

• Shore facilities - Two service jetties - Slipways - Buoy yard - Repair workshop

• Staff and administration buildings

The canal proposed had two legs, one near the Point Calimere called

the Bay of Bengal Channel and another across the narrow Danushkody Peninsula

near Kodandaramasamy Temple. The Bay of Bengal Channel traverses the Palk Bay

wherein the sea-bed is mostly soft to hard clayey-sand in nature and not corals or

rock. The channel proposed was 19.3 km away from Point Calimere and Kanakesan

Thurai where the coast consists of only clayey-sand. The second leg of the canal 802

m long would have crossed the narrow Danushkody Peninsula through the land

portion. The entire coast of Danushkody Peninsula on the North and the South is all

sandy. In the North Approach Channel, soft sand-stone was met with below 12 m

depth and cutting this sand-stone was not necessary even in the ultimate stage of the

canal. The canal would have, however, cut the road connecting Rameswaram and

Danushkody. This road is being used by the Rameswaram fisherman to go to

Danushkody for daily fishing as there is no habitation at Danushkody. The project

envisaged a high-level or a swinging bridge at the crossing point to enable the traffic to

go through. Tracer studies conducted at two places along the 'K' alignment

established that the pattern of movement of sea-bed silt would almost be in the same

direction as that of the proposed canal, and that the chances of siltation would be very

minimal.

The cost estimates for the proposed canal project were worked out by PTCS

Ltd. based on the same quantities of dredging as in the 1983 report but with updated

rates for the year 1996. The costs of dredging for various segments of channel for

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three different drafts viz. 30, 31 and 35 feet were worked out alongwith cost estimates

for other components of the project including those of navigational aids and floating

crafts. The construction period for 31 feet draft was estimated as four years with a

capital expenditure of Rs. 760 crores. The operation and maintenance cost was

estimated by PTCS Ltd. at Rs. 4.52 crores per year.

An economic appraisal of the Sethusamudram Ship Canal project, taking into

account cost estimates and cost benefits of the proposal, were made by PTCS Ltd.

Based on Net Present Value (NPV) method of appraisal, an Internal Rate of Return

(IRR) of 10 to 17% on the project investment was arrived at. Considering the then

interest rate of 9% per annum of government lending to ports on the capital employed

the project would have generated surplus from the 16 or 17th year of its operation, and

thereafter the benefits to the canal company would have been 47 crores in the first

year, and this would have increased to

100-120 crores every year.

The traffic potential through the canal at various draughts projected by both

the studies for 2000 AD were as follows :

Upto 30' draught 31~32' draught Above 32' draught 1983 Committee 2,100 2,200 2,300 1996 Report 3,791 3,875 4,211

Later a report was prepared by NEERI in 1998 comprising the examination of

environmental status of the project region based on information available on

hydrography, marine water quality and ecological resources etc. An environmental

impact study was recommended by NEERI as essential for fuller description and

appreciation of the natural processes occurring in the region to delineate the

environmental consequences including the ecological risks associated due to the ship

canal and suggest measures for minimisation and mitigation of potential adverse

impacts.

The study for initial environmental examination of proposed canal also

recommended that the canal route should pass through Adams Bridge area

circumventing the Pamban Island instead of cutting through it. A detour was

suggested from earlier alignment. Keeping in view the location biosphere reserves, it

was suggested that an environmental viable alignment of route be selected in GOM so

that proper distance from Biosphere reserves can be maintained and the available

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navigational route can be selected based on both environmental and technical

viability. The EIA studies recommended in IEE report of NEERI was therefore

subjected to proper scoping so that all the environmental concerns due to this project

can be addressed and resolved through this report. The technical viability would

depend on quantity of dredging required in the vicinity of Adams Bridge area keeping

in view the draft required to operate the channel. This study report addresses

environmental, technical and commercial viability of the proposed ship canal project.

1.3 Project Region The Palk Bay and the Gulf of Mannar together sprawling over an area of

10,500 sq.km (8O35’N to 9O25’N latitude and 78O8’E to 79O30’E longitude) in which the

ship channel is proposed to be constructed are biologically rich and rated as the highly

productive seas of the world and their biodiversity is considered globally significant. In

the Gulf of Mannar, there are 21 islands covering an area of 623 ha which have been

declared as National Marine Parks by the Tamilnadu Forest Department and the

MoEF, Government of India. The islands are distributed in 4 groups namely

Mandapam, Keezhakarai, Vembar and Tuticorin group.

The islands have luxurient growth of mangroves in their shores and swampy

regions. The coral reef of fringing and patch type are present around the 21 islands

from Rameshwaram to Tuticorin covering a distance of 140 km. However, a major part

of the reef is fringing type arising from shallow sea floor of not more than 5 m in depth.

About 3600 species of flora and fauna have been recorded in this area. Fringing type

of reef is present in Palk Bay.

The hydrography data shows that there are two circulations of water masses

in the region, the clockwise circulation of south-west monsoon and the counter

clockwise circulation of north-east monsoon. The reported current velocities in the Palk

Bay and the Gulf of Mannar are as mild as 0.2 - 0.4 m/sec except on few days during

south-west monsoon when it rises upto 0.7 m/sec. The directions of currents follow the

directions of predominant winds.

The presence of corals along the proposed ship channel alignment is

negligible however occurrence of major groups of biological resources like sea fan,

sponges, pearl oysters, chanks and holothuroids at various locations have been

reported. All the three groups of prochordata organisms, considered as the connecting

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link between invertebrates and vertebrates, viz., hemichordata, cephalochordata and

urochordata have been recorded mostly around the islands of the Gulf of Mannar.

There are 87 fish landing stations between the south of Point Calimere and

Pamban 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, 72 are commercially

important. During 1992-2001, the fish production has increased gradually from 55,300

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.

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, brown algae, red algae, blue-green algae and

sea grasses are recorded in the Gulf of Mannar and the Palk Bay. A few of the 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,

dugong, holothuroids and marine algae are along the coast and around the islands.

Along the coast in the Gulf of Mannar and the Palk Bay there are 138 villages

and towns spread over 5 districts.

1.4 Geomorphology of Study Region The study region stretches between Tuticorin and Dhanushkoti including its

coastal and offshore water in Gulf of Mannar and Palk Bay area between Pumban and

Point Calimere.

The coastline near Tuticorin is extensively used due to the presence of major

port. Beach is very flat and narrow between Tuticorin and Sippikulam. Offshore islands

viz; Pandyan Tivu, Van Tivu, kasuvari Tivu, Vilangu Shuli Tivu and Kariya Shuli tivu

are present within 5 km distance from the coast line along this segment and offer

protection from wave action. The backshore of this costal segment largely consists of

salt pans. The Viappar river joins Gulf of Mannar near Sippikulam. An extensive

coastal low land is seen between Sippikulam and Vembar (Loveson, 1994).

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The coastal segment between Sippikulam and Naripaiyur is open without any

offshore islands or submerged coral banks and is exposed to direct action of waves

both during southwest monsoon and northeast monsoon. The coastline near

Kannirajapuram is found with large extent of beach rocks with pear luster (Loveson,

1994). Wide and flat sandy beach with numerous small dunes are seen between

Naripaiyur and Mukkaiyur .

The formation of sand island off Tuticorin indicates this region as sediment

sinks with progressive accumulation of sand. The large beach storage of sand

between Manppad and Tiruchendur, Vembar and Valinokkam and Rameswaram

Island is an indication of depositional features of littoral sediments.

Gundar river joins the sea near Mukkaiyur. The presence of offshore islands

are once again noticed from Mukkaiyur till Mandapam. There are 16 islands noticed

along this coastal segment viz., Uppu Tivu, Shalli Tivu, Nalla Tanni Tivu, Anaipar Tivu,

Palliyarmunai Tivu, Puvarasanpatti Tivu, Appa Tivu, Talairi Tivu, Valai Tivu, Muli Tivu,

Musal Tivu, Manali Tivu, Pumorichan Tivu, Kursadi Tivu, Kovi Tivu, and Shingle Tivu.

The beaches between Mukkaiyur and Valinokkam are very wide with elevated dunes.

Extensively developed beach is seen at Kilamundal. Flat rocky shorelines are noticed

near Valinokkam (Loveson, 1994). Extensive spread of rocky shore with hard sand

stone platform is seen off Valinokkam. There is a Bay formation immediately on the

northern side of Valinokkam.

No beach is present especially during high tide Kilakarai. A narrow and flat

beach is noticed near Sethukarai with the abundance of algae along the coastline.

Loveson and Rajamanickam (1987, 1989) have identified a spit growth near

Pariyapattinam. They described well-developed hooked nature spit extending

southeast and connecting the main land in southwest direction. This formation of spit

extending southeast and connecting the main land in southwest direction indicated

seaward progradation of the coast between Tuticorin and Mandapam.

Wave cut cliff is seen at places like Valinokkam, Sethukarai and Mandapam.

Very low and narrow sandy beach is noticed between Kalimangundu and Vedalai

(loveson, 1994). Sea is found to be very calm in this region. Wave cut platform is once

again noticed along the coast of Vedalai. A patch of rocks is observed along the coast

between Mandapam camp and Mandapam tip. Agrawal (1988) observed that the area

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between Mandapam tip and Pamban Island is attributed to a sand spit later emerging

as a high water land. The coastline between Mukkaiyur and Mandapam is totally

protected from northeast monsoon waves. Chandrasekar et al. (1993) indicated

reversal trend in the direction of sediment transport between Mandapam and Cape

Comorin due to change in the coastal configuration, deposition as the formation of

numerous spits along this coast that too, in a region where fluvial activities are

negligible. The presence of three offshore islands viz., Pumorichan Tivu, Kursadi Tivu,

Shingle Tivu are noticed off Rameswaram Island in Gulf of Mannar. The stretch of

shoreline around Rameswaram Island exhibits distinct variation (Loveson, 1994).

The central zone of the northern part of Rameswaram is made up of

undulatory sandy bodies with a relief upto 21 m above Mean Sea Level (MSL). This

area is partially covered with huge dunes. Northern part of Rameswaram Island is

occupied by raised coral plain. Characteristically, this zone is flat with dead corals and

numerous minor circular depressions. These depressions are liable to get filled with

water during rainy season and is entirely devoid of vegetation. Huge sand dues of

medium grain and white sands are found in the central part of the island. Dune

patterns are well developed by the active Aeolian processes, resulting in the migration

of dunes with frequent changes in their shapes and patterns from time to time but

generally trends due east to west. The sand sheet covers the southwestern zone of

the island. Within this unit, on the western part, localized sand mound of about 19 m

height is noted (Loveson, 1994). The beach zones in this area are broader with wide

inter tidal zones. The tail portion of Rameswaram occupying the southeastern part of

the island has coral swampy plain, which is considered to be of recent in age. This

vast flat and low-lying plain, which is considered to be of recent in age. This vast flat

and low lying plain is essentially composed of thin sheet of silt and clay materials in

which coral fragments are impregnated. Invariably, this zone is often inundated by

seawater during high tides, monsoons and storm seasons.

At east, a long sand spit of about 20 km length is formed up to Arimunai and it

tends to grow longer and wider. The width of this sand spit which is about

2 km near Uthalai, reduced to Arimunai and it tends to grow longer and wider. The

width of this sand spit which is about 2 km near Uthalai, reduced to 1250 m at

Mukkuperiyar, 750 at Dhanushkodi and 150 m at just east of Arimunai and coverages

on tip at Arimunai. The beach berm is found to be highly elevated along the sand spit

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bordering Gulf of Mannar, but very low and flat along the side bordering Palk Bay.

There is a marked depression in the sand spit level between Palk Bay and Gulf of

Mannar between Dhanushkodi and Arimunai. Due to such level difference, the water

overflows during spring tide particularly from Bay carrying the fine sediment to the

backshore regions. Most of the time, the water is stagnant and remains along the

trough of the spit. This low lying region is fully occupied by water column during the

monsoon season.

The coastal process between Arimunai (India) and Talaimannar (Sri Lanka),

i.e. along Adman’s Bridge is quite complex which predominantly control the exchange

of sediment between Gulf of Mannar and Palk Bay. Adam’s Bridge is formation of

submerged sand shoals and there are around 17 islands present with bushes and

plants. The average length of these islands vary between 0.8 km to 3 km. This is

exposed to complex current pattern with the presence of quicksand. The currents near

Adam’s Bridge and Pamban Pass are found to be more seasonal. Submerged sand

shoals are seen shifting south of Arimunai and remain quasi-steady.

The nearshore on the northern side of the Rameswaram Island is found to be

very shallow causing the northeast monsoon waves to break far offshore. The coastal

stretch between Mandapam and Ariyaman in Palk Bay shows the presence of wide

beach with elevated dunes.

Loveson et.al. (1990) classified the coastal zone of Palk Bay into 3 groups; (i)

uplands/highlands with scantly vegetation, comprised of Cuddalore sandstone

formations, (ii) along the lower elevations sedimented Cuddalore sand stones, and (iii)

coastal lands mainly of microdeltas, swamps, and beach ridges based on the

geomorphological features. A large amount of sediments from those pediments are

removed constantly by rainfall and minor rivers. Because the pediments are placed

over the substratum which is appreciably sloping towards the sea, the erosion is found

to be intensive along the coastal islands. The eroded sediments brought to the littoral

zone are dumped in Palk Bay. As Palk Bay is shallow and protected from the high

waves and currents, the materials brought by these minor rivers is deposited in the

mouth of each river/stream, leading to the formation of micro-deltas in due course,

encouraging the formation of new shorelines.

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Palk Bay is very shallow and is largely occupied by sand banks and shoals

(Agrawal, 1988). Abundant growth of corals, oysters, sponges, and other sea bottom

communities flourish in the relatively calm waters of Gulf of Mannar.

Sea level variations along the Tamilnadu coast were studied by Loveson et.al., (1990)

using satellite imageries and photographs. About 300 sediment samples were

collected along the central Tamilnadu coast by Chandrasekhar and Rajaminckham

(1993) and suggested to possibility of the supply from ultrabasic, pegmatitic and

granitic source of material to the depositional basic.

River Influx and Sedimentation in Palk Bay/Palk Strait

Vaigai River basin is located between latitude 9O15’ and 10O25’N and

longitude 77O15’ to 79O covering an aerial extent of 8600 sq. km. in the Madurai and

Ramanathapuram districts of Tamil Nadu, India. The river Uaigai, originates at an

altitude of 2200 m above mean sea level in the western ghats, drains through the

plains and confluences with the Bay of Bengal near Attangarai of Ramanathapuram

district. The basin is bounded by western ghats, in the west, Palni hills in the north, a

stretch of mountain ranges comprising Varushanad and Andipatti hills in the south and

the Bay of Bengal in the east.

Vellar estuary also comes under Palk Bay (lat. 11029'N ; long. 79046'E).

Sediment in estuarine region are rich in organic carbon, phosphorus and nitrogen and

finally finds its way into Palk Bay. The nutrient rich water (due to settling of unified feed

particle) discharges periodically from the shrimp farms however did not show influence

on nutrients content of sediment in estuary.

Sea Bed Characteristics

Geomorphology of the area exhibits tidal flats, estuaries and marsh zones as

well as linear stabilized older younger sand dunes. Beach dunes run parallel to the

sea.

Geologically, thick section of Quaternary alluvium overlies the Archean

charnockite rocks and these are in turn overlain by the Holocene tidal flat deposits.

The detailed lithological observation of cores reveals that the sediments have

been depositing in phases and that there has been pulsating supply of fine sediments

onto the tidal flats and estuaries. Sediment in the cores show very heterogeneous

mixture of quartz sand, biogenic carbonate and clay. Geomorphologic observations

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reveal that the coarse sand in the tidal zones reflect ample sediment supply during the

Northeast monsoons. A number of different types of topographical features are found

in the study area, such as continental shelves, deep sea basins, troughs, trenches and

continental slopes.

Sediments are moderately well stored and slightly well skewed. Kurtosis

value of 0.3 shows less sorting in grain size distribution. Clay is absent and sediments

are made of detritus. Different grain size sediment show variable levels of heavy metal

(Fe, Mn, Cr, Cu, Pb, Zn, Cd & Hg) concentration (Table 1.1).

1.5 Environmental Impact Assessment (EIA) The pre-construction phase would involve land acquisition, resettlement

and rehabilitation of affected population as also compensation hence impacts due to

such activities are required to be assessed.

During the construction phase there will be considerable increase in rail and

road traffic to and from the island for transportation of men, material, machinery and

equipment. Also, the land access, now available to the local fisher folks, to

Dhanushkody area for traditional fishing may be hindered unless alternative

arrangements are made. The potential sites for dredging and disposal of dredged

material are to be decided as also shipping operations will have to be regulated so as

to cause minimum disturbance to the normal fishing activities.

During the operation phase 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 hence

impacts due to such wastes are to be assessed.

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 disposal of

endemic species outside the Palk Bay and the Gulf of Mannar may occur.

The project is expected to 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

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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 canal which will add to the national economy.

1.5.1 Objectives of EIA Study The objectives of the study is to carry out assessment of environmental impacts, its

quantification and for delineating environmental management plan for Sethusamudram Ship

Channel project to enable the Ministry of Shipping to obtain environmental clearances from

concerned local, state and central Government authorities. The environmental assessments

are to be carried out in keeping with the applicable guidelines and notifications of the

regulatory agencies as also the International transboundary concerns.

The rapid environmental impact assessment study report was prepared incorporating

primary data collected for the region and also available secondary data, environmental impact

statement based on identification, prediction and evaluation of impacts, ranking of

environmentally viable alternatives and environmental management plan for the acceptable

route. The comprehensive EIA report was prepared later based on the primary data collection

for region.The area for Environmental Impact Assessment Study is shown in Fig. 1.3.

1.5.2 Scope of the Study The scope of the comprehensive EIA study is summarised as follows :

i. Assessment of the present status of coastal water, marine, land, biological and

socio-economic components of environment including parameters of human

interest along the proposed ship canal route

ii. Identification of potential impacts on various environmental components due

to activities envisaged during pre-construction, construction and post-

construction/ operational phases of the proposal

iii. Prediction of impacts on the various environmental components using

appropriate mathematical/simulation models

iv. Preparation of environmental impact statement based on the identification,

prediction and evaluation of impacts

v. Preparation of detailed Environmental Impact Statement (EIS) duly bringing

out the likely impacts of the project, mitigation, protection and enhancement

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measures including impacts due to the disposal of dredged materials,

consideration of alternatives, etc.

vi. Short-listing of viable routes for the proposed shipping canal based on

technical requirements, and delineation of acceptable canal route for shipping

based on environmental considerations

vii. Delineation of Environmental Management Plan (EMP) outlining preventive

and control strategies for minimising adverse impacts for various stages of the

proposed project including the costs and time schedules for its implementation

viii. Formulation of environmental quality monitoring programme for various

phases of the project to be pursued as per the requirements of statutory

authorities

1.5.3 Plan of Work • Collation/ collection of primary and secondary data on benthic flora/

fauna, meiobenthos, bacrobenthos

• Collation/collection of primary and secondary data on phytoplankton,

zooplankton in water column

• Assessment of general physico-chemical quality of water

• Assessment of sediment quality and its texture

• Fishery potential of the region

• Collation of secondary data on bathymetry, sediment transport, water

current and directions, wave height, tidal variation, dispersion

coefficients and other hydrographic parameters

• Collection of information about marine parks and ecologically sensitive

species

• Qualitative and quantitative assessment of waste loads likely to accrue

from proposed activities in the hinterland all along the canal

• Assessment of change in hydrographic pattern in the region during and

after implementation of dredging activities vis-à-vis impact on coastal

ecosystems

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• Assessment of impacts on food chain productivity, growth of benthos

and vegetation, phytoplankton densities predatory fish and birds in the

coastal waters

• Assessment of impacts on ecological health due to hydrodynamic and

water quality changes

1.5.4 Components included in the Study 1.5.4.1 Coastal Water Environment

• Study of coastal water environment with respect to its physico-chemical

and biological characteristics

• Assessment of mangrove forests/vegetation in the coastal and inter-

tidal zones

• Determination of primary and secondary productivity in the coastal

region

• Prediction of impacts of discharges during dredging on marine water

quality

• Evaluation of impacts due to shipping activities in keeping with the CRZ

regulations

1.5.4.2 Marine Environment

• Establishing abiotic and biotic characteristics of water and sediment

component of marine environment

Page 37: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

• Delineation of hydrodynamic conditions (tide, current, wind and waves)

including the pattern of movement of sea-bed material in the project

region

• Assessment of impacts of dredging, transportation and disposal of

dredged materials like interference with fishing, increased turbidity and

disturbance to the flora and fauna

• Identification of likely impacts on the islands/region along the shipping

canal

• Prediction of impacts of the project on other natural marine processes

1.5.4.3 Land Environment

• Study of existing landuse pattern, vegetation and forestry along the

coastline of the region

• Assessment of impacts on landuse pattern of main land and islands

with respect to agriculture and forestry due to proposed project

1.5.4.4 Biological Environment

• Identify the sensitive receptors and ecological systems within the study

region

• Collection of information about flora and fauna and determination of

species diversity, density, abundance etc.

• Collection of available information on both terrestrial and aquatic flora

and fauna, including rare and endangered species in the study region

• Assessment of potential impacts on aquatic flora and fauna due to

effluent discharges

• Prediction of stress on biological environment in the study region

• Estimation of anticipated impacts on fisheries and other useful aquatic

flora and fauna

• Delineation of measures for abatement/reduction of biological stress

1.5.4.5 Socio-economic and Health Environment

Page 38: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Collection of baseline data related to socio-economic profile of the study region

with reference to :

• Human settlements, occupational pattern, employment and income in

the region

• Infrastructure resource base, viz. Medical, education, water resources,

power supply

• Economic resource base, viz. Agriculture, industries, forest, trade and

commerce

• Health status, viz. morbidity pattern with reference to prominent and

endemic diseases

• Cultural and aesthetic attributes in the study region including places of

historical/ archeological, religious, recreational importance

- Estimation of disruption in social life due to relocation of human

settlements and assessment of rehabilitation requirement

- Assessment of impacts on places of historical/ archeological importance

and aesthetic impairment

- Assessment of economic benefits to community and environment due to

the proposed activities

1.5.4.6 Ecological Risks

• Quantification of ecological risks and delineation of ecological risk

mitigation measures

• Study and survey of environmentally sensitive sites viz. spawning and

breeding grounds and coral reefs

• Analysis of information with regard to environmental impact (direct,

synergistic and cumulative) and associated nagivational and landward

activities in and around the project region

• Quantification of ecological risks with recourse to appropriate

ecosystem models

1.5.5 Environmental Management Plan

Page 39: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Environmental Management Plan (EMP) is to be drawn for the pre-

construction, construction and operational phases after identifying, predicting and

evaluating the impacts on each component of the environment with a view to

maximising the benefits from the proposed project. The EMP to be prepared would

mainly cover mitigation measures at dredging sites, transportation route (of dredged

spoil), and dumping site. EMP would essentially consist of details of work proposed

under mitigation measures, implementation schedule of such measures, fund and

manpower requirements.

1.6 Techno-economic Viability 1.6.1 Traffic Potential

The future traffic potential is to be studied over short, medium and long term

time horizons in terms of volumes of cargoes in tonnage like container, dry, liquid,

bulk, also number, size and category of ships and other types of vessels taking into

due consideration the future economic growth.

1.6.2 Alignment of Channel Alignment of the channel is to identified with reference to environmental

factors, navigational aspects, morphological aspects, seabed movements/

sedimentation likely to be induced by the cross currents in the canal after its creation

and during operation.

Page 40: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

1.6.3 Dredging and Disposal Areas The disposal areas (within Indian territory) of the dredged materials are to be

spelt out to satisfy the statutory requirements of State/ Central Govt. Deptts./Ministry of

Environment & Forests and other concerned Archeological Deptt., Tamilnadu Pollution

Control Board, Tamilnadu Maritime Board etc. so as to ensure that the dumping of

dredged materials will not adversely affect the environment. Study the transboundary

effects such as flooding and effects of fishery potential etc. on the Sri Lankan side due

to the disposal of dredged materials. Also, the quantum of maintenance dredging per

annum, its periodicity, disposal areas etc. are to be assessed.

1.6.4 Cost Estimates and Economic Viability This would include the project cost estimates towards preliminary surveys and site

investigations; dredging costs, transportation and dumping of dredged material at the chosen

sea/land locations. The economic analysis for a selected route will also be carried out.

1.7 Permits and Approvals Permits and approvals from the following mentioned agencies / organisations

are envisaged :

• Tamilnadu State Pollution Control Board

• Tamilnadu State Forest & Environment Department

• Tamilnadu Maritime Board

• State Wildlife Warden

• Chief Conservator of Forests

• Ministry of Environment & Forests

• Ministry of Defence / Indian Navy

• Archeological Department

• Ministry of External Affairs

• Sri Lankan Government

Page 41: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 1.2 : The Gulf of Mannar and Palk Bay/Palk Strait Area

Page 42: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 1.3 : The Study Area

Page 43: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 1.1

Texture, Mineralogy and Elemental Composition of Sediments in Palk Strait

Statistical Parameters of Sediments (units in φ)

Area Mean Dispersion Skewness Kurtosis Median

Palk strait 2.4 0.4 -0.07 0.3 2.3

Percentage of Various Minerals in Sediments

Area Quartz Feldspar Carbonates Clays

Palk strait 64 4 32 --

Chemical Composition of Bed Sediments

Area Fe %

Mn ppm

Cr ppm Cu ppm

Pb ppm

Zn ppm

Cd ppm

Hg ppb

Org carb %

Palk strait / Palk Bay

0.38 110 122 8 8-40 34 1-2 107 0.09

Gulf of Mannar 0.35 90 BDL-10 BDL-70 10 BDL-40 BDL BDL 0.3-0.4

Page 44: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

2. Prrooppoosseedd PPrroojjeecctt aanndd OOcceeaannooggrraapphhiicc

EEnnvviirroonnmmeennttaall SSeettttiinngg

2.1 Proposed Project

The project envisages a ship navigation channel across Adam’s bridge

connecting Gulf of Mannar with Palk Bay and further Palk Bay with Bay of Bengal with

dredging of navigational channel in Palk strait. The project enables the direct

movement of ship between the east & west coast of the country instead of going via

Srilanka. The route will originate from Tuticorin harbor, extend N-E up to south of

Pamban island using available navigation depths which is more than 20 m, cut through

Adam’s Bridge where a channel will be required to be dredged with depth suiting the

draft requirement and proceed parallel to medial line for fishing rights in Palk Bay

through available navigation depth, pass through a channel to be created in Palk strait

by dredging and join Bay of Bengal. The construction of ship channel will be done to

suit different drafts 9.15m, 10.7m & 12.8m by dredging & Excavation in Adam’s Bridge

area and Palk strait.

• Tentative specification of Navigational channel are :

− First phase : 9.15-m draft. 300m width

− Second phase : 10.7 m draft 300m width − Third phase : 12.8 m draft 500 m width

• Phase wise development

− First phase : control two way traffic

− Second phase : control two way traffic

− Third phase : two way traffic

The project besides creating a channel envisages deployment of Vessel

Traffic Management System (VTMS) to be located on Rameshwaram Island and at pt.

Calimere to control navigation. Provision will be made for necessary navigational aids

which include lighted Fairway Buoys, channel marked, Buoys, Recons, flotilla etc.

Page 45: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

NEERI has undertaken studies for assessing environmental status of the region and

have engaged services of National Ship Design Research Center (NSDRC),

Visakhapattanam for oceanographic & hydrographic surveys besides drilling

operations along proposed alignment, to collect borehole data. Services of National

Hydrographic Office (NHO) Dehradun were engaged to conduct bathymetry and

bottom profile studies in Palk Bay Strait area.

2.2 Oceanographic Status in Project area along Route Alignment

The stability of the study area along the alignment is influenced by number of

environmental factors, primarily due to geological, biological, meteorological and

oceanographical parameters, which distinctly vary from one sector of the coast to

another. The most influencing factors in coastal waters are the tides, waves and

currents, and they interact each other to produce an energy input, which shapes and

modifies the shore. Any attempt to study these problems require a thorough

understanding of the factors and processes involved in the coastal geomorphological

system, the pattern of sediment transport in the littoral zone, the volume of exchange

of littoral drift from one region to another, the monthly and seasonal variation, and the

intermittent oceanographic factors acting on the system.

2.2.1 Waves

The winds blowing over the ocean surface has the direct effect on wave

generation as it is related to wind speed, extent of fetch and wind duration. Pilot (1953)

gives a detailed account of the southern part of the Bay of Bengal. The oceanographic

pattern along the Indian coast is mainly governed by the monsoons. The southwest

monsoon influences this pattern from June to September. The average speed of the

wind during southwest monsoon period is about 35 km per hour frequently rising up to

45-55 km per hour. The average speed of the wind during northeast monsoon

(October to January) prevails around

20 km per hour. Tropical storms known as cyclones frequently occur in the Bay of

Bengal during October to January.

In eastern coast, the wave activity is significant both during southwest and

northeast monsoons.

Page 46: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

2.2.1.1 Wave Measurement

The observations on wave measurement show that significant wave height

varied from 0.46 to 1.12 m in March, 0.33 to 1.18 m in April, 0.46 to 1.74 m in May,

0.71 to 1.78 m in June, 0.68 to 1.6 m in July, 0.68 to 1.49 in August, 0.64 to 1.76 m in

September, 0.54 to 1.35 m in October, 0.40 to 1.13 m in November, 0.40 to 1.12 m in

December, 0.35 to 1.03 m in January and 0.35 to 1.23 m in February. Measured

significant wave height is given in Fig. 2.1

The maximum wave height varied from 0.67 to 1.78 m in March, 0.44 to 1.73

m in April, 0.66 to 2.81 m in May, 0.98 to 2.72 m in June, 0.91 to 2.45 m in July, 0.89

to 2.48 in August, 0.89 to 2.96 m in September, 0.66 to 2.94 m in October, 0.59 to

1.60m in November, 0.48 to 1.73 m in December, 0.47 to 1.68 m in January and 0.45

to 1.79 m in Febraury. Wave heights are relatively higher during southwest monsoon.

Measured maximum wave height is depicted in Fig. 2.2.

Monthly variation of breaking wave height (m) is depicted in Table. 2.1

The wave direction (with respect to north) mostly prevailed 140O to 230O in

southwest monsoon (June to September), 85O to 150O during northeast monsoon

(October to January), and 90O – 200O during fair weather period (February to May).

The wave direction is highly variable in January and May. The zero crossing wave

period predominantly varied 3-8 s in December to April, 4-10 s in May and 4-9 s during

rest of the year.

The wave heights recorded in west and east coast offshore area of India are

compared. In west coast the wave heights off Mumbai are in between 2.0-6.0 m in

southwest monsoon, 2.0-3.0 in north east monsoon, and 1.0-2.5 m in fair weather

period. Off Goa the wave heights are between 0.8-5.1 m in southwest monsoon. Off

Mangalore wave heights are around 3.2 m in southwest monsoon and 0.8 m in fair

weather period. Off Trivandrum the wave heights are 2-4.3 m in southwest monsoon

and 1-2.0 m in fair weather period. Off Cochin the wave heights are between 0.9-2.0 in

southwest monsoon. In east coast off Chennai the wave heights are 2.5 m in

southwest monsoon and 1 m in northeast monsoon. Off Visakhapatnam coast these

heights are between 0.8-3.9 m in southwest monsoon 0.6-2.9 m in northeast monsoon

and 0.5-3.8 m in fair weather period. Off Orissa the wave heights are between 1.0-2.5

Page 47: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

m in southwest monsoon and 0.8-2.5 m in northeast monsoon, and around 1-2.2 m in

fair weather period.

The wave climate reported in the literature indicates that the wave activity in

the study region remains relatively low compared to the rest of Indian coast.

2.2.1.2 Wave Refraction

Tuticorin to Arimunai

Wave refraction during the southwest monsoon shows appreciable

divergence of wave orthogonal near Adams Bridge, Arimunai, and south of

Sippikulam. Wave activity was found to be extremely reduced between Mandapam

and north of Valinokkam due to the presence of offshore islands, which causes waves

to break offshore. Wave energy concentration was observed at Mukkuperiyar,

Valinokkam, Mukkaiyur and Vember. The region between Sippikulam and Tuticorin is

again protected from southwestern waves due to the presence of islands. The

presence of offshore islands is observed to protect the coastal stretch from Mandapam

to Valinokkam, and Veppalodai to Tuticorin from northeasterly waves. Wave refraction

between Tuticorin and Arimunai during NE Monsoon and SW Monsoon is shown in

Figs. 2.3-2.5 respectively.

Arimunai to Vedarnyam

This segment of the coastline lies in Palk Bay and waves propagating from

south (during southwest monsoon and fair weather period) do not enter in this region.

Studies are indicating that even during the northeast monsoon, waves are found not

entering the bay and get attenuated across the shoals of middle banks and south

banks between Vedaranyam (India) and Matakal (Sri Lanka). Part of wave energy with

less magnitude enters the bay through Pedro Channel and reach the coast between

Puduvalasai and Gopalpatnam. Wave refraction between Arimunai and Vedaranyam

during NE Monsoon is shown in Fig. 2.6 respectively.

Page 48: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

2.2.1.3 Wave Period

During southwest monsoon, the wave period predominantly persisted 9 –10 s

between Vembar and Keelamunadal, and 6 – 8 s between Uthalai and Dhanushkodi.

During the northeast monsoon, it predominantly persisted 5 –10 s between Vembar

and Keelamundal, and 5 –8 s between Uthalai and Dhanushkodi east. In fair weather

period, it remained 6 –10 s along Vembar to Keelamundal, and 9 –10 s along Uthalai

to Dhanushkodi. The study shows that the waves approaching the coastline consist of

both seas and swells.

Monthly variation of wave period is depicted in Table 2.2. Predominent wave

character buoy data off Vembar from wave rider is given in Table 2.3.

2.2.2 Tides and Currents

The tides in this region are semidiurnal. The various important tide heights

with respect to chart datum near Pamban pass are as follows.

Mean Higher High Water Springs = 0.70 m Mean High Water Neaps = 0.48 m Mean Sea Level = 0.41 m Mean Low Water Neaps = 0.32 m Mean Low Water Springs = 0.06 m

It shows that the average spring tidal range is about 0.64 m and the neap tidal

range is about 0.16 m. The tidal range is relatively low compared to the northern part

of the Indian coast, which inturn would restrict the influence of tidal currents.

2.2.2.1 Longshore Currents

The longshore current speed remained weak (<0.1 m/s) throughout the year

between Keelamundal and Vedalai and along the northern coast of Rameswaram

from Arimunai to Ariyaman. Consequently, it was relatively moderate (>0.1 m/s)

throughout the year between Sippikulam and Naripaiyur and along the southern coast

of Rameswaram i.e. from Uthalai to Mukkuperiyar.

The spit between Dhanuskodi and Arimunai in Gulf of Mannar experienced

relatively stronger currents during fair weather period (March to May) and remained

weak during southwest monsoon and northeast monsoon periods (June to February).

It indicates that the stronger currents prevailing in the adjacent coasts during

Page 49: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

southwest/northeast monsoons becoming weaker between Dhanushkodi and

Arimunai. This phenomenon of sudden weakening of littoral currents causes the littoral

drift to deposit and form series of sand shoals near Arimunai. Such prolonged

deposition of littoral drift over many years can be attributed to formation of numerous

islands and shallow shoals across the strait between Arimunai (India) and

Talaimannar (Sri Lanka) called Adam’s Bridge.

The Uthalai coast facing Gulf of Mannar experienced stronger longshore

currents (0.2 – 0.5 m/s) throughout the year, followed by a segment of the coast

between Vembar and Naripayur (0.2 – 0.4 m/s) with exposure to relatively high wave

energy environment.

The prevalence of weak longshore currents between Keelamundal and

Vedalai is causing deposition of littoral drift on either side, as evidenced by the

occurrence of many offshore islands and submerged shoals.

Although the Pamban Pass, connecting Palk Bay and Gulf of Mannar break

the continuity of longshore current between the mainland and Rameswaram Island,

the magnitude of the current on either side of Pamban Pass is found to be very weak.

This reduces the volume of littoral sediments approaching the Pamban Pass which

inturn reduces the quantity of sediment passing through Pamban Pass from Gulf of

Mannar to Palk Bay.

The longshore current direction prevailed northerly during southwest

monsoon and fair weather period, and southerly during northeast monsoon between

Sippikulam and Uthallai. The entire coast of Rameswaram facing Gulf of Mannar,

experienced the current in westerly direction throughout the year, except in June and

July. This phenomenon of northerly currents along the mainland and westerly current

along Rameswaram create a zone, wherein, most of the littoral drift will get deposited.

Only a fractional proportion is expected to move from this region by tide induced

currents towards the Adams Bridge. This would reduce the volume of littoral sediment

reaching the Adam’s Bridge and intrun. The quantity of sediment entering Palk Bay

from Gulf of Mannar. These sediments deposited at

shoals is supplied back to the littoral system for the mainland, when the longshore

currents move towards south during the ensuing northeast monsoon.

Page 50: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Although the longshore current was extremely weak along the sand spit

facing Palk Bay, it tends to be easterly during southwest monsoon/fair weather period

and westerly during northeast monsoon. Similarly, at Ariyaman, the longshore current

direction was southerly during southwest monsoon/fair weather period and northerly

during northeast monsoon, indicating just opposite to the phenomenon observed in

Gulf of Mannar. Such processes once again indicate the accumulation of littoral drift

on either side of Rameswaram Island during southwest monsoon and removal during

northeast monsoon, making this region as a sediment storage reservoir.

Monthly variation of longshore current (m/s) is given in Table 2.4.

2.2.2.2 Currents Studies

Continuous measurements on tidal current speed and direction were carried

out for three seasons at 4 locations viz., i) stn. C1 - off Arimunai-Adam’s Bridge, ii) stn.

C2 - off Uthalai (Gulf of Mannar), iii) stn. C3 - Pamban Pass, and iv) stn. C4 - off

Tharuvai (Palk Bay). The measured currents were resolved into parallel and

perpendicular components with respect to the coastline. The variation of current speed

and direction and the resolved components are presented in Figs. 2.7 to 2.35.

Southwest monsoon (June to September)

Near Arimunai (stn. C1) the average current speed occurred around 0.2 m/s

with the maximum and minimum speed of 0.3 m/s and 0.05 m/s respectively both at

surface and bottom (Fig. 2.7). The variation of current direction had not followed the

tidal phase. It showed consistent northwesterly flow over one tidal cycle and changed

to southeasterly flow for the subsequent tidal cycle. It indicates that current shifted its

flow direction for alternate tidal cycles rather than flood and ebb tidal phases. The

shore parallel component of currents indicates that for larger tidal range, the flow was

in westerly direction and for small range in easterly direction. The shore perpendicular

component of currents indicates that the flow consistently existed from Gulf of Mannar

into Palk Bay. The northwesterly and southeasterly currents over different tidal cycles

were found to be equally predominant.The component of currents near surface and

bottom off Ariminai during southwest monsoon is depicted in Fig. 2.8 and Fig. 2.9

respectively.

At Uthalai (stn. C2) in Gulf of Mannar, the average current prevailed around

0.1 m/s with the maximum and minimum of 0.2 m/s and 0.05 m/s respectively (Fig.

Page 51: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

2.10). Similar to stn. C1, the bottom current was seen responding to tides flowing east

over one tidal cycle and west during the subsequent tidal cycle. The direction of flow

was predominant in southeasterly direction for larger tidal range and northwesterly

direction for small tidal range. The shore parallel component of currents indicates that

the flow shifted in southeast and northwest both at surface and bottom. The shore

perpendicular component of currents indicates that the flow shifts towards northeast

and southwest both at surface and remains consistently northeast at bottom. The

component of currents near surface and bottom off Rameswaram during southwest

monsoon is depicted in Fig. 2.11 and Fig. 2.12 respectively.

The variation of currents at surface measured near Pamban Pass (stn. C3) is

shown in Fig. 2.13. The current speed was found to be strong showing an average of

0.5 m/s, with the maximum of 1 m/s and minimum of 0.1 m/s. Current direction

remained consistently northeast flowing from Gulf of Mannar into Palk Bay. Variation

of current speed shows that the magnitude of the current speed was more during flood

and less during ebb tide indicating the influence of tides over the seasonal

unidirectional flow. The shore parallel component of currents indicates that the flow is

into Palk Bay with high speed during flood tide and low speed during ebb tide. The

shore perpendicular component of currents indicates that the flow is across the

Pamban Pass towards Rameswaram Island. The component of currents near surface

off Pamban Pass during southwest monsoon is depicted in Fig. 2.14.

At Tharuvai (stn. C4), the average current speed of 0.2 m/s with the maximum

of 0.3 m/s and minimum of 0.1 m/s were observed both at surface and bottom (Fig. 2.15). The flow was unidirectional towards southeast but the current speed varied with

tidal phase. Current speed was high during flood tide and low during ebb tide

indicating the strong influence of seasonal circulation current towards northeast during

southwest monsoon period. The shore parallel component of currents indicates that

the flow was towards southeast at surface and bottom. The shore perpendicular

component of currents indicates the flow was towards northeast both at surface and

bottom. The component of currents near bottom off Tharuvai during southwest

monsoon is depicted in Fig. 2.16.

The measurement shows that during southwest monsoon when the tidal

range is large, the opposite direction of flow prevail between Adam’s Bridge (stn. C1)

and Uthalai (stn. C2) would cause the water mass to flow from Gulf of Mannar to Palk

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Bay. This flow would transport sediments into Palk Bay from Gulf of Mannar. On the

other hand, when the range is small, the divergence of flow occurring near Adams’s

Bridge (stn. C1) and Uthalai (stn. C2) would initiate a flow from Palk Bay into Gulf of

Mannar through Adam’s Bridge. Thus the sediment exchange taken place into Palk

Bay during large tidal range day would return back to Gulf of Mannar.

Northeast Monsoon (October to January)

Near Arimunai (stn. C1), current was generally weak showing an average of

0.1 m/s, with the maximum of 0.2 m/s and minimum of 0.05 m/s (Fig. 2.17). The flow

direction remained unidirectional towards west both at surface and bottom. The

current speed increased during flood tide and reduced during ebb tide. The shore

parallel component of currents indicates that the flow was consistently towards

northwest at surface and bottom. The shore perpendicular component of currents

indicates the flow prevailed northeast at surface and southwest at bottom. The

component of currents near surface and bottom off Arimunai during northeast

monsoon is depicted in Fig. 2.18 and Fig. 2.19 respectively.

The variation of currents at Uthalai (stn. C2), showed an average current

speed of 0.08 m/s, with the maximum of 0.15 m/s and a minimum of 0.04 m/s (Fig. 2.20). The bottom flow was nearly unidirectional towards southeast. The shore parallel

component of currents indicates that the flow was oscillating in southeast and

northwest at surface and remaining consistently southeast at bottom. The shore

perpendicular component of currents indicates that the flow was towards northeast

both at surface and bottom. The component of currents

near surface and bottom off Rameswaram during northeast monsoon is depicted in

Fig. 2.21 and Fig. 2.22 respectively.

The currents at Pamban Pass (stn. C3) prevailed strong with the average of 1

m/s, maximum of 1.4 m/s and minimum of 0.5 m/s (Fig. 2.23). Currents remained

consistently unidirectional around 2250. The change in tidal phase caused the variation

in current speed showing stronger currents during ebb tide and reduction in current

speed during flood tide. It indicates that the flood tide propagates from Gulf of Mannar

to Palk Bay and vice versa. The shore parallel component indicates that the flow was

consistently from Palk Bay into Gulf of Mannar during ebb tide and flood tide. The

shore perpendicular component of currents indicates the flow was across the Pamban

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Pass from Rameswaram to Mandapam. The component of currents near surface off

Pamban Pass during northeast monsoon is depicted in Fig. 2.24 respectively.

The current was found to be weak off Tharuvai at Palk Bay (stn. C4) showing

the average speed of 0.1 m/s, maximum of 0.13 m/s and minimum of 0.04 m/s (Fig. 2.25). Similar to stn. C3, the current flow was unidirectional towards 250O, but the

speed was high during ebb tide and low during flood tide. The shore parallel

component of currents indicates that the flow was towards northwest both at surface

and bottom. The shore perpendicular component of currents indicates that the flow

was towards southwest both at surface and bottom. The component of currents near

surface and bottom off Tharivai during northeast monsoon is depicted in Fig. 2.26 and

Fig. 2.27 respectively.

The observation during northeast monsoon indicates that the current flow was

more influenced by seasonal flow than by tides. Stronger currents were observed

during ebb tides flowing from Palk Bay into Gulf of Mannar through Pamban Pass. The

currents were generally weak in Gulf of Mannar and Palk Bay (stns. C2 and C4).

Significant flow from Palk Bay to Gulf of Mannar was observed through Adam’s Bridge

also. Such current pattern during northeast monsoon can transport and exchange the

sediments from Palk Bay into Gulf of Mannar.

Fair weather (February to May)

The variation of currents near Arimunai (stn. C1) at surface and bottom are

shown in Fig. 2.28. The current was generally weak showing average of

0.1 m/s, with the maximum of 0.2 m/s and minimum of 0.05 m/s. The current flow was

found to be unidirectional towards northwest both at surface and bottom. The shore

parallel component of currents indicates that the flow was towards northwest both at

surface and at bottom. The shore perpendicular component of currents indicates the

flow was changed its direction in northeast and southwest both at surface and bottom.

The component of currents near surface and bottom off Arimunai during fair weather is

depicted in Fig. 2.29 and Fig. 2.30 respectively.

At Gulf of Mannar (stn. C2), the current was weak with average of 0.1 m/s,

maximum of 0.2 m/s and minimum of 0.04 m/s (Fig. 2.31). The flow remained

unidirectional consistently towards 305O, but the current speed varied randomly

between 0.04 and 0.12 m/s. The shore parallel component of currents indicates that

the flow was towards northwest both at surface and bottom. The shore perpendicular

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component of currents indicates the flow changed the direction from northeast to

southwest both at surface bottom. The component of currents near surface and

bottom off Rameswaram during fair weather is depicted in Fig. 2.32 and Fig. 2.33

respectively.

The flow through the Pamban Pass (stn. C3) was quite distinct, showing the

average speed of 0.3 m/s, maximum of 0.6 m/s and minimum of 0.04 m/s. The varition

of currents off Pamban Pass at surface and bottom are shown in Fig. 2.34.Current

flow was noticed towards 45°, i.e., into Palk Bay during flood tide and towards 225°,

i.e., into Gulf of Mannar during ebb tide. The shore parallel component of currents

indicates that the flow was into Palk Bay during flood tide and into Gulf of Mannar

during ebb tide. The shore perpendicular component of currents indicates the flow was

changing its direction across the Pamban Pass between Mandapam and

Rameswaram. The component of currents near surface off Pamban Pass during

southwest monsoon is depicted in Fig. 2.35.

During fair weather period, the change in current direction was observed over

the tidal phases at Pamban Pass. The study shows that the current flows mostly

parallel to the coast. The general circulation of current in northwesterly direction

dominates the tide induced current. This would help the sediments to move by tide

induced currents from Gulf of Mannar to Palk Bay prevailing through Pamban Pass

and to some extent through Adam’s Bridge.

Page 55: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

2.2.3 Sediment Transport

In Indian coast, various investigations pertaining to different fields of

oceanography were carried out by a number of research workers. Sediment transport

along the east coast of India was initiated by Lafond and Prasada Rao (1954) and

subsequently by many other investigators.

The formation of sand islands off Tuticorin region indicates this region acts as

a sediment sink with progressive accumulation of sand. The large beach storage of

sand between Manppad and Tiruchendur, Vembar and Valinokkam and Rameswaram

Island indicates the depositional features of littoral sediments.

The geographical formation of Tamilnadu coast plays a vital role maintaining

the stability of the Indian shoreline. It determines the extent of sources and sinks for

the littoral drift moving around the Indian peninsular tip across the east and west

coasts of India. Based on the characteristics of the sediment processes and the

various influencing parameters, the Tamilnadu coastline can be classified into 6

segments viz., i) open coast in Bay of Bengal – Pulicat to Pondicherry, ii) partly

protected coast in Bay of Bengal – Pondicherry to Vedaraniyam, iii) protected coast in

Palk Bay – Vedaraniyam to Dhanushkodi, iv) protected coast in Gulf of Mannar –

Dhanushkodi to Tuticorin, v) partly protected coast in Indian Ocean – Tuticorin to Ovari

and vi) open coast in Indian Ocean – Ovari to Thengaipattinam. The typical formation

of Tamilnadu coast comprises of long sandy beaches on the northern part. The stretch

between Pondicherry and Vedaraniyam has been experiencing a recession of

coastline since historical period. The coastlines between Vedaraniyam and

Rameswaram in Palk Bay and between Rameswaram and Tuticorin in Gulf of Mannar

are substantially protected from monsoon waves due to the proximity of Srilanka

Island. Palk Bay is very shallow and is largely occupied by sandbanks and submerged

shoals.

Rameswaram Island, the geological formation of coral atoll with huge sand

cover between India and Srilanka plays a vital role on the processes of exchange of

littoral drift between east coast and west coast. It separates the sea in the north by

Palk Bay and south by Gulf of Mannar. The wave sheltering effect due to Sri Lanka

Island, the large siltation in Palk Bay, the presence of numerous offshore islands in

Gulf of Mannar, the growing sand spit along Dhanushkodi and the shallow reef

Page 56: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

(Adam’s Bridge) between Arimunai (India) and Thalaimannar (Sri Lanka) largely

modify the sediment movement. It is strongly evident that the coastal processes taking

place around the Rameswaram Island and the exchange of the littoral drift between

Gulf of Mannar and Palk Bay significantly determine the supply of sediments to the

rest of the east coast and in turn the stability of the region.

2.2.3.1 Longshore Sediment Transport

The longshore sediment rate varies with season for different location in the

study area. The detais of observation stations is given below and their longshore

sediment transport rate is given in Table 2.5 and shown in Fig. 2.36 to Fig. 2.40.

Sippikulam

The longshore sediment transport rate varied between 0.06-0.84 x 103

m3/month in southwest monsoon (June to September), between 0.05-2.14 x 103

m3/month in northeast monsoon (October to January) and between 0.03-0.09 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 5.0 x 103 m3/year. The annual net transport was 1.4 x 103 m3/year towards south.

Vember

The longshore sediment transport rate varied between 0.35-3.84 x 103

m3/month in southwest monsoon (June to September), between 0.53-20.28 x 103 m3/

month in northeast monsoon (October to January) and 0.02-1.9 x 103 m3/month in fair

weather period (February to May). The annual gross transport rate was 34.0 x 103

m3/year. The annual net transport rate was 9.6 x 103 m3/year towards south.

Kannirajapuram

The longshore sediment transport rate varied between 3.7-23.94 x 103

m3/month in southwest monsoon (June to September), between 1.98-23.37 x 103

m3/month in northeast monsoon (October to January) and between 0.02-2.21 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 97 x 103 m3/year. The annual net transport rate was 25.6 x 103 m3/year towards

north.

Naripaiyur

The longshore sediment transport rate varied between 2.3-29.29 x 103

m3/month in southwest monsoon (June to September), between 0.06-14.46 x 103

m3/month in northeast monsoon (October to January) and between 0.02-2.47 x 103

Page 57: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

m3/month in fair weather period (February to May). The annual gross transport rate

was 66 x 103 m3/year. The annual net transport rate was 22.6 x 10 3 m3/year towards

south.

Keelamundal

The longshore sediment transport rate varied between 0.01-0.9 x 103

m3/month in southwest monsoon (June to September), between 0.55-17.46 x 103

m3/month in northeast monsoon (October to January) and between 0.14-5.73 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 36 x 103 m3/year. The annual net transport rate was 3.1 x 103 m3/year towards

south.

Valinokkam

The longshore sediment transport rate varied between 0.01-0.06 x 103

m3/month in southwest monsoon (June to September), between 0.01-1.06 x 103

m3/month in northeast monsoon (October to January) and between 0.01-1.76 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 3.0 x 103 m3/year. The annual net transport rate was 3.0 x 103 m3/year towards

north.

Kalimangundu

The longshore sediment transport rate varied between 0.01-0.68 x 103

m3/month in southwest monsoon (June to September), between 0.01-0.03 x 103

m3/month in northeast monsoon (October to January) and between 0.01-0.11 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 1 x 103 m3/year. The annual net transport rate was 0.5 x 103 m3/year towards

north.

Vedalai

The longshore sediment transport rate varied between 0.02-0.88 x 103

m3/month in southwest monsoon (June to September), between 0.01 x 103 m3/month

in northeast monsoon (October to January) and between 0.01-0.05 x 103 m3/month in

fair weather period (February to May). The annual gross transport rate was 1 x 103

m3/year. The annual net transport rate was 1 x 103 m3/year towards north.

Kondugal

Page 58: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

The longshore sediment transport rate varied between 0.88-14.96x103

m3/month in southwest monsoon (June to September), between 0.12-1.22 x 103

m3/month in northeast monsoon (October to January) and between 0.02-1.85 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 25 x 103 m3/year. The annual net transport rate was 10.2 x 103 m3/year towards

north.

Uthalai West

The longshore sediment transport rate varied between 6.88-48.7 x 103

m3/month in southwest monsoon (June to September), between 0.25-4.61 x 103

m3/month in northeast monsoon (October to January) and between 2.28-27.0 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 140x103 m3/year. The annual net transport rate was 72.6 x 103 m3/year towards

north.

Uthalai East

The longshore sediment transport rate varied between 9.12-44.97 x 103

m3/month in southwest monsoon (June to September), between 0.18-19.64 x 103

m3/month in northeast monsoon (October to January) and between

1.76-24.84 x 103 m3/month in fair weather period (February to May). The annual gross

transport rate was 190x103 m3/year. The annual net transport rate was 48.9x103

m3/year towards north.

Mukkuperiyar West

The longshore sediment transport rate varied between 5.16-44.96x103

m3/month in southwest monsoon (June to September), between 0.26-6.02 x 103

m3/month in northeast monsoon (October to January) and between 2.64-20.83 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 120x103 m3/year. The annual net transport rate was 5.6 x 103 m3/year towards

north.

Mukkuperiyar East

The longshore sediment transport rate varied between 1.78-28.65x103

m3/month in southwest monsoon (June to September), between 0.02-17.98 x 103

m3/month in northeast monsoon (October to January) and between 1.98-20.10 x 103

Page 59: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

m3/month in fair weather period (February to May). The annual gross transport rate

was 110x 103 m3/year. The annual net transport rate was 79 x 10 3 m3/year towards

north.

Dhanushkodi West

The longshore sediment transport rate varied between 2.31-17.05x103

m3/month in southwest monsoon (June to September), between 0.04-5.16 x 103

m3/month in northeast monsoon (October to January) and between 1.32-28.35 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 83 x 103 m3/year. The annual net transport rate was 22.1 x 103 m3/year towards

north.

Dhanushkodi Mid

The longshore sediment transport rate varied between 1.76-14.0 x 103

m3/month in southwest monsoon (June to September), between 0.02-0.90 x 103

m3/month in northeast monsoon (October to January) and between 8.59-29.35 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 96.0x103 m3/year. The annual net transport rate was 32.0 x 103 m3/year towards

north.

Page 60: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Dhanushkodi East

The longshore sediment transport rate varied between 1.20-19.28x103

m3/month in southwest monsoon (June to September), between 0.06-13.75 x 103

m3/month in northeast monsoon (October to January) and between 2.43-31.73 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 125x103 m3/year. The annual net transport rate was 80.0x10 3 m3/year towards

north.

Arimunai West

The longshore sediment transport rate varied between 1.05-27.77x103

m3/month in southwest monsoon (June to September), between 0.07-0.44 x 103

m3/month in northeast monsoon (October to January) and between 1.06-8.99 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 65.0x103 m3/year. The annual net transport rate was 43.7x103 m3/year towards

north.

Arimunai East

The longshore sediment transport rate varied between 0.90-35.97x103

m3/month in southwest monsoon (June to September), between 0.01-2.18 x 103

m3/month in northeast monsoon (October to January) and between 0.53-8.99 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 73.0x103 m3/year. The annual net transport rate was 36.4x10 3 m3/year towards

north.

Mukkuperiyar West (Palk Bay)

The longshore sediment transport rate varied between 0.02-0.12x103

m3/month in southwest monsoon (June to September), between 0.02-1.90 x 103

m3/month in northeast monsoon (October to January) and between 0.02-0.34 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 3.0x103 m3/year. The annual net transport rate was 2.7x103 m3/year towards

north.

Page 61: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Uthalai West (Palk Bay)

The longshore sediment transport rate varied between 0.02-0.11x103

m3/month in southwest monsoon (June to September), between 0.02-1.70 x 103

m3/month in northeast monsoon (October to January) and between 0.02-2.65 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 5.0 x 103 m3/year. The annual net transport rate was 4.6 x 103 m3/year towards

north.

Villuvandithirtham

The longshore sediment transport rate varied between 0.01-0.03x103

m3/month in southwest monsoon (June to September), between 0.02-1.47 x 103

m3/month in northeast monsoon (October to January) and between 0.01-0.05 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 2.0x 103 m3/year. The annual net transport rate was 1.6x10 3 m3/year towards

north.

Light House

The longshore sediment transport rate was 0.01 x 103 m3/month in southwest

monsoon (June to September), between 0.01-0.02 x 103 m3/month in northeast

monsoon (October to January) and between 0.01-0.07 x 103 m3/month in fair weather

period (February to May). The annual gross transport rate was 1.0 x 103 m3/year. The

annual net transport rate was 0.1 X 103 m3/year towards north.

Ariyaman

The longshore sediment transport rate varied between 0.01-0.06x103

m3/month in southwest monsoon (June to September), between 0.02-5.29 x 103

m3/month in northeast monsoon (October to January) and between 0.01-0.07 x 103

m3/month in fair weather period (February to May). The annual gross transport rate

was 23.0x103 m3/year. The annual net transport rate was 23.0x10 3 m3/year towards

north.

During southwest monsoon, the longshore sediment transport was

considerable (>10 X 103 m3/month) along the spit facing Gulf of Mannar and negligible

on Palk Bay side. Very close to the tip i.e., near Arimunai, the longshore transport

direction dominated in easterly direction indicating the movement from Gulf of Mannar

to Palk Bay through Adam’s Bridge.

Page 62: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

In northeast monsoon, the values of longshore transport rate was relatively

low along the spit facing Gulf of Mannar and negligible in Palk Bay. It is noticed that

the long shore sediment transport rate was considerable (>10 X 103 m3/month) in

January between Uthalai and Mukkuperiyar. The sediment transport direction was

consistently towards west in Gulf of Mannar and east in Palk Bay.

In fair weather period, the longshore sediment transport was low along the

spit facing Gulf of Mannar and also Palk Bay. The transport direction was observed to

be westerly near the tip facing Gulf of Mannar. It shows that in February, April and May

the sediment drifts from Palk Bay to Gulf of Mannar and the net quantity is found to be

8000m3, 6000 m3, 20000 m3 respectively. Consequently, in March, June, July, August

and September, it drifts from Gulf of Mannar towards Palk Bay and the respective

quantities are 8000 m3, 35000 m3, 10000 m3, 4000 m3 and 1000 m3 respectively.

There was no significant movement of sediment observed during October to January.

It means that during southwest monsoon, the sediments move from Gulf of Mannar to

Palk Bay and during fair weather period from Palk Bay to Gulf of Mannar. No

noticeable exchange due to wave induced longshore transport takes place in

northeast monsoon. It is noticed that over a period of one year, a net volume of 24000

m3 sediments as a wave induced longshore transport move from Gulf of Mannar to

Palk Bay around Adam’s Bridge.

The study indicates that, in general, the entire study region between Tuticorin

and Ariyaman including the Rameswaram Island experiences very low sediment

transport rate compared to the rest of Indian east coast. The east coast between

Chennai and Paradeep experiences a gross transport rate of more than 1x10 6

m3/year. On the otherhand, along the study region, it remained always less than

0.1x106 m3/year, which shows only 10 percent of the rest of the Indian east coast.

The sediment transport rate is practically negligible throughout the year,

particularly between Valinokkam and Kondugal in Gulf of Mannar, and between

Arimunai and Ariyaman in Palk Bay. The geomorphological formation of inner part of

Gulf of Mannar and the presence of many offshore islands are the main reasons for

wave attenuation and reduction in sediment transport.

The coastal segment between Tuticorin and Valinokkam experienced

relatively higher sediment transport rate during northeast monsoon, but remained calm

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during the rest of the year. However, the small stretch between Vember and

Naripaiyur experienced relatively higher sediment transport rate also during southwest

monsoon. The only coastline between Uthalai and Arimunai experienced relatively

higher sediment transport rate both during southwest monsoon and fair weather

period, with relatively low sediment transport during northeast monsoon.

The direction of sediment transport during southwest monsoon remained

easterly between Tuticorin and Arimunai except near Kondugal and Dhanushkodi,

where it was in opposite direction, i.e. towards west. Due to the reversal of sediment

transport direction near Kondugal, the easterly transport gets deposited in the vicinity

of Pamban Pass, Kursadi Tivu, Kovi Tivu and Shingle Tivu. Once again the easterly

transport along Vedalai terminates near Dhanushkodi which would cause the

formation of shoals in the vicinity off Arimunai. Such formation of submerged shoals

was observed south off Arimunai during the study period. The prevalence of easterly

transport at Arimunai might cause part of the sediments deposited as shoals to

migrate towards Adam’s Bridge and enter into Palk Bay. This processes of sediment

migration were noticed close to Adam’s Bridge. Hence a small proportion of littoral drift

deposited during southwest monsoon close to Pamban Pass and Arimunai has the

tendency to enter Palk Bay.

During the northeast monsoon, the sediment transport rate was very low

moving in southerly direction between Tuticorin and Valinokkam and it was negligible

between Valinokkam and Mandapam. Between Kondugal and Arimunai, the transport

was relatively low in westerly direction. It implies that there will be a deposition of

littoral drift in the vicinity of Pamban Pass. Due to low littoral drift taking place during

northeast monsoon, the quantity of sediments entering Gulf of Mannar from Palk Bay

will be much lower than the quantity moving from Gulf of Mannar to Palk Bay during

southwest monsoon.

Page 64: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

During fair weather monsoon, the sediment transport rate along the entire

study region except between Uthalai and Arimunai remains negligible. The sediment

transport between Uthalai and Arimunai exists relatively low in westerly direction for

which the source of sediment is expected from Palk Bay though Adam’s Bridge.

Due to low sediment transport rate prevailing in the study region, which

comprises of about 10 percent compared to the rest of Indian east coast, the volume

of sediment exchange is expected to be low. During southwest monsoon, the sizeable

portion of littoral drift from west coast passing around Kanyakumari is seen getting

deposited before reaching Tuticorin. This deposited sediment is supplied back for the

westerly transport during northeast monsoon. Such deposition is evidenced from the

occurrence of large beach deposition is evidenced from the occurrence of large beach

deposits and elevated dunes along Tiruchendur – Manapad region. Similarly, the

southerly transport along the east coast during northeast monsoon gets deposited

between Vedaranyam and Manmelkudi in Palk Bay, which is supplied back to the

littoral drift cycle during southwest monsoon.

Thus the study indicates that there is a break in the chain of littoral drift at

Tuticorin on the south and Vedaranyam is relatively low and there exits limited quantity

of exchange through Pamban Pass and Adam’s Bridge.

It signifies that the region around Adam’s Bridge forms as significant sink for

the littoral drift. The prolonged accumulation may lead to the emergence of new

islands. In case of occurrence of cyclones in Gulf of Mannar, such prolonged

deposition of sediments move north and enter in Palk Bay through Pamban Pass and

Adam’s Bridge. Once the sediments enter Palk Bay, the environment favours

immediate deposition. Hence the occurrence of cyclones in Gulf of Mannar and the

associated high northerly waves might exchange more sediments from the southern

part of Peninsular India to northern part of east coast. Similarly any cyclones moving in

Palk Bay, would generate large southerly waves and transport sizeable amount of

deposited sediments into Gulf of Mannar. In the event of absence of cyclones, the

deposition will increase causing the enlargement of sand

spit and shoaling across Adam’s Bridge, but the order of sediment exchange will be

limited.

Page 65: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

2.2.3.2 Spit Configuration

The numerical modelling study for the region around Rameswaram indicates

that due to tidal currents, in southwest monsoon (june-september), the sediment

transport is 6000 m3 and 30000 m3 through pamban pass and Arimunai respectively

moving from Gulf of Mannar to palk Bay. The same phenomenon continued in fair

weather period (February- May) indicating 3000 m3 and 16500 m3 through pambam

Pass and Arimunai respectively moving from Gulf of Mannar to Palk Bay.

On the other hand ,during northeast monsoon( October-january), about

15000 m3 and 21000 m3 of sediments are being transported through Pamban Pass

and Arimuani respectively from Palk Bay to Gulf of Mannar. It shows that in an annual

cycle, a net exchange of 6000 m3 of sediment is found to move from Palk Bay Pass to

Gulf of mannar through Pamban Pass and 25,500 m3 of sediment moves from Gulf of

Mannar to Palk Bay through Arimunai. The modelling study indicated that the volume

of sediment exchange due to tidal current (25, 500 m3 /year) is very close to the

volume being transported through littoral drift in breaker zone (24000 m3/ year).

Season Pamban pas (m3) Adam’s Bridge (m3)

Southwest monsoon (June to September)

-6000 -30000

Fair weather (February to May)

- 3000 - 16500

North-East monsoon (October to January)

15000 21000

Net 6000 m3 /year -25500 m3 /year

(-) = Towards Palk Bay (+) = Towards Gulf of Mannar The annual gross longshore sediment transport rate along the study region

remained less than 0.1 x 106 m3 /year, which shows only 10 percent of the rest of the

Indian east coast.

Page 66: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

In February, April and May the wave induced littoral drift is taking place from

Palk Bay to Gulf of Mannar and the net quantity is found to be 8000 m3, 6000 m3, 2000

m3, respectively. Consequently, in March, june July, August and September , it drifts

from Gulf of Mannar to Palk Bay and the quantity is 8000 m3, 35000 m3, 10000 m3,

4000 m3, and 1000 m3, respectively. There was no significant movement of sediment

between October and January. Over a period of one year, a net volume of 24000 m3, /

year sediments moves from Gulf of Mannar to Palk Bay. Adam’s Bridge forms as

noticeable sink for the littoral drift. The prolonged accumulation leads to the

emergence of new islands.

The modelling study indicates that over an annual cycle, the net volume of

sediment exchange due to tidal current is 6000 m3, form Palk Bay to Gulf of Mannar

through pamban pass and 25500 m3, from Gulf of Manar to Palk Bay through

Arimunai.

The satellite imageries show that the spit gets deflected towards palk Bay

during southwest monsoon indicating erosion on Gulf of Mannar side and deposition

on Palk Bay side. During northeast monsoon, the spit gets deposited on Gulf of

Mannar side and eroded in Palk Bay side, but the over all length increased by 150 m

towards Adam’s Bridge.

The sand spit extended 455 m in seven years indicating an average growth of

65 m in a year. the width increased 200 m at 1 km distance from the tip.

2.2.4 Geological Strata along Navigational Channel in Adams Bridge Area

NSDRC with the help of M/s Indomer Coastal Hydraulics Pvt. Ltd, has taken

up jet probe drilling operations on the sea floor to identify the type of geological strata

along the navigational canal.

Scope

i) to carry out wash boring at 3 locations at 2m , 3m and 5m water depths along

the proposed navigational route,

ii) to carry out drilling upto 12 m penetration into the sea floor or till reaching the

hard strata whichever is minimum,

iii) to collect wash boring sediment samples, and

Page 67: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

iv) to analyze the soil classifications of the collected sediment samples.

Methodology

Drilling jet probe was constructed on board a vessel with 5 HP pumps driven

by diesel generator. The outlet of 75-mm diameter pipe was connected to 30 m long

hose. To the other end of the hose, a drilling jet, having a tapered mechanism varying

from 75 mm to 40 mm diameter was attached. During the operation of pump at full

capacity, the jet velocity remained about 10 m/s. The jet was capable of penetrating

into sea floor up to a depth of 12 m in case of sandy bed. The jet drilling was carried

out at 3 points in each location to confirm the type of strata. During the last attempt of

jet drilling, divers collected sediment samples. These sediment samples were

analyzed for grain size distribution using sieve shaker with sieves of different mesh

sizes.

The locations of the jet probes are shown in Fig.2.41. The details of the

locations are given in the table below:

Co-ordinates Bore hole No. Latitude Longitude

Water depth (m)

Depth of drilling (m)

BH1 09O08.364′N 79O27.675′E 1 12

BH2 09O08.811′N 79O27.868′E 2 12

BH3 09O10.109′N 79O28.008′E 5 12

BH1 : The sediments collected at different layers (S1-surface, S2-2.5m, S3-

5.0m, S4-7.5m, S5-9.0m and S6-12.0m) at BH1. The composition of sediments shows

that it consists of light brownish Grey loose medium sand from 0 to 7.5 m, medium

sand with debris shells and shellsand from 7.5 to 12 m. The grain size distributions for

sediment collected at different layers are shown in Figs. 2.42a, 2.42b and 2.42c.

BH2 : The sediments collected at different layers at (S1-surface, S2-2.5m,

S3-5.0m, S4-6.5m and S5-11.0m) BH2. The composition of sediments shows that it

consists of grayish medium sand from 0 to 5 m, silty sandy from 5 to 6.5 m and

medium sand with whitish shell sand from 6.5 to 11.0 m. The grain size distribution for

sediment collected at different layers is shown in Fig. 2.43a through 2.43c.

BH3 : The sediments collected at different layers (S1- surface, S2-0.7m to

8.5m, S3-8.5m to 10m and S4-10.5m to 12.7m) at BH3. The composition of sediments

Page 68: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

shows that it consists of fine sand from 0 to 0.7m, silty medium sand with shell debris

from 0.7 to 8.5m, little silty coarse sand from 8.5 to 10.5 m and silty medium sand from

10.5 to 12 m. The grain size distribution for sediment collected at different layers is

shown in Figs. 2.44a through 2.44b.

2.2.5 Bathymetry and Shallow Seismic Survey In Gulf of Mannar and Palk Bay Area

Bathymetry Mapping

Any changes in sea floor may be the result of sea-level variation or to a

change in the elevation of land surface. Changes in absolute water-surface levels are

worldwide due to the interconnectivity of the oceans and are termed eustatic changes.

Changes in the absolute level of the land are localized. They may be due to tectonic

adjustments or due to adjustments caused by their distribution of weight on the land

surface. As and when sedimentation or ice build-up occurs, such changes are known

as isostatic. A rise in the sea level or down warping of land would involve the opposite

movements of sea and land. Synonymous with positive and negative changes are the

forms of sea-level transgression and regression, although in many cases these terms

also refer to the horizontal movement of the shoreline associated with vertical changes

of sea level. Recent depth contour map of 1999 has been compared with bathymetry

map of 1975; it reflects that the seafloor level has decreased along the coastal areas

and around the islands in the study area. It may be either due to emergence of land or

lowering of sea level (due to tectonism) and sediment deposit. In very few places,

particularly at river mouths and in island areas, the sea floor level has increased,

which may be due to erosion caused by anthropogenic activities.

The average depth reduction of seafloor along the coast of the study area has

been estimated as 0.51m over a period of 24 years. The average decrease and

increase of depth around the islands in the study area have been calculated as 0.56m

and 0.38m respectively. Assuming that the rate of change of depth of sea floor is

uniform over a year, the rate of decrease of depth is estimated as 0.021m/year along

the coast and 0.023 m/year around the island, and also the rate of increase of depth

as 0.015 m/year around the island. The annual sediment deposit on Gulf of Mannar

sea floor is about 0.001m/year (Basanta Kumar Jena 1997), or 0.024m for a period of

24 years. As found from the present study, the decrease of depth for the period of 24

years (1975 to 1999) is about 0.51m. Sedimentation accounts for about 0.024m in the

Page 69: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

total of 0.5 from clearance depth. The remaining 0.486 m reduction in depth may be

due to emerging of land or lowering of sea level (by tectonic activities). Based on the

above data, the rate of emerging of land or lowering of sea level can be estimated as

0.02m/year. Bathymetry maps of Gulf of Mannar (1975) and Bathymetry Map of

Tuticorin Coastal Region is given in Figs. 2.45-2.46 respectively. The general

bathymetry in Palk Bay area is shown in Drawing 2.1.

2.2.5.1 Bathymetry and Shallow Seismic Survey in Area Identified for Channel in Adam’s Bridge

An area of 4 km x 20 km showing bathymetry less than 12 m was identified

for detailed bathymetry and seismic survey in Adam’s Bridge area based on admiralty

chart. This location is shown in the Fig. 2.47. Bathymetry survey was carried out in

May 2003 and February 2004 over 100 line km across the 20 km by 4 km area. (Fig. 2.48).

Out of the total survey area of 4 km x 20 km marked for bathymetry and

shallow seismic survey, micro bathymetry survey was also carried out in 4 km x 4 km

as per the requirement. Bathymetry and shallow seismic survey (five lines) in 4 x 20

km section in Adam’s Bridge Area, beyond which safe navigation route is available on

both sides of the Adam’s bridge, has been completed. The charts detailing bathymetry

and geotech profile are shown in drawings listed as Drawing 2.2 to 2.11.

The bathymetry survey of 4 km x 4 km. area also has been undertaken and

completed during the second phase of the survey work. The bathymetry is shown in

Drawing 2.12.

Page 70: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Site survey Line Pattern

Bathymetry and shallow seismic survey conducted in 4 kms x 20 kms area

along the proposed ship canal longitudinal lines spaced at 1 km intervals. Lines run in

000O /180O direction. Echosounder, sub bottom profiler has run on all survey lines up

to the safe navigation limit.

• The Bathymetry and shallow seismic survey of 4 km x 10 km (five

lines) on south side of Adam’s Bridge

Bathymetry

For study propose 5 imaginary lines separated by 1 km distance have been

considered to explain bathymetry pattern across Adam’s Bridge covering 20 km

length. Thus each line is 20 km long stretching north-south across the Adam’s Bridge

as shown in Fig. 2.48. Line no. one is boundary of box facing Pamban island where

line 5 is boundary towards medial line for fishing.

a) Line No. 1 The bathymetry along the line no.1 reveals that the seabed from the North

end of the survey line to the South end gradually increases with depths ranging from

0.8 m to 11.8m. The bathymetry is presented in Drawing 2.2.

b) Line No. 2 The bathymetry along the second line reveals gradual fall in the seabed with

depths varying between 1.4m at the North end and 12.7 m on the South end of the

line. The bathymetry of this route is presented in Drawing 2.3.

c) Line No.3 The bathymetry along the 3rd line reveals gradual fall in the seabed with

depths varying between 2.4m at the North end and 11.7 m on the South end of the

line. The bathymetry of this route is presented in Drawing 2.4.

d) Line No.4 The bathymetry along the line no.4 reveals gradual fall in the seabed with

depths varying between 2.9m at the North end and 11.8 m on the South end of the

line.

Page 71: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

The bathymetry of line no.4 is presented in Drawing 2.5.

e) Line No. 5 The bathymetry of line no.5 is presented in Drawing 2.6.

The bathymetry along the line no.5 reveals gradual fall in the seabed with

depths varying between 3.8m at the North end and 7.9 m on the South end of the line.

Shallow Stratigraphy

a) Line No. 1

Information regarding shallow geological conditions is presented in Drawing 2.2.

The shallow geological successions within the window examined by the digital

data along this route can be differentiated into essentially four units.

The shallow seismic survey could not be carried out in less than 5m depth as

it was not feasible to take the survey boat in that area due to depth limitation and

presence of heavy breakers in the area. The note to that effect is shown in the

geological profile panel on the chart

Unit A is the uppermost of the sedimentary sequence and recorded all along

the surveyed corridor. The high acoustic transparency of this unit without any well-

defined internal reflectors indicates that it is comprised of soft sediments. Maximum

thickness of this unit along the proposed route is 0.5 m sub-seabed.

Underlying Unit A is Unit B. This unit is characterised by chaotic reflection

configuration. The surface and internal reflectors show medium acoustic impedance to

the seismic energy indicating more strength of material. This unit is interpreted as

comprising very high density to high density sands.Thickness of this layer varies

between 1 m to 3.5m.

Underlying Unit B is Unit C which can be identified from records with high

acoustic reflectivity from the surface. This unit is interpreted as medium to low density

sand. The thickness of this layer varies between 2m to 4m.

Page 72: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

b) Line No. 2

Information regarding shallow geological conditions on line no.2 is presented

in Drawing 2.3. The shallow geological successions within the window examined by

the digital data along this route can be differentiated into essentially four units.

The shallow seismic survey could not be carried out in less than 5m depth as

it was not feasible to take the survey boat in that area due to depth limitation and

presence of heavy breakers in the area. The note to that effect is shown in the

geological profile panel on the chart.

Unit A is the uppermost of the sedimentary sequence and recorded all along

the survey corridor. The high acoustic transparency of this unit without any well-

defined internal reflectors indicates that it is comprised of soft sediments. Maximum

thickness of this unit along the proposed route is 0.3 m.

Underlying Unit A is Unit B. This unit is characterised by chaotic reflection

conFiguration. The surface and internal reflectors show high acoustic impedance to

the seismic energy indicating more strength of material. This unit is interpreted as

comprising completely to very high density sands. Thickness of this layer varies

between 0.5m and 1.5m.

Underlying Unit B is Unit C which can be identified from records with medium

acoustic reflectivity from the surface. This unit is interpreted as comprising completely

of very high density sands.Thickness of this unit varies from 1.0m to 2.5m.

Underlying Unit C is Unit D which can be identified from records with low

acoustic reflectivity from the surface. This unit is interpreted as comprising low density

loose sands. Thickness of this unit varies from 0.5m to 2m

c) Line No. 3

Information regarding shallow geological conditions of line no.3 is presented

in Drawing 2.4.

The shallow geological successions within the window examined by the digital

data along this route can be differentiated into essentially three units.

The shallow seismic survey could not be carried out in less than 5m depths

as it was not feasible to take the survey boat in that area due to depth limitation and

Page 73: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

presence of heavy breakers in the area. The note to that effect is shown in the

geological profile panel on the chart.

Unit A is the uppermost of the sedimentary sequence and recorded all along

the survey corridor. The high acoustic transparency of this unit without any well-

defined internal reflectors indicates that it is comprised of soft sediments. Thickeners

of this unit along the line is 0.40 m sub seabed.

Underlying Unit A is Unit B. This unit is characterised by chaotic reflection

configuration. The Surface and internal reflectors show high acoustic impedance to the

seismic energy indicating more strength of material. This unit is interpreted as

comprising very high density sands. Thickness of this layer along the line is 0.5m to

3.5m.

Underlying Unit B is Unit C which can be identified from records with medium

to low acoustic reflectivity from the surface. This unit is interpreted as comprising

medium to low density loose sands. Thickness of this unit varies from 0.5m to 1.5m.

d) Line No. 4

Information regarding shallow geological conditions is presented in Drawing 2.5.

The shallow geological successions within the window examined by the digital

data along this route can be differentiated into essentially three units.

The shallow seismic survey could not be carried out in less than 5m depths

as it was not feasible to take the survey boat in that area due to depth limitation and

presence of heavy breakers in the area. The note to that effect is shown in the

geological profile panel on the chart.

Unit A is the uppermost of the sedimentary sequence and recorded all along

the survey corridor. The high acoustic transparency of this unit without any well-

defined internal reflectors indicates that it is comprised of soft sediments. The

maximum thickness of this unit along the line is 0.30 m.

Underlying Unit A is Unit B. This unit is characterised by chaotic reflection

conFiguration. The surface and internal reflectors show high acoustic impedance to

the seismic energy indicating more strength of material. This unit is interpreted as

Page 74: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

comprising of high density sands. Thickness of this layer varies between 0.5 and 1.5

m.

Underlying Unit B is Unit C which can be identified from records with medium

to low acoustic reflectivity from the surface. This unit is interpreted as comprising of

medium to low density sands. The thickness of this unit along the line varies between

2.5 m to 3.5 m.

Underlying Unit C is Unit D which can be identified from records with low

acoustic reflectivity from the surface. This unit is interpreted as comprising of low

density sands. The thickness of this unit along the line varies between 2 m to 3 m.

e) Line No. 5

Information regarding shallow geological conditions is presented in Drawing 2.6.

The shallow geological successions within the window examined by the digital

data along this route can be differentiated into essentially three units.

The shallow seismic survey could not be carried out in less than 5m depth as

it was not feasible to take the survey boat in that area due to depth limitation and

presence of heavy breakers in the area. The note to that effect is shown in the

geological profile panel on the chart

Unit A is the uppermost of the sedimentary sequence and recorded all along

the survey corridor. The high acoustic transparency of this unit without any well-

defined internal reflectors indicates that it is comprised of soft sediments. Maximum

thickness of this unit along the proposed route is 0.50 m.

Underlying Unit A is Unit B. This unit is characterised by chaotic reflection

configuration. The surface and internal reflectors show high acoustic impedance to the

seismic energy indicating more strength of material. This unit is interpreted as

comprising of very high density sands. Thickness of this layer varies between 0.5 and

4.5 metres.

Underlying Unit B is Unit C, which can be identified from records with medium

to low acoustic reflectivity from the surface. This unit is interpreted as comprising of

medium density sands. The thickness of this unit along the line varies between 2m to

3m.

Page 75: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

The Bathymetry and shallow seismic survey of 4 km x 10 km (five lines) on north side of Adam’s bridge

a) Line No. 1

The bathymetry of the rout is presented in Drawing 2.7. The bathymetry

along the line no.1 reveals that seabed from the north end of the survey line to the

south end gradually falls with depths from 7.0 m to 1.4 m.

b) Line No. 2

The bathymetry of the route is presented in Drawing 2.8. The bathymetry

along the second line reveals gradual fall in the seabed with depths varying between

9.1 m at the North end and 2.1 m on the south end of the line.

c) Line No. 3

The bathymetry of line no. 3 is presented in Drawing 2.9. The bathymetry

along the 3rd line reveals gradual fall in the seabed with depths varying between 9.5m

at the North end and 2.5 m on the South end of the line.

d) Line No. 4

The bathymetry of line no.4 is presented in Drawing 2.10. The bathymetry

along the line no. 4 reveals gradual fall in the seabed with depths varying between

10.1 m at the North end and 2.8 m on the South end of the line.

e) Line No. 5

The bathymetry of line no. 5 is presented in Drawing 2.11. The bathymetry

along the line no. 5 reveals graduals fall in the seabed with depths varying between

10.1 m at the North end and 2.8 m on the south end of the line.

Shallow Stratigraphy

a) Line No. 1

Information regarding shallow geological conditions is presented in Drawing 2.7. The shallow geological successions within the window examined by the digital

data along this route can be differentiated into essentially four units.

Unit A is the uppermost of the sedimentary sequence and recorded all along

the surveyed corridor. The high acoustic transparency of this unit without any well-

defined internal reflectors indicates that it is comprised of soft sediments. Maximum

thickness of this unit along the proposed route is 0.5 m sub-seabed.

Page 76: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Underlying unit A is Unit B. This unit is characterised by chaotic reflection

configuration. The surface and internal reflectors show medium acoustic impedance to

the seismic energy indicating more strength of material. This unit is interpreted as

comprising very high density to high density sands. Thickness of this layer varies

between 1m to 4m.

Underlying unit B is Unit C which can be identified from records with high

acoustic reflectivity from the surface. This unit is interpreted as medium to low density

sand. The thickness of this layer varies between 1 m to 3 m.

Underlying unit C is D which can be identified from records with low acoustic

reflectivity from the surface. This unit is interpreted as low density loose sand. The

thickness of this layer varies between 1 m to 2m.

b) Line No. 2

Information regarding shallow geological conditions online in Drawing 2.8.

The shallow geological successions within the window examined by the digital data

along this route can be differentiated into essentially four units.

Unit A is the uppermost of the sedimentary sequence and recorded all along

the survey corridor. The high acoustic transparency of this unit without any well-

defined internal reflectors indicates that it is comprised of soft sediments. Maximum

thickness of this unit along the proposed route is 0.5 m.

Underlying Unit A is Unit B. this unit is characterised by chaotic reflection

configuration. The surface and internal reflectors show high acoustic impedance to the

seismic energy indicating more strength of material. This unit is interpreted as

comprising completely to very high density sands. Thickness of this layer varies

between 1.5 m and 3m. At places bottom of this unit is not discenrnible from records.

Underlying Unit B is Unit C which can be identified from records with medium

acoustic reflectivity from the surface. This unit is interpreted as comprising medium to

low density sands. Thickness of this unit varies from 1 m to 3 m.

Underlying Unit C is Unit D which can be identified from records with low

acoustic reflectivity from the surface. This unit is interpreted as comprising low density

loose sands. Thickness of this unit varies from 1 m to 2 m.

Page 77: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

c) Line No.3

Information regarding shallow geological conditions of line in Drawing 2.9.

The shallow geological successions within the window examined by the digital data

along this route can be differentiated into essentially three units.

Unit A is the uppermost of the sedimentary sequence and recorded all along

the survey corridor. The high acoustic transparency of this unit without any well-

defined

internal reflectors indicates that it is comprised of soft sediments. Thickness of this unit

along the line 0.50 m sub seabed.

Underlying Unit A is Unit B. This unit is characterised by chaotic reflection

conFiguration. The surface and internal reflectors show high acoustic impedance to

the seismic energy indicating more strength of material. This unit is interpreted as

comprising very high density sands. Thickness of this layer along the line is 1 m to 3

m.

Underlying Unit B is Unit C which can be identified from records with medium

to low acoustic reflectivity from the surface. This unit is interpreted as comprising

medium to low density loose sands. Thickness of this unit varies from 3 m to 5 m.

d) Line No.4

Information regarding shallow geological conditions is presented in Drawing 2.10. The shallow geological successions within the window examined by the digital

data along this route can be differentiated into essentially three units.

Unit A is the uppermost of the sedimentary sequence and recorded all along

the survey corridor. The high acoustic transparency of this unit without any well-

defined internal reflectors indicates that it is comprised of soft sediments. The

maximum thickness of this unit along the line is 0.50m.

Underlying Unit A is Unit B. This unit is characterised by chaotic reflection

conFiguration. The surface and internal reflectors show high acoustic impedance to

the seismic energy indicating more strength of material. This unit is interpreted as

comprising of high density sands. Thickness of this layer varies between 1 and 3 m.

Underlying Unit B is Unit C which can be identified from records with medium

to low acoustic reflectivity from the surface. This unit is interpreted as comprising of

Page 78: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

medium to low density sands. The thickness of this unit along the line varies between

1 m to 3m.

Underlying Unit C is D which can be identified from records with low acoustic

reflectivity from the surface. This unit is interpreted as comprising of low density sands.

The thickness of this along the line varies between 1m to 3m.

e) Line No. 5

Information regarding shallow geological conditions is presented in Drawing 2.11. The shallow geological successions within the window examined by the digital

data along this route can be differentiated into essentially three units.

Unit A is the uppermost of the sedimentary sequence and recorded all along

the survey corridor. The high acoustic transparency of this unit without any well-

defined internal reflectors indicates that it is comprised of soft sediments. Maximum

thickness of this unit along the proposed route is 0.50 m.

Underlying Unit A is Unit B. This unit is characterised by chaotic reflection

configuration. The surface and internal reflectors show high acoustic impedance to the

seismic energy indicating more strength of material. This unit is interpreted as

comprising of very high density sands. Thickness of this layer varies between 1 and

3.5 meters. The maximum thickness being around 1022250 northing.

Underlying Unit B is Unit C, which can be identified from records with medium

to low acoustic reflectivity from the surface. This unit is interpreted as comprising of

medium density sands. The thickness of this unit along the line varies between 2 m to

3 m.

Under lying unit C is unit D which can be identified from records with low

acoustic reflectivity form the surface. The unit is interpreted as comprising of low

density loose sand. The thickness of this unit is 1 m to 1.5 m.

The bathymetry survey of the proposed five survey lines across the Adam’s

Bridge reveals that the seabed has gradual slope from North towards south and also

East to West with depths between 11.3 m at the North East corner of the survey area

and 1.4 m at the south west corner of the survey area and 9.0m at North west corner

to 4.4m at South East corner of the survey area. The seabed is thus seen deepening

from southwest corner of the survey area to North East corner of the survey area.

Page 79: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Unit A is the uppermost of the sedimentary sequence and recorded all along

the surveyed corridor and comprised of soft sediments. Unit B is interpreted as

comprising completely to moderately with very high density sand to medium density

sand. Underlying Unit B is Unit C which is interpreted as low density sand. No

anomalies associated with any type of rock is evident from the records up to the

penetration of about 6 to 7m.

In view of very high density sands lying below a very thin layer of soft

sediments in the entire area of survey the penetration of the seismic system has been

restricted to that in the sand to a maximum depth of about six to seven meters,

however, no rocky strata was observed in the entire survey area up to the depth of

penetration.

2.2.5.2 Bathymetry Survey of Area of 4 km. X 4 km.

The bathymetry survey of 4km. x 4km. area at 50m interval reveals that

depths are gradually decreasing from South-West corner of the survey area to South-

East corner of the survey area with maximum depth of 6.3m around the South-West

corner to a minimum of 0.6m depth around South-East corner of the survey area in

general with considerable depth variation in between. The depth contours drawn at 1

m interval in the survey area reveal that almost all contours run in approximately in

North West-South East direction (Drawing 2.12).

A shallow patch showing strip of exposed land area runs from North West

corner of the survey area in approximately towards the South East corner of the

survey area. This stretch of the area has all along heavy breakers breaking almost all

the times from the South West as well as from the North East directions making it

extremely difficult to negotiate the area.

2.2.5.3 Bathymetry and Seismic Survey along the Channel in Palk Bay Area

Hydrographic survey along the proposed channel in Palk Bay area was

undertaken by National Hydrographic Office (NHO) during January 25-February 18,

2004. The survey was carried out 250 m on either side of the line joining points

indicated in Drawing 2.13 detailed below :

C 9O21′26″N 79O21′37″E

D 9O40′30″N 79O25′30″E

Page 80: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

E 9O58′20″N 79O33′30″E

F 10O11′30″N 80O12′30″E

In addition NHO covered points A and B adjoining Adams Bridge Area at

9O08′43″N, 79O2539″E and 09O13′42″N and 79O28′50″E in addition to data collected

by NSDRC. The survey was undertaken using long range HF Sercel Differential

Global Positioning System, Echo Sounder Atlas Deso 20 with duel frequency

transducers of 210/33 k3H, Smart Acoustic Current meter, Geostar

SB-216 full spectrum sonar system to measure sediment thickness.

The seabed of the complete area comprise sand and mud with few broken

shells. The depth contours in the area are in agreement with those depicted on the

existing navigation Chart 358 (Drawing 2.1). The area between point C to E (refer

Drawing 2.13) has depth more than 12 m and thus no dredging will be required.

However area north of point E and south of point C will require to be dredged to 12 m

depth. Since the sea bed is mud and sand capital dredging would not be difficult

proposal. Sub bottom profiler indicates that there is some hard strata under the soft

sediment (Figs. 2.49-2.50).

The tides in this area are variable. Both semidiurnal and diurnal tides were

observed. The range of tide varied from 0.4 to 0.7 m at the spring. Current in the area

is along N-S direction and speed varied from 0.1 m/sec to 1.0 m/sec.

2.2.6 Selection of Route in Adam’s Bridge Area

The area for navigation route in Adam’s Bridge area was selected keeping in

view the proximity to international Medial line for fishing as well as national park

boundary. The purpose of selecting the stretch under study was to avoid / minimize

impacts on marine national park. The selected area is approximately 10 km away from

Arimunai tip and about 20 km away from Sringle island which is a part of national park.

The bathymetry data collected in this stretch was used to identify possible alignment of

route within the block. Zeroing down on to the option of 10.7 m draft and 300 m width

of channel availability or creation of 12 m deep channel with minimum dredging

requirement was considered as a critical parameter to arrive at alignment across the

Adam’s Bridge. From the assessed bathymetry, line 2 was considered as route for

navigation as dredging requirement will be minimum. This line is also at least 4 km

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away from medial line. The details on quantity and quality of dredged spoil likely to be

generated by dredging in this route is discussed under chapter on environmental

impacts.

2.2.7 Navigation Route in Palk Bay and Palk Strait

The ships after traveling through the channel in Adam’s Bridge area will tread

through available navigation depth in Palk Bay.

It could be seen that channel further needs to be created in Palk Strait area

where the bathymetry varies from 7.0 m to 10.8 m. Based on the available chart the

exercise for computing of dredging requirement to attain 12.0 m depth has been taken

up and is explained in chapter on Environmental Impacts. The

selection of route is guided by minimum dredging requirement and distance from

medial line. The proposed channel alignment with its bathymetry is shown in

Fig. 2.51.

2.2.8 Computation of Dredged Material

Based on bathymetry data, quantity of dredged spoil with 12 m depth and 300

m with for a proposed channel is about 38x106 m3 in Adam’s Bridge Area and is about

44x106 m3 for Palk strait area. Thus total capital dredging required for

continuous navigation channel of 12 m depth will be of the order of 82 million m3. The

quality of dredged spoil in Adam’s Bridge area is mostly sand with small percentage of

silt and clay. The quality of dredged spoil in Palk strait area also comprise clay and

sand upto 12 m as per data collected by NHO Dehradun.

2.3 Environmental Setting in Project Area

The sea coast stretching along the proposed canal project region is broken by

a few minor rivers like Agniar, Ambuliar, Vellar, Koluvanaru, Pambar, Manimukta nadi,

Kottangarai aru and Vaigai draining vast areas of irrigated lands. In the Gulf of Mannar

along the coast there are 21 islands (Table 2.6) which have been declared as National

Marine Park by the Tamilnadu Forest Department and the Ministry of Environment and

Forests, Government of India.

Page 82: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

The Palk Bay (PB) and the Gulf of Mannar (GOM) are considered biologically

rich and are rated among the highly productive seas of the world. The Gulf of Mannar

harbours one of the richest biodiversity of living resources which have evolved in the

past millennia. Primarily due to its semi enclosed nature, seclusion, shallowness, and

having more or less stable temperature regimen, presence of multiple niches,

recycling and enrichment of nutrients amply derived from land drainage by the rich

variety of coastal, sedimentary, medowan, reef and paar biota, the Gulf of Mannar has

acquired ecological uniqueness, biodiversity, pluralism alongwith endemism. It is a

natural heritage, and is often called the 'Biologist's Paradise'. Through an executive

communication from the Secretary to the Government of India, Ministry of

Environment & Forests to the Chief Secretary, Government of Tamilnadu, the Gulf of

Mannar Marine Biosphere Reserve (GOMMBRE) has been notified in 1989. There is,

however, no legislation as yet on the biosphere reserve either at the national or at the

state level.

The Gulf of Mannar is endowed with a combination of ecosystem including

mangroves, seagrass and coral reefs, supporting over 3,600 species of plants and

animals. Its biodiversity is considered globally significant. The Gulf of Mannar islands

constitute a resting place for birds migrating to and from Sri Lanka. Approximately 168

types of birds use the islands in the Gulf as a resting place while migrating or as

wintering and molting grounds. All five species of marine turtle nest in various

locations in the Gulf of Mannar. Dolphins are more common here than in any other

region in the Bay of Bengal. The endangered dugong uses many of the islands as

browsing grounds. Marine life also includes many coloured coral fishes, eels,

molluscs, and stomatopoda. Sea anemones, crabs, starfish, sea urchins and

numerous other organisms are found in the Gulf of Mannar waters.

There are no hills on any of the islands, most of which are less than three

metres above the level of the high water springs. The islands are irregular in shape,

with spits and partially enclosed bays. Sandy beaches are located on many of the

islands and along the mainland coast. Fringing and patch coral reefs are located in the

Gulf of Mannar. The eastern side of the islands has the greatest expanse of living

coral reefs, because human exploitation of the reefs is concentrated on the northern

and western sides. The vegetation on the islands is not uniformly spread and generally

consists of thorny shrubs. Mangroves are located on Shingle, Krusadai, Pullivasl,

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Poomarichan, Manoli and Manoliputti islands. Tree species such as palmyra,

casuarina, coconut, and tamarind grow on Shingle, Krusadai, Hare and Nallathanni

islands. Most of the islands have been significantly deforested. Some reforestation is

also taking place.

Located within the Biosphere Reserve, Krusadai island exemplifies the

biological significance of the area. The island harbours three species of seagrasses

endemic to the Gulf of Mannar. Representatives of every animal phyla known (except

amphibians) occur on this island. The island harbours a unique, endemic organism

called "balanoglossus" (Ptychodera fava), a living fossil which links vertebrates and

invertebrates.

Supporting the Gulf's biodiversity are its extensive and diverse assemblage of

seagrass. Six of the world's twelve seagrass genera and eleven of the world's fifty

species, occur in the Gulf. The Gulf harbours the highest concentration of seagrass

species along India's 7,500 km of coastline. These seagrass beds are some of the

largest remaining feeding grounds for the globally endangered dugong (Dugong

dugon). The seagrass beds also provide feeding areas for all the five species of

marine turtles, the Green (Chelonia mydas), the Loggerhead (Caretta caretta). Okive

Ridleys (Lepidochelys olivacea). Hawksbill (Eretmochelys imbricate) and Leather

backs (Dermochelys coriacea). Many species of crustaceans, molluscs, gastropods

and fishes have been observed to inhabit the seagrass beds.

The Gulf's seagrass communities are valuable habitats for commercially

harvested species, particularly the green tiger prawn Penaeus semisulcatus, which is

extensively harvested for the export market. Holothurian, an endemic echinoderm

found in abundance in the Gulf of Mannar, is extensively exploited for export to Japan

and other Southeast in the Gulf of Mannar, is extensively exploited for export to Japan

and other Southeast Asian countries as a highly, priced food item for human

consumption. The economically viable species of seaweeds such as Hypnea,

Gelidiella, Gracilaria, Stoechosperum, Hydrochlathrus, Clathratus, Padina, Caulerpa

are largely distributed in the Gulf of Mannar. In addition, ornamental shells, chanks,

and pearl oysters are exploited in the Gulf. Sea fans and seaweeds are exported for

industrial and decorative purposes.

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The Gulf of Mannar harbours a total of 128 species of coral belonging to 37

genera. Coral reefs serve as the spawning grounds for fisheries, seagrass beds as

nursery grounds, and mangroves and shelters form a unique component of life-

support system of coastal biodiversity that relates to global benefits and local needs.

Seventeen different mangrove species occur within the biosphere reserve area. The

coastal mangrove Pemphis acidula is endemic to the Gulf of Mannar. Coastal

mangroves are important nursery habitats and biodiversity reservoirs in coastal areas.

Both the reserve area and the adjacent coastline have been degraded to

some extent by overuse and pollution as evidenced by the declining catch/effort ratios

in the fisheries, the absence of significant numbers of herbivorous fish on coral reef

areas, low coral cover and widespread growth of green marine algae in coraline areas

and absence of large vegetation on many parts of the islands. Some areas of the

coast also show visible effects of pollution, most of it emanating from the mainland.

In Palk Bay area, there are ecologically sensitive coastal areas harboring

mangrove forests, marshlands etc. Point calimere a wild life and bird sanctuary is in

coastal areas adjoining palk strait. This sanctuary is situated at southern end of

Nagapattinam district at 100 17’ - 100 22’ N and 790 25’- 79052’ E. The sanctuary may

be divided into three divisions: the point calimere forest; the GVS which includes the

mangrove forests at Muthupet and the mangroves of TRF. It is the breeding ground or

nursery for many species of marine fishes which are vital to the fisheries of the coast.

It is a marine-coastal wetland with a wide diversity of habitats and ecological features,

including: intertidal salt marshes, forested wetlands, mangroves and brackish to saline

lagoons. The sanctuary has been designated as a Ramsar site in November 2002.

• The GVS is one of the largest waterbodies and major wintering ground

for water birds in southern India. The forests of point Calimere are also

rich in both resident and migratory species of forest birds. A total of 257

species of birds have been recorded from the Sanctuary of which 119

are waterbirds and 138 forestbirds.

• The wetland supports the vulnerable species spoonbill sandpiper

‘Eurynorhynchus pygmaeus’ and grey pelican ‘Pelecanus philippensis’

according to the IUCN Red List.

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• It supports about 30,000 flamingos, 200-300 endangered grey pelican,

the endangered Asian dowitcher, the rare spoonbill sandpiper and tens

of thousands of other waterbirds. A total of 119 waterbird species have

been recorded from the area.

• The wetland is the breeding ground or nursery for many species of

marine fishes which are vital to the fisheries of the coast. GVS is the

spawning and/or nursing ground for commercially important prawns,

crabs and fishes. Eastern part of the GVS harbours 23 fish species,

mainly mullets, whereas the Mullipalam Lagoon at Muthupet has a

more direct influence of the sea and harbours more marine species of

fish, some 20 species.

Fauna

Some of the major waterbird species are the greater flamingo and the lesser

flamingo, spot- billed pelican, spoonbilled sandpiper, Asian dowitcher, whitebellied

seaeagle, brahminy kite and osprey. Landbirds include paradise flycatcher, Indian

pitta, Rosy starling, Blyth reed warbler, crested serpent eagle and brown shrike.

Fourteen species of mammals have been reported from the Sanctuary. The larger

mammals are the blackbuck, spotted deer, wild boar and jackal. The flying fox resides

in large groups on trees in the point Calimere forest and the mangrove forest at

Muthupet. The blackbuck of point Calimere represents one of the three isolated

populations of blackbuck existing in Tamil Nadu with the other populations in the

Guindy National Park and near Satyamangalam.

A sanctuary provides for local income and employment specially in areas of

salt production, forest produce, firewood and fish products. About 35,000 fishermen

and agriculturists live around the sanctuary.

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3. Marine Environment

The data generated by NEERI in locations along the 60 km long alignment

and further verified at select locations in vicinity of Gulf of Mannar, Adams bridge and

Palk Bay besides secondary data from CMFRI, CECRI is used for describing the

marine environment. The locations 1 to 4 in Palk Bay and 5 to 8 in Gulf of Mannar

were selected in the vicinity of Adams bridge area which will be dredged to achieve

required draft and 9 and 10 near Tuticorin Port area (Fig. 3.1). The details of the

locations for which data on physico-chemical parameters, phytoplankton,

zooplankton and benthos was collected, are presented in Table 3.1. The depths at

these locations are in the range of 3 m to 23 m, the maximum being in the Tuticorin

port area and the minimum near the Adam's Bridge.

Apart from primary data, secondary data was collected from various

government departments like Department of Ocean Development, Central Marine

Fisheries Research Institute (CMFRI), Central Electro-chemical Research Institute

(CECRI), Forest Department, Fisheries Department, Wildlife Department, Non-

Governmental Organisation (NGO), Project Authority etc.

3.1 Physico-chemical Characteristics

Marine Water

The samples were collected 20 cm below the water level to assess physico-

chemical quality of marine water. The physico-chemical characteristics of marine

water at various locations along the route are presented in Tables 3.2 and 3.3. The

pH of sea water is alkaline and ranges between 8.0 to 8.2.

All living organisms are dependent upon oxygen in one form or another to

maintain the metabolic processes that produce energy for growth and reproduction.

Dissolved oxygen (DO) plays an important role in precipitation and dissolution of

inorganic substances in water and it is in the range from 3.2 to

5.7 mg/L.

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The concentration of heavy metals viz. iron, selenium, chromium, zinc, lead,

cadmium, nickel, boron, manganese and copper in marine water samples are below

detectable limits except for iron, boron and arsenic. The concentration of boron is in

the range of 2.29 mg/L - 3.06 mg/L. High concentrations of arsenic (0.07-0.13 mg/L)

are observed at locations near Tuticorin port area that may be attributed to arsenic

used in making wood preservatives/ paints for ships.

It is well known that diatoms and other organisms deplete silicate from the

lighted zone of the sea, and that, on the death of the organisms, the silicate may

either re-enter in solution or may reach the bottom. The silicate content in the marine

water varies from 0.003 mg/L to 0.017 mg/L. No significant variation in salinity is

observed in surface and bottom samples (Fig. 3.2). An inverse relationship between

salinity and silicate is found to exist at some of the locations (Fig. 3.3). The nitrate

concentration varies from 0.78 mg/L to 1.1. mg/L.

Sediments

The data on physico-chemical parameters and metals of the sediments is

presented in Table 3.4. The sediments comprise loose black mud, fine clayey sand

with dead shells, coarse white sand with dead shells, coarse sand slightly reddish

with shell fragments and hard corralline bottom covered with coarse sand and shell

pieces. The particle sizes of sediments are depicted in

Fig. 3.4.

The organic carbon content of the sediment ranges from 0.06% to 0.09%.

The total Kjeldahl nitrogen (N), total phosphorus (P2O5) and sulphates (SO4) are in

the range of 0.02% to 0.11%, 0.02% to 0.84% and 0.06% to 0.75% respectively. Oil

and grease are present at all locations in the sediments. Concentrations of heavy

metals such as iron and arsenic are high in sediments. Cadmium and cobalt are also

detected in sediments.

Many animals that live buried in sediment are selective deposit feeders,

lifting and sucking food particles out of the mud; and others feed unselectively on

sediment deposits. These include different molluscs, sea cucumbers and many

worms. Fine muds, easily suspended by bottom currents, are generally not a

satisfactory substrate for filter feeders. Muds and clays, however, are well suited to

organisms that feed unselectively by ingesting sediments because the smaller

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particles normally contain more organic matter. Such detritus supports bacteria and

meiofauna that are food for deposit feeders.

Excess organic material in the sediment may cause oxygen depletion in the

near-bottom waters that is intolerable to most benthic animals. About 3% of organic

matter in the sediment appears to be optimal for deposit-feeding bivalves. Predatory

forms, such as brittle stars, are more abundant where organic carbon content is

higher (Gross, 1982). In areas of red clay deposits, where sediment accumulation is

slow and deposits contain less than 0.25% of organic carbon, filter feeders are

conspicuous.

Published data on abiotic characteristics of sediment from the Gulf of

Mannar and the Palk Bay is very limited. The fine black mud of Palk Bay collected a

decade back from a site north of Adam's Bridge and on analysis it indicated to

contain - silica 55.0%, carbonate of lime 3.5%, phosphate of lime 2.25%, ferric oxide

4.10%, alumina 15.80%, magnesia 2.75% and organic matter and water 16.60%.

The mineral composition was of sand grains, quartz, tourmaline, felspar, zircon,

corundum, kyanite, garnet, mica (biotite), rutile, and ilmenite. At some places

patches of black grains containing magnetic iron were also observed by earlier

workers (Salvadori, 1960, 1961).

3.2 Biological Characterstics

Primary Productivity

Primary productivity in the sea is dependent on photosynthesis of green

plants, principally of the phytoplankton, with possible minor contribution from very

few species of photosynthetic bacteria. The energy necessary for the process, which

gets accumulated as chemical energy in the organic matter, is derived from sun light.

The level of primary productivity is associated with the concentration of nutrients.

The data on primary productivity in the Gulf of Mannar and the Palk Bay is presented

in Table 3.5.

The gross primary productivity values varied from 143 to 472 gC/m3/day

between the stations. The mean values of 205 and 223 mgC/m3/day for the Palk Bay

and the Gulf of Mannar respectively are comparable. Literature reveals that in the

Gulf of Mannar off Mandapam there are two peaks of production - one in April-May

and another in October. During a study period of two years, the primary productivity

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was found to range from 77 mgC/m3/day in April with an average of 200 mgC/m3/day

(Prasad and Nair 1963). Thus, the mean value of primary productivity in the Gulf of

Mannar has not been altered significantly during a span of over two decades.

It is further reported that in the near shore areas where the euphotic zone

used to be about 6 m due to turbidity, the productivity was 1.2-1.5 gC/m2/day which

is equal to the annual gross productivity of about 450 gC/m2. While further inside the

sea where the euphotic zone is deeper (upto 15-40 m), the average daily productivity

used to be 3-5 gC/m2 (Nair 1970). The average primary productivity values in central

ocean basins and coastal zones of the world were estimated at 50 and 100 gC/m2/yr

respectively (Ryther 1969). Thus, the shallow regions of the Gulf of Mannar and the

Palk Bay constitute one of the most productive regions of the world. This means it is

clear that turbidity adversely affects primary productivity.

Marine Organisms

A complex food web is present in GOMMBRE due to high diversity of flora

and fauna present in the area (Fig. 3.5). The details of marine organisms recorded in

Gulf of Mannar during different periods are given in Table 3.6.

The prawns Penaeus semisulcatus feed on a variety of food items viz.,

polychaetes, crustaceans, molluscs, diatoms, foraminiferans and radiolarians

(Thomas, 1980). Four species of Foraminifera, namely Fissurina ventricosa, Nonion

grateloupi, Nonionella auricula and Bolivina variabilis were found in the stomach

contents of the prawn, Penaeus semisulcatus. (Ameer Hamsa, 1981). The two

species of Chirocentrus i.e. C. nudus and C. dorab found in the Palk Bay and Gulf of

Mannar appear to be diurnal predators preying mostly on fishes (Luther, 1985).

These are some of the examples of marine organisms present in food web in Gulf of

Mannar.

However, the biodiversity in Gulf of Mannar is now under severe threat due

to destruction of sensitive ecosystems like corals and seagrass through

indiscriminate and intensive trawling, coral mining, dynamite fishing, commercial

fishing of specific fauna such as sea fans, chanks, sea cucumber, sea horse and

endangered species like dugongs and turtles. The similar cases are of gargonids in

the Gulf of Mannar and the sacred chanks and the pearl oyster Pinctada fucata

along south-east coast, the sping lobsters Panulirus sp. and deep sea lobsters off

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south-east coast (Dehadrai et al., 1994). A survey of 20 islands in Gulf of Mannar

during 1977-81 revealed the extensive destruction of fauna and flora by human

interference and require immediate action for flora and fauna (Mahadevan & Nayar,

1983). These activities have depleted the resources and reduce the biological wealth

of this region. The status of the biota of Gulf of Mannar is depicted in Table 3.7.

Phytoplankton : Phytoplankton are mostly unicellular organisms which are either

solitary or colonial. These autotrophs synthesise organic material from inorganic

substances in the presence of sunlight through the process of photosynthesis.

Consequently, the depth of light penetration decides the volume of sea water in

which photosynthesis can occur. Phytoplankton provide food to herbivores and

hence form a major link in the food chain. In turbid waters of many coastal areas, the

compensation depth is exiguous and the phytoplankton contribution to primary

productivity is minimal. Conversely, in deep clear waters, the compensation depth is

considerable and the contribution of the phytoplankton to primary productivity is

significant.

126 species of Phytoplankton were reported (Table 3.8).

Diatoms : 97 species (33 genera)

Dinoflagellates : 16 species (6 genera)

Blue-green algae : 7 species (5 genera)

Green algae : 3 species (3 genera)

Others : 3 species (3 genera)

The population density varied from 34000 to 86000 cells/liter.

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Maximum Diversity Index values of phytoplankton for 19 islands are shown

in Table 3.9 and Fig. 3.6. The values ranged from 2.708 to 3.583 showing moderate

diversity of phytoplankton in study area.

The blooming of Trichodesmium a blue-green alga has been observed in

the Palk Bay and in the northern portion of the Gulf of Mannar (Tables 3.10 and 3.11). This alga on blooming forms clumpy aggregates. The maximum value for this

alga is 0.8 x 106 per m3 which indicate that the blooming occurs in the northern part

of the Palk Bay and extends to south of the region. It is of interest to note that since

plankton move alongwith water current, it indicates that depending on the prevailing

current conditions the algal cells do not drift to the inshore waters of Rameswaram.

The blooming results in low diversity values, as indicated at several locations.

However, diversity index values exceeding 2.0 are also observed at some of the

locations.

In the Palk Bay and the Gulf of Mannar the phytoplankton peaks do not

seem to follow monsoons strictly as do zooplankton. In general, in a year 2 to 3

phytoplankton peaks have been recorded in the earlier years, mostly in January

(prominent), April-May and October-November. At times during July-August too, a

minor peak had been observed (Prasad, 1954, 1956). Blooming or swarming of

unicellular biota, observed in these studies, were Trichodesmium theibauti,

T. erythraeum, Noctiluca, Ceratium, Gymodinium and rarely Gonyaulax. The studies

had further revealed considerable variation from year to year in abundance,

composition and succession in phytoplanktons.

Zooplankton : This is a very important group in the aquatic ecosystem, acting as the

primary consumer and ultimately serving as the natural food sources for many

aquatic organisms including fishes. Depending on the season, the plankton

community shows pronounced variation in its character and composition. This is

because many are planktonic throughout their life, while others are so only during

part of their life.

Approximately 360 species of zooplankton were reported (CMFRI, 1998).

The population density of zooplankton varied from 8000 to 65000 nos/cu.m and the

species belonging to the following phyla were commonly found : Protozoa,

Coelenterata, Ctenophora, Annelida, Chaetognatha, Mollusca, Echinodermata,

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Arthropoda, Chordata and other minor phyla. The details of distribution of

zooplankton during Oct. 98 to Aug 99 in Gulf of Mannar is presented in Table 3.12.

Shannon Weaver Diversity Index of zooplankon in Palk Bay and Gulf of Mannar

along with other coastal waters in India is recorded in Table 3.13.

In the present survey, the diversity and various groups of organisms present

at different locations are presented in Tables 3.14 and 3.15. While copepoda form

the most prominent group, the diversity index varies between 2.67 and 4.24. The

stations which are close to the shore usually exhibit low index values. The data

indicates higher diversity among zooplankton in the offshore waters. In the Palk Bay

and the Gulf of Mannar the zooplankton have been observed to show a bimodal

cycle, with a minor peak between January and March, and a primary peak during

September - October due to the monsoon conditions (Krishna Kartha 1959).

Copepods and chaetognaths reach their maximum when the salinity was low. But

there were few copepods and lucifor when molluscan larvae and fish eggs

constituted high percentages (Marichany, Siraimeetan , 1979).

Seven deep sea decapod crustaceans belonging to sections Penaeidae (4

species), Caridae (2 species) and Astacidae (1 species) are found from the Gulf of

Mannar (Thomas, 1979).

Maximum Diversity Index values for zooplankton in 21 islands of Gulf of

Mannar are shown in Table 3.16 and Fig. 3.7. Highest diversity was observed at 11

islands and moderate diversity (beween 2 to 3) at other 8 islands.

Benthos : The organisms which inhabit the bottom of an aquatic body are called

benthos. Many of them are sessile, some creep over a burrow in mud. The quality

and quantity of animals found at the bottom are not only related to the nature of

substrate but also to the depth, and the kind and quality of the other associated

aquatic biota. Their number and distribution also depend upon physico-chemical and

biological characteristics of water. Benthic organisms of different groups have been

recorded from Gulf of Mannar. (GOI, DOD and ICMAMPD, 2001) (Table 3.17).

The sediment samples collected from different stations in the Gulf of Mannar

and the Palk Bay were passed through 500 µ mesh sieve and again through 45 µ

sieve for segregation of macrobenthos and meiobenthos respectively, as described

below.

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Macrobenthos : The details of biota observed along with the sedimentary conditions

of benthos at various locations are presented in Tables 3.18 and 3.19. Some of the

locations are rich in flora and fauna. The diversity index values are observed to be

above 3. In general, contrary to the zooplankton, the near shore stations exhibited

higher diversity indices than those of offshore. Most of the offshore stations have

indices around 1.0. Altogether 78 varieties of macrobenthos from 14 groups have

been recorded. Details of the major groups of macrobenthos recorded in the study

area are presented hereunder.

Meiobenthos : Meiofauna comprises animals intermediate in size between

micro and macrofaunal organisms. In benthic environment, meiofauna consumes

unicellular organisms such as bacteria, microscopic algae and protozoa; in turn

meiofauna are consumed by macrofaunal organisms such as shrimps, gobids,

juveniles of flat fish etc. Meiofauna associates fluctuate seasonally with respect to

density, biomass and species composition in different locations of the sea. The

meiofauna in terms of number vary from 0-132 and in biomass 0-19.40 mg per 100

cm-2 of sediment (Table 3.20). The meiofauna comprises larval polychaetes,

nematodes, other worms, and shrunken bodies probably of juvenile tunicates,

actinids etc.

Corals (Coelenterate) : The animals in the Phylum Coelenterata have a

radial symmetry, and food capture by means of specialized stinging cells. Amongst

the three classes of this phylum, the class anthozoa comprises the coral and seafan

which are ecologically important in the Gulf of Mannar Marine Biosphere Reserve

(GOMMBRE).

The coral is a colony of tiny sea anemone-like polyps living together in

thousands and secreting a calcareous skeleton of calcium carbonate which they

extract from sea water. Coral reefs are diverse and a vulnerable ecosystem

characterised by a complex interdependence of plants and animals. Reefs are the

centres of high biological productivity, sites of CO2 sink and sources of huge deposits

of CaCO3. The ecological significance of coral reefs is outlined below :

– Coral reef constitutes one of the most valuable natural heritages

of the GOMMBRE.

– Healthy coral reef provides a home for a number of species

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comprising a large number of individual colourful fishes,

invertebrates and seaweeds.

– Coral reef provides an ideal feeding ground for various marine

animals.

– They also serve as a nursery and breeding ground for many

invertebrates and enhance the level of fishery production.

– Coral reef absorbs CO2 and converts it into CaCO3, thereby,

reducing the CO2 in the global environment.

– They protect the sea shore from erosion.

The coral formations in and around Rameshwaram indicate local

emergence and are presumed to be formed around 4000 years B.C. (Rao, 1990).

Around Rameshwaram Island, northwest of Pamban, enormous coral stages were

found. They are still seen at low tide level, having a height from

1.5 to 3 m (Rajamanickam, Loveson, 1990)

On analysis of data on corals in the Gulf of Mannar and the Palk Bay,

solitary coral at each of 3 locations, 1 & 2 have been observed, locations 2 and 1

possess only 1 and 3 types of macrofauna respectively. Smaller size and poor

density of coral might be the principal factors for not attracting other flora and fauna

in these locations. In general, the presence of corals along the proposed alignment

of Sethusamudram ship canal appears to be negligible.

The reefs of Gulf of Mannar are fringing or patchy thriving in shallow waters

(0.2-5.0m) around almost all islands. Most of the framework of coral reef is made up

of dead or semi fossilised Porites spp. Literature survey indicates that about 128 (42

endemic) species of corals have been recorded (Pillai, 1986 and CMFRI, 1998) and

the coral reefs lying on the southern side of the island are more dense and exhibit

greater species diversity than the reefs on northern side. The dominant genera are

Pocillopora, Porites, Acropora, Montipora, Favia, Favites, Goniopora, Goniastrea,

Platygyra, Echinopora, Galacea, Turbinaria, Leptoria, Poavona and Pochyseris. The

details of distribution pattern of corals and live coral percentage is presented in

Table 3.21 and Figs. 3.8-3.9.

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Gorgonids are observed in the Palk Bay while in the Gulf of Mannar these

are recorded only near the islands. Gorgonid community is popularly known as

“Flowers of underwater gardens”. Fourteen species of gorgonids were recorded

(Tomas and George, 1987). The dominant genera were Subergorgia, Plexauroides,

Muricella, Echinomuriceae, Echinogorgia, Thesea, Heterogorgia, Junceela and

Gorgonella.

For diversity, density and distribution of corals in the Palk Bay and the Gulf

of Mannar, the available information is debatable and needs detailed systematic

investigation. While Gopinadha Pillai (1969, 1971) listed 20 and 94 species of corals

in the Palk Bay and the Gulf of Mannar respectively, Asir Ramesh and Kannupandi

(1997) recorded 25 species of corals from a specific area like Vellaperukkumunai

reef in the Palk Bay. Santhanam and Venkataramanujam (1996) identified 18

species of stony corals only at Tuticorin (Gulf of Mannar), and Petterson Edward and

Asir Ramesh (1996) reported 32 species of corals from Pulli island alone in the Gulf

of Mannar. However, studies carried out by Zoological Survey of India (Anonymous,

1998) revealed only 21 species of corals in the Gulf of Mannar Marine Biosphere

Reserve.

Maximum Diversity Index values of corals in 21 islands of Gulf of Mannar

are shown in Table 3.22 and Fig. 3.10. The diversity is good (>2) on 9 islands while

it is very less (0.69) at Appa island and 0 at Vilanguchalli island. Other islands have

moderate diversity.

Quarrying of corals for various purposes has been in vogue in the Gulf of

Mannar and the Palk Bay for a long time. Three factories in Tirunelveli district were

using corals as a raw material for their products. Mandapam and Tuticorin were the

two important bases for the collection and stacking of the coral stones. While (Patel

and Bhaskaran, 1978), it has been stopped totally at Mandapam after establishment

of the National Marine Park Authority. However, in Tuticorin area quarrying of corals

still goes on, and the landing has been estimated at 5000 t/yr (Anonymous 1998).

The areas wherein live coral reefs are prominent are shown in Fig. 3.9. It is

believed that inspite of large scale removal of corals, still there may be areas

wherein the endemic corals are available. As per earlier records, there were 53

species of endemic stony corals inhabiting this area. The reefs of Manauli area

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appear to be very important. It has been postulated by Stoddart (1973) that the

modern reef growth in the region began about 5000 years ago.

Sea fan (Coelenterata) : The Sea fan is yet another colonial form, but it branches

only in one plane and the branches may fuse with each other to form a 'fan'. White or

cream-coloured polyps may grow on a base of contrasting maroon colour, attached

to stones by a broad disc-like holdfast. The colourful sea fans have long been

objects of attraction to man.

Foraminifera : 51 species (2 endemic) of foraminiferans (CMFRI, 1998) were

reported and the dominant genera were Trochammina, Robulus, Nonion, Operculina,

Bolivina, Bulimina, Streblus, Poroeponides and Cancris.

Sponges (Porifera) : 275 species (31 endemic) of sponges were reported from Gulf

of Mannar and Palk Bay (Thomas, 1986).

Order No. of Species

Keratosida : 22

Haplosclerida : 39

Poecilosclerida : 74

Halichondrida : 31

Hadromerida : 43

Epipolasida : 17

Choristida : 30

Carnosida : 19

The dominant genera were Heteronema, Spongia, Dysidea, Haliclona,

Callyspongia, Spirastrella and Cliona.

Sponges, although at a casual glance look like plants, are animals, living

singly or in colonies. They have no fixed shape, and form flat encrustations on

stones in the region of strong waves. In the crevices, these sponges are found

associated with many animals, ranging from tiny crabs and brittle star to bivalve

molluscs. Sponges show commensalism as several crustaceans, worms, molluscs

and fishes live in the internal cavities of sponges for protection against enemies, and

also act as a shelter bed.

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Regarding macrobenthos, altogether 77 sponges comprising 11 genus have

been recorded in the region. The density is higher (3333 ha-1) in Tuticorin area,

followed by 533 and 440 ha-1 in the Palk Bay and northern side of the Gulf of Mannar

respectively. The estimated sponges along the proposed alignment of

Sethusamudram canal are 1050 ha-1. Upreti and Shanmugaraj (1997) recorded 275

species of sponges inhabiting the Palk Bay and the Gulf of Mannar area. Sponges

prefer both the island biosphere as also the open sea-ward areas, preferably upon

30 metre depth (CMFRI 1998).

Boring sponges form the major group among the marine organisms causing

considerable destruction to the reef system. The 'bores' left by the sponges weaken

the reef making it more susceptible to wear and tear caused by the waves and the

associated impact. There are altogether 20 known species of boring sponges in the

Gulf of Mannar and the Palk Bay.

Polychaeta : 75 species were recorded (CMFRI, 1998). The dominant genera were

Iphione, Harmothoes, Eurythoe, Chloeia, Eulalia, Syllis, Ceratonereis, Perinereis,

Eunice, Marphysa, Onuphis and malacoceros.

Nematoda : 9 species were recorded (Ayyakkannu, 1974). The dominant genera

were Anticoma, Halalaimus, Oncholainmus and Chromadora.

Crustacea : The crustaceans rank second in the diversity of fauna in the coaral reef

ecosystem and many of them are exploited for commercial purpose. The knowledge

about marine crustaceans in incomplete. They consist of crabs, lobster, prawns, and

shrimps.

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Planktonic and Larval forms

Group Species recorded

Copedods 223

Cumacea 10

Amphipods 52

Ostracods 57

Isopoda 18

Decapod larva 8

The dominant groups were Acrtia, Acrocalanus, Centropages,

Canthocalanus, Eucalanus, Microsetella, Oithona, Lucifer and penaeid larvae.

Mollusca : The Mollusca includes a variety of most conspicuous, invertebrates such as

bivalves, gastropods and cephalopods of which the class gastropoda covers the largest

number of diversified forms. The gills of molluscs act as a filter to collect microscopic food

particles. While mussels, oysters etc. come under bivalvia, cephalopods including squids,

octopus etc. are primarily pelagic forms. The benthic molluscs have economic significance as

under.

– Bivalves, cephalopods and gastropods are delicious sea food

items locally and in Southeast Asian countries.

– Pearls of high value as gems are produced by the pearl oyster of

the genus Pinctada under the family Pleriidae.

– The sacred chank (Xancus pyrum) are much in demand for the

manufacture of bangles, ornamental and decorative materials.

– Oyster shell is used to produce lime for poultry and other uses.

– Molluscs absorb CO2 and convert it into CaCO3, thus reducing the

level of CO2 in the global environment.

– The operculum of gastropods is used for manufacturing perfumes

and making incense sticks.

731 species of molluscs belonging to three classes namely Bivalvia,

Gastropoda and Cephalopoda were recorded (Satyamurthi, 1952; CMFRI, 1969).

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– Bivalvia : Arca, Modiolus, Lithophaga, Perna, Isognomon,

Malleus, Pteria, Pinctada, Pinna, Cardium, Crassostrea, Meretrix,

Donax and Tellina.

– Gastropods : Trochus, Turbo, Nerita, Littorina, Turritella,

Cerithidea, Janthina, Tibia, Strombus, Cypreaea, Bursa, Tonna,

Chicoreus, Xancus, Babylonia and Hemifusus.

– Cephalopods : Sepia, Sepiella, Loligo and Octopus.

Information on the two important groups of molluscs, viz. pearl oyster and

chank outlined hereunder.

Pearl oysters : Pearl oysters are available in large numbers from 24 groups of 87

paars in the Gulf of Mannar. Pinctada fucata yields gem quality pearls for which the

Gulf of Mannar is famous from time immorial. The other species found are P.

chemnitzii, P. anomioides, P. atropurpura, and P. margaretifera. Of the 24 groups of

pearls, 14 occur between the shore and proposed canal in the Gulf of Mannar (Fig. 3.11). The proposed alignment of sethusamudram canal passes through the groups

I, VIII, XI, XII and XIII. Out of 14 paars in these five groups, the maximum number of

seven is in group XI which is located close to Tuticorin. However, five specimens of

P. fucata in 25 m2 area are found far away from the proposed alignment of the canal

and close to the island at the northern side of the Gulf of Mannar.

Considerable mortality of young pearl oyster, Pinctada fucata, was noticed

on the oyster beds in Gulf of Mannar due to predation by gastropods, Cymatium

cingulation and Murex virgineus (Chellam, et al., 1983).

Chanks : The sacred chank, Xancus pyrum is another resource of economic

importance in the region. The demand for chanks from the bangle industry is about

2.5 million pieces per year. The present supply, which meets only about 40% of the

demand, comes mainly from the Gulf of Mannar. On an average 9 x 105 and 49 x 103

sacred chanks are exploited per annum from the Gulf of Mannar and the Palk Bay

respectively (Devraj and Ravichandran 1988). Among the chanks, the variety acuta

(or jathy in Tamil), found in the Gulf of Mannar fetches higher prices than the rest

available elsewhere. The dominant variety present in the Palk Bay is obtusa. The

chank habitats, which are within 5-25 m (often upto 35 m) depth are shown in Fig. 3.12. Areas with high population density have also been depicted in the Figure.

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Usually chanks prefer fine sandy areas with rocky beds, wherein nereids abound.

The sinistral freak is also available from this area.

Echinoderms : Echinoderms are common and conspicuous organisms of the

intertidal region. Their body structure is modified to live on different substrate such

as rocky shores, sandy beaches, muddy flats, algal beds and coral reefs. Their

concentration in the coral reefs is maximum (James, 1982). The phylum

Echinodermata comprises the classes asteroidea, ophiuroidea, echinoidea, crinoidea

and holothuroidea representing starfish, brittle star sea urchin, feather star and sea

cucumber respectively, and all occur in the Gulf of Mannar and the Palk Bay. Dried

holothurians, marketed as beche-de-mer are used as food items. These are

delicious and nutritious containing 35-52% of protein. Other classes of

echinodermata have decorative/ ornamental use.

264 species belonging to five classes namely Crinoida, Asteroidea,

Ophiuroidea Echinoidea and Hologhuroidea have been recorded (James, 1985,

CMFRI, 1998). The major genera were:

– Crinoidea : Capillaster, Comatella, Comanthus, Comaster,

Heterometra, and Tropiometra.

– Asteroidea : Astropecten, Craspidiaster, Goniodiscaster,

Stellaster, Culcita, Pentaseraster, Linckia, Asterina and

Echinaster.

– Ophiuroidea : Ophiacits, Macrophiothrix, Ophiogymna,

Ophiothela and Ophiothrix.

– Echinoidea : Astrophyga, Salmacis, Echinometra and

Echinodiscus.

– Holothuroidea : Holothuria, Stichopus, Pentacta, Hemithyone

and Synaptula. Economically only Holothuroidea (12 species) are

exploited on a commercial scale for export.

The processed sea cucumber (beche-de-mer) is entirely exported mainly to

Singapore and Hong Kong yielding about Rs. 1 crore per annum (CMFRI, 1998 :

personal communication). Holothuria scabra is mostly (90%) exported followed by H.

spinifera, H. atra, Actinopyga echinites, A. miliaris and Bohadschia marorata. The

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marketable size of H. scabra is about 40 cm in length and 500 g in weight. Tuticorin,

Kelakkarai, Periyapattinam, Vedalai, Pamban, Rameswaram, Tondi, Deviptinam and

Tiruppalaikudi are the important centres of sea cucumber. Flourishing export market

for the processed sea cucumbers has increased their exploitation. Over 90% of

beche-de-mer exported from India, is from the Palk Bay and the Gulf of Mannar of

which the contribution of the former and the latter is 60 and 30% respectively. Sea

cucumbers are mostly collected by skin divers in shallow waters from 2-10 m depth

(James 1994). Presently, operation of a modified trawl net called Chanku madi yields

good catches of sea cucumbers alongwith chanks (Xancus pyrum). The harvest

composition of this gear is Xancus pyrum (61.22%), sea cucumbers (20.4%), rays

(Amphotistus kuhlii) (16.33%) and starfish, sea shells and small fishes (2.04%).

Holothuria being detritus feeders are found among the marine macro-algae and

seaweeds. Their habitats in the Gulf of Mannar and the Palk Bay are shown in Fig. 3.13.

Prochordata : All the three groups of prochordata, viz. hemichordata,

cephalochordata and urochordata comprising 1,6 and 59 species respectively were

recorded in the Gulf of Mannar and the Palk bay. These organisms are considered

as the connecting link between invertebrates and vertebrates.

Hemichordata : The limited publications on this group has indicated the occurrence

of the only species Ptychotera fava (balanoglossus) in the Gulf of Mannar (Upreti

and Shanmugaraj, 1997). Balanoglossus in the Gulf of Mannar is in a very much

restricted area, viz. Kunthugal in the Pamban island and Kurusadai island. The

presence of the animal is discernibel by the characteristic iodoform odour present in

the mud. Balanoglossus are zoologically a very interesting group from evolutionary

point of view and their importance is enhanced by their rarity.

Cephalochordata : Another group of prochorates of significance is the

cephalochordates which measure 4-5 cm in length. Though the animals belonging to

this group are limited in number but are not as rare as the balanoglossus. In the Gulf

of Mannar and adjacent areas 6 species are reported to be available. Except

Branchiostoma pelagicum which is pelagic, as the name itself indicates, the rest are

benthic, habitating depths ranging from 5 to 25 m. The Gulf of Mannar and the

adjacent marine areas seem to be the western most geographical limit of their

distribution.

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Urochordata : The Palk Bay and the Gulf of Mannar have good resources of

tunicates. These jelly-like organisms are mostly sedentary and contain variety of

bioactive compounds useful as drugs.

Fisheries

Marine capture fishery is the major economic activity of Gulf of Mannar. The

total area of Gulf of Mannar under Indian Exclusive Economic Zone is about

15000 sq. km. and commercial fishing is done in about 5500 sq. km. within 50 m

depth. Both mechanized and non-mechanized fishing units are mainly responsible

for exploitation of sea fish resources in Gulf of Mannar (Kasim and Hamsa, 1987).

Fishing in the Palk Bay and the Gulf of Mannar is multigear, multispecies

and is carried out throughout the coast of mainland and the Pamban island. Within

the study area, there are 87 fish landing centres between the south of Point Calimere

and Pamban in the Palk Bay, and 40 centres in the Gulf of Mannar from Pamban to

Tuticorin Harbour (Table 3.23).

Fishes : The Gulf of Mannar and the Palk Bay with their peculiar topography are

noted for their faunal diversity and richness. Mahadevan and Nayar (1967) made

detailed observations on the rock bottom of this area and described its faunal

diversity. Gulf of Mannar is one of the best regions in the Indian subcontinent in fish

biodiversity richness. The Shannon Weaver Diversity Index (H’ values) for the

ornamental fishes around each island in the Gulf of Mannar exceeds 2.5 in 2/3 of the

islands. The variation in its value with species richness and density is depicted in

Table 3.24. Although over 600 species of fishes, crustaceans and molluscs (out of

which no. of fish species is 441) are reported (Anonymous 1998), to support the

fishery in these regions, the commercially important species (200 species out of total

441 fish sp.) (Table 3.25) are limited in number.

The chief fisheries are the pelagic sardines, seer fish, tunas, mackerel,

sharks, caranids, barracudas, wolf herring, full and half beaks, the demersal perches

such as sweetlips, groupers, rock-cods, snappers, goat fishes, croakers, sharks,

rays, skates, coral fishes, threadfin, breams, silverbellies, the shell fishes like

chanks, squids, cuttlefish shrimps, crabs and lobsters. Most of these resources are

commercially exploited by mechanised trawlers.

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There was overfishing of silverbellies in 1973-74 and 1974-75 when the

effort far exceeded the optimum level. (Venkataraman et.al., 1981). Pair trawling

carried out in Palk Bay yielded large catches of Rainbow sardines (Dussumieria) and

pomfrets (Pampus argenteus). (Pillai, Sathiadhas, 1982). Fishery of the swimming

crab Portunus pelagicus Linnaeus is done on large scale along the Palk Bay and

Gulf of Mannar. Vedalai is found to be the most productive centre for crabs (Hamsa,

KMSA, 1978).

The sunfish M. oxyuroptenus is found in the Gulf of Mannar (Devaraj,

Nammalwar and Thiagarajan, 1976). Silverbellies (Leiognathus jonesi) form an

important demersal fishery of India particularly on the coasts of southern maritime

states, the annual average catch amounting to about 3% of the total marine fish

catch in India (Annam, Raja, 1981). The marine mammals – dolphins and dugongs

form a part of fishery. The smaller cetaceans that are caught along the Indian coast

are Stenella longirostris, Delphinus delphis, Jousa chinensis and Tursiops truncates.

Annually about 25 dugongs are caught in the Gulf of Mannar and Palk Bay and

about 250 dolphins are caught along the Indian Coast (Mohan, 1987).

Shore seines, boat seines, trawl nets and hooks and lines are the principal

gear operated. The shore seines are of two types namely Kara valai and Olavalai.

The former is operated with the help of vallam fitted with out board engines and is

mainly used for capturing small pelagic fishes while the latter is operated with the

help of nonmechanised vallam craft for capturing small shrimps and small pelagic

fishes. Boat seines are operated using vallam with inboard engine. Specialised gears

are also used such as chala valai for small pelagic fishes, paru valai for perches and

tunas, thirukkai valai for rays, nandu valai for crabs and lobster etc. Traps are used

to catch reef dwellers such as groupers, snappers, lobsters,shrimps etc. Shrimp and

fish trawl nets are operated to capture a variety of demersal fishes such as

silverbellies, carangids, perches, pomfrets, ogatfishes, rays, prawns etc. Among

hooks and lines, longolines are used for hooking perches, catfish, sharks etc. and

troll lines for scombroids, fishes, sharks, carangids etc. Depending on the tide and

fishing season kalamkatti valai is operated at night on the shores of the islands for

catching shore fishes and mullets.

The commercial importance of fish is either as food for human being or as

fishery by-products like fish oil from sardines, liver oil from sharks and skates,

Page 104: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

processed fish skin from sharks, rays and bigger groupers and fish meal from small

sized low value fish for use in cattle and poultry farms. The commercially important

species include sardines, mackerel, anchovies, seerfishes, tunas, ribbon fishes,

elashmobranchs, perches, catfishes, silver bellies, goatfish, lizard fishes, ribbon

fishes, mullets, barracudas, penaeid and non-penaeid shrimps, lobsters, crabs,

cephalopods, bivalves and gastropods.

Capture Fishes : 441 species (Dorairaj, 1997) were reported in the following orders,

namely Lamniformes, Squaliformes, Torpediniformes, Elopiformes, Anguilliformes,

Clupeiformes, Aulopiformes Gadiformes Ophidiiformes, Batracoidiformes,

Lophiiformes, Cyprinodontiformes, Atheriniformes, Bercyciformes, Pegasiformes,

Syngnathiformes, Scorpaeniformes, Perciformes and Pleuronectiformes.

Ornamental Fishes : About 100 species (Murthy, 1969) have been recorded. The

dominant genera were Chaetodon, amphiprion, Abudefduf, Holocentrum, Upeneus

Parupeneus, Pomacanthodes, Acanthurus and Lactoria.

Crafts and gears : Fishing is carried out in the Palk Bay and the Gulf of Mannar

almost through out the day. The various gears operating in the Palk Bay and the Gulf

of Mannar are listed in Table 3.26. Primarily, various types of gill nets and seine nets

are used for pelagic fishing, while trawlers are used for harvesting demersal fishes.

Thangal (stay put) fishing which lasts for 5 to 7 days is also being practised by the

fishermen of Mandapam and Pamban island. Catamarans, dug-out canoes, plank

built Tuticorin type of thony/vallam, stitched masula boats are the traditional crafts in

use. The Tuticorin type of boats are operated either undersail or with inbuilt diesel

engine or in combination. Often catamarans and canoes too are used with outboard

engines.

The changing trend in fishing gears and crafts in this region is remarkable.

In early fifties, while 55% of the catch was made by boat seines operated from

catamarans, 34% came in gill nets operated from Tuticorin type of traditional crafts.

In late fifties, nylon nets were introduced and the harvest increased by 30%. Post

1970 period marked a revolution in fishing with the introduction of mechanised

trawlers and emergence of prawn fishery and an increase of over 40% in the total

fish catch. During 1980's in Tuticorin around 20,000 tonnes of fishes were landed by

trawlers and 10,000 tonnes by traditional fishing units.

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Fishing Limits : Mechanised trawl fishing is being conducted usually upto 50 m (20

fathom) depth, while during November - February the fishermen go upto 180 metres

(100 fathom) for harvesting deep sea prawns. For collection of gorgonids, trawl nets

are operated beyond 50 metres depth. Non-mechanised units usually operate within

a depth of 36 metres (20 fathom).

Fishing in Mandapam and Rameswaram : Fishing units in the Palk Bay and the

Gulf of Mannar operate from Rameswaram. During the south-west monsoon period

(June - September), as the Gulf of Mannar side gets rough, fishing is carried out

mostly in the Palk Bay. During north-east monsoon (October - February), the fishing

shifts to the Gulf of Mannar which becomes calmer than the Palk Bay. The trawl

landings are concentrated at Mandapam, Pamban and Rameswaram. The most

important catch in the Mandapam area is silver bellies (48%), rays, croakers,

clupeids, goatfishes, perches, catfishes, lizardfishes and carangids. At Rameswaram

also, silver bellies dominate (51%), followed by rays (13%), croakers (9.5%) and

penaeid shrimps (9.4%), goatfishes, carangids, catfishes, flat fishes, clupeids,

cephalopods and crabs. Mackerel and carangids dominate the catch by the

indigenous gears. Anchovies and seerfishes also support a seasonal fishery. During

the lean inshore fishing season the fishermen of this area resort to 'Thangal fishing'.

Fish Production : The marine fish landings in the Gulf of Mannar can broadly be

classified into four groups, viz. pelagic, demersal, crustaceans and molluscs. During

1992 - 1996, the production has increased gradually from 55,325 tonnes in 1992 to

1,02,897 tonnes in 1996 (Table 3.27). In general, contribution of pelagic varieties is

maximum (54%) followed by demersal (35%), crustaceans (6%) and molluscs (5%).

While the harvest in the Gulf of Mannar is 20% of the total production in

Tamilnadu, it is estimated that exploitation in this area is 800 tonnes in excess of

sustainable yield, and the production rate is 14 tonnes km-2.

The major varieties contributing to fish production in this area are sardines,

carangids, silver bellies, perches, rays, penaeid prawns and cephalopods (Table 3.28). Higher salinity conditions and the temperate range 27.8-29.4OC favor the

Sardinella fishery at Tuticorin, Gulf of Mannar (Nalluchinnappan, et. al., 1982). Water

temperature and salinity appeared to influence the distribution of major finfishes

compared to dissolved oxygen. Groups such as threadfin breams were found

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preferring cooler waters of wadge Bank area, while Barracudas appear to occupy

warmer waters of Gulf of Mannar (Balachandran, Agadi, 1996). While other sardines

dominated the catch in all the years between 1992 and 1996, the subdominant

varieties were cephalopods in 1992 and silver bellief during 1993 to 1996. Sardines

and Cephalopods are usually harvested by different gears in pelagic region.

However, the demersal varieties like silver bellies, penaeid prawns, rays, thryssa,

corakers etc. are primarily exploited by trawlers (Table 3.29). The catch through

trawlers further indicates that certain varieties like silver bellies, rays, croakers,

crabs, sardines, goat fishes and catfishes prefer the northern side of the Gulf of

Mannar, that is, Pamban and Rameswaram; while thryssa, carangids, stolephorus

and seer fishes are predominantly caught in the southern side, that is, Tuticorin

(Table 3.30).

The oil sardine, Sardinella longiceps fishery in the canal zone is a new

event. Even a few years ago this variety was rarely found in this area. During 1996

its catch was 1419 tonnnes. In the area adjoining Pamban island, its eggs and larvae

have been observed, indicating that the fish stock has become localised and breeds

in this area. Another important change is the unusual increase in mackerel

Rastrelliger kanagurta harvest. In 1992 the mackeral fishery was only 213 tonnes

and in 1996 it was 3711 tonnes. Sand lobster Thenus orientalis fishery of Tuticorin is

another newly emerging minor fishery.

– Penaeid and Non-Penaeid shrimps: 41 species were reported

and the dominant genera were Penaeus, Metapenaeus,

Parapenaeopsis and Acetes. (CMFRI, 1998).

– Lobster : 7 species namely Panulirus homarus, P. ornatus,

P.versicolor, P. longipes P. polyphagus, Puerulus sewelli and

Thenus orientialis were recorded (George, 1973).

– Crabs : 210 species were observed (CMFRI, 1969 and 1998).

The dominant genera were Dromia, Cryptodromia, Rania,

Dorippe, Calappa, Scylla, Portuneus, Charybdis, Thalamita,

Demania, Leptodius, Atergatis, Phymodius and Doclea.

The green tiger prawns Penaeus semisulcatus, contributes to over 50% of the

total prawns catch landed along the Palk Bay coast. Intense fishing for juvenile

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prawns, which inhabit the seagrass ecosystem near the shore, is taking place all along

the coast. The results of a survey carried out on this exploitation pattern are reported.

The prawn catch, the bulk of which is composed of juvenile P. seisulcatus, is found to

vary from 2 kg to 10 kg per unit per day. The size of the exploited P. semisulcatus

ranges from 31 mm to 100 mm total length with the dominant size group at 45-70 mm.

(Rao, 1988).

At coastal villages 16 potential landing centres were identified, 12 in Gulf of

Mannar region and 4 in the Palk Bay region and there came to know that the

Chicoreus ramosus and Pleuroploca trapezium fishery is mainly associated with

lobster fishery. The export value of the meat of these 2 gastropods has attracted the

attention of the fisher folk and it has emerged as an additional source of income for

them. In addition to the fishermen involved in fishing these gastropods, there are about

60 other persons engaged in the gastropod meat trade (Spec. Pub. Phukat Mar. Biol.

Cent. 1994). The seasonal prawn fishery (mainly of Penacus indicus) of Periathalai, a

fishing village on the south-east coast of Tamilnadu, lasts for a period of three to four

months in a year. But it is found that there is a gradual decrease in the female

population of this species (Rajamani, Manickaraja, 1990)

Non-conventional fishery : The Gulf of Mannar and the Palk Bay support select non-

conventional fishery resources. A historical pearl fishery exists here and the pearl oysters are

the property of the Tamilnadu Government. The areas where pearl oysters are found from

near shore region to the canal zone are shown in Fig. 3.11 and Table 3.31. The pearl oysters

settle and grow on hard rocky substrata called 'Paars' found abundantly from Pamban in the

north to Manapad in the south over a stretch of 160 km where 83 well known 'Paars' exist.

The beautiful natural pearls produced by these oysters are of high economic importance. The

Tamilnadu Pearl and Chank Fisheries Rules, 1978 under the Indian Fisheries Act 1897,

prohibit harvesting of pearl oysters and chanks in specified areas except with a licence

granted under the rules.

The natural production a pearl oysters in the pearls banks of the Gulf of

Mannar is Characterised by very wide fluctuations. Therefore, ability of producing pearl

oyster seed through hatcheries is of great importance for the development of pearl

culture industry in India. The barnacle Balanus amphitrite variegates was the major

fouling organism and Polychaete Polydora ciliata and the sponge (Clions vastifica)

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were the main boring organisms responsible for heavy loading on the pearl systems.

(Symposium on coastal aquaculture, 1983).

In the vicinity of the pearl culture farm located off Veppalodai in the Gulf of

Mannar, the salinity remains high during the period of the south-west monsoon and

low during the north-east monsoon. There was not much variation in pH values and

dissolved oxygen content. The water was studied during the most part of the year, with

higher dissolved oxygen content. (Symposium on coastal aquaculture, 1983).

The specific fishing of sea horse (Hippocampus kuda) commenced in the

year 1992. The fisher folk of both the Palk Bay and the Gulf of Mannar consider this

specific fishing as a boon. The records of Marine Products Exports Development

Authority (MPEDA) show export of sea horse to the tune of 6 tonnes in 1991-92

followed by a decline to 2 tonnes in 1992-93, thus indirectly indicating a decrease in

sea horse population (Anonymous 1998).

Other non-conventional fisheries practised are for seaweeds, ornamental

shells, gorgonids and holothurians. The export data of MPEDA on sea fans and sea

ferns clearly shows a declining trend of 25 tonnes during

1975-79, 11 tonnes during 1980-84, one ton in 1990-91 and nil in 1992-93

(Anonymous, 1993). Similarly sea cucumbers are also indiscriminately fished in the

Gulf of Mannar and the Palk Bay. According to MPEDA records the export trend of

holothurians has started showing declining trend from 40 to 38 and finally 24 tonnes

in 1990-91, 1991-92 and 1992-93 respectively. One species of Holothuria (Metriatyla

scaber) is exclusively used in Gulf of Mannar and Palk Bay for the preparation of

beche-de-mer (James, 1987). The use of metal scrapers and other implements on

the sea grass beds to drag out the sea cucumbers are powerful enough to damage

the niche (James, 1989).

Breeding ground : There is not specific locality identifiable as breeding ground for

fishes. The fishes breed throughout the Palk Bay and the Gulf of Mannar and almost

through out the year. Fish eggs have been observed in the Gulf of Mannar

throughout the year with a peak in March and minor peaks in May, September and

November. In the Palk Bay also maximum number of fish eggs were collected in

March. The eggs were identified as belonging to clupeoids, carangids, Cynoglossus

and muraenids. There exists a minor fishery for juvenile fishes in the Pamban island

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and in Theedai area during January-March, in which mostly baby sardines are

caught by torch (Choondu) fishing during night hours. At Kunthukal Point (Pamban)

very good quantities of juvenil milk fish (Chanos chanos) are caught during April-

June and September for use as seed stock for fish farming in various parts of

Tamilnadu and Kerala.

Spawning takes place in areas between 20m and 60 m depth in the northern

Gulf of Mannar. The spent adults migrate to the central Gulf of Mannar coast by

November – December. Spawning takes place around the full moon period.

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The fry and fingerlings of the Indian sand whiting, Sillago sihama (Forskal),

which can serve as seed, have been found to occur in the coastal waters of the Palk

Bay throughout the year with at least three months of peak abundances in January,

May and October. The overall abundance was highest during full moon period, while a

direct relationship of the abundance of the fry and fingerlings could be noticed with the

increase in temperature and dissolved oxygen content (James, 1984).

A potential ground for milkfish (Chanos chanos) seed collection has been

located at Manoli Island in the Gulf of Mannar, where eggs and fingerlings of the

species congregate in large numbers in the tidal pools under the dense shades of the

mangrove bushes in April-May (Dorairaj et al., 1984). Juveniles of Penaeus

semisulcatus are found in large concentrations in the shallow inshore sea, between

Pattannamarudar and Tuticorin along the Tinnerelly coast in Tamilnadu and they are

fished throughout the year by an indigenous gear known as ‘Ola Valai’ operated in the

waters within 2 m depth. (Manisseri, 1982).

Turtles : Marine turtles are mainly omnivorous and often consume algae. For the purpose of

respiration they periodically surface like the marine mammals. The turtles migrate to the

shore for egg laying and prefer to come to the same site where they themselves once had

hatched out. Their nesting migration is during September - January. Five species of marine

turtles were recorded in the Gulf of Mannar and little is known about their distribution under

water. There are Chelonia mydas (green turtle), Hepidochelys olivacea (olive ridley), Caretta

caretta (loggerheads turtle), Eretmochelys imbricata (Hawk bill turtle), Dermochelys

coriacea (leather bask turtle). All are endangered species as per Wildlife (Protection) Act,

1972. A soft shelled turtle P. bibroni from Palk Bay can tolerate the marine environment, as

against the belief that it is purely a freshwater form (Nair and Badrudeen, 1975). Prior to

about 40 years, turtles used to lay eggs in the sandy beaches throughout the Gulf of Mannar

coast, both in the main lands and also in the islands including Sri Lanka. However, due to

increased human activity, presently they avoid Indian mainland coast but they do continue to

visit the Sri Lankan coast and the islands. Though their number is low in the Gulf of Mannar,

all the 5 species still lay eggs in these islands. Presently, capturing turtles is prohibited.

Mammals : 11 species have been recorded (Jamer and Lal Mohan, 1987, CMFRI, 1998)

including 6 species of whales, 4 species of dolphins and 1 species of dugong. All are

endangered species (Wildlife Protection Act, 1972). The cetacea (whales and dolphins) and

sirenia (sea cow) represent the main groups of marine mammals in the Gulf of Mannar.

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Marine mammals have a layer of dermal fat or blubber. This acts as a stored reserve food for

future use in case of deficiency of food. The sirenia (sea cow) graze with their well developed

lips, in consequence, their teeth are little used and are greatly reduced in size. In cetacea,

whales and dolphins are mostly carnivorous and feed on crustaceans, squids, and fishes. In

sirenia, sea cow is herbivorous and feeds mainly on sea grasses.

A total of 187 species of shore birds including wadors, terns and gulls were

recorded in the Gulf of Mannar, of which 84 were of aquatic species and the remaining

terrestrial. The uncommon waders to India such as knot Calidris canuta, eastern knot

C. tenuirostris, Numenius arquata, whimbrel N. phaeophus and bar-tailed gotuit

Limosa lapponica were recorded as regular winter visitors to this area (Balachandran,

1995).

Dolphins and Whales : The dolphins found in the Gulf of Mannar and the Palk Bay

are oceanic and roam about in the area. It is most likely that only the frail and the

infirm whales move towards this area as known from standings of whales. So far no

mass standing of whales has been observed in the canal area. A male sperm whale P.

macrocephalus Linnaeus is rarely found on the southern side of Krusadai Island (Gulf

of Mannar), (James and Soundararajan, 1979). The dolphins Stenella longirostris and

Tursiops truncatus are often caught in various nets and the ones thus caught and

injured (probably) are clandestinely butchered for food. However, capture or harming

of the sea mammals is prohibited by law.

Sea Cow : Unlike dolphins and whales, sea cow (Dugong dugon) inhabits

the Palk Bay and the Gulf of Mannar preferably within 10 m depth limit not far from

the shore (1-3 km). Usually sea cows move in groups of 5-7 among the seagrass

Cymodocea, which is their chief diet. Their habitat extends from Adiramapattinam in

the Palk Bay to Taliyari island in the Gulf of Mannar (Fig. 3.13). The dugong which

grows to over 300 kg measuring 1-1.5 m in length, is harmless and sluggish in

nature. Its gestation period lasts for 13-14 months and gives birth to a single calf at a

time. Though young male adults compete among themselves for female, once they

have paired, they remain paired for the whole life. Their attachment to the partner

and calf is such that if one of the partners or calf gets caught the rest also shall

follow; thus becoming easy victims. They have no natural enemies except the

civilised man. The exact number of sea cows living in the Gulf of Mannar & the Palk

Bay is not known. Due to uncontrolled fishing carried out till recently and also due to

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reduction in their grazing area and Cymodocea, their numbers have gone down

drastically. During 1980's, about 200 sea cows were killed per year. Now they are

protected by the Wildlife (Protection) Act, and are under threatened status.

Occasionally, marine mammals and turtles have been observed to get washed

ashore, and on examination it is found that the death was often due to propeller

cutus or eating of floatsam.

Marine Macroflora : Seaweeds or marine algae are primitive plants without any

root, stem and leaves. They grow in the intertidal and subtidal areas of the sea and

flourish wherever rocky, coral or any other suitable substrates are available for their

attachment. Based on the type of pigments, external and internal structures,

seaweeds, are divided into green, brown, red and blue-green algae. Seaweeds

constitute one of the commercially important marine living and renewable resources.

They contain more than 60 trace elements, minerals, protein, iodine, bromine,

vitamin and many bioactive substances.

Four seaweeds that are commercially collected along the coast of the Gulf

of Mannar are – Gracilaria edulis, Gelidiella acerosa, Sargassum wrightii and

Turbinaria sp. and these are one of the main sources of income in the concerned

villages. In the Hindu villages these also give the women one of their few fast

income. But now there is lack of sufficient quality and quantity of these sea weeds

(Uusitalo, 1987).

The 6 genera and 9 species of seagrasses of the marine flowering plants

recorded from the Gulf of Mannar are : Halodule uninervis, Cymodocea serrulata, C.

rotundata, Syringodium isoetifolium, Enhalus acoroides, Thalassia hemprichii,

Halophila ovalis, H. ovata and H. Stipulacea (Mahalingam and Gopinath, 1987).

Sea grasses are also marine plants belonging to two monocotyledonous

families, viz. Hydrocharitaceae and potamogetonaceae. These are the only

submerged marine angiosperms to have successfully adapted and survived in the

saline environment. Of the 52 species of seagrasses available in both tropical and

temperate waters around the world, 13 species are recorded in the Gulf of Mannar

Biosphere Reserve areas. The distribution of seagrass areas around the islands of

Gulf of Mannar is shown in Fig. 3.14.

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Seagrass beds are highly productive and act as breeding and nursery

ground for many epiphytic fauna and feeding ground for sea cow (Dugong dugong).

Seagrass roots bind sediments and prevent erosion. Of the 52 species of

seagrasses recorded worldwide, 12 species were recorded in Gulf of Mannar

(Ramamurthy et al, 1992). The dominant genera are Cymodocea, Thalassia,

Halophila, Halodule, Enhalus and Syringodium. The details of distribution pattern of

seagrass in the islands of Gulf of Mannar is depicted in Table 3.32.

Importance of Seaweeds and Sea Grasses

– Seaweeds are the only source for the production of agar,

carageenan and sodium alginate. While agar is manufactured

from red algae like Gelidiella, Gelidium, and Gracilaria,

carageenan is prepared from other varieties of red algae like

Fucheums, Chondrus, Hypnea and Cigartina. The sodium alginate

is obtained from brown algae such as Sargassum, turbinaria,

Laminaria, Undaria, Macrocystis and Ascophyllus.

– The brown algae Dictyota bartayresiana collected in the Gulf of

Mannar of the Indian Ocean yielded diterpenes consisting of one

known dolastane, five known dolabellanes and five new

compounds (Rao et al., 1994)

– Seaweeds act as a breeding and nursery ground from some

species of fishes and invertebrates.

– Brown seaweeds are used for manuring, as feeds, fodder for

cattle, sheep, goats and pigs, and also for extraction of potash

and iodine.

– Although a few animals may feed directly on the seagrass, the

major food chains are based on seagrass detritus and its resident

microbes.

– Seagrass is the main feed for the sea cow Dugong dugon

(endangered marine mammal). The organic matter in the detritus

and in decaying roots initiates sulfate reduction and maintains an

active sulfur cycle.

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A total of 42 species of green algae, 31 species of brown algae,

69 species of red algae, 5 species of blue-green algae and 13 species of grasses

were recorded in the Palk Bay and the Gulf of Mannar (CSMCRI, 1978,

Parthasarthy, et al., 1991). The area covered from Athankarai to Rameswaram (45

km coastline) in the Palk Bay and from Mandapam to Welamidalam (413 km

coastline) including 21 islands of the Gulf of Mannar possess higher density of algal

distribution. Standing crop of the macroalgae from the total area of 17,125 ha (above

said area) is 22,044 tonnes (wet wt.), consisting of 1,709 tonnes of agarophyses,

10,266 tonnes of alginophyses and 10,069 tonnes of other seaweeds. The

commercially important species, viz., Gelidiella acerosa Gracillaria sp., Hypnea sp.,

Sargassum sp. and Turbinaria sp. contribute

74, 974, 798, 9381 and 714 tonnes respectively (Kalimuthu et al. 1990).

Maximum Diversity Index Values for seagrasses in 21 islands of Gulf of

Mannar are shown in Table 3.33 and Fig. 3.15. The values ranged from 2.07 to

2.48. Thus, variation in diversity of seagrass at different islands is less.

Mangrove : Mangroves are salt tolerant forest eco-systems found in select islands

and also at certain intertidal regions. These are exposed at low tides and partially

submerged during the high tides. The plants comprise the true mangroves as well as

other flora which are associated with the mangroves to form the 'Mangrove

community'. The significance of mangroves is as follows :

– Mangroves help to prevent coastal erosion and built land from the

sea.

– Mangrove vegetations help to provide food and shelter during part

or all of the cycle of many marine species and act as a nursery

ground for many marine organisms.

– Mangroves help to stabilize the coastal areas by reducing wind

damage and wave energy during storms.

Maximum Diversity Index values of mangroves in 21 islands of Gulf of

Mannar are shown in Table 3.34 and Fig. 3.16. The locations of mangroves in Gulf

of Mannar and Palk Bay are shown in Fig. 3.17. Relatively good diversity (>2) was

observed at 9 islands, no diversity at 2 islands and moderate diversity at 10 islands.

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The list of mangrove species recorded in Palk Bay and Gulf of Mannar is given in

Table 3.35.

It is believed that mangroves along the main land coast and river mouths of

the canal zone have been reduced or replaced by habitation and saltpans.

Mangroves and the associated vegetations in the islands are said to be under

constant pressure. Although detailed studies have not been carried out, the islands

like Krusadai, Shingle, New Manauli and Poomarichan islands possess patches of

mangroves (Stoddart & Fosberg, 1972). The genera Avicennia and Rhizophora are

predominant in these islands. The Pamban Islands also have dense mangrove forest

cover with several species, which are degraded due to human activities like grazing

by domestic cattle & firewood exploitation by rural poor people.

The coastal mangrove has little value & occupy very narrow strip of few

meter widths along the coast or lagoon. The mangrove formation around

Rameshwaram is discontinuous & about 100 years old (Venkatesan, 1986). From

the seacoast of Rameshwaram island, Rhizophora apiculata, Ceriops tagal,

Aricennia alba, Bruguiera, Gymnorhiza are identified. Stoddart & Fosberg (1972)

have reported minor patch of mangroves near Rameshwaram. The species of

mangroves found in the estuarine coast of Palk Bay and deltaic ecosystem of Gulf of

Mannar are given in Table 3.35.

Around 9 species of mangroves (Krishnamurthy, 1987) and 7 associated

species were found in Gulf of Mannar. The dominant genera were Avicennia,

Rhizophora, Bruguiera, Lumnizera, Ceriops and Pemphis. The genera Avicennia and

Rhizophora are found to be dominant in Krusadai, Poomarichan, Pullivasal, Musal,

Anaiparand and Upputhanni islands. Manoli and Manoliputti show a high species

diversity of mangroves (Avicennia, Rhizophora, Bruguiera, Lumnitzera and Ceriops).

Pemphis acidula is found in all the islands. The details of distribution pattern of

mangrove vegetation in the islands of Gulf of Mannar is given in Table 3.36.

Out of 3140 km2 area of mangroves in India, the contribution of Tamilnadu is

only 100 km2. Major regions of mangrove formations in the state are Killai, Muthupet

and Chatrom (Puthupatinam and Talanayer 1993, Anonymous 1997). In general,

mangroves in coastal regions along the study area as also in the 21 islands in the

Gulf of Mannar are negligible in India is total.

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Biodiversity : The GOMMBRE is endowed with various ecosystems, viz. coral reef,

sea grass and mangrove. In these ecosystems different flora and fauna with varying

ecological habitats are represented in great numbers. In order to indicate the rich

biodiversity, pluralism and endemism the important groups of biota and species

composition have been studied by different agencies. A review by CMFRI, Kochi on

select literature published during 1903-1986 towards flora and fauna in GOMMBRE

indicates that over 3268 varieties of organisms under different groups were present

in this area (Table 3.6). However, the booklet published by Tamilnadu Forest

Department, Ramanathapuram (Upreti and Shanmugaraj 1997) mentioned that

GOMMBRE possesse 3600 species. Further, studies carried out by Zoological

Survey of India (Anonymous 1998) concluded that presently there are 1060 species

in GOMMBRE (Table 3.6). It is of interest to note that the only species of marine

insects present in the region is Halobates herdmani which is also endemic in the Gulf

of Mannar. Wide fluctuation of diversity of biota as reported by different agencies is

attributed to following factors.

– The papers reviewed by CMFRI cover the species recorded in the

area during long wide period of time, while the species enlisted by

ZSI is based on 5 surveys undertaken during 1993-97 in the

GOMMBRE. All the species recorded by CMFRI may not be

available in present years due to ecological changes over a

course of time.

– Certain groups of species, viz. mangroves, phytoplankton,

chaetognatha, etc. were not included in the list prepared by

CMFRI, while the species of major groups like mangroves, sea

grass, marine algae, zooplankton, avifauna etc. were not

encountered in the list of ZSI.

– While referring occurrence of 3600 species of plants and animals

in the GOMMBRE, the report (Anonymous 1998) from M.S.

Swaminathan Foundation documented availability of 168 types of

birds in its 21 islands. The number is more than double than that

(61) recorded by CMFRI. It may be mentioned that the number of

species varied widely during different seasons in the same year.

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Literature on number of species and diversity index reveals that, in

general, the biodiversity of this region is fairly high. This is supported by

comparatively higher diversity indices of zooplankton in the Gulf of Mannar and the

Palk Bay from the records at different coastal regions of India (Table 3.13).

However, comparative account of primary productivity values at different seas (Table 3.37) support that the productivity in the Gulf of Mannar is substantially low from

those of other reef ecosystems, viz. Minicoy, Andaman, Kavaratti etc. Maximum

Diversity Index values of corals, mangroves and seagrass are shown in Fig. 3.18

which show that most of the islands have good biodiversity of these plants and

animals.

3.3 Biodiversity of Islands in Study Region

The 21 islands of Gulf of Mannar are divided into four groups namely

Mandapam, Keezhakarai, Vembar and Tuticorin due to the proximity of islands to

these locations.

3.3.1 Mandapam Group

There are seven islands present in Mandapam group covering an area 262.3

ha. It is nearest group of island to the proposed project site.

Seven islands present in this region are biologically very rich. Krusadai island

is the “Biologist’s Paradise”, as it holds maximum genetic diversity. Patch reefs are

found on the southern and northern side of the islands. Fringing reefs occur along the

southern side at a distance of about 1 to 5 km. Dugong foraging grounds are

extensive. 35 species of corals, 12 species of seagrasses and

9 species of mangroves are found in this group.

Coral reefs were surveyed during low tide times. They were observed at

different zones in exposed areas. Some of the islands were small with an area less

than 5 to 7 km2. Around Muyal theevu (Hare Island) coral reefs were noticed along the

entire southern portion as a stretch and into the sea for about 2 km. On the northeast it

extended to a distance of about 1 km in width. Manoli and Manoliputti islands have

coral reefs occupying an area of about 8 km2, in the shallow region. Pullivasal and

Shingle region could be seen clearly during low tide. Krusadai Island had coral reefs

on the eastern side, which was about 200 meters wide and ran to about 1-km length

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on the southwest direction. The common coral fauna found around the Mandapam

group of island is given in Table 3.38.

Corals are mostly found upto 5m depths. More number of live coral points

exists around Manoli and Manoliputti islands. Coral reef area around the islands is

about 41 sq.km. Seagrass covers an area of about 23 sq.km around the islands.

Fringing reefs were found from 100 to 500 meters away from the shore

around the islands. They were not continuous but were broken here and there. They

occurred mostly abound all the islands. Underwater survey of coral reefs yielded

information on the various species of corals found surrounding the Mandapam group

of islands in the Gulf of Mannar and are given in Table 3.38. There was a rich variety

of coral fauna. There were more than 31 species of

7 genera of coral fauna. Of this 7 species belonging to 7 genera were hermatypic.

The most commonly occurring genera of corals were Acropora, Montipora

and Porites. Coral associated animals included a variety of fishes. Other associated

fauna included sea anemones, star fishes, sea urchins, pipe fishes, sea fans,

holothurians, shell fishes such as lobsters, gastropod molluscs, and fin fishes such as

Epinephelus (grouper), Siganus (rabbit fish), Lethrinus (pig fish), Caranx (horse

mackerel), and Serranus. Various coral associated fauna, their shelter and food items

are given in Table 3.39.

Seaweeds occur in the intertidal, shallow and deep water of the sea upto 180

m depth and also in estuaries and backwater. They grow on dead corals, rocks,

stones, pebbles and other substrate and as epiphyte on sea grasses. Several species

of green, brown and red algae with luxuriant growth are observed in this area.

Total 180 species of seaweeds are growing in Mandapam region, of which

about 40 species are economically important. These species are Enteromorpha, Ulva,

Caulerpa, Codium (Green algae), Colpomenia, Hydroclathrus, Cystoseira,

Hormophysa, Sargassum, Turbinaria (Brown algae), Asparagopsis, Gelidiella,

Gracilaria, Sarconema, Hypnea, Acanthophora and Laurencia (Red algae). The

biomass of economically important seaweed of Gulf of Mannar is estimated as 8445

tonnes (Wet weight).

The giant sea anemone, Stoichaetis giganteum (Forsk), was found to grow

both on sandy areas as well as on rocky bottom. Often many clown fishes such as,

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Amphiprion spp. and damselfishes such as, Dascyllus trimaculatus (Ruppells) were

found swimming over the anemones. Sacred chanks (Xancus pyrum Linnaeus) were

found in shoreward areas, shallow waters and also at greater depths of 10 meters and

above. Other invertebrates are found Clypeaster humilis, Salmacis bicolor, and Murex

tribulus. Sea cucumber (Holothuria atra) and (Holothuria scabra) were also found.

Dense growth of Echinolampus spp., Clypeaster humilis, and some Astropecten spp.,

was also observed. Alcyonarians, Pennatulids, and filamentous green algae were also

found at deeper areas. Lobsters, sea fans, sea horses, echinoderms, ornamental

shells like cowries and tiger shells and a number of species of crabs including edible

and non-edible ones were also found.

The green turtle Chelonia mydas (Linnaeus) is found in Mandapam region.

The major food items observed in their stomachs are sea grasses and sea weed (Pillai

and Thiagarajan, 1979).

3.3.1.1 Shingle Island

Coral distribution

Fringing reefs on the eastern, northern and western sides occur at distance of

300 m from the shore. Coral reef covers an area of about 2 sq.km. Live coral coverage

is about 46%. 15 species have been recorded in the current study.

The species recorded are Acropora hyacinthus, Montipora digitata, M.

divaricata, M.foliosa, Echinopora lamellosa, favia pallida, F.valenciennesi, Favites

abdita, Goniastrea pectinata, G.retiformis, Leptastrea transversa, Platygyra lamellina,

Galaxea fascicularis, Pocillopora damicronis and Porties solida.

Seagrass distribution

Seagrass is distributed all around the island covering an area of about 0.21

sq.km. 11 species have been recorded. They are Cymodocea rotundata,

C. serrulata, Syringodium isoetifolium, Halodule uninervis, Halophila ovalis, Halophila

ovata, Thalassia hemprichii, Halophila stipulacea, Halophila decipiens, Halophila

beccarii and Halodule pinifolia.

Mangrove distribution

The swamp in the island possesses mangroves. Six species of mangroves

and 5 associated species are recorded. The recorded species are Avicennia marina,

Rhzophora mucronata, Ceripos tagal, Bruguiera cylindrica, Lumnitzers racemosa,

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Pemphis acidula, Salvadora persica, Pandanus sp, Sesuvium sp, Scaevola sp and

Thespesia populnea.

3.3.1.2 Krusadai island

Krusadai Island known for its rich biodiversity is referred to as the “Paradise of

biologists”. The island is about 3.5 km from Mandapam and covers an area of about

66 ha. The southeast part of the island is sandy and the northern part muddy with

marshy vegetation.

The Krusadai group of islands, serve as windbreaks and help to prevent soil

erosion. The Krusadai island, is 125 acres rectangular and somewhat (inverted) boat-

shaped, it is separated by 250 m of sea from the nearest point of Rameshwaram

Island. For protection of Krusadai Island, the proper mangrove vegetation and its

proper management is necessary. (Lakshmanan, K.K.; Rajeswari, M.; Jayalakshmi,

R., 1984).

Coral distribution

Continuous fringing reefs on the southern side extends upto 500 m. Coral

reefs cover an area of about 1.5 sq. km. Live coral coverage is about 33%. 19 species

have been recorded in the current study.

The recorded species are Acropora humilis, A. hyacinthus, Montipora digitata,

M. divaricata, M. foliosa, M. verrilli, Echinopora lamellose, Favia pallida, F.

valenciennesi, Favites abdita, Goniastea pectinata, G. retiformis, Leptastrea

transversa, Platygyra lamellina, Galaxea fascicularis, Pocillopora domicornis,

Goniopora planulata, Porites lichen, Coscinaria monile and Psammocora contigua.

Seagrass distribution

Seagrass is distributed all around the island covering an area of about 3 sq.

km. About 12 species have been recorded and the species are Cymodocea rotundata,

C. serrulata, Syringodium isoetifolium, Halodule uninervis acidula, Halophola ovalis,

Halophila ovata, Thalassia hemprichii, Enhalus acoroides, Halophila stipulaceae, H.

decipiens, H. beccarii and Halodule pinifolla.

Mangrove vegetation

Mangroves are located in the peripheral region along the northern side of the

island. Seven species of mangroves and 6 associated species are recorded. They are

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Avicennia marina, Rhizophora mucronata, Ceripos tagal, Brugiera cylindrical, Pemphis

acidula, Exoecaria aggallocha, Aegiceras corniculatum, Salvadora persica, Pandanus

sp., Sesuvium sp., Scaevola sp, Suaeda sp. and Thespesia populnea.

3.3.1.3 Pullivasal and Poomarichan Island

Pullivasal island is located about 3 km east of Mandapam. It covers an area

of about 29 ha and the maximum elevation of the island is 3 m. The island is

adjacent to Krusadai Island and accessible from Poomarichan island by crossing a

shallow stretch of water. Thickly wooded trees are found in the island.

Poomarichan Island is located about 3 km east of Mandapam and covers an

area of about 27 ha and the maximum elevation of the island is 1.5 m. The island is

‘U’ shaped and has marshy soil with good vegetative cover.

Coral Distribution

Fringing reefs occur at a distance of 400 m in the southern side and patch

reef occurs beyond the muddy area in the northern side of Pullivasal Island. Coral

patches close to the island are exposed during low tide.

Coral reefs are found in the western and eastern side of the Poomarichan

Island at a distance of 150 m from the shore. On the southern side continuous reef

exists close to the shore.

Coral reefs cover an area of about 4 sq.km. Live coral coverage is about

14% (includes area around both the islands). Sixteen species of corals are recorded

around the Pullivasal island in the current study. The recorded species are Montipora

digitata, M. foliosa, Echinopora lamellosa, Favia pallida, Goniastrea, G. retiformis,

Leptastrea transversa, Pocillopora damicornis, Porites solida, P. lichen,

Psammocora contigua, Symphyllia radians, Acropora hyacinthus, A. humilis, A.

formosa and A. abdita.

Twelve species of corals are recorded around the Poomarichan island in the

current study. The species recorded are Acropora corvmbosa,

A. plantaginea, A. valenciennesi, Montipora digitata, M. divaricata, M. divaricata,

Favia pallida, F. valenciennesi, Favites abdita, Goniastrea pectinata,

G. retiformis, Pocillopora damicornis and Porites mannarensis.

Seagrass distribution

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Seagrass is distributed all around both the islands and covers an area of

about 5 sq. km. Twelve species are recorded and the dominant species are

Cymodocea rotundata, C. serrulata, Syringodium isoetifolium, Halodule uninervis,

Halophila ovalis, Halophila ovata, Thalassia hemprichii, Enhalus acoroides,

Halophila stipulaceas, Halophila decipiens, Halophila beccarii and Halodule pinifolia.

Mangrove distribution

Dense mangrove vegetation observed along the periphery region of the both

islands. Seven species of mangroves and 5-associated sp. are recorded. They are

Avicennia marina, Rhizophora mucronata, R. apiculata, Lumnitzera racemosa,

Ceriops tagal, Bruguiera cylindrica, Pemphis acidula, Salvadora percisa, Pandanus

sp, Sesuvium sp, Scaevola sp and Tespesia populnea.

3.3.1.4 Manoli and Manoliputti Islands

Manoliputti island is located at about 5 km from Mandapam and covers an

area of about 2 ha. The maximum height of the island from sea level is about 2 m.

Manoli island is located about 5 km from Mandapam and covers an area of

about 26 ha. Manoli is separated from the nearby Manoliputti island by an extensive

mudflat, which gets exposed during low tide. The islands were formed of sandy clay

and dead coral pieces. The northern and southern beach ridges were found

separated by an area of Thespesia woodlands. Pools and open mudflats were found.

The maximum elevation of the island is 2 m.

Coral distribution

Massive corals are observed along the northern portion of the island. On the

southern side fringing reefs extend far outside upto a distance of 1.25 km from the

shore. Coral reefs cover an area of about 15 sq. km. Live coral coverage is about

25% (includes area around both the islands). Thirteen species of corals are recorded

around Manoliputti island and they are Montipora digitata, M. divaricata, M.foliosa,

Echinopora lamellosa, Favia pallida, Favities abdita, Goniastrea pectinata, G.

retiformis, Platygyra lamellina, Pocillopora damicornis, Porities lichen, P. lutea and P.

solida.

Twenty five species of corals are recorded around Manoli island and they

are Acropora corymbosa, A. humilis, A. millepora, A. nobilis, A. plantaginea, A.

valenciennesi, Montipora digitata, M. divaricata, M. foliosa, M. granulosa,

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M. verrilli, Echinopora lamellosa, Favia pallida, Favites abdita, Favites pentagona,

Goniastrea pectinata, G. retiformis, Leptastrea transversa, Platygyra lamellina,

Pocillopora damicornis, P. verrucosa, Goniopora planulata, Porites lichen, P. lutea

and P. solida.

Seagrass distribution

Seagras are distributed all round both the islands. Twelve species of

seagrass are recorded. Seagrass beds cover an area of about 5 sq. km. The

recorded species are Cymodocea rotundata, Cymodocea serrulata, Syringodium

isoetifolium, Halodule uninervis, Halophila ovalis, Halophila ovata, Thalassia

hemprichii, Enhalus acoroides, Halophila stipulacea, Halophila decipiens, Halophila

beccarii and Halodule pinifolia.

Mangrove distribution

In Manoliputti very thick mangrove vegetations are found along the

periphery region of the channel and around the island. Six mangroves and

6 associated sp. are recorded and they are Avicennia marina, Rhizophora

mucronata, Ceriops tagal, Bruguiera cylindrica, Excoecaria agallocha, Pemphis

acidula, Salvadora persica, Pandanus sp, Sesuvium sp, Scaevola sp, Thespesia

populnea and Salicornia sp.

In Manoli island, mangrove vegetations show dense distribution along with

high species diversity. Eight mangroves and 6 associated as recorded are

Rhizophora apiculata, Avicennia marina, Rhizophora mucronata, Ceriops tagal,

Bruguiera cylindrica, Excoecaria algallocha, Pemphis acidula, Salvadora persica,

Pandamus sp., Sesuvium sp., Scaevola sp., Thespesia populnea and Salicornia sp.

3.3.1.5 Musal Island

Musal Island is the largest among the Mandapam Group in the Gulf of

Mannar. This island is located at about 7 km from Mandapam in the southwest

direction and covers an area of about 29 ha. The total surface area is about

1.3 sq. km. The length of the island is about four kilometers with a width of 250 to

1800 m at different places. The elevation is about 3.5 to 4 m. It is a fairly large island

characterized by thick cover of vegetation consisting of Acacia trees, coconut and

palmyra plantations.

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Coral Distribution Boulder reef patches occur in the southern side of the lagoon. Fringing reef

occurs at about 1.5 km on the southern side and runs continuously eastwards. It

however becomes discontinuous towards the north. Coral reefs cover an area of

about 18 sq. km. Live coral coverage is about 52%. Twenty nine species are

recorded in the current study.

The recorded species are Acropora corymbosa, A. formosa,

A. millepora, A. nobilis, A. plantaginea, A. Ualenciennesi, Montipora digitata,

Montipora divaricata, M. foliosa, M. verrilli, Echinopora lamellosa, Favia pallida,

Favites abdita, F. Pentagona, Goniastrea pectinata, G. retiformis, Leptastrea

transversa, Platygyra lamellina, Symphyllia nobilis, Galaxea fascicularis, Pocillopora

daicornis, Goniopora nigra, G. planulata, Porites lichen, P. mannarensis, P. lutea, P.

solida and Coscinarea monile.

Seagrass distribution Seagrass are present all around the island covering an area of about 9.5 sq.

km. Twelve species of seagrass have been recorded as Cymodocea rotundata, C.

serrulata, Syringodium isoetifolium, Halodule uninervis, Halophila ovalis, Halophila

ovata, Thalassia hemprichii, Enhalus acoroides, Halophila stipulacea, Halophila

decipiens, Halophila beccarii and Halodule pinifolia.

Mangrove Distribution Dense mangrove vegetation with high species diversity is found to occur is

this island. Six species of mangroves and 6 associated species are recorded. The

recorded species are Avicennia marina, Rhizophora mucronata, Lumnitzers

racemosa, Ceriops tagal, Bruguiera cylindrica, Pemphis acidula, Salvadora persica,

Pandanus sp., Sesuvium sp., Scaevola sp., Salicornia brachiata and Thespesia

populnea.

3.3.2 Marine Organisms Observed around the Mandapam Group of Island

Phytoplankton distribution

Seventy eight species of phytoplankton are recorded in Gulf of Mannar. In the

Mandapam group, 59 species of Bacillariophyceae, 9 species of Dinophyceae, 4

species of Cyanophyceae and 2 species of Chlorophyceae totalling to 74 species of

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phytoplankton were recorded. Maximum number of species was recorded in

Manoliputti, Poomarichan and Musal. The phytoplankton count varied from 3 – 872

nos/ml.

Zooplankton distribution

Sixtytwo species of zooplankton are recorded in Gulf of Mannar. In the

Mandapam group alone 46 species of Crustacea, 1 species of Granuloreticulosa, 1

species of Hydrozoa, 2 species of Polychaeta, 5 species of Polyhymenophora, 3

species of Sagittoidea and 2 species of Thaliacea totalling 60 species of zooplankton

were recorded. Maximum number of species was recorded around Musal and Shingle

islands. The density of zooplankton varied from 1000-9000 nos/cu.m.

Benthos distribution

In the current study (1998-99), 198 species of benthic organisms were

recorded in Gulf of Mannar. In the Mandapam group 11 species of Protozoa,

16 species of Porifera, 37 species of Cnidaria, 17 species of Annelida, 2 species of

Platyhelminthes, 9 species of Nematoda, 1 species of Echiura, 3 species of Sipuncula,

31 species of Mollusca, 41 species of Arthropoda, and 15 species of Echinodermata, 1

species of Hemichordata, totalling184 species of benthic organisms were recorded.

Musal island exhibited maximum species diversity.

Ornamental fishes distribution

A total of 128 species of ornamental fishes are recorded in Gulf of Mannar, of

which 91 species were recorded around the Mandapam group. The dominant species

were recorded in the families of Chaetodontidae, Pomacentridae, balistidae and

Apogonidae.

Capture fisheries

A total of 130 species of fishes were recorded in Gulf of Mannar. In the

Mandapam group 9 species of Chondrichthyes (Elasmobranchs), 66 species of

Actinopterygii (Teleostei), 12 species of Crustaceans and 5 species of Cephalopods,

totalling 92 species were recorded.

3.3.3 Trend of Fish Catch in Mandapam Region

Trap fishing was carried out in and around Mandapam group of islands

normally from January to March and September to December every year. About 500

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to 600 traps were operated daily in the Gulf of Mannar along the coast of Mandapam,

Vedalai, Pullivasal and Pudumadam. Altogether 23 species of fishes belonging to 15

families were found to occur in the Mandapam area. A study of the percentage

composition of the different species in the total catches from the Gulf of Mannar

revealed that Lethrinus cirereus (emperor fish) formed 57%, the next important being

Callyodon ghobbon forming 26%. The species Lutjanus Johsuii (snapper) formed 5%

and Therapon puta formed 4%. Other fishes such as Psammoperca wigiensis,

Epinephelus tauvina, (grouper fish), Teuthis marmorata, Pelates quadrilineatus,

Plectorhynchus schotat (sweet lip fish), Parapenaeus indicus (Goat fish), Upeneoides

tragula, Halichaers spp., Chiloscyllium indicum, Plotosus spp., Gerres spp., and

Acanthurus spp., (surgeon fish) formed 8%. Underwater photographs of some of these

fishes were taken.

3.3.4 Keezhakarai Group

Keezhakarai group consists of seven islands located about 8 to 10 km from

the main land. Patch and fringing reefs occur along the northwestern and southern

side of the islands. Dugong foraging grounds are extensive around Valai and Appa

islands. Thirty one species of coral, 12 species of seagrass and 6 species of

mangroves are found in the Keezhakarai group of islands.

Field survey was carried out during Jan. 2000 in all the seven islands of

Keezhakaria Group for mapping the extent of coral distribution. Information on the

distribution of corals was collected using DGPS, scuba diving and skin diving. By

underwater survey, areas of abundance of corals were identified and observation

points fixed. At each point, percentage of live corals was determined visual

confirmation of coral reef areas. Corals are mostly found upto 5 m depth. Live corals

are found beyond 0.5 m depth. More number of live coral points exist around

Poovarasanpatti and Valimunai islands. Coral reef area around the islands is about 37

sq. km.

Field survey was carried out during Jan 2000 in all seven islands for mapping

the extent of seagrass. Information on the distribution of seagrass was collected using

DGPS, scuba diving and skin diving. GIS has facilitated overlay of depth contours on

seagrass areas. Seagrass covers an area of about

43.5 sq. km around this island.

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3.3.4.1 Mulli Island

Mulli Island is located at about 10 km from Keezhakarai and covers an area

about 10 ha. It is a small sandy island with a vegetative cover consisting of bushes

and shrubs. The swampy regions are surrounded by muddy terrain.

Coral distribution

Boulder reef occurs in the northern side and fringing reef on the eastern side

of the island. Coral reef covers an area of about 7 sq. km. Live coral coverage is about

25%. 18 species have been recorded in the current study. The species recorded are

Acropora corymbosa, A. millepora, A. humilis,

A. hyacinthus, Coscinarea monile, Turbinaria peltata, Porites lutea, P. solida,

Goniastrea retiformis, G. pectinata, Favites abdita, Leptoria phrygia, Montipora foliosa,

M. spumosa, M. digitata, Echinopora lamellosa, Pavona varians and Pocillopora

damicornis.

Seagrass distribution

Seagrass beds occur all around the islands covering an area of about

2 sq. km. Eleven species of seagrass have been recorded and the recorded species

are Cymodocea rotundata, C. serrulata, Syringodium isoetifolium, Halodule uninervis,

Halophila ovalis, Halophila ovata, Thalassia hemprichii, Halophila stipulacea, Halophila

decipiens, Halophila beccarii and Halodule pinifolia.

Mangrove Distribution

Dense Distribution of Pemphis and other halophytic plants occur in the island.

Five species of mangroves and 5 associated species are Avicennia marina,

Rhizophora mucronata, Ceriops tagal, Bruguiera cylindrica, Pemphis acidula,

Salvadora persica, Sesuvium sp, Thespesia populnea, Suaeda sp. and Scaevola sp.

3.3.4.2 Valai and Talairi Islands

Valai is a small linear island parallel to the mainland covering an area of

about 10 ha. Talairi is an extensive elongated island with linear axis parallel to the

shore and covering an area of about 75 ha. The broadest portion of Talairi is on the

western tip and is densely covered with trees. A channel connects the islands, which

is submerged during high tide. The islands are located at a distance of about 9 km

from Keezhakarai.

Coral distribution

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Boulder and fringing reefs occur along the northwestern and southern side of

the islands. Coral reef covers an area of about 14 sq. km. and the live coral coverage

is about 16% (includes area around both the islands).

In the current study 11 species (51 species – past data) of corals are

recorded around Valai island. The recorded species are Montipora digitata, M.foliosa,

Pocillopora damicornis, Porites solida, P. lutea, Goniastrea sp. Montipora digitata, M.

foliosa, Porites lutea, P. solida, Acropora corymbosa,

A. formosa, A. humilis, Goniastrea retiformis, G. pectinata and Favites abdita

Segrass distribution

Seagrasses occur all around the islands covering an area of about

8 sq. km. Eleven species of seagrass have been recorded. The recorded species are

Cymodocea rotundata, C. serrulata, Syringodium isoetifolium, Halodule uninervis,

Halophila ovalis, Halophila ovata, Thalassia hemprichii, Halophila stipulacea, Halophila

decipiens, Halophila beccarii and Halodule pinifolia.

Mangrove Distribution

Dense distribution of Pemphis and other halophytic plants occurs in the

island. Two species of mangroves and 5 associated species are recorded. The

recorded species are Avicennia marina, Pemphis acidula, Salvadora persica,

Sesuvium sp, Scaevola sp, Salicornia sp and Thespesia populnea.

3.3.4.3 Appa Island

Appa Island is located at about 8 km from Keezhakarai and covers an area of

about 28 ha. The southern island portion is highly elevated standing on fossilised coral

stones of large dimensions. The northern portion of the island has an elevation of 6 m

from the spring tide level.

Coral distribution

Coral reefs occur all around the island except for a small patch on the eastern

side covering an area of about 5 sq.kms. Live coral coverage is about 2%. In the

current study 10 species have been recorded and they are Montipora digitata,

Montipora foliosa, Porites lichen, P. lutea, P. solida, Coscinarea monile, Acropora

hyacinthus, Goniastrea retiformis, G. pectinata and Favites abdita.

Seagrass distribution

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Seagrass beds are distributed all around the island covering an area of about

8 sq.km. Nine species of seagrass have been recorded and they are Cymodocea

serrulata, Syringodium isoetifolium, Halophila ovata, Thalassia hemprichii, Halophila

stipulacea, Halophila decipiens, Halophila beccarii and Halodule pinifolia.

Mangrove vegetation

Dense distribution of Pemphis and other halophytic plants occurs in the

island. One species of mangrove Pemphis acidula and 2 associated species

Salvadora persica and Sesuvium sp are recorded.

Poovarasanpatti island is completely submerged and gets exposed

occasionally during low tide. The island occurs between Appa and Valimunai islands

and is about 8 km from Keezhakarai. Valimunai is located at about 9 km from

Keezhakarai mainland and covers an area of about 7 ha. The island is characterized

by sandy shore and thick cover of Acacia trees and tall bushes.

Coral distribution

Coral reef occurs all around the island covering an area of about

6 sq. km. Live coral coverage is about 50% (including area around both the islands). In

the current study, 11 species were recorded around Poovarasanpatti island. The

recorded species are Goniastrea retiformis, Porites lutea, Acropora hyacinthus, A.

nobilis, Montipora spumosa, M. foliosa, M. digitata, Turbinaria peltata, Favia pallida,

Platygyra lamellina and Favites abdita.

In the current study, 12 species were recorded around the Valimunai island.

The species are Goniastrea retiformis, Porties mannarensis, Portites solida, Acropora

hyacinthus, A. humilis, Montipora spumosa, Turbinaria peltata, Favia pallida, Favia

favus, Echinopora lamellosa, Platygyra lamellina and Favites abdita.

Seagrass distribution

Seagrass beds occur all around the islands covering an area of about 11.5

sq. km. Nine species of seagrass are recorded and the recorded species are

Cymodocea serrulata, Syringodium isoetifolium, Halophila ovalis, Halophila ovata,

Thalassia hemprichii, Halophila stipulacea, Halophila decipiens, Halophila beccarii and

Halodule pinifolia.

Mangrove distribution

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Dense distribution of Pempbis and other halophytic plants occurs in Valimunai

Island. One species of mangrove and 4 associated species are recorded. The

recorded species are Pemphis acidula, Salvadora persica, Sesuvium sp, Scaevola

and Thespesia populnea.

3.3.4.4 Anaipar Island

Anaipar is located at about 9 km from Keezhakarai and covers an area of

about 11 ha. The maximum elevation of the island is about 3 m.

Coral distribution

Coral reef occurs all around the island covering an area of about

5 sq. km. Live coral coverage is about 37%. Twety one species of corals were

recorded in the present study (30 species – past data) and the recorded species are

Acropora corymbosa, A. formosa, A. hyacinthus, A. humilis, Montipora digitata, M.

foliosa, M. spumosa, Turbinaria peltata, T. crater, Leptoria phrygia, Goniastrea

pectinata, Goniastrea retiformis, Hydnophora exesa, Favia apllida, Porites solida, P.

mannarensis, Goniopora sp. Psammocora contigua, Merulina ampliata, Platygyra

Lamellina and Favites abdita.

Seagrass distribution

Seagrass beds occur all around the island covering an area of about

14 sq. km. Eleven species of seagrass are recorded and they are Cymodocea

rotundata, C.serrulata, Syringodium isoetifolium, Halodule uninervis, Halophila ovalis,

Halophila ovata, Thalassia hemprichii, Halophila ovata, Thalassia hemprichii,

Halophila stipulacea, Halophila decipiens, Halophila beccarii and Halodule pinifolia.

Mangrove Distribution

Dense distribution of Pemphis and other halophytic plants occurs in the

island. Two species of mangroves and 4 associated species are recorded. The

recorded species are Avicennia marina, Pemphis, Salvadora persica, Sesuvium sp,

Scaevola sp and Thespesia populnea.

3.3.5 Marine organisms recorded around Keezhakarai Group Islands

Phytoplankton

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In the Keezhakarai group, 53 species of Bacillariophyceae, 9 species of

Dinophyceae, 3 species of Cyanophyceae and 2 species of Chlorophyceae totalling

67 species of phytoplankton were recorded. Appa island exhibited maximum species

diversity. The phytoplankton count varied from 5-935 nos/ml.

Zooplankton

In the Keezhakarai group, 45 species of Crustacea, 1 species of

Granuloreticulosa, 1 species of Hydrozoa, 3 species of Polychaets, 1 species of

Polyhymenophora, 1 species of Sagittoidea and 2 species of Thaliacea totalling 54

species of zooplankton were recorded. Appa island exhibited maximum species

diversity. The density of zooplankton varied from 1000-9000 nos/cu.m.

Coral distribution

In the Keezhakarai group, 6 species of Acropora, 3 species of Montipora, 4

species of Porites, 2 species each of Favia, Goniastrea & Turnbinaria, 1 species each

of Coscinarea, Echinopora, Favites, Galaxea, Goniopora, Hydnopora, Leptoria,

Merulina, Pavono, Platygyra, Pocillopora and Psammocora totalling 31 species of

corals were recorded. Maximum number of coral species were recorded around

Anaipar and Kulli Islands.

Benthos distribution

In the Keezhakarai group 1 species of Porifera, 32 species of Cnidaria, 1

species of Annelida, 7 species of Mollusca, 12 species of Arthropoda and 3 species of

Echinodermata totalling 56 species of benthic organisms were recorded. Anaipar and

Valimunai islands exhibited maximum species diversity.

Ornamental fishes distribution

100 species of ornamental fishes were recorded around the Keezhakarai

group. The dominant species were recorded in the families of Pomancentridae,

Chaetodontidae, Lutjanidae and Holocentridae.

Capture fishes

In the Keezhakarai group 5 species of Chondrichthyes (Elasmobranch), 54

species of Actinopterygii (Teleostei), 9 species of Crustaceans and 4 species of

Cephalopodas, totalling 72 species were recorded.

3.3.6 Vembar Group

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The Vembar group consists of three islands. Patch reefs are found around the

islands and fringing reefs occur along the southern side at a distance of about 500 m.

Dugong foraging grounds are extensive around Nallathanni island. Dense distribution

of mangroves occurs in Upputhani Island. 25 species of coral, 11 species of seagrass

and 3 species of mangroves are found in the Vembar group of islands.

Live corals are found beyond 0.5 m depth. Maximum number of live coral

points exists around Upputhanni islands. Coral reef area around the islands is about

12 sq. km. Seagrass covers an area of about 9 sq.km. around the islands.

3.3.6.1 Nallathanni Island

Nallathanni island is the second largest island apart from Musal island in the

Gulf of Mannar. It is located about 10 km from Vembar and covers an area of area of

about 110 ha. The island as its name suggests has potable water.

Coral distribution

Coral reef and coral boulders occur all around the island at a distance of

400-500 m on the southern side and very close to northern shore. Coral reef covers

an area of about 2 sq.km. Live coral coverage is about 38%. Twenty species have

been recorded in the current study. The recorded species are Sarcophytum sp.,

Montipora foliosa, M. spumosa, M. digitata, Turbinaria peltata, T. crater, Favia

pallida, Favia sp. Fvites abdita, Goniastrea pectinata, Goniastrea retiformis,

Hydnophora sp, Goniopora sp Porites lutea, Porites solida, Acropora formosa, A.

hyacinthus, A. corymbosa, Symphyllia radians, Leptoria phrygia, Galaxea

fascicularis and Psammocora contigua.

Seagrass distribution

Seagrass around the island covers an area of about 5 sq. km.

Eleven species of seagrass have been recorded. The recorded species are

Cymodocea rotundata, C. serrulata, Syringodium isoetifolium, Halodule uninervis,

Halophila ovalis, Halophila ovata, Thalassia hemprichii, Halophila stipulassia,

Halophila decipens, Halophila beccarii and Halodule pinifolia.

Mangrove distribution

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Dense distribution of Pemphis and other halophytic plants occurs in the

island. One species of mangroves and 4 associated species are recorded. The

species are Pemphis acidula, Salvadora persica, Sesuvium sp. and Thespesia

populnea.

3.3.6.2 Pulivinichalli Island

Pulivinichalli Island is located about 8 km from Vembar and covers an area of

about 6 ha. The island is characterised by sandy beach and thick vegetation. The

eastern side of the island has sparse distribution of Thespesia.

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Coral distribution

Coral reefs were found in the southern side of the island. A huge mass of

dead coral stones and boulders were found in the northwest corner of the island which

extended upto a distance of 1.5 km. Coral reefs cover an area of about 7 sq.km. Live

coral coverage is about 38%. Seventeen species have been recorded (41 species -

past data) in the current study and they are Montipora digitata, Montipora foliosa,

Montipora spumosa, Montipora turgescens, Favia pallida, Favites sp, Porites lutea,

Porites solida, Gonistrea retiformis, Leptoria phrygia, Acropora formosa, A. hyacinthus,

A. humilis, A. nobilis, A. corymbosa, Turbinaria crater and Pocillopora damicornis.

Seagrass distribution

Seagrass occurs all around the islands covering an area of about

1.5 sq. km. Eleven species of seagrasses have been recorded and the species are

Cymodocea rotundata, C. serrulata, Syringodium isoetifolium, Halodule uninervis,

Halophila ovalis, Halophila ovata, Thalassia hemprichii, Halophila stipulacea, Halophila

decipiens, Halophila beccarii and Halodule pinifolia.

Mangrove distribution

Pemphis and other halophytic plants occur in the island. One species of

mangrove and 4 associated species are recorded. The dominant species are Pemphis

acidula, Salvadora Persica, Sesuvium sp, Scaevola sp and Thespesia populnea.

3.3.6.3 Upputhanni Island

Upputhanni island is located 8 km from Vembar and covers an area of about

30 ha. The island is fairly big with plenty of coral rubble all over it. A number of trees

along with numerous bushes are present

Coral distribution

Fringing reefs occur at a distance of 150 to 300 m all around the island except

in the north. Coral reefs cover an area of about 3 sq. km. Live coral cover is about

28%. Sixteen species of corals are recorded in this study and they are Montipora

digitata, Monitipora foliosa, Montipora spumosa, Montipora turgescens, Favia pallida,

Favites sp, Porites lutea, Porites solida, Goniastrea retiformis, Hydnophora exesa,

Turbinaria peltata, T. crater, Leptoria phrygia, Acropora corymbosa, Psammocora

contigua and Symphyllia radians.

Seagrass distribution

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Seagrass occur all around the islands covering an area of about

2.5 sq. km. Ten species of seagrasses have been recorded and they are Cymodocea

serrulata, Syringodium isoetifolium, Halodula uninervis, Halophila ovalis, Halophila

ovata, Thalassia hemprichii, Halophila stipulasia, Halophila decipiens, Halophila

beccarii and Halodula pinifolia.

Mangrove distribution

Dense distribution of mangroves occurs in the southeastern side of the island.

Three species of mangroves and 4 associated species are recorded and the species

are Avicennia marina, Rhizophora mucronata, Pemphis acidula, Salvadora persica,

Sesuvium sp., Scaevola sp. and Thespesia populnea.

3.3.7 Marine Organisms around Vember Group of Islands

Phytoplankton

In the vembar group, 48 species of Bacillariophyceae, 11 species of

Dinophyceae, 2 species of Cyanophyceae and 1 species of Chlorophyceae, totalling

62 species of phytoplankton were recorded. Nallathanni island exhibited maximum

species diversity. The phytoplankton count varied from 6 - 478 nos/ml.

Zooplankton

In the vembar group, 37 species of Crustacea, 1 species of Hydrozoa, 1

species of Polychaeta, 1 species of Polyhymenophora, 3 species of Saggitoidea and 1

species of Thaliacea totalling 45 species of zooplankton were recorded. Maximum

number of species was recorded around Pulivinichalli and Upputhanni islands. The

density of zooplankton varied from 1000-9000 nos/cu.m.

Coral distribution

In the Vembar group, 5 species of Acropora, 4 species of Montipora,

2 species each of Porites, Goniastrea and Turbinaria, 1 species each of Favia,

Favites, Galaxea, Hydnopora, Goniopora, Leptoria, Pocillopora, Symphyllia,

Psammocora and Sarcophytum totalling 25 species of corals were recorded.

Maximum number of coral species was recorded around Nallathanni island.

Benthos distribution

In the Vembar group, 1 species of porifera, 27 species of Cnidaria,

7 species of Mollusca, 8 species of Arthropoda and 2 species of Echinodermata

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totalling 45 species of benthic organisms were recorded. Nallathanni island exhibited

maximum species diversity.

Ornamental fishes distribution

128 species of ornamental fishes were recorded in the Gulf of Mannar.

Around 104 species of ornamental fishes were recorded around the Vembar group.

The dominant species were recorded in the families of Pomacentridae,

Chaetodontidae, Labridae and Apogonidae.

Capture fisheries

In the Vembar group, 8 species of Chondrichthyes (Elasmobranchs), 69

species of Actinopterygii (Teleostei), 9 species of Crustaceans and 5 species of

Cephalopods, totalling 91 species were recorded.

3.3.8 Tuticorin Group

The Tuticorin group consists of four islands, one of, which is submerged. Reef

patches exist all around the islands. The islands have sparse vegetation. Twenty three

species of corals, 11 species of seagrass and

3 species of mangroves and asociated species are found in the Tuticorin group of

islands.

Live corals are found beyond 0.5 m depth. Maximum number of live coral

points exists around Karaichalli island. Coral reef area around the islands is about 10

sq. km. Field survey was carried out during March 2000, in all four islands for mapping

the extent of seagrass. Seagrass covers an area of about 10 sq.km.

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3.3.8.1 Karaichalli Island

Karaihalli island is about 15 km from Tuticorin. It covers an area of about 16

ha and has very poor vegetative cover. Fishermen from the nearby mainland visit the

island for illegal coral mining operations.

Coral distribution

Patches of coral reef exist all around the island and cover the area of 0.31

sq.km. Live coral coverage is about 14%. Twenty five species of corals have been

recorded and the species are Acropora hyacinthus, A formosa,

A nobilis, Acropora sp., Montipora digitata, M. foliosa, M. foliosa, M. spumosa, Favites,

abdita, Favites sp., Favia pallida, F. favus, platygyra, T. crater, Goniastrea, retiformis,

G. pectinata, Galaxea fasicularis, Symphyllia radians, Leptastrea transversa, Leptoria

phrygia and Goniopora stokesi.

Seagrass distribution

Seagrass occur all around the islands covering an area of about 1 sq km.

Eleven species of seagrass have been recorded . The recorded species are

Cymodocea rotundata, C. serrulata, Sysringodium isoetifolium, Halodule univervis,

Halophila ovalis, Halophila ovata, Thalassia hemprichii, Halophila stipulacea,

Halophila decipiens, Halophila beccarii and Halodule pinifolia.

Mangrove vegetation

There is sparse distribution of Pemphis and other halophytic plants in the

island. Two species of mangroves and 4 associated species are recorded. The

dominant species are Avicennia marinam, Pemphis acidula, Salvadora persicam,

Sesuvium sp, Scaevola sp and Thespesia populnea.

3.3.8.2 Vilanguchalli island

Vilanguchalli island is completely submerged and gets exposed during low

tide. The island is located at about 15 km. from Tuticorin.

Coral distribution

Coral reef patches occur all around the submerged island. Coral reefs cover

an area of about 1 sq. km. Live coral coverage is about 8%. Eight species of corals

were recorded in the current study (21 species- past data) . The recorded species

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are Acropora hyacinthus, A formosa, Montipora spumosa, Favia pallida, porties

lutea, Turbinaria crater, Goniastrea retiformis and Leptastrea sp.

Seagrass distribution

Seagrasses occur all around the island covering an area of about

1.5 sq. km. Eleven species of seagrass have been recorded and they are

Cymodocea rotundata, C. serrulata, Syringodium isoetifolium, Halophila stipulacea

and Halophila decipiens.

3.3.8.3 Kasuwar Island

Kasuwar is the largest and elongated island in the Tuticorin group and is

located at about 7 km from Tuticorin. The island is sandy and strewn with shingles and

covers an area of about 19 ha. The whole island is covered with xerophytic vegetation.

Coral distribution

Coral reef patches occur all around the island. Coral reefs cover an area of

about 6 sq. km. Live coral coverage is about 5%. Fourteen 14 species are recorded

and the species are Acropora hyacinthus, A formosa, Montipora digitata, M. foliosa,

Favites abdita, Favia favus, Platygyra lamellina, Porites mannarensis, Turbianria

Peltata, T. crater, Goniastrea retiformis, Goniastrea sp., Goniopora stokesi and

Leptoria phrygia, Digitata, M. foliosa, M. spumosa, Favites abdita, Favites sp, Favia

pallida, Platygyra lamellina, Porites lutea,

P. mannarensis, Hydnopora sp., Turbinaria peltata, T. crater and Goniastrea

retiformis.

Seagrass distribution

Seagrass occurs all around the island covering an area of about 5 sq. km.

Nine species of seagrass have been recorded and they are Cymodocea serrulata,

Syringodium isoetifolium, Halophila ovalis, Halophila ovata, Thalassia hemprichii,

Halophila stipulacea, Halophila decipiens, decipiens, Halophila beccarii and Halodule

pinifolia.

Mangrove distribution

Pemphis and other halophytic plants occur in the island. Two species of

mangroves and 4 associated species are recorded. The recorded species are

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Avicennia marina, Pemphis acidula, salvadora percisa, Sesuvium sp, and Thespesia

popuinea.

3.3.9 Marine Organisms aroung Tuticorin Group of Islands

Phytoplankton

In the Tuticorin group, 4 species of Bacillariophyceae, 8 species of

Dinophyceae, 5 species of Chlorophyceae totalling 70 species of phytoplankton were

recorded. Kasuwar island exhibited maximum species diversity. The phytoplankton

count varied from 2-835 nos/ml

Zooplankton

One species of Granuloreticulosa, 1 species of Hydrozoa, 3 species of

Polycheata, 5 species of Polyhymenophora, 1 species of Sagittoidea and

2 species of Thaliacea totalling 59 species of zooplankton were recorded. Van island

exhibits maximum species diversity. The zooplankton count varied from 1000 –

10,000 nos / cu.m.

Coral

In the Tuticorin group, 3 species each of Acropora, Montipora and Porites, 2

species each of Goniastrea, Turbinaria and Favia, 1 species each of Favites,

Galaxea, Hydnopora, Goniopora, Leptoria, platygyra and Symphyllia, totalling 23

species of corals were recorded. Maximum number of coral species was recorded

around Karaichalli island.

Benthos

In the Tuticorin group, 1 species of Porifera, 24 species of Cnidaria, 4

species of Mollusca, 3 species of Arthropoda and 2 species of Echinodermata,

totalling 34 species of benthic organisms were recorded Kasuwar island exhibited

maximum species diversity.

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Ornamental Fishes

In the current study (1998-99), 128 species of ornamental fishes were

recorded in the Gulf of Mannar. 101 species of ornamental fishes were recorded

around Tuticorin group. The dominant species were recorded in the families of

Pomacentridae, Cheatodontidae, Mullidae and Lutjanidae.

Capture fisheries

In the Tuticorin group, 14 species of Chondichthryes (Elasmobranchs), 96

species of Actinopterygii (Teleost), 11 species of Crustaceans and 5 species of

Cephalopods, totalling 126 species were recorded.

3.4 Palk Bay/Palk Strait

3.4.1 Marine Water Quality

Marine water quality in Palk Bay area near the proposed channel is assessed

from secondary data and is summarised in Table 3.40. It is observed that suspended

solids vary from 28-30 mg/l at the surface and is uniformly distributed up to bottom.

The could be due to shallow depths 2-12 m in Palk Bay. Salinity is observed to vary

from 30.4-32.5 parts per thousand. High dissolved oxygen (DO) levels at the surface

are indicative of healthy aquatic life and low organic pollution loads particularly away

from the coastal areas. DO was observed to decrease towards bottom and is

attributed to demand excercised by sediment. Observed levels of nitrogen and

phosphorus support biological growth. Heavy metals were in traces and levels of

polynuclear aromic hydrocarbons observed in parts per billion (ppb) levels. This could

be attributed to fishing activity in the region.

3.4.2 Biological Productivity

The Palk Bay is biologically rich and are rated among the highly productive

seas of the world. The Palk Bay is endowed with a combination of ecosystem

including mangroves, seagrass and coral reefs, supporting over 3,600 species of

plants and animals. Its biodiversity is considered globally significant. The Palk Bay

islands constitute a resting-place for birds migrating to and from Sri Lanka.

Approximately 168 types of birds use the islands in this area as a resting-place while

migrating or as wintering and molting grounds. All five species of marine turtle nest in

various locations in Palk Bay. Dolphins are more common here than in any other

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region in the Bay of Bengal. The endangered dugong uses many of the islands as

browsing grounds. Marine life also includes many colored coral fishes, eels, molluscs,

and stomatopoda. Sea anemones, crabs, starfishes, sea urchins and numerous other

organisms are found in the Palk Bay.

Biological diversity of Palk Bay/Palk Strait is in influenced by point colimer

sanctuary which is bestowed with mangrove forests, mud flats, wettalnds and brackish

to saline lagoons. The sanctuary provides breeding ground for marine fishes which are

vital to the fisheries of the region. The sanctuary has been designated as Ramsar site

in November 2002 by world wildlife fund (WWF) - India.

3.4.2.1 Primary Productivity

Primary productivity in the offshore area was relatively less than in the shelf

and slope area for Palk Bay region. The productivity at surface is more than

subsurface layers. The southwest monsoon was more productive compared to

pre-monsoon season. Phytoplankton analysis showed that diatoms contributed 70%,

flagellates 23% and dinoflagellates 7%, of the biomass at the surface.

Integrated values of chlorophyll at the surface along Palk Bay is

<0.1 mg/m3 and at 0-50 m and 0-100 m depth it is 5-15 mg/m2. The gross primary

productivity values varied from 143 to 472 mgC/m3/day. The mean values are 205

mgC/m3/day for Palk Bay. It is further reported that in the near shore areas where the

euphotic zone used to be about 6 m due to turbidity, the productivity was reported to

be 1.2-1.5 gC/m2/day which is equal to the annual gross productivity of about 450

gC/m2. While further inside the sea where the euphotic zone is deeper (upto 15-40 m),

the average daily productivity used to be 3-5 gC/m2 (Nair 1970). The average primary

productivity values in central ocean basins and coastal zones of the world were

estimated at 50 and

100 gC/m2/yr respectively (Ryther, 1969). Thus, the shallow regions of Palk Bay

constitute one of the most productive regions of the world. It is also clear from the

above that turbidity adversely affects primary productivity.

Link in the Food Chain

As already mentioned, the phytoplankton constitute the food for the smallest

of animals, viz. zooplankton which in turn form the food of the largest mammal, the

Antarctic whale (Balanoptera) which feeds on small shrimp like zooplankton known as

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krill (Euphausia superba). The krill is wholly dependent on the bloom of phytoplankton

for its survival and growth. The largest of the fishes, the basking shark, is also a

planktonic feeder, mainly feeding on the copepod Calanus which in turn survives on

the phytoplankton. The fishery for oil sardine and mackerel are entirely dependent on

the bloom of phytoplankton. There are several other fishes and mammals in the sea

whose life is linked with phytoplankton, only the number of links in the food chain vary

in each instance. Each species has its own period of growth and growth intensity

depends on many external factors such as temperature, salinity, nutrients and the

physiological state of the species itself and these in turn are influenced by seasons

and climatic factors.

Productivity and Potential Yield

In Palk Strait area potential primary production during June-September,

average for surface layer 0-50 m is 10-15 mg C m-3h-1 and for December-March it is

<10 mg Cm-3h-1.

Primary productivity in SW & NE monsoon is 0.56 & 0.23 g C m-2 day-1 and 101

and 60 g C m-2 180 day-1.

Peak Periods of Production

The maximum production occurs during the south west monsoon season,

followed by one or two peaks of production of lesser magnitude during the north east

monsoon season. The peaks of production are mainly due to the multiplication of

diatoms, dinoflagellates and nannoplankters. The blue-green algae chiefly composed

of filamentous bundle like structures called Trichodesmium occur generally during the

warmer months. Investigations on the factors responsible for the production of

phytoplankton have shown that during the monsoon months, optimum condition such

as abundance of nutrients due to upwelling and river discharge fall in temperature and

salinity are common features of these waters. The nature of phytoplankton flora

changes frequently and each species appears to have its own peak periods of

occurrence and associations. The species which contribute to the bulk during periods

of maxima also vary from year to year, though a few appears to be common. A total of

56 species of phytoplankton have been observed from Palk Bay / Palk Strait.

3.4.2.2 Secondary productivity

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The secondary productivity is influenced by the dominance of ostracods,

decapods, mysids and other zooplanktonic forms. The distribution of zooplanktons in

Palk Bay assessed from secondary data is shown in Table 3.41.

Ostracods

Ostracods are tiny bivalve crustaceans more during April, followed by July,

that may be attributed to high temperature, salinity and dissolved oxygen of the

bottom water, high calcium carbonate and low organic matter content of the

sediments. The most congenial substrate for better thriving of the fauna are found to

be silty - sand. About 51 ostracod species (both living and dead forms) belonging to

40 genera in 22 families were identified of which the following

8 spp are considered to be abundant viz. Actinocythereis scutigera, Bairdoppilata

atcyonicola, Callistocy flavidofusca C. intricatoides, Cytherelloidea leroyi, Keijella

reticulata, Loxoconcha gruendeli, L., mandiensis and Tanella gracilis.

Decapoda

Decapods are Prawns and Shrimps. Both the type of animals are having 10

sets of legs. They are highly sensible creatures and occur mostly beyond

50 m depth. Distribution of decapods in Palk Bay is shown in Table 3.42.

Mysids

A rich and varied mysid fauna exist in the littoral and shallow areas of the

seas around Palk Bay / Palk Strait. Reports on the abundance of mysid population

reveal a greater concentration (74%) in the nighttime collections indicating diel

migrations, characteristics of the fauna. The population density is high during the post-

monsoon (October-January) in the shelf waters and during the pre-monsoon

(February-May) in the oceanic region. The population of mysids occurred throughout

the year even in the deeper layers beyond 200m. The predominance is prominent

(63%) during the pre-monsoon and to lesser extent (23%) in the northeast monsoon

seasons in the neritic area.

Other zooplanktonic forms

Meroplanktonic stages of Anthozoan larvae is 4-6 nos of individual under 1

m2 area. Chaetognaths types are Pterosagitta draco, Sagitta bedoti, Sagitta enflata,

Sagitta pacifica and S. reularis commonly present during

SW & NE monsoon; Sagitta bipunctata are only observed during NE monsoon , while,

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Sagitta neglecta only during SW monsoon. Distribution of copepoda is 9000-26999

nos/haul. Epiplanktonic calanoid observed are Clausocalanus minor, C. farrani,

Pontellina plumata and Eucalanus elongates. Other species in vicinity are

Centrophagus furcatus and Temora discaudata. Day and night collection of pelagic

amphipods during April-October has density of 26-50 and 51-100 nos/ m2, while, for

October-April, it is 100-250 nos under 1 m2 net area scanned upto 200 m depth. The

distribution of euphausiids : Pseudoeuphausia latifrons and Nyctiphanes capensis

during May-September and November-March is 1-249 nos/1000 m3 of water; for E.

distinguenda and E. diomediae it is 1-499 nos/1000 m3 from November to March. The

larvae, juveniles and adults of ‘Nematoscelis gracilis’ were observed only during

November-March. The Gastropoda ‘Limacina inflata’ were observed only during night-

time from April to October & vice-versa, the catch being 11-100 per haul.

Zooplankton biomass during March-April is 40-80 ml m-2 / haul at 200 m

column, whereas, for May-June it is 10-20 ml m-2/haul; for July-September it is 0.1-

10.0 ml m-2/haul and for December-February it is 10-20 ml m-2/haul.

Secondary stock and secondary production in SW & NE monsoon is

101 & 60 g C m-2 180 day-1.

Bottom Water Characteristics

The temperature range of 22.3 to 28.6OC seems favourably for all living population

of zooplankton fauna, throughout the year. Salinity range from 32.93 to 35.81‰ favourable

for the standing crop. Dissolved oxygen content is one of the important factors governing

distribution and abundance of standing crop.

Sediment Characteristics

Distribution of zooplanktons in relation to the sediment composition reveals

that silty - sand followed by sandy - silt and sand are the most favourable substrates

for the population abundance.

Temporally, higher values of temperature, salinity, dissolved oxygen and

calcium carbonate are recorded in April whereas organic matter content is maximum

during January. Spatially, however, the values of all these environmental parameters

show steady increase except temperature. The organic matter content in the

sediments is 0.36 to 3.51 % by weight.

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CaCO3 percentage in the sediment varies from 2.5 to 7.2 %, CaCO3 does

not show much variation. In general, CaCO3 content of the sediment is found to be

directly proportional to the population size and it is inferred that it is one of the

important parameters that governs the population size, especially its spatial

distribution.

3.4.2.3 Tertiary productivity

The tertiary production in SW & NE monsoon is 20-40 & 10-20x105 tons wet

weight.

3.4.2.4 Benthos

Sediments led to the recognition of 108 benthic species consisting of both

living and dead fauna. They belong to 50 genera, 27 families and 10 superfamilies.

Among the 108 species, 12 species (viz. Rhabdommina scabra, Ammonbaculites

exiguus, Textularia agglutinans, T. aura, T. candeiana, T. conica, T. foliacea, T.

foliacea var occidentalis, T. palustris. Bigenerina irregularis, Trochammina inflata

and Eggerella advena) are arenaceous agglutinated (suborder Textulariina); 43

species are calcareous porcelaneous (viz. Edentostomina cultrata, Spiroloculina

angulata, S. communis, S. corrugata, S. costifera, Spiroloculina sp., Vertibralina

striata, Quinqueloculina agglutinana, Q. bicostata, Q. bidenta Q. compressa, Q.

lamarckiana, Q. parkeri, Q. polygona,

Q. pseudoreticulata, Q. rameswarensis, Q. seminulam, Q. sulcata, Q. tenagos, Q.

undulose costata, Pseudomassilina australis, P. australis, P. reticulata, P. macilenta,

Pyrgo elongata, P. subspherica, Triloculina carinata, T. striata, T. insignis, T.

schreiberiana, T. terquemiana, Milolinella circularis, M. labiosa, Hauerina bradyi, H.

fragilissima, Articulina mayori, Parrina bradyi, Peneroplis plantus, Monalysidium

politum, Spirolina acicularis S. arietinus, Sorities marginalis and S. orbiculus

(Suborder Miliolina) and the rest 53 are calcareous perforate forms (viz. Lagena

costata amphora, L. gracillima, L. laevis, L. setigara, L. striata, Guttulina sp.

Fissurina marginata, Bolivina doniezi, B. lanceolata Brizalina lowmani, B. striantula,

Rectobolivina glabro, R. raphanus, Chrysolidinella dimorpha, Reusella atlantica,

Rosalina globularis, R. valvulata granulosa, Cancris oblonga, Spirillina vivipara,

Ammonia beccarii, A. dentata, A. tepida, Asterorotalin inflate, A. trispinose,

Pararotalia nipponica, P. azawai, Pseudorotalia sehroeteriana, Calcarina umblicats,

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Elphidium advenam, E. crispum, E. discoidale, E. excavatum, E. hispidium, E.

incertum, E. limbatum, E. poeyanum, E. verriculatum, Poroeponoides laterolis,

Cibicides lobatulus, C. refulgens, Planorbulina mediterranensis, Planorbulinella

larvata, Acervadina inhaerens, Cymbaloporetta bradyi, C. squammosa, Fursenkoina

compressa, F. punctata, Sigmavirgulina tartuosa, L. limbatum costudata, Florilus

boucamum, F. grateloupi, F. labradoricum and O. venusta (sub order Rotaliina).

Among living forms, only the eight taxa (viz. Spiroloculina insignis, T.

trigonula, Ammonia beccarii, A. tepida, Pararotalia nipponica and Osangularia

venusta) are considered to be widespread and abundant in the Palk Bay area.

3.4.3 Sponges and corals

Sea - Cucumbers

Sea cucumbers are a group of economically important echinoderms with a

wide range of distribution in coral to mangrove habitats.

Although nearly 200 species of sea cucumbers are distributed in the seas

around India, only about a dozen species are of commercial importance. Only

species belonging to the families Holothuridae and Stichopodidae are of commercial

importance since they are large in size and the body wall is also thick. These are

distributed in good numbers in the Palk Bay. Nearly 30 corals are recorded from

Palk Bay (Table 3.43).

Species observed are, Family, Holothuriadae, sp., Actinopyga miliaris,

A.mauritiana, A echinites, Bohadschiaargus, B. marmorata, Holothuria nobilis, H.

atra, H. scabra, H. spinifera, Family-Stichopodidae, sp., S. chloronotus, S.

variegatus.

Flourishing export market for the processed sea cucumbers has increased

their exploitation. Over 60% of beche- de-mer exported from India, is from the Palk

Bay. Sea cucumbers are mostly collected by skin divers in shallow waters from 2-10

m depth. Presently, operation of a modified trawl net called Chanku madi yields good

catches of sea cucumbers alongwith chanks (Xancus pyrum). The harvest

composition of this gear is Xancus pyrum (61.22%), sea cucumbers (20.4%), rays

(Amphotistus kuhlii) (16.33%) and starfish, sea shells and small fishes (2.04%).

Holothuria being detritus feeders are found among the marine macro-algae and

seaweeds.

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Sea fan

The Sea fan is yet another colonial form, but it branches only in one plane

and the branches may fuse with each other to form a 'fan'. White or cream-colored

polyps may grow on a base of contrasting maroon colour, attached to stones by a

broad disc-like holdfast. Gorgonides are reported in Palk Bay in deeper waters,

beyond 50 m (CMFRI 1998). The colorful sea fans have long been objects of attraction

to man. Gorgonid community is popularly known as "flowers of under water gardens".

Sponges

Sponges, although at a casual glance look like plants, are animals, living

singly or in colonies. They have no fixed shape, and form flat encrustations on stones

in the region of strong waves. In the crevices, these sponges are found associated

with many animals, ranging from tiny crabs and brittle star to bivalve molluscs.

Sponges show commensalisms as several crustaceans, worms, molluscs and fishes

live in the internal cavities of sponges for protection against enemies, and also act as a

shelter bed. About, 60 desmosponges are recorded from Palk Bay (Table 3.43).

3.4.4 Fishing in Palk Bay

The distribution and abundance of different groups of fish in the areas are

shown in the Table 3.44. It is evident that highest catch was recorded for

Pomadasys, Leiognathus and Lethrinus sp. Along Palk Bay region, very high values

of organic production to the tune of 435 mgC/m/day to 2340 mgC/m/day were

reported from June to July. The threadfin breams along SE coast of Palk Bay

(10O/18O) has no catch at all upto depths from 40-100 m. The depth range of 60-90

m along 10ON Lat. of SE coast (Palk Bay) has only one form of threadfin breams as

Nemipterus japonicus (100%). Off the south east coast the fishing area at 10O/80O

has recorded the highest catch of 1,033 kg/hr with major perches (Pristipomoides

typus, Epinephelus and Lutjanus) forming the bulk. The abundance of demersal fin

fish kg/hr along Palk Bay (10O/80O) in Table 3.45 shows the dominance of fish in the

order Carangids>Perches> Rastrelliger> miscellaneous fish between 51-100 m

depth, whereas there is no catch below

50 m depth. Other types of fishes (13 types) are not found in this area. The perches

in SE coast at 10ON below 50 m show presence of serranids, whereas at depth 51-

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100 m Lutjanus, Lethrinus, Plectorhynchus and other perches are uniformly caught

(Table 3.46).

3.4.5 Marine Mammals

The cetacea (whales and dolphins) and sirenia (sea cow) represent the

main groups of marine mammals in the Palk Bay. Marine mammals have a layer of

dermal fat or blubber. This acts as a stored reserve food for future use in case of

deficiency of food. The sirenia (sea cow) graze with their well developed lips, in

consequence, their teeth are little used and are greatly reduced in size. In cetacea,

whales and dolphins are mostly carnivorous and feed on crustaceans, squids, and

fishes. In sirenia, sea cow is herbivorous and feeds mainly on sea grasses.

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Dolphins and Whales

The dolphis found in the Palk Bay are oceanic and roam about in the area. It

is most likely that only the frail and the infirm whales move towards this area as

known from strandings of whales. So far no mass stranding of whales has been

observed in the canal area. The dolphins Stenella longirostris and Tursiops truncatus

are often caught in various nets and the ones thus caught and injured (probably) are

clandestinely butchered for food. However, capture or harming of the sea mammals

is prohibited by law.

Sea Cow

Unlike dolphin and whales, sea cow (Dugong dugon) inhabits the Palk Bay

preferably within 10 m depth limit not far from the shore (1-3 km). Usually sea cows

move in groups of 5-7 among the seagrass Cymodocea, which is its chief diet. The

dugong which grows to over 300 kg measuring 1-1.5 m in length, is harmless and

sluggish in nature. Its gestation period lasts 13-14 months and gives birth to a single

calf at a time. Though young male adults compete among themselves for female,

once they have paired, they remain paired for the whole life. Their attachment to the

partner and calf is such that if one of the partners or calf gets caught the rest also

shall follow; thus becoming easy victims. They have no natural enemies except the

civilised man. The exact number of sea cows living in the Palk Bay is not known.

Due to uncontrolled fishing carried out till recently and also due to reduction in their

grazing area and Cymodocea, their numbers have gone down drastically. During

1980's, about 200 numbers used to be killed per year. Now they are protected by the

Wildlife (Protection) Act, and are under threatened status. Occasionally, marine

mammals and turtles have been observed to get washed ashore, and on

examination it is found that the death is often due to propeller cuts or eating of

floatsam.

3.4.6 Distribution Of Palk Bay Reef

The reef in Palk Bay runs parallel to land (east to west direction) from

Pamban Channel at the Pamban end of the bridge to Rameswaram island between

longitudes 79° 17' E and 79° 8'E at the latitude 9° 17'N. The Bay is a very shallow flat

basin and the depth never exceeds 15 metres. The average depth is 9 meters. The

coral reef in Palk Bay starts from Munakad as a wall-like formation 1-2 m broad and

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runs east upto Tonithurai a distance of nearly 5.5 km. Here the reef width is more than

300 metres. East of Pamban pass, the reef again starts near Thangachimadam and

ends near Agnitheertham (Rameswaram) (Mahadevan and Nair, 1969). This reef is

25-30 km long and generally less than 200 m wide. Visibility is poor due to siltation.

The Palk strait between India and Ceylon is about 75 km wide, with a water depth of 9-

13 m, except where local coral reef rises above sea level.

Coral reefs on the Tamil Nadu coast (south east coast) are located in Palk

Bay near Rameswaram and in the Gulf of Mannar. Mandapam peninsula and

Rameswaram Islands separate Palk Bay from the Gulf of Mannar. The reef is

centered at 9O17’ N and 79O15’ E. There is only one fringing reef in the Palk Bay,

which lies along the mainland from the Pamban channel at the Pamban end of the

bridge to Rameswaram Island. This reef is 25-30 km long, and generally less than

200 m wide; maximum depth is around 6 m. Visibility is poor due to siltation and it is

influenced by the north east monsoon. The reef flat is relatively broad from Pamban

channel to the southern end near Ramnad and narrow from Pamban to south of

Rameswaram.

3.4.7 Review of the Coral Reef Ecosystem of Palk Bay

Gopinadha Pillai (1969) classified the reefs of Palk Bay into five zones -

shore, lagoon, shoreward slope, reef crest and seaward slope. The shore of the reef

is mostly sandy with dead pieces of corals, except at the extreme eastern and near

the Pamban bridge where one can see traces of sandstone. The vegetation on the

shore comprises Cocos nucifera, Borassus flabellifera, Casurina equisetifolia,

Azadirdicata indica and few other thorny shrubs.

The width of the lagoon varies from 200 to 600 meters at different places

with a depth of 1 to 2 metres. The bottom is sandy with molluscan shells and pieces

of disintegrating corals. Living corals are practically absent in the lagoon, probably

due to the absence of any hard substratum on which coral planulae can settle.

Sponges such as Hercina fusca, Dysidea fragilis,

Spirastrella inconstans and Calispongia diffusa are fairly common at the bottom. The

vegetation is composed commonly occurring of Cymodocea sp., Ulva reticulata,

Turbinaria sp., Padina sp., Halimeda sp. and Amphiora sp. Holothuria scabra,

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Holothuria arta and Pentaceraster australis are common inhabitants of the sandy

lagoon floor (Pillai, 1969).

Corals distributed along the shoreward slope are encrusting and of massive

types with comparatively large polyps, such as Favia pallida, Favus, Favites virens,

Goniastrea pectinata, G. retiformis, Platygyna lamellina, Hydrophora sp., Cyphastrea

sp., Leptastrea sp., symphillia sp. and Goniopora sp. Living colonies of Ponies sp

are rare or small in size. Galaxea fascicularis and Turbinaria peltala, Pavona varians

are the rarest species. This zone of the reef supports a good many reef dwellers like

encrusting sponges, bryozoans and calcareous algae. Among the fleshy corals

Lobophylum sp and Sarcophylum sp are represented.

The reef crest is often completely exposed at low tides. Corals are very rare

at the reef crest, probably because of the influence of exposure to sun light. However

Heptastrea transversa and Goniopora duofaciata are occasionally seen under the

rocks.

The coral growth of the reef along the seaward side slope is comparatively

richer than on the shoreward side. Majority of corals are ramose genera viz.,

Pocillopora sp, Acropora sp and Montipora sp. The vegetation comprises of

Turbinaria sp, Sargassum sp, Padina sp, Caulerpa sp and rarely Cymodocea sp.

Halimeda sp and a few other encrusting calcareous algae are commonly seen.

A total of 61 species of algae has been collected. They are distributed

among the three major groups - green algae (14 genera and 28 species), brown

algae (8 genera and 13 species) and red algae (17 genera and 20 species). The

frequency occurrence of different species in the quadrate samples show that

Halimeda opuntia is the dominant algal member of the reef. Species of Caulerpa and

Sargassum are the other most common plants found in the reef. The physical

conditions such as the nature of the substratum and water level above the

substratum influence the distribution of flora in the coral reef area (Umamaheswara

Rao, 1989). Boring sponges is the major group among the marine organisms

causing considerable destruction to the reef system. The bores made by the

sponges weaken the entire reef, making it more susceptible to the wear and tear

caused by the waves. There are altogether 20 known species of boring sponges

from the Gulf of Mannar and Palk Bay, falling into nine genera. The most

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conspicuous genus is Cliona, both in number of species and in distribution (Thomas,

1969). Among the coral boring organisms, bivalve molluscs cause considerable

destruction to coral reefs. They act as biological agents in the erosion of hard coral

stones. In Palk bay and Gulf of Mannar, only 17 boring bivalve species have been

recorded from this area (under 10 genera of six families) (Appukuttan, 1969). Asir

Ramesh (1996) recorded a total of 73 species of molluscs associated with corals in

Palk Bay viz., 46 species of gastropods belonging to 17 families, and 27 species of

bivalves belonging to 13 families.

The dried sea horse (Hippocampus kunda) is in great demand in south-east

Asian countries, especially in Singapore and China - not only for extraction of soup

which is a delicacy but also for its medicinal values. Along the Ramnad coast, the

dried sea horse is used as a medicine to arrest whooping cough in children. The

dried sea horse is finely powdered and then roasted. This powder is mixed with

honey and administered as a engulfing medicine. In some places the powder is

mixed with coconut oil and pasted on the cut wounds. It is also used for curing

asthma (Marichamy et al., 1993).

Dugongs are long living animals with a low reproductive rate. They have a

long gestation period and a large gap between each off spring. Around 25 dugongs

were caught accidentally in this region during 1960. In Palk Bay Karangadu,

Nambuthaalai, Morepanai and Mullimunai are minor fishing villages. Valivalai (drift

net) shore seins and Thirukkaivalai are used to capture dugong in the shallow

regions. Explosives (Country bombs and dynamites) are used for capturing the

dugong in Thiruppalaikudi and Devipatnam (Ramnad District). During the 1960's the

fisherman of Palk Bay region bitterly complained about the disappearance of large

beds of algae owing to the cyclone in 1964, and turtles and dugongs almost

disappeared in this area. Fishermen, now report that the algal beds have sprung up

once again (Silas and Fernando, 1985).

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3.4.8 Present Status of Palk Bay

Nearshore areas of Palk bay are polluted because of increased coastal

urban development. Sewage outlets are increasing the suspended load, turbidity,

nutrient etc. The coral reefs are under stress wherever processing industries let out

their sewage. The indiscriminate cutting of near shore forest, leads to coastal soil

erosion with huge quantities of nutrients that aggravate the physical stress on the

coral reef.

The Palk Bay lagoon has a width of around 230 m. from the shore. The

lagoon contains a large number of boulders, occupied by various species of

scleractinian corals. Table reef are also found in the lagoons. These newly found

boulders and table reef are formed by a process of wind drift. The green algae

population is greater in areas close to the sewage outlets of processing industries

than in healthy reef systems. Perna virdis, a rare component of the coral reef

ecosystem, is densely distributed in Palk Bay. Six scleractinian coral species are

recorded from the lagoon of Vellaperukkumanthai reef whereas Gopinadha Pillai has

identified two species (Porities somaliensis and Favia pallida) from the lagoon.

Fishermen suggest that the sponge population and soft coral population have

decreased over the past two decades. Our investigations also confirm an increase in

the boring sponge species and a decrease in the macrosponge species.

The shoreward slope of the reef has a width of 70 m in the area between

230 m and 300 m from the shore. The coral population has been increasing

remarkably in distribution and diversity along the shoreward slope. The 1969 record

of Gopinadha Pillai shows 11 species in this area, however, present investigation

shows 20 coral species with a density of 50 colonies/10m2. Padina sp and Halimeda

sp are most common algae present in this zone. The sponge population is

comparatively higher than in the lagoon. The coral species Platygyra lamellina,

Hydnophora sp, Galaxea fascicularis and Turbinaria pelata recorded by Pillai (1969)

are no longer present in Palk Bay.

Gopinadha Pillai recorded all the ramose corals in the seaward slope of the

reef. However, our present investigation shows that ramose corals are also

distributed along the shoreward slope and lagoon. The present study indicates that

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10 scleractinian species are present in the seaward slope, whereas the previous

record (Gopinadha Pillai, 1969) shows only 6 species.

3.4.9 Wildlife Sanctuary Adjoining Palk Strait

Situated at the southern end of Nagappattnam district, Tamil Nadu the Point

Calimere region was first identified as an area of high conservation significance,

birds by the late Dr.Salim Ali in 1962. The sanctuary may be divided into three

divisions: the Point Calimere Forest; the GVS, which includes the mangrove forests

at Muthupet and the mangroves of TRF. It is the breeding ground or nursery for

many species of marine fishes, which are vital to the fisheries of the coast.

It is a marine - coastal wetland with a wide diversity of habitats and

ecological features, including: intertidal salt marshes, forested wetlands, mangroves

and brackish to saline lagoons. The sanctuary has been designated as a Ramsar

Site in November 2002.

– The GVS is one of the largest waterbodies and major wintering

ground for waterbirds in southern India. The forests of Point

Calimere are also rich in both resident and migratory species of

forest birds. A total of 257 species of birds have been recorded

from the Sanctuary of which 119 are waterbirds and 138

forestbirds.

– The wetland supports the vulnerable species spoonbill sandpiper

Eurynorhynchus pygmaeus and grey pelican Pelecanus

philippensis according to the IUCN Red List.

– It supports about 30,000 flamingos, 200-300 endangered grey

pelican the endangered Asian dowitcher the rare spoonbill

sandpiper and tens of thousands of other waterbirds. A total of

119 waterbird species have been recorded from the area.

– The wetland is the breeding ground or nursery for many species

of marine fishes which are vital to the fisheries of the coast. GVS

is the spawning and/or nursing ground for commercially important

prawns, crabs and fishes. Eastern part of the GVS harbours 23

fish species, mainly mullets, whereas the Mullipalam Lagoon at

Muthupet has a more direct influence of the sea and harbours

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more marine species of fish, some 20 species.

Biodiversity Values

Flora

Due to the diversity of habitats, the vegetation of the Point Calimere Wildlife

Sanctuary is equally diverse, ranging from dry evergreen forests, mangrove

vegetation, salt marsh to grasslands.

The dominant trees of the forest are Manilkara hexandra and Salvadora

persica in the open areas. Insectivorous plants such as Drosera burmanii and

D.indica are also present in the grassland habitat. Dominated by Halophytes such as

Arthrocnemum indicum, Salicornia brachiata and Sessuvium portulacastrum are

common along the marshy areas of the shore. Patches of Prosopis chilensis,

Calotropis gigantea, Clerodendrum inerme and Pandanus tectorius occur in elevated

areas. Ipomoea pes- capre, Spinifex littoreus and Zoysia matrella are common on

the sand dunes. Avicennia marina is the dominant mangrove species in the area. At

Talaignayar, the vegetation is charateristic salt - marsh vegetation. During the

monsoon, aquatics such as Aponogeton natans, Bergia capensis, Najas graminea

and Sphenoclea zeylanica occur. Pentatropis microphylla is a common twiner on

many plants.

Fauna

Some of the major waterbird species are the greater flamingo and the lesser

flamingo, spot - billed pelican, spoonbilled sandpiper, Asian dowitcher, whitebellied

seaeagle, brahminy kite and osprey. Landbirds include paradise flycatcher, Indian

pitta, Rosy starling, Blyth reed warbler, crested serpent eagle and brown shrike.

Fourteen species of mammals have been reported from the Sanctuary. The larger

mammals are the blackbuck, spotted deer, wild boar and jackal. The flying fox

resides in large groups on trees in the Point Calimere forest and the mangrove forest

at Muthupet. The blackbuck of Point Calimere represents one of the three isolated

populations of blackbuck existing in Tamil Nadu with the other populations in the

Guindy National Park and near Satyamangalam.

Social & Cultral Values

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It provides for local income and employment specially in areas of salt

production, forest produce, firewood and fish products. About 35,000 fishermen and

agriculturists live around the sanctuary.

Threats

– Threats to the sanctuary mainly comes from illegal extraction of

timber and non timber produce.

– There is danger from industrial pollution and poaching.

– Domestic and industrial saltworks operating in GVS also pose a

serious problem.

Conservation Measures

To conserve the blackbuck and other wild animals, an innovative freshwater

source has been created. In the watchtowers, overhead tanks have been

constructed, to supply water during the drought period and underground pipeline is

laid up to 3 kms. to connect the overhead tank for the supply of water. The water

source is from the bore - well equipped with motor. In 1988 a proposal was sent to

the Tamil Nadu Government to extend the area of the Sanctuary to include the Great

Vedaranyam Swamp and the Talaignayar Reserve Forest and rename the sanctuary

as the Point Calimere Wildlife and Bird Sanctuary. The promulgation of this new

sanctuary is still in process.

3.5 Gulf of Mannar

The Gulf of Mannar reefs on the other hand are developed around a chain

of 21 islands that lie along the 140 km stretch between Tuticorin and Rameswaram.

These islands are located between latitude 8O47’ N and 9O15’N and longitude

78O12’E and 79O14’ E. The islands lie at an average of about

8 km from the main land. They are a part of the Mannar Barrier reef, which is about

140 km long and 25 km wide between Pamban and Tuticorin. Different types of reef

forms such as shore, platform, patch and fringing type are also observed in the Gulf

of Mannar. The islands have fringing coral reefs and patch reefs around them.

Narrow fringing reefs are located mostly at a distance of

50 to 100 m from the islands. On the other hand, patch reefs rise from depths of

2 to 9 m and extend to 1 to 2 km in length with width as much as 50 meters. Reef flat

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is extensive in almost all the reefs in the Gulf of Mannar. Reef vegetation is richly

distributed on these reefs. The total area occupied by reef and its associated

features is 94.3 sq. km. Reef flat and reef vegetation including algae occupies 64.9

and 13.7 sq. km, respectively. (DOD & SAC, 1997). Visibility is affected by

monsoons, coral mining and high sedimentation load. These reefs are more luxuriant

and richer than the reefs of Palk Bay.

Pillai (1986) provides a comprehensive account of the coral fauna of this

region. There are about 96 species of corals belonging to 36 genera in the Gulf of

Mannar. The most commonly occurring genera of corals are Acropora, Montipora

and Porites. Coral associates such as ornamental fishes belonging to the family

Chaetodontidae, (butterfly fish); Amphiprion sp. (clown fish), Holocentrus sp.

(squirrelfish), Scarus sp. (parrotfish), Lutjanus sp. (snapper fish) and Abudefdul

saxatilis (sergeant Major) are found. Extensive sea grass beds are present; green

turtles, olive ridley turtles and dugongs are dependent on the sea grasses.

The mainland coast of India has the Gulf of Kutch in the Northwest (Gujarat

State) and Palk Bay and the Gulf of Mannar in the southeast (Tamil Nadu State).

Other than these important off shore island groups of India, the Andaman and

Nicobar in the Bay of Bengal and Lakshadweep in the Arabian Sea also have

extensive reef growth. The total area of coral reefs in India is estimated to be 2,374.9

sq. km.

3.6 Issues Related to Coral Reefs

Reef’s resources have traditionally been a major source of food for local

inhabitants and of major economic value in terms of commercial exploitation. Reefs

in India provide economic security to the communities that live alongside them.

There are millions of poor fishers in India whose livelihood depends on coral reefs.

Coral reefs provide up to 25 percent of all the fisheries harvested and 75 percent of

animal protein consumed. Thus, the aspect of coral reefs is significant to the

livelihood and social welfare of communities.

The terms “stress” and “disturbance” have been applied to coral reefs and

many other biological communities, with a variety of interpretations. Stress is a

physiological condition which results from adverse or excessive environmental

factors and in corals this can be measured by decreased growth rates, metabolic

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differences and biochemical changes. Disturbance is an ecological phenomenon,

which includes departure from a routine set of conditions.

There are varying levels of degradation which can be observed on coral

reefs, from the extreme and obvious (mortality) to more sublime changes in

characteristics including competitive dominance among organisms, decreased

growth rates, breakdown of organisms association, reduced fecundity, reproductive

failure and declining recruitment of larvae. Essentially, whether a coral reef is killed

in a week, due to sediment burial, or over a ten-year period, due to attrition and lack

of recruitment, the result is the same. The loss of the coral reef community results in

the loss of all the benefits that it offers.

Recent reports indicate that coral reefs are under considerable stress and

are experiencing considerable damage. Coral reefs have been resilient ecosystems

since the Mesozoic (about 200 million years ago), surviving major environmental

events such as ice ages, meteor strikes and large changes in solar activity. Not

withstanding these events, coral reefs have recovered to form the extensive reefs we

see today, although recovery may have taken thousands to hundreds – of thousands

of years. Coral reefs also have the capacity to regenerate rapidly after catastrophic

tropical storms, plagues of the coral-eating Crown-of-thorn starfish, and severe

bleaching. Recovery often takes 15 to 20 years. However, over the past 50 years,

there has been major increase in stresses on coral reefs from direct and indirect

human activities. These stresses are threatening the existence of reefs in some

areas, and will diminish the extent of reefs in other areas.

3.6.1 Natural Stresses to Coral Reefs

The major stresses on reefs are storms and waves, particularly tropical

storms and cyclones. These cause major intermittent damage to reefs, particularly to

those reefs that rarely experience these storms. Cyclone disturbances develop during

certain months (October-November) along the Indian Seacoast and elsewhere in the

tropical region.

These cyclones have sustained winds with speed ranging from 65 to 120 km

per hour. High-speed winds cause extreme wave action that break coral into rubbles

and sometimes large amounts of sand and other materials may be dumped onto the

coral reef. Due to 1969 cyclone a large area of coral was buried under the sand in

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Rameswaram area of Gulf of Mannar. Likewise the cyclone of December 1987 in Bay

of Bengal devastated the coral reefs of the Mahatma Gandhi Marine National Park of

Port Blair, Andaman, that resulted in large quantities of broken coral colonies getting

heaped and scattered near the shore.

Freshwater runoff damages reefs in semi-enclosed bays and lagoons (a

channel near the Mahatma Gandhi Marine National Park entrance) by lowering salinity

and depositing large amounts of sediments and nutrients. Reefs are also damaged by

volcanic activity (earthquakes, volcanic lava flows, severe uplifting) in the Andaman

Islands, for example in Barren Island. The major biological stress on reefs is predation

by Crown-of-Thorns starfish and coral diseases have been particularly devastating in

Andaman & Nicobar reefs (Mahatma Gandhi Marine National Park, 1989) and

Lakshadweep respectively. There is now considerable speculation that the incidence

of both these stresses has been exacerbated by human activities.

3.6.2 Impacts of Human Activity on Coral Reefs

Varied man’s activities which are, a cause for concern includes runoff and

sedimentation from development activities (projects), eutrophication from sewage and

agriculture, physical impact from maritime activities, dredging, collecting and

destructive fishing practices, pollution from industrial sources, golf courses and oil

refineries and the synergistic impacts of anthropogenic disturbance on top of natural

disturbance.

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3.6.2.1 Sedimentation

Sedimentation, which is the most well studied impact, may affect corals

three different ways: photosynthetically, physically and chemically. As most reef-

building corals obtain the majority of their nutritional requirements through

translocation of metabolites from their photosynthetic partners (Zooxanthellae), any

reduction in the availability of light will affect coral nutrition, growth, reproduction and

depth distribution.

Physically, sediments also interfere with coral nutrition by coating the

feeding surfaces responsible for catching prey items needed to supplement the

energy provided by zooxanthellae. While corals do have the ability to cleanse

themselves using a combination of mucus secretion and ciliary action, chronic

sedimentation may end up in a high energetic cost, adding to the overall impact on

the colony. Sedimentation can alter species composition of reefs through

photosynthetic and physical effects. Change in relative abundance of morphological

types as well as individual species are an important reflection of how sedimentation

as a disturbance affects community structure. The standing examples are the coral

reefs of Gulf of Mannar islands and the reefs of Little Andaman. So far, the presence

of sediment load in the coral reef areas has been confirmed in Gulf of Mannar and

Andaman & Nicobar islands, however, quantitatively they are not reported.

Venkataraman and Rajan (1994) reported the amount of silt carried by the rainwater

from Port Blair City into the sea. Only few studies have been focussed on the effect

of sedimentation and siltation on the damages the reef quantitatively.

Sedimentation can also physically interfere with recruitment of coral larvae,

which require a solid substratum upon which to settle and metamorphose. Dredging

projects have been particularly damaging to reefs, (Sethu Samudram project, Gulf of

Mannar region) primarily through the initial physical disturbance, habitat alteration

and the subsequent problems associated with sedimentation. Sand mining in

Andaman Islands and coral quarrying in Gulf of Mannar (Tuticorin group of Islands)

cause a lot of sedimentation and siltation on coral reefs.

Very few studies have focussed on the chemical effects of sediment on

corals that can be important. Dumping of fly ash near Pandian island at Tuticorin

may contain a variety of heavy metals particularly detrimental to coral reefs.

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3.6.2.2 Runoff/Chemical Pollution/ Water Quality

A general rule for coastal zone: whatever is used on land today ends up in

the aquifer or coastal zone tomorrow. Salinity changes alone have proven to affect

corals, especially on shallow water reef flats which are most likely to be affected by

freshwater runoff. The amount of sediments and chemicals the runoff water carries

to the sea has profound effects on fertilization of eggs of coral species. Likewise, the

quality of runoff water can affect the metamorphosis of the larvae of corals. Many

experiments have demonstrated that the actual coastal surface water quality above

reefs during coral spawning events has sufficiently reduced reproductive failure.

Many areas in Andaman & Nicobar islands and Gulf of Mannar area have large

quantities of sediment laden freshwater runoff impinged on coastal reefs, causing

high levels of coral mortality, rapid growth of fleshy algae species, and large areas of

reduced salinity/quality seawater. Local fishermen of Gulf of Mannar have

complained of decreased fisheries and reef vitality not only on these coastal reefs,

but also on off shore islands and reefs not directly affected by contact with the

sediment. Inspection of these reefs revealed (Zoological Survey of India, Chennai)

live adult coral colonies, but no signs of larval recruits with increased levels of

sedimentation.

Oil pollution is an extreme example of how chemicals, in this case

hydrocarbons, can affect reefs. Research performed in many areas have

documented coral mortality, decreased fecundity and recruitment failure in response

to chronic oil pollution.

Industrial waste discharged in to the sea near Tuticorin islands, Chattam

Sawmill wastes in Port Blair are the standing examples of how pollution deteriorates

the reef ecosystem. All the near shore reefs and island reefs of Tuticorin, Gulf of

Mannar and Port Blair area, Andaman & Nicobar area have become barren rocks.

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3.6.2.3 Sewage

The overall impact of sewage on a coral reef community depends on

sewage, level of treatment, presence of toxic materials and receiving water

characteristics. The effects of sewage-related nutrient enrichment on coral reef

communities have been documented and include alteration of competitive

interactions, reduction of coral calcification rates from decreased light levels and

increased phosphate concentrations and increased mortality from bacterial infection.

Corals are adapted to live in nutrient poor environments and are relatively slow

growing compared to algae, sponges, tunicates and other groups of sessile benthic

organisms. Nutrients not only increase the bio-mass of phytoplankton, affecting light

transmission and increasing the biological oxygen demand (B.O.D.) which may have

some impact on the corals but also give a competitive advantage to faster growing

benthic species. The green algae has formed large mats, covering and killing corals

in Keelakarai coast coral reefs in Gulf of Mannar due to sewage pollution from the

town. The nutrient enrichment via sewage reduces the photosynthetic efficiency of

corals, as alga cells increase in density to the point of becoming self-shading. Since

the coral zooxanthellae symbiosis evolved under nutrient limited conditions, it is

reasonable to assume that the relationship will become altered in response to

changes in the level of nutrients available. Further studies of the physiological effects

of such changes are needed to determine the sub lethal or long-term effects of

sewage and nutrient enrichment on coral reefs of Gulf of Mannar Islands and

Andaman & Nicobar.

While the effects of suspended solids from sewer out falls have been

compared to those from terrigenous runoff and sedimentation, the two types of

sediment differ in physical, chemical and toxicological characteristics, which must be

considered when assessing impacts. Sewage suspended solids primarily organic,

can contain absorbed toxins, and increase B.O.D more than inorganic sediment

associated with runoff. The toxic component of sewage depends on the sources of

input and is primarily a concern in industrial or agricultural areas where industrial

wastes and pesticides are included in the effluent.

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3.6.2.4 Temperature Stress and Bleaching

The negative impacts of increased temperature on corals have been

documented from both anthropogenic and natural sources. There are many

documented evidences for coral mortality associated with the hot water discharge

from a cooling system for a power plant and wide spread mortality with increased

temperatures accompanying the El Nino event. In both cases, the cause of mortality

appeared to be the breakdown of the symbiotic association between the

zooxanthellae and the coral host (bleaching).

There has been unprecedented bleaching of hard and soft corals throughout

the coral reefs of the world from mid-1997 to late-1998. Much of the bleaching

coincided with a large El Nino event followed by a strong La Nina but bleaching in all

the coral reefs is uncorrelated. During this event bleaching and mortality were most

pronounced in shallow water (less than 15 m) and particularly affected staghorn and

plate Acropora and other fast growing corals. Many of the massive, slow-growing

species bleached, but many recovered within one or two months. This bleaching

event has resulted in poor coral cover (recent study by Zoological Survey of India,

Chennai) and possibly fewer new coral recruits on many reefs in India for the next 10

years until recovery gains speed. In the short term, this will affect adversely the

economics of India, particularly fisheries. There will be a shift in the composition of

coral communities; some will have greater dominance of slow growing massive

corals, whereas other reefs will lose century-old colonies. Nevertheless, such shifts

have occurred in the past and are part of the normal variability of many coral reefs. If

however, the recent bleaching event is linked to global climate change, and will be

repeated regularly in the immediate future, the consequences would be serious for

many coral reefs if sea temperatures show a continuing upward trend.

The relationship between bleaching events and ozone depletion/global

warming is presently being studied by several groups of researchers. If the

connection can be proven, it will be an example of global rather than local

anthropogenic impacts on coral reefs.

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3.6.2.5 Coral diseases

Four types of coral diseases have been identified : white band disease, black

band disease, bacterial infection, and shutdown reaction. While there is a degree of

uncertainty over the causes responsible for each disease, they all appear to be stress-

related. Synergism is believed to play an important role, as stressed coral seems to be

the most susceptible for the above diseases. Sediment, sewage, pesticides, heavy

metals, bleaching and other human impacts have stressed tumors, bacterial attack

and parasitic worms. White Band disease has been reported from Andaman and

Nicobar and Lakshadweep islands. In addition, a new disease called Pink Line

disease is also reported from Lakshadweep.

3.6.2.6 Destructive fishing practices

The use of destructive fishing practices has been responsible for the

destruction of coral reefs throughout the world. Destructive fishing practices have

seriously damaged many of the Gulf of Mannar’s richest and most diverse coral reefs,

necessitating an urgent warning that immediate and far-reaching action is needed.

The Gulf of Mannar stands out as one of the hardest hit areas, with 60% of its reef in

varying stages of deterioration. Because of the large size of the areas concerned (Gulf

of Mannar and Andaman & Nicobar Islands or other areas in India), and the lack of

general resources for enforcement, education appear to be more successful than

legislation in controlling these practices. Poverty reduces the alternatives for fishermen

who must feed their families and rely on fishing as a source of protein and income.

This same problem has lead to another anthropogenic disturbance on reefs : over

fishing. The use of fish traps made of long-lasting materials with small mesh sizes

results in the capture of pre-reproductive juveniles, affecting future populations and the

death of fish when traps become dislodged during storms, yet continue to capture fish

which eventually starve. Several types of net fishing have also been responsible for

over-exploitation of reef. As with all biological communities in a coral reef, each

species plays an important role in the dynamics of balance. The depletion of grazers,

for example, may eventually lead to an overgrowth of alga as in the case Gulf of

Mannar reefs.

Blast Fishing

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Although it is now illegal, blast fishing has been a widespread and accepted

fishing technique in some of the developing countries. Schooling reef fishes are

located visually, after which the capture boat moves within close range and a lighted

bomb is thrown into the middle of the school. After the bomb is exploded, fishermen

enter the water to collect the fish that have been killed or stunned by the resulting

shock wave. Due to blasting, branching, tabulate and foliose hard corals are shattered

while massive and columnar corals are often fractured. Although this effect of blasting

is quite localized, reefs subject to repeated blasting are often to little more than shifting

rubble fields, punctured by the occasional massive coral head. In addition to damaging

the reef framework, blast fishing results in side-kills of non-target and juvenile fishes

and invertebrates.

Trap Fishing- (Koodu)

The use of bamboo mesh traps, locally known as koodu, is wide spread

throughout Gulf of Mannar islands reef fisheries. In Ramanathapuram alone 3312

(37% of the total trap in the Tamil Nadu State) traps are found. Although this gear is

not intrinsically destructive, the process of setting and retrieving the trap is largely

responsible for the destruction wrought on the reef. These traps set by simply lowering

the trap from boat-side via a buoyed rope are responsible for the most reef damage.

The traps are often heavily weighted with wooden runners or stones and can destroy

entire stands of branching and foliose corals on the reef during their installation and

especially removal (by pulling on the rope). If the current trend continues, Koodu trap

activities will become an increasingly important cause of reef damage in Gulf of

Mannar.

Ola valai and Shore Seine

Ola valai is a type of drive-in net fishing technique where by a line of

fishermen in the water use scare-lines, lines with palm leaves tied off at regular

intervals to drive fish down a bag net. The scare lines are rhythmically lifted and

dropped into the shore areas, often breaking live corals while the fish are driven

ahead. Next to this the shore seines form the major gear of Gulf of Mannar. There are

about 1523 numbers of shore seines found in Ramanathapuram district alone, forming

about 33% of the total shore seines in the state. Although this gear is not intrinsically

destructive, the process of shore seines is largely responsible for the destruction of

new colonies emerging near lagoon.

Page 166: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

While it is simple to prove how damaging destructive fishing practices are to

the productivity of fisheries, the economic realities of day-to-day life on Gulf of

Mannar and Andaman & Nicobar islands makes the solution difficult to obtain.

3.7 Impacts in Palk Bay and Gulf of Mannar

There are about 47 fishing villages along the coast of which 38 are in the

Ramanathapuram district and nine in V.O. Chidambaranar district bordering the Gulf

of Mannar Park area. Exploitation of fishery resources in the inshore waters has been

the sole occupation of hundreds of fishing families along the coast for centuries. The

reefs are used to carry out reef fishery, chanks and pearl fishery, ornamental shell

trade and illegal mining of corals. The villagers around Palk Bay harvest holothurians,

seahorse and pipe fishes. Other harvesting activities include chanks and milk fish fry.

Turtles are being harvested up to 1000 annually; dugongs are also poached.

The destruction of reefs and reef associated organisms in the Gulf of Mannar

and Palk Bay is perhaps unparalleled in the history of environmental damage to nature

and natural resources in the recent past (Pillai, 1996). The coral reefs on Palk Bay and

Gulf of Mannar were quarried for industrial purposes from early sixties from

Mandapam to Tuticorin. The estimate of coral quarried varies. At Tuticorin the

estimate was 80,000 t per year. Pillai (1973) estimated the exploitation of corals from

Mandapam area during sixties and early seventies to the tune of 250 m3 per day. It is

found that some of the islands (Vilanguchalli in Tuticorin group and Poovarasanpatti

Island in Keelakari group) are totally submerged and vanished because of quarrying. A

recent survey in Palk Bay and Gulf of Mannar has revealed that damage to reef due to

human interference is still rampant. The huge colonies of corals that occupied large

areas in the lagoons of many islands are no more there due to over exploitation of

algae and shells by fishermen in an extensive scale. Fishermen during collection of

algae to negotiate their boats brake most of the corals. The live export of crabs and

lobsters from this area in the recent years is also causing damage to live corals. Fish

traps (Koodu) to collect live crabs are causing a lot of destruction to coral reefs in

these areas. Other than these disturbances, siltation, agricultural run off, sewage

discharge as well as the fecal pollution are the major problems in these areas.

3.8 Conservation

Page 167: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

The Federal Government Coastal Regulation Zone Notification 1991

regulates onshore development activities, which affect coastal environments, and

strictly prohibits the collection and trade of corals. Wildlife Protection Act, 1972

provides protection for protected areas and certain marine species. Efforts continue

to bring corals under this act and to encourage enforcement that is more stringent.

Coral reef conservation is also included in the Environmental Protection Act (1986),

the National Conservation Strategy and Policy Statement on Environmental

Development (1992) and the Action Plan of the Ministry of Environment and Forests.

The conservation and management of coral reef resources is within the mandate of

the Ministry of Environment and Forests, the focal point for the Indian Coral Reef

Monitoring Network and the National focal point of ICRI.

India has 6 marine protected areas; the largest is the Gulf of Mannar

Biosphere Reserve (GOMMBRE), which encompasses 10,500 sq km. Coral Reef

Monitoring Action Plans (CRMAPs), prepared under the first phase of the GCRMN,

have been launched within the framework of the ICRMN for all reef areas except the

Gulf of Kutch. Government support has been extended for the implementation of the

CRMAPs and to build capacity to monitor reefs through training. However, activities

are still at a beginning and overall the capacity for monitoring and management is

lacking. Other significant international initiatives on the Indian coral reefs underway

and under development include. UNDP/GEF DPFB projects on the Gulf of Mannar

and Andaman and Nicobar Islands.

Page 168: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

3.9 Future Direction

Coral reefs in India are under increasing pressure. In many cases, the

sources of stress due to human pressure are known. However, the etiology of a

growing number of diseases and pathologies now being reported in corals is not

widely understood, highlighting the need for more search to unravel the complex

interactive effects between natural and anthropogenic forms of stress and their effects

on coral reefs. The inability of scientists to predict with any certainty where the critical

thresholds of resilience to stress lie along the continuum of human-induced and

natural disturbances, make it inherently difficult to manage reefs sustainably. Solutions

to these conservation and management problems will need to incorporate effective

science, robust economic analysis and sound policies and laws. Participatory actions

grounded in the cultural and social reality of local people who depend on and benefit

directly from coral reefs must be part of the solution. Creating political will, through

communication and environmental education, will be essential in mobilising and

sustaining conservation efforts.

Studies such as qualitative and quantitative estimation of biodiversity,

percentage cover of live and dead coral estimation by standard methods, estimation of

standing crops of reef resources, their recruitment, growth, mortality, standing stock,

and level of exploitation are necessary to suggest norms for judicious exploitation.

These aspects need intense and long-term study in India. In general, the percentage

cover of live coral estimation is not the only criteria for the health of reefs but also the

ratio of dead and live coverage.

Presence or absence of indicator species may be an index of environmental

stress or pressure on reefs. The taxonomically extended surveys of sessile

organisms such as sponges, alcyonarians and polychaetes can give clue to the state

of art environmental conditions. Assessment of heterotrophic macroinvertebrates

such as sponges, barnacles, hydroides, tunicates, echinoderms etc. may yield clue

to stress conditions due to pollution. Such studies are very important for

management of coral reefs.

Page 169: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

3.10 Strategies for Coral Reef Ecosystems in India

3.10.1 Analyzing the Short Comings in Coral Reef Conservation in India

Recommendations

• Understand the problems facing coral reefs by assembling information from

within India and nearby countries.

• Determine the true economic value of reefs so that rational decisions can be

made on the cost of management.

• Transfer that understanding via education to the principal users, the public

and decision makers.

• Focus management around the user to ensure compliance with and

assistance in resource management.

• Incorporate reefs into marine protected areas to buffer the reefs against

outside damaging influences.

• Control damaging practices and monitor the effectiveness of control.

• Promote sustainable uses to realise the full economic potential of healthy

reefs.

• Monitor the effectiveness of management so that procedures can be

adjusted to ensure long-term sustainability.

3.10.2 Understand The Coral Reef Problems

Recommendations

The coral reef areas in India should be determined using satellite and aerial

images with ground truthing. Assistance may be needed from large agencies such as

the National Aeronautics and Space Application Centre.

• These data should be used to find out the status of the coral reefs and how

they are changing.

• National programmes to monitor the status of coral reefs should be

implemented.

Page 170: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

• The knowledge base of scientists, tourists operators, SCUBA divers and

local users should be combined to determine the status of reefs and how

they have changed during living memory.

• Central and State Government may convene national and local committees

including user groups, local government authorities, tourism developers,

scientists and Non governmental organizations (NGOs) to advise on

sustainable management of coral reefs.

3.10.3 Determine the True Economic Value of Coral Reefs in India

Recommendations

• Direct ‘extractive’ values like fisheries, aquarium fish and other animals,

ornamental products and sand production.

• Potential ‘extractive’ values like pharmaceutical drugs and species

developed for future Mariculture activities.

• Direct ‘non-extractive’ uses such as tourism and educational and research

values.

• ‘Indirect use ‘ values such as the commercial species that migrate to other

areas the physical barrier, role in protecting the shoreline, the value in

extending exclusive economic zone.

• As well as the less tangible ‘non use and aesthetic ‘ values of high

biodiversity habitats for endangered species and roles as part of the global

environment.

• Determination of coral reef fisheries, how these are being exploited (catch

per unit effort) and the dependence by local fishermen on reef fisheries.

• Determination of other values of coral reefs and potential economic losses if

these values are foregone through reef degradation.

• Assessment of the current and potential future income from coral reef

tourism and the contribution of health of reefs towards attracting tourists to

India.

3.10.4 Coral Reef Conservation Education

Page 171: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Recommendations

• Information on the nature and value of coral reefs should be provided to all

users, students and public using appropriate methods. e.g. many fishermen

will not read written material whereas videos and talking are effective.

• Summaries of the status of coral reef resources and sustainable

management methods should be prepared for decision makers and

development agencies, donors and banks.

3.10.5 Focus Management of Coral Reef around the Stakeholder

Recommendations

• National and state governments of India should devolve sufficient

responsibility for the management of coastal resources to local authorities at

the village level.

• Legislation for coastal reef resource management should include the

involvement of the users especially fishermen.

• Developers especially those involved in tourism should consult directly with

local users on resource management and then employ local people to

compensate for restrictions on resource use.

3.10.6 Incorporate More Coral Reefs in Marine Protected Areas

Recommendations

• Large areas of relatively undamaged marine habitat including good coral

reefs should be designated as marine protected areas and management

plans developed to involve all users.

• Assistance for training, planning and management of MPAs should be

requested from international donors, particularly to staff, local authorities

with education officer and MPA Range officers.

• Tourism operators should be involved in the management of MPA and be

prepared to fund some of the management.

3.10.7 Control Managing Practices

Recommendations

Pollution

Page 172: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

• Emphasize the treatment of sewage at the source or divert them away from

coral reef onto the land or as deep ocean outfalls.

• New domestic and industrial development should be ‘encouraged’ to treat

sewage as it is cheaper to install sewerage lines and systems during

construction.

• Tourism developments near coral reefs should have full secondary or

tertiary treatment and adequate methods for removing garbage.

• Guidelines should be provided to governments, villagers and developers on

the range of appropriate methods for treating sewage at all scales.

Sedimentation

• Government should request developers and farmers to minimize the amount

of sediment that is lost into rivers and the ocean.

Overfishing

• Fishermen should be discouraged from using destructive methods

(dynamite, cyanide, bleach, poisons) through education, local cooperative

discussion and where possible be provided with other employment.

• Anchor damage should be minimized either by encouraging anchoring on

sandy areas, or with better designed anchors, or through the installation of

permanent mooring buoys for tourist operators in Lakshadweep and

Andaman and Nicobar Islands.

• Remote reefs require special protection through international treaties to

control damaging practices that destroy parent fish stocks and poaching.

Page 173: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

3.10.8 Promote Sustainable Uses

Recommendations

• Selective sustainable fishing and harvesting in all the coral reef areas in

India.

• Controlled harvesting or aquarium fish in all the coral reef areas of India.

• Mariculture of reef species for stock enhancement.

• Limited fish cage culture and rack culture of pearl shell edible oyster and

algae.

• Removal of the excess production of sand in coral reef areas especially

Andaman and Nicobar Islands.

• Snorkeling and scuba diving and other tourism activities.

• Advice on sustainable methods of establishing tourism ventures should be

given to developers, which may require government interventions to ensure

that environment departments and universities are involved.

• Reef users require information on sustainable harvesting practices and

assistance to develop markets for those products.

3.10.9 Monitor the Effectiveness of Coral Reef Management in India

Recommendations

• A committee of experts by the National Coral Reef Committee should

monitor all MPAs and other managed areas in India for the effectiveness of

management particularly to assess whether the health of reefs is stable.

• Inventories of all the coral fauna present in the region and the status of the

coral reefs and the associated fauna are to be monitored on a long-term

basis.

− Increase the capacity of scientists to undertake studies on corals such

as coral taxonomy, biophysical monitoring and database.

− Reduce the risk for coral reef such as destructive fishing practices,

siltation, industrial and domestic sewage and over fishing.

Page 174: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

− Developmental projects detrimental to coral reef should be implemented

with caution.

− Alternative employment to coastal fishermen should be provided to

reduce the pressure on the coral reef where the coastal population is

depending on the coral reef.

− Increase the awareness among the local public and made as curriculum

in the schools about the importance of coral reefs.

− Protected areas should be managed properly with modern technology

with the lessons learnt elsewhere.

− Need for central policy decisions to recognise the essential uniqueness

of each of the coral reef areas when creating policy.

− Strengthen the network of coral reef information providers within India

and develop the role of the ICRMN to act as the body to provide

coordination and coherence for policy and programmes relating to coral

reef resources, to provide better integration between government

departments, institutions and local groups and to support the

implementation of Management Action Plans;

− Provide training and awareness raising at all levels to better appreciate

the concepts of conservation and sustainable use of coral reef

resources.

− Artificial reefs should be allowed with more caution and only with EIA

studies.

− More funds to be provided for intensive coral reef research in India

− Collaboration with International agencies on coral reefs should be

encouraged for coral reef conservation.

− NGO’s to be encouraged to educate the coastal population about the

importance of coral reefs in India and their uses.

Page 175: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

− Networking of all the stakeholders of coral reef should be made.

− Tourism in coral reef area should not be detrimental to the coral reef

ecosystem and Eco-tourism should be encouraged.

− Establish a separate coral reef research institute in India exclusively for

coral reef studies.

Page 176: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
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Fig. 3.2 : Variation in Salinity

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%

%

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Fig. 3.4 : Particle Size Distribution of Sediments (1-10 Sampling Stations)

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00.5

11.5

22.5

33.5

4

Shingle

Krusad

ai

Pulliva

sal

Poomari

chan

Manoli

putti

Manoli

Musal

Mulli

Valai

Appa

Valimun

ai

Anaipu

r

Nallath

anni

Pulivin

ichall

i

Upputh

anni

Karaich

alli

Vilang

ucha

lli

Kasuw

ar Van

Name of island

Max

imum

Div

ersi

ty In

dex

Fig. 3.6 : Maximum Diversity Index values of Phytoplankton in 21 Island of Gulf of Mannar

Page 183: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

0

0.5

1

1.5

2

2.5

3

3.5

4

Shingle

Krusad

ai

Pulliva

sal

Poomari

chan

Manoli

putti

Manoli

Musal

Mulli

Valai

Appa

Valimun

ai

Anaipu

r

Nallath

anni

Pulivin

ichall

i

Upputh

anni

Karaich

alli

Vilang

ucha

lli

Kasuw

ar Van

Name of island

Max

imum

Div

ersi

ty In

dex

Fig. 3.7 : Maximum Diversity Index values of Zooplanktons in 21 Island of Gulf of Mannar

Page 184: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

3.8

: Lo

catio

n of

Cor

als

in th

e G

ulf o

f Man

nar a

nd th

e Pa

lk B

ay

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Page 186: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

0

0.5

1

1.5

2

2.5

3

Shingle

Krusa

dai

Pullivas

al

Poomarich

an

Manolip

utti

Manoli

Musal

MulliVala

i

Talairi

Appa

Poovaras

anpatt

i

Valimunai

Anaipur

Nallath

anni

Pulivinich

alli

Upputhanni

Karaich

alli

Vilanguch

alli

Kasuwar Van

Name of island

Max

imum

div

ersi

ty In

dex

Fig. 3.10 : Maximum Diversity Index values of Corals in 21 Island of Gulf of Mannar

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1.81.9

22.12.22.32.42.52.6

Shingle

Krusad

ai

Pulliva

sal

Poomari

chan

Manoli

putti

Manoli

Musal

Mulli

Valai

Talairi

Appa

Poova

rasan

patti

Valimun

ai

Anaipu

r

Nallath

anni

Pulivin

ichall

i

Upputh

anni

Karaich

alli

Vilang

ucha

lli

Kasuw

ar Van

Name of island

Max

imum

Div

ersi

ty In

dex

Fig. 3.15 : Maximum Diversity Index values of Seagrass in 21 Island of Gulf of Mannar

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0

0.5

1

1.5

2

2.5

3

Shingle

Krusad

ai

Pulliva

sal

Poomari

chan

Manoli

putti

Manoli

Musal

Mulli

Valai

Talairi

Appa

Poova

rasan

patti

Valimun

ai

Anaipu

r

Nallath

anni

Pulivin

ichall

i

Upputh

anni

Karaich

alli

Vilang

ucha

lli

Kasuw

ar Van

Name of island

Max

imum

Div

ersi

ty In

dex

Fig. 3.16 : Maximum Diversity Index values of Mangroves in 21 Island of Gulf of Mannar

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0

0.5

1

1.5

2

2.5

3

Shingle

Krusad

ai

Pulliva

sal

Poomari

chan

Manoli

putti

Manoli

Musal

Mulli

Valai

Talairi

Appa

Poova

rasan

patti

Valimun

ai

Anaipu

r

Nallath

anni

Pulivin

ichall

i

Upputh

anni

Karaich

alli

Vilang

ucha

lli

Kasuw

ar Van

Name of island

Max

imum

Div

ersi

ty In

dex

CoralMangroveSeagrass

Fig. 3.18 : Maximum Diversity Index values of Corals, Mangroves

and Seagrass in 21 island of Gulf of Mannar

3.92

Page 195: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 3.1 : Data Locations

Page 196: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 3.3 : Variation in Salinity and Silicate

Man

Avifauna - Aquatic

Fish 441 Species

Arthropods - Crutacea 368 Species

Echin264 S

Mammals 11 Species

Avifau Bacteria and Funji Arthropods

Mollusca 721 Species

Annellids - Polychata 75 Species

CoelenteratCoral –128 Gorgonids -

3.94 3.96

Page 197: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 3.5 : Trophic Relations of Marine Ecosystem in study area of Sethu Samudram Ship Canal Project

Page 198: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 3.9 : Coral Reef and Seagrass Areas around the Islands of Gulf of Mannar

3.100

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Fig. 3.11 : Locations of Pearl Banks in the Gulf of Mannar

3.102 3.103

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Fig. 3.12 : Chank Habitats in the Gulf of Mannar and the Palk Bay

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Fig. 3.13 : Habitats of Sea Cow (Dugong-dugong) in the Gulf of Mannar and the Palk Bay

G U L F O F M A N N A R

Dugong dugong Ha

3.104

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Fig. 3.14 : Habitats of Sea Weed, Sea Grass and Holothuria in the Gulf of Mannar and the Palk Bay

3.105 3.108

Page 203: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 3.17 : Locations of Mangroves in Gulf of Mannar and the Palk Bay

Table 3.2

Physico-Chemical Quality of Marine Water

Location Palk Bay Gulf of MannarSr.

No. Parameter Sample

1 2 3 4 5 6 7

Surface 32.8 32.4 32.0 32.6 32.4 32.3 32.1 1. Temperature (oC)

Bottom 32.2 31.9 32.0 32.3 32.5 32.4 31.8

Surface 2.8 4.0 4.9 3.4 3.4 2.8 3.2 2. Turbidity (NTU)

Bottom 3.2 4.3 4.3 3.5 3.6 2.5 6.0

Surface 8.0 8.1 8.0 8.0 8.2 8.2 8.2 3. pH

Bottom 8.0 8.0 8.0 8.0 8.2 8.2 8.2

Surface 51.4 52.1 59.3 50.0 59.3 59.7 60.2 4. Conductivity

(mS/cm) Bottom 52.2 49.9 59.5 52.3 59.4 59.8 60.0

Surface 33.4 34.4 39.7 32.8 39.7 40.0 40.4 5. Salinity (o/oo)

Bottom 34.7 32.2 39.9 34.5 39.9 40.1 40.3

6. TDS (gm/L) Surface 33.2 33.4 37.9 32.0 37.9 38.2 38.5

Mangroves

3.111

Page 204: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Bottom 33.7 31.4 38.1 33.4 38.1 38.3 38.4

Surface 5.4 5.6 4.5 4.8 4.1 3.6 4.2 7. DO (mg/L)

Bottom 5.1 4.6 4.4 4.9 4.2 4.1 4.2

Page 205: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.4

Sediment Quality

Location Palk Bay Gulf of Mannar Sr.

No. Parameter 1 2 3 4 5 6 7

1. pH 7.6 7.4 8.2 8.0 7.9 7.8 8.2

2. Moisture 71.46 72.63 74.51 72.05 71.72 72.02 76.62

3. Ash 27.72 26.50 25.07 27.59 27.62 27.41 21.91

4. Volatile Solids 0.82 0.87 0.42 0.36 0.66 0.57 1.47

5. Total Organic Carbon (C) 0.4 0.4 0.2 0.2 0.2 0.1 0.13

6. Total Phosphorus (P2O5) BDL BDL 0.02 0.84 0.015 0.02 BDL

7. Total Kjeldhal Nitrogen (N) 0.14 0.13 0.08 0.05 0.06 0.05 0.09

8. Chloride (C) 1.25 1.63 2.05 3.15 3.1 4.9 4.25

9. Sulfate (SO4) 0.68 0.65 0.06 0.2 0.08 0.4 0.18

10. Sodium (Na) 2.88 3.8 0.4 0.7 1.6 0.9 1.44

11. Potassium (K) 0.66 0.72 0.04 0.07 0.06 0.07 0.08

12. Iron (Fe) 3.04 3.5 0.40 0.36 0.356 0.254 0.528

13. Manganese (Mn) 0.27 0.32 0.005 0.012 0.003 0.013 0.012

14. Copper (Cu) 0.002 0.004 0.001 0.003 0.007 BDL 0.002 0

15. Zinc (Zn) 0.009 0.01 BDL 0.002 0.01 BDL 0.004

3.113

Page 206: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.4 (Contd…)

Location Palk Bay Gulf of Mannar Sr.

No. Parameter 1 2 3 4 5 6 7

16. Arsenic (As) 0.033 0.041 0.006 0.006 0.005 0.004 0.007

17. Chromium (Cr) 0.007 0.008 0.001 0.001 BDL BDL 0.001

18. Lead (Pb) 0.004 0.005 0.001 0.001 0.001 0.001 0.001

19. Nickel (Ni) 0.004 0.005 0.001 BDL BDL BDL 0.001

20. Selenium (Se) 0.005 0.006 0.001 0.001 0.001 0.001 0.002

21. Cadmium (Cd) 0.001 0.001 BDL BDL BDL BDL BDL

22. Boron (B) 0.023 0.028 0.002 0.002 0.002 0.001 0.003

23. Cobalt (Co) 0.001 0.002 BDL BDL BDL BDL BDL

24. Calcium (Ca) 5.675 5.662 6.500 6.5 7.3 8.24 7.50

25. Magnesium (Mg) 1.86 3.30 2.04 3.16 3.832 3.12 4.24

26. Oil and Grease 0.07 0.11 0.24 0.15 0.12 0.09 0.08

BDL : Below Detectable Limit All values are expressed in g/100 g dry wt. Except pH

3.114

Page 207: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.14

Enumeration and Diversity of Zooplankton

Percent Organisms in Group Sampling

Station Total Zoo-plankton (no. m-3) Cteno-

phora Cnid-aria

Poly-chaeta

Clado-cera

Cope-poda

Deca-poda

Ptero-poda

Moll-usca

Chaeto-gnatha

Appenicular

1 1649 - 0.73 0.61 0.18 63.67 15.77 0.73 0.91 1.82 0.12

2 1531 0.13 1.31 0.98 0.33 65.38 17.64 0.65 0.52 2.61 -

3 1459 0.55 1.23 1.37 0.21 69.77 8.50 0.55 0.69 1.37 -

4 1177 0.51 0.85 1.70 - 66.86 10.21 0.85 0.51 1.27 0.25

5 972 0.51 2.06 3.09 - 71.92 8.23 1.03 0.82 1.03 0.51

6 1233 0.24 1.22 1.62 - 73.56 12.17 0.65 0.81 2.03 0.41

7 1370 1.31 0.58 1.46 0.15 66.72 18.25 0.73 0.22 2.19 0.36

8 787 1.90 1.27 3.18 - 5.57 16.52 2.54 0.64 2.54 0.51

9 1116 1.79 1.34 4.03 0.18 62.19 17.03 0.45 1.34 0.72 0.18

10 1273 1.18 1.18 3.39 0.31 64.40 18.07 0.24 1.96 0.79 0.08

3.130

Page 208: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.18

Enumeration and Diversity of Macrobenthos

Percent Organisms in Group Sampling Station

Total Macro-benthos Chloro-

phyceae Phaeo-

phyceae Sperm-tophyta

Pori-fera

Alcyo-nacea

Sclera-naeta

Poly-chaeta

Brach-yara

Gastro-poda

Bivvi

1 8 - - - 37.50 50.00 12.50 - - - -

2 2 - - - - - 50.00 - - - 50.0

3 44 25.00 4.55 20.45 - - - - - 22.73 11.3

4 18 - - - - - - - - - 55.

5 23 - - - - - - - 13.04 - 86.9

6 5 - - - - - - 80.00 - - 20.0

9 67 7.46 - - 31.34 - - - - 5.97 25.3

10 8 - - - 37.50 - - - - - 12.

Note : Data is not available for 7 & 8 locations due to poor visibility

Table 3.1

Particulars of Sampling Locations along the Proposed Canal Alignment

Station Latitude Longitude Depth (m)

Palk Bay

1 9o 27’ 14 ”N 79o 27’ 00” E 16

2 9o 21’ 26 ”N 79o 27’ 37” E 16

3 9o 13’ 42 ”N 79o 28’ 57” E 10

4 9o 10’ 58 ”N 79o 27’ 17” E 7

Gulf of Mannar

5 9o 09’ 04 ”N 79O 26’ 16” E 3

6 9o 08’ 43 ”N 79O 25’ 35” E 7

7 9o 07’ 08”N 79O 19’ 07” E 14

3.134

Page 209: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

8 9o 03’ 38 ”N 79O 11’ 30” E 23

Tuticorin Port Area

9 8o 45’ 44” N 78O 17’ 52” E 23

10 8o 47’ 09” N 78O 20’ 01” E 21

Page 210: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 211: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.3

Marine Water Quality (Inorganic, Nutrient and Heavy Metals)

Location Sr.

No. Parameter 2 4 6 8 10

1. Total Alkalinity (as CaCO3) 104 104 104 106 106

2. Nitrate Nitrogen (as N) 0.87 0.83 0.83 0.93 0.78

3. Chloride (as Cl) 20080 19580 19580 20580 20080

4. Total Phosphate (as P) 0.02 0.01 0.03 0.02 0.03

5. Silicate (as SiO2) 0.013 0.008 0.005 0.004 0.003

Heavy Metals

6. Arsenic (as As) ND ND ND 0.02 0.13

7. Selenium (as Se) ND ND ND ND ND

8. Chromium (as Cr) ND ND ND ND ND

9. Zinc (mg/L, Zn) ND ND ND ND ND

10. Lead (as Pb) ND ND ND ND ND

11. Cadmium (as Cd) ND ND ND ND ND

12. Nickel (as Ni) ND ND ND ND ND

13. Boron (as B) 2.96 2.91 2.74 2.70 2.38

14. Manganese (as Mn) ND ND ND ND ND

15. Iron (as Fe) ND ND 0.03 0.08 ND

16. Copper (as Cu) ND ND ND ND ND

ND : Not Detectable All values are expressed as mg/L

Page 212: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 213: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 214: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.5

Gross Primary Productivity

Position Location

Latitude Longitude Productivity mgC/m3/day

Palk Bay

1 9O 27’ 14” N 79o 27’ 00” E 269

2 9O 21’ 26” N 79o 27’ 37” E 240

3 9O 13’ 42” N 79o 28’ 57” E 154

4 9O 10’ 58” N 79o 27’ 17” E 148

Gulf of Mannar

5 9o 09’ 04” N 79o 26’ 16” E 210

6 9o 08’ 43” N 79o 25’ 35” E 210

7 9o 07’ 08” N 79o 19’ 07” E 180

8 9o 03’ 38” N 79o 11’ 30” E 257

11* 9o 14’ 04” N 79o 14’ 19” E 128

12* 9o 11’ 18” N 79o 12’ 36” E 472

13* 9o 11’ 03” N 79o 08’ 47” E 194

Tuticorin Port Area

9 9o 45’ 44” N 79o 17’ 52” E 267

10 9o 47’ 09” N 79o 20’ 01” E 126

* Locations near Marine National Park

Page 215: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.6

Number of Species Recorded in the Gulf of Mannar Marine Biosphere Reserve during Different Periods

No. of Species recorded during Groups

1903-1986* 1993-1997*

Chlorophyceae 32 Pheaphyceae 35 Rodophyceae 59 Cyanophyceae 3 Sea grass 13 Foraminifera 51(2) Tintinida 12 Sponges 275(31) Coelenterata (non-coral) 123 (48) 27 Corals 128 (42) 21 Polyzoa 100(15) Polychaeta 75(22) 6 Copepoda 223(63) Cumacea 10(9) Amphipoda 52 (28) Ostracoda 57(23) Isopoda 18(9) Lobster 5 3 Prawns 41(4) 24 Leptostraca 1 Schizopoda 1 Mysidae 1 Squillidae 25(2) Anomura 38(1) Brachyura 172 (13) 95 Mollusca 731 (23) 75 Chaetognatha - 17 Echiompdemata 264 (2) 116 Hemichordata 1 (1) 2 cephalochordata 6 (1) 2 Urochordata 59 (38) 79 Fishes 580 581 Turtles 5 6 Birds 61 Mammals 11 6

Totals Species 3268 1050

Figures in parenthesis indicate number of endemic species

* Complied by CMFRI, Kochi from studies carried out by different authors (refer list of references)

# Based on survey undertaken by ZSI (Anonymous 1998)

Page 216: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.7

Status Report of Biota of Gulf of Mannar Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) Phylum : Protozoa Class : Forminifera

1. Trochammina inflata

X

2. Robulus limbosus X

3. Nonionia scapha X

4. Operculina gaimairdi

X

5. Bulimina elegans X

6. Bolivinia rhomboidalis

X

7. Bolivinia robusta X

8. Bolivinia subrenlusts

X

9. Streblus catesbyarus

X

10. Poroeponides lateralis

X

11. Cancris auriculus X

Phylum : Porifera Class : Desmosponglae

12. Heteronema oracta X

13. Spongta officinatis X

14. Dysidea fragilis X

Page 217: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) 15. Haliclona exigua X

16. Callyspongia fibrosa

X

17. Callyspongia difusa X

18. Spirastrella coccinea

X

19. Spirastrella cuspidifera

X

20. Cliona carpenteri X

21. Cliona orientalis X

22. Cliona vastifica X

23. Ecionemia acervus X

24. Myriastra purpurea X

25. Paratettlla baca X

26. Dercitopsis ceylonica

X

27. Dercitopsis minor X

28. Pellona ditchela X

Phylum : Coelenterata Class : Anthozoa Order : Scleractinla

29. Psammacora contigua

X

30. Pocillopora damicomis

X

Page 218: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) 31. Pocillopora danae X

32. Acropora corymbosa

X X

33. Acropora Formosa X

34. Acropora nobills X

35. Acropora multicaulis

X

36. Acropora surculosa X

37. Acropora lnimilis X

38. Acropora crythraea X

39. Montipora granulose

X

40. Montipora digitata X

41. Montipora divaricata

X

42. Montipora turgescens

X

43. Montipora verrtilli X

44. Montipora foliosa X

45. Pavona decussata X

46. Coscinaraea monile X

47. Goniopora duofaciata

X

48. Goniopora nigra X

Page 219: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) 49. Porites

mannarensis

X

50. Porites solida X

51. Porites lutea X X

52. Porites somaliensis X

53. Porites lichen X

54. Favia favus X X

55. Favia valenctennesii

X

56. Favia pallida X

57. Favites abdiata X

58. Favites pentagona X

59. Goniastrea retiformis

X

60. Goniastrea pactinata

X

61. Platygyra lamellina X

62. Leptastrea transvera

X

63. Echinopora lamellose

X

64. Galaxea fascicularis X

65. Symphyllia recta X

66. Turbinaria peltata X X

Page 220: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) Class : Hydrozoa

67. Halammohydra octopodides

X

Phylum : Annelida Class : Polychaeta

68. Aphrogenia alba X

69. Photogenia indica

70. Harmothoe minuta X

71. Iphione muricata X

72. Chloeia rosea X

73. Eurythoe complanata

X

74. Syllis (Syllis) gracilis X

75. Ceratonereis mirabilis

X

76. Perinereis cultrifera X

77. Perinereis nuntia X

78. Eunice antennata X

79. Eunice (Palolo) siciliensis

X

80. Marphysa corallina

81. Onuphis (Nothria) conchylega

X

82. Malacoceros indicus

X

Page 221: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) 83. Armandial

lanceolata

X

84. Axiothella obockensis

X

85. Nicolea gracilibranchis

X

86. Hypsicomus phaeotaenia

X

Class : Sipunculida 87. Phascolosoma

nigrescens

X

88. Phascolosoma scolops

X

89. Phascolosoma stephensoni

X

Class : Echiura 90. Thalassema

diaphanes

X

Phylum : Platyhelminthes Class : Turbellaria

91. Acanthomacrostomum gerlachi

X

92. Octoplana subterranean

X

Phylum : Nematoda Class : Aphasmidea

93. Anticoma X

Page 222: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) acuminata

94. Halalaimus supercirrhatus

X

95. Oncholaimus brachycerus

X

96. Chromadora vulgaris

X

97. Halichoanolaimus robustus

X

98. Latronema orcimum X

99. Metachromadora clavata

X

100. Desmodora brevicclis

X

101. Camacolaimus prytherchi

X

Phylum : Arthropoda Class : Crustacea

102. Penaetus semisulcatus

X

103. Penaeus indicus X

104. Alpheus frontalis X

105. Alpheus macrocelas

X

106. Pontophilus candidus

X

Page 223: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) 107. Pontophilus incisus X

108. Corallicaris gramines

X

109. Leptocarpus potamuscus

X

110. Perclimenes (Harpilius) agag

X

111. Perclimenes (Perclimenes) digitalis

X

112. Perclimenes (Perclimenes) impar

X

Anomura 113. Clibanarius

longitarus

X

114. Clibanarius merguiensis

X

115. Diogenes investigators

X

116. Pagurus megistos X

Brachyuran Crabs 117. Dromia dehaani X

118. Portunus (Portunus) pelagicus

X

119. Portunus (Portunus) X

Page 224: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) sanguinolentus

120. Scylla serrata X

121. Thalamita crenata X

122. Thalamita prymna X

123. Charybdis (Charybdis) anmulata

X

124. Charybdis (Charybdis) anisodon

X

125. Trapezia areolata X

126. Trapezia cymodoce X

127. Trapezia ferruginea X

128. Halimede ochtodes X

129. Atergatis floridus X

130. Etisus laevimarus X

131. Chlorodiella nigra X

132. Cymo andreossyi X

133. Pseudoliomera speciosa

X

134. Composcia retusa X

135. Phalangipus hystrix X

136. Schizophrys aspera X

137. Doclea canalifera X

Page 225: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) 138. Myra fugax X

139. Philyra syndactyla X

140. Leucosia anatum X

141. Matuta lunaris X

142. Matuta miersi X

143. Grapsus albolineatus

X

144. Percnon planissimum

X

Phylum : Mollusca Class : Crustacea Order : Stomatopoda

145. Gonadactylus chiragra

X

146. Gonadactylus falcatus

X

147. Heterosquilla jonest X

Brachyuran Crabs 148. Cellana radiata X

149. Trochus radiatus X

150. Angaria plicata X

151. Turbo intercostalis X

152. Lambis lambis X

153. Cypraea moneta X

154. Cypraea tigiris X

155. Fucus ficus X

Page 226: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) 156. Chicoreus

virgeneus

X

157. Chicoreus ramosus X

158. Babylonia spirata X

159. Hemifusus pugilimus

X

160. Xancus pyrum X

161. Conus araneosus X

162. Conus fugilimus X

Class : Bivalvia 163. Arca inaequivalis X

164. Arca fusa X

165. Modiolus sp.

166. Lithophaga nigra X

167. Lithophaga gracilis X

168. Pernna viridis X

169. Pinna vexillum X

170. Pinna bicolor X

171. Placenta placenta X

172. Ostrea forskalii X

173. Cardium assimile X

Class : Cephalopoda 174. Sepia aculeate X

175. Sepia pharaonis X

Page 227: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) 176. Sepia kobiensis X

177. Sepia brevimana X

178. Logigo duvauceli X

179. Octopus rugosus X

180. Octopus macropus X

Phylum : Echinodermata Class : Asteroidea

181. Culcita novaeguineae

X

182. Pentaceraster regubus

X X

183. Dactylosaster cylindericus

X

184. Disasterinaleptalacantha

X

Class : Ophiuroidea 185. Ophiomyza

australis

X

186. Ophiactis savgnyi X

187. Ophiothrix (Keystonea) nereidina

X

188. Ophiocoma erinaceus

X

Class : Echinoidea 189. Diadema savignyi X

Page 228: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Sr. No.

Species Common

(C)

Rare

(R)

Endangered

(End)

Endemic

(En)

Commercially Threatened

(CT)

Scientific Collections

(SC) 190. Echinothrix

diadema

X

191. Echinometra mathaei

X

Class : Holothuroidea 192. Holothuria

(Halodeima) atra

X

193. Holothuria (Haloteima) edulis

X

194. H. (Lessonothuria) pardalis

X

195. Holothuria (Metriatyla) scabra

X X

196. Holothuria (Thymiosycia) hilla

X

Phylum : Hemichordara Class : Enteropneusta

197. Ptychodera flauva X

Page 229: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.8

Distribution of Phytoplankton in Gulf of Mannar (Number of Species Recorded During October ’98, August ’99)

Sr. No.

Island Bacillario Phyceae

Dino Phyceae

Cyano Phyceae

Chloro Phyceae

Total

1 Shingle 16 3 0 1 20

2 Krusadai 19 3 1 1 24

3 Pullivasal 21 2 1 0 24

4 Poomarichan 22 2 2 0 26

5 Manoliputti 22 4 0 0 26

6 Manoli 13 1 0 1 15

7 Musal 22 2 2 0 26

8 Mulli 21 3 0 0 24

9 Valai 11 3 1 0 15

10 Appa 26 2 1 2 31

11 Valimunai 21 1 1 0 23

12 Anaipur 17 1 0 0 18

13 Nallathanni 28 4 2 1 35

14 Pulivinichalli 21 4 0 0 25

15 Upputhanni 19 5 0 0 24

16 Karaichalli 18 3 2 0 23

17 Vilanguchalli 18 2 0 0 20

18 Kasuwar 30 4 2 0 36

19 Van 27 3 1 1 32 Source : Resources information system for Gulf of Mannar (India), GOI, DOD,

Integrated Coastal and Marine Area Management Project Directorate, Chennai, April 2001

Page 230: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.9

Maximum Diversity Index Values of Phytoplankton in 21 Islands of Gulf of Mannar

Sr. No. Name of island Maximum diversity index

1 Shingle 2.996

2 Krusadai 3.178

3 Pullivasal 3.178

4 Poomarichan 3.258

5 Manoliputti 3.258

6 Manoli 2.708

7 Musal 3.258

8 Mulli 3.178

9 Valai 2.708

10 Appa 3.434

11 Valimunai 3.135

12 Anaipur 2.89

13 Nallathanni 3.555

14 Pulivinichalli 3.218

15 Upputhanni 3.178

16 Karaichalli 3.135

17 Vilanguchalli 2.996

18 Kasuwar 3.583

19 Van 3.465

Formula : Maximum Diversity Index (MD) = log2 (TT) Where TT is total taxa Source: Evaluation of Fourteen Trophic State Indices for Phytoplankton of Indian Lakes and Reservoirs Environmental Pollution (Series A) 27 : 143-153 Editor : Sullivan P.I and Carpenter S.R (1982) The data of Poovaransapatti and Talairi island is not available

Page 231: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.10

Enumeration and Diversity of Phytoplankton

Percent organisms in group Location

Total Phytoplankton

(No.m3) Cyano-phyceae

Bacillario-phyceae

Dino-phyceae

Shannon Wiener

Diversity Index

1 801300 99.84 0.07 0.09 0.03

2 121100 99.09 0.50 0.41 0.14

3 35400 98.87 0.85 0.28 0.12

4 120200 99.83 0.14 0.03 0.03

5 144300 99.79 0.21 - 0.02

6 130670 99.87 0.10 0.03 0.02

7 90320 99.64 0.18 0.18 0.40

8 220 - 59.10 40.90 2.59

9 250 - 40.00 60.00 2.28

10 400 - 37.50 62.50 2.13

Page 232: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.11

List of Phytoplankton Recorded

Sr. No.

Station Name of Alga 1 2 3 4 5 6 7 8 9 10

Cyanophyceae

1. Trichodesmium Theibautii

+ + + + + + + - - -

Bacillariophyceae

2. Rhizosolenia sp. + + - + + + + + + +

3. Coscinodiscus sp. - + + + - + - + + +

4. Biddulphia sp. - - - - - + + + - -

5. Pleurosigma sp. + - - - - - - - - -

6. Bacteriastrum hyalinum

- - - - - - + + + -

7. Gunieardia sp. + - - - - - - - - -

8. Thallasiothrix sp. - + + + - - + + + +

9. Chaetoceros sp. - - + + - + - - - -

Dianophyceae

10. Peridinium sp. + + - - - + + + + -

11. Ceratium sp. + + + + - + + + + +

12. Dianophysis caudata + + - - - - + + + +

13. Diplosalis lenticulata + + + - - - - - - -

14. Triceracium sp. - - - - - - + + - +

Page 233: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.12

Distribution of Zooplankton in Gulf of Mannar (Number of Species Recorded During October ’98, August ’99)

Sr. No.

Island Granuloret Iculosa

Hydrozoa Polyhymeno phora

Poly-chaeta

Crus-tacea

Sagi-ttoidea

Thali-acea

Total

1 Shingle 1 - 2 1 17 2 1 24

2 Krusadai - 1 1 - 18 - 1 21

3 Pullivasal - 1 - - 17 1 - 19

4 Poomarichan 1 - 1 1 24 - 1 28

5 Manoliputti 1 - 2 - 12 1 1 17

6 Manoli 1 - 1 - 19 1 - 22

7 Musal - 1 1 1 19 - 1 23

8 Mulli - 1 - 1 14 - - 16

9 Valai 1 - - 2 15 - 1 19

10 Appa 1 - 1 1 21 1 - 25

11 Valimunai - - - - 18 - 1 19

12 Anaipur - - - 1 18 - - 19

13 Nallathanni 1 - - - 17 2 - 20

14 Pulivinichalli 1 1 - 1 19 - - 22

15 Upputhanni - 1 1 - 18 1 1 22

16 Karaichalli - - 1 1 20 - - 22

17 Vilanguchalli - - 2 - 18 1 1 22

18 Kasuwar - - 1 1 24 - - 26

19 Van 1 1 1 1 31 - 1 36

Source : Resources information system for Gulf of Mannar (India), GOI, DOD, Integrated Coastal and Marine Area Management Project Directorate, Chennai, April 2001

Page 234: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.13

Shannon Weaver Diversity Indice of Zooplankton Recorded at various Coastal Waters in India

Area Year Diversity indices

Bombay High 1989 0.5-4.04

Bombay Bassein 1989 1.21-3.93

Heera ratna 1989 0.72-3.89

Tapti 1989 2.23-3.47

Surat 1997 1.00-2.55

Jamnagar 1992 0.48-2.80

Sursanyam 1989 1.50-2.04

Kaveri basin 1989 1.00-3.72

Godavari basin 1989 1.69-3.42

Manglore 1988 1.07-1.45

Gandhar 1991 0.70-2.16

Gopalpur 1996 1.8-3.4

kavaratti 1997 0.97-3.26

Agatti 1997 1.38-3.74

Kolaba 1991 1.00-3.09

Worli 1991 0.92-3.25

Kashid Bay 1991 0.95-2.76

Muttukadu (near Chennai) 1995 1.80-3.08

Palk Bay (present study) 1998 2.94-4.24

Gulf of Mannar (present study) 1998 2.36-3.68

Source : NEERI, Nagpur and CMFRI, Kochi

Page 235: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 236: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.15

List of Zoolplankton at Different Locations

Sr. No. Name 1 2 3 4 5 6 7 8 9 10

Cnidaria 1. Medusae + + + + + + + + + +

Ctenophora 2. Beroe sp. - + + + + + + + + +

Chaetognatha 3. Unidentified + + + + + + + + + +

Polychaeta 4. Polychaete larvae + + + + + + + + + +

Pteropoda 5. Unitentified + + + + + + + + + +

Mollusca 6. Molluscan larvae + + + + + + + + + +

Cladocera 7. Evadne sp. + + + - - - + - + +

8. Penilia sp. + - - - - - + - + +

Copepoda 9. Acartia sp. + + + + + + + + + +

10. Tortanus sp. + + + + + + + + + +

11. Calanopia sp. + + + + + + + + + +

12. Centropages sp. + + + + + + + + + +

13. Pontella sp. + + + + + - + + + +

14. Paracalanus sp. + + + + + + + + + +

15. Canthocalanus sp. + + + + + + + + + +

16. Eucalanus sp. + + + + + + + + + +

17. Metis sp. + + - + + + + + + -

18. Oithona sp. - + + - + + + + - +

Decapoda 19. Lucifer sp. + + + + + + + + + +

20. Decapod larvae + + + + + + + + + +

Appendicularia 21. Oikopleura sp. + - - + + + + + + +

Pisces 22. Fish eggs and larvae + + + + + + + + + +

23. Others + + + + + + + + + +

Page 237: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.16

Maximum diversity index values of Zooplankton in 21 islands of Gulf of Mannar

Sr. No. Name of island Maximum diversity index

1 Shingle 3.178

2 Krusadai 3.044

3 Pullivasal 2.944

4 Poomarichan 3.332

5 Manoliputti 2.833

6 Manoli 3.09

7 Musal 3.135

8 Mulli 2.772

9 Valai 2.944

10 Appa 3.218

11 Valimunai 2.944

12 Anaipur 2.944

13 Nallathanni 2.995

14 Pulivinichalli 3.091

15 Upputhanni 3.091

16 Karaichalli 2.3026

17 Vilanguchalli 3.091

18 Kasuwar 3.258

19 Van 3.583 Formula : Maximum Diversity Index (MD) = log2 (TT) Where TT is total taxa Source : Evaluation of Fourteen Trophic State Indices for Phytoplankton of Indian Lakes and Reservoirs Environmental Pollution (Series A) 27 : 143-153 Editor : Sullivan P.I and Carpenter S.R (1982) The data of Poovaransapatti and Talairi island is not available

Page 238: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.17

Distribution of Benthic Organisms in Gulf of Mannar

Sr. No.

Island

Pro

tozo

a

Por

ifera

Con

idar

ia

Ann

elid

a

Ech

iura

Sip

uncu

la

Pla

tyhe

lmin

thes

Nem

otod

a

Arth

ropo

da

Mol

lusc

a

Ech

inod

erm

ata

Hem

icho

rdat

a

Tota

l

1 Shingle 7 5 14 13 - 2 2 8 25 16 4 - 96

2 Krusadai 10 6 19 12 - 3 1 7 26 18 8 1 111

3 Pullivasal 5 3 16 8 - 1 1 4 14 6 5 0 63

4 Poomarichan 4 5 13 15 - 3 1 8 21 11 1 - 81

5 Manoliputti 7 8 13 12 - 2 1 9 28 19 7 - 106

6 Manoli 7 11 26 16 1 3 2 8 31 21 13 - 139

7 Musal 10 7 30 18 1 3 2 8 37 26 11 - 153

8 Mulli - - 18 - - - - - 7 4 - - 29

9 Valai - - 11 - - - - - 6 3 1 - 21

10 Talairi - 1 15 - - - - - 8 3 3 - 30

11 Appa - - 11 - - - - - 10 4 1 - 26

12 Poovarasanpatti - - 11 - - - - - 2 - 1 - 14

13 Valimunai - 1 12 1 - - - - 7 5 1 - 27

14 Anaipur - 1 22 1 - - - - 9 4 2 - 39

15 Nallathanni - - 23 - - - - - 8 6 2 - 39

16 Pulivinichalli - 1 7 - - - - - 1 - 1 - 10

17 Upputhanni - - 17 - - - - - 2 3 2 - 24

18 Karaichalli - - 26 - - - - - - 3 1 - 30

19 Vilanguchalli - - 9 - - - - - 2 1 1 - 13

20 Kasuwar - 1 15 - - - - - 2 2 2 - 22

21 Van - - 15 - - - - - 1 1 1 - 18

Source : Resources Information System for Gulf of Mannar (India), GOI, DOD and Integrated

Coastal and Marine Area Management Project Directorate, Chennai, April 2001

Page 239: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 240: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.19

List of Macrobenthos Recorded

Sr. No. Name 1 2 3 4 5 6 7 9 10

Chlorophyceae

1. Halimeda sp. - - + - - - + - -

2. Caulerpa sp. - - + - - - - + -

3. Ulva sp. - - - - - - - - -

4. Enteromorpha sp. - - - - - - - - -

5. Codium sp. - - + - - - - - -

Phaeophyceae

6. Padina sp. - - - - - - - - -

7. Hydroclathus sp. - - - - - - - - -

8. Sargassum sp. - - - - - - - - -

9. Turbinaria sp. - - + - - - - - -

Rhodophyceae

10. Galidiella sp. - - - - - - - - -

11. Gracillaria sp. - - - - - - - - -

12. Porolithon sp. - - - - - - - - -

13. Lithothamnion sp. - - - - - - - - -

Spermatophyta

14. Phakellia sp. - - + - - - - - -

15. Euspongia sp. - - + - - - - - -

Porifera

16. Phakellia sp. - - - - - - - - -

17. Euspongia sp. - - - - - - + - -

18. Phyllospongia sp. + - - - - - - + -

19. Acarnus sp. - - - - - - - - -

20. Acathella sp. - - - - - - - - -

21. Clathria sp. - - - - - - - - -

22. Hiricinia sp. - - - - - - - + -

23. Spongilla sp. - - - - - - - - +

24. Raspailia sp. - - - - - - - - -

25. Petrosia sp. - - - - - - - - -

Page 241: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.19 (Contd…)

Sr. No. Name 1 2 3 4 5 6 7 9 10

Alcyonaria

26. Juncella sp. + - - - - - - - -

27. Alcyonium sp. - - - - - - - - -

28. Alcyonid sp. - - - - - - - - -

29. Antipathes sp. - - - - - - - - -

30. Sclcrophytum sp. - - - - - - - - -

31. Sarcophytum sp. - - - - - - - - -

32. Scirpearia sp. - - - - - - - - -

33. Verucella sp. + - - - - - - - -

34. Virgularia sp. - - - - - - - - -

35. Acanthogorgia sp. - - - - - - - - -

Scleractinia

36. Solitary coral + - - - - - - - -

37. Fungia sp. - + - - - - - - -

Hydroida

38. Halicornaria insignis - - - - - - - - -

Polychaeta

39. Eunice sp. - - - - - - - - -

40. Nereid - - - - - + - - -

Brachyura

41. Uca sp. - - - - + - - - -

Anomura

42. Hermitcrab - - - - - - - - -

Gastropoda

43. Xancus sp. - - + - - - - + -

44. Lambis lambis - - - - - - - + -

45. Oliva sp. - - + - - - - - -

46. Conus sp. - - + - - - - - -

47. Murex sp. - - + - + - - - -

48. Terebra sp. - - - - - - - - -

49. Thais sp. - - + - - - - - -

50. Umbonium sp. - - + - - - - - -

51. Siliqua radiata - - - - - - - - -

Page 242: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.19 (Contd…)

Sr. No. Name 1 2 3 4 5 6 7 9 10

Bivalvia

52. Pecten sp. - - - - - - - - -

53. Pinna sp. - + - - - + - - -

54. Pteria sp. - - - - - - - - -

55. Arca sp. - - - - - - - - -

56. Cardium sp. - - + - + - - - -

57. Donax sp. - - - + + - - - -

58. Solen sp. - - + - - - - + -

59. Tellina sp. - - - - + - - + -

60. Pinctada sp. - - - - - - - - -

61. Sunnetta sp. - - - - - - - + -

Scaphopoda

62. Dentalium sp. - - - - - - - - -

Echinodermata

63. Clypeaster sp. - - - - - - - - -

64. Astropecten sp. - - - - - - - + -

65. Salmacis sp. - - - + - - - - -

66. Sticopus sp. - - + - - - - + -

67. Ophiuroid - - + - - - - - -

68. Hologhuria atra - - + - - - - - -

69. H. Scabra - - + + - - - + -

70. Protoreaster lincki - - - - - - - - -

71. Pentaceros lincki - - - - - - - - -

72. Luidia maculata - - - - - - - + -

73. Pentacta fucata - - - - - - - - +

Urochardata

74. Rhodocynthia sp. - - - - - - - - -

75. Solitary ascidian - - - - - - - - -

76. Colonial ascidian - - - - - - - - -

77. Polycarpa sp. - - - - - - - - -

Pisces

78. Remora sp. - - - - - - - + -

Page 243: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.20

Density and Biomass of Meiofauna in Sediment Samples

Station Number mg (wet weight)

1 32 4.70

2 44 6.47

3 111 16.32

4 110 16.17

5 98 14.40

6 120 17.64

7 93 13.66

8 28 4.12

9 118 17.34

10 115 16.90

Values are expressed per 100 cm2 area

Page 244: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.21

Distribution Pattern of Corals, Live Corals (Percentage) and Seagrases

Sr. No.

Name of Island Area (ha)

Corals distribution

(sq.km.)

Live Corals

(%)

Sea grass distribution

(sq.km.)

Mandapam Group

1. Shingle 12.69 2.0 46 0.21

2. Krusadai 65.80 1.5 33 3.0

3. Pullivasal & Poomarichan

9.95 & 16.58 4.0 14 5.0

4. Manoli & Manoliputti 25.90 & 2.34 15.0 35 5.0

5. Musal 129.04 18.0 522 9.5

Keezhakarai Group

6. Mulli 10.20 7.0 25 2.0

7. Valai & Talairi 10.15 & 75.15 14.0 16 8.0

8. Appa 28.63 5.0 2 8.0

9. Poovarasanpatti & Valimunai

0.25 & 6.75 6.0 50 11.5

10. Anaipur 11.00 5.0 37 14.0

Vember Group

11. Nallathanni 110.00 2.0 38 5.0

12. Pulivinichalli 6.12 7.0 38 1.5

13. Upputhanni 29.94 3.0 26 2.5

Tuticorin Group

14. Kasuwar 19.50 6.0 5 3.0

15. Karaichalli 16.46 0.3 4 1.0

16. Vilanguchalli 0.95 1.0 8 1.5

17. Van 16.00 2.5 7 5.0

Source : Resources Information System for Gulf of Mannar (India), GOI, DOD and Integrated Coastal and Marine Area Management Project Directorate, Chennai, April 2001

Page 245: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.22

Maximum diversity index values of Corals in 21 islands of Gulf of Mannar

Sr. No Name of islands Maximum diversity index

1 Shingle 2.48

2 Krusadai 2.56

3 Pullivasal 2.39

4 Poomarichan 2.48

5 Manoliputti 2.48

6 Manoli 2.56

7 Musal 2.48

8 Mulli 2.3

9 Valai 1.79

10 Talairi 2.07

11 Appa 0.69

12 Valimunai 1.61

13 Anaipur 1.79

14 Nallathanni 1.79

15 Pulivinichalli 1.61

16 Upputhanni 1.94

17 Karaichalli 1.38

18 Vilanguchalli 0

19 Kasuwar 1.79

20 Van 1.79

Formula : Maximum Diversity Index (MD) = log2 (TT) Where TT is total taxa

Source : Evaluation of Fourteen Trophic State Indices for Phytoplankton of Indian Lakes and Reservoirs Environmental Pollution (Series A) 27 : 143-153

Editor : Sullivan P.I and Carpenter S.R (1982)

Page 246: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.23

List of Fishlanding Centres within Sethusamudram Ship Canal Zone

Palk Bay 44. Pasipattinam 1. Point Calimere 45. Damodarapattinam 2. Muthupet 46. Naraneiyandal 3. Adiramapattinam 47. Valasapattinam 4. Karayur Street 48. Purakkudi 5. Sunnambukkarar Street 49. Purakkudi 6. Eripurakarai 50. Nambuthalai 7. Kollakadu 51. Soliyakudi 8. Pudupattinam 52. Pudupattinam 9. Mallipallinam 53. Mullimunai

10. Chinnamanai 54. Karankadu 11. Manova Colony 55. Morepannal 12. Pillaiyar Thidd 56. Thiruppalaikudi 13. Sethubavachatram 57. Devipattinam 14. Kalumankuda 58. Mudiveerampattinam 15. Othaiveedu 59. Pazhaneelavalasai 16. Karankuda 60. Puduvalasai 17. Sambaipattinam 61. Pannaikulam 18. Adamcathevan 62. Alagankulam 19. Senthalaipattinam 63. Athankarai 20. Mantadipattinam 64. Thoppuvalasai 21. Puthur 65. Dhangavalasai 22. Somanathanpattinam 66. Alagathanvalasai 23. Vallabanpattinam 67. Eiyerumeeli 24. Vadakur 68. Pirrappanvalasai 25. Kattumavadi 69. Pillaimadam 26. Pradabiramanpattinam 70. Munaikkadu 27. Krishnajiramanpattinam 71. Mandapam – Palk Bay 28. Thulasipattinam 72. Pamban light house 29. Thulasipattinam – South 73. Akkalmadam 30. Ammapattinam 74. Nallupanai 31. Pudukudi – North 75. Thangachimadam 32. Pudukudi – South 76. Villundy 33. Kottaipattinam 77. Pillaikulam 34. Jegathipattinam 78. Vadakadu 35. Embavayal 79. Narikkzhli 36. Palakudi 80. Oolaiyadipallam 37. Kumarappan Vayal 81. Oolaikuda 38. Gopalpattinam 82. Changumaal 39. Pudur 83. Kariyur 40. Arsantarai 84. Cherankottai 41. Pudukuda 85. Kothandaramarkovil 42. Sundarapandiyanpattinam 86. Moontayiruppuchatram 43. Theerthanthanam 87. Dhanushkodi

Page 247: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.23 (Contd…)

Gulf of Mannar 1. Oothaiputti 21. Keelakkarai 2. Paradi 22. Sennaevadi 3. Thavukadu 23. Vallinokkam 4. Otthathalai 24. Mundal 5. Rameswarampudu Road 25. Mariyur 6. Naduthurai 26. Oppillan 7. Kadarpachapadu 27. Mukaiyur 8. Punkammapadu 28. Narippaiyur 9. Kundukaal point 29. Rochemaanagar

10. Chinnappaliam 30. Vembar 11. Therkuvadi 31. Keelavaipar 12. Thonithurai 32. Sippikulam 13. Vedalai 33. Pattinamarudur 14. Seeniyappadharga 34. Taruvaikulam 15. Pudumadam 35. Vellapatti 16. Thalaithoppu 36. Alangarathattu 17. Muthupettai 37. Tuticorin-North 18. Periyapattinam 38. Tuticorin-Fishing Harbour 19. Kalimankundu 39. Titocorin- South 20. Sethukkarai 40. Tuticorin Harbour Point

Source : CMFRI, Kochi (1998)

Page 248: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.24

Shannon Weaver Diversity Index (H’ value) for the Ornamental Fishes Recorded Around each Island in the Gulf of Mannar

Sr. No.

Island Species Richness/ Density

H’ value

Families Observed

Species Observed

1 Van 1.96/10 sq.m. 2.46 21 49

2 Kasuwar 1.76/10 sq.m 2.47 22 44

3 Vilanguchalli 0.92/10 sq.m 1.35 23 11

4 Karaichalli 2.80/10 sq.m 2.34 21 70

5 Upputhanni 2.00/10 sq.m 2.47 22 50

6 Pulivinichalli 2.52/10 sq.m. 2.78 22 63

7 Nallathanni 3.24/10 sq.m. 2.54 22 81

8 Anaipur 2.52/10 sq.m. 2.92 21 63

9 Valimunai 2.40/10 sq.m. 3.40 20 60

10 Poovarasanpatti 0.88/10 sq.m. 1.09 12 22

11 Appa 2.68/10 sq.m. 2.72 23 67

12 Talairi 2.36/10 sq.m. 2.27 20 5

13 Valai 2.36/10 sq.m. 2.39 18 5

14 Mulli 2.36/10 sq.m. 2.29 19 59

15 Musal 2.64/10 sq.m. 2.78 23 66

16 Manoli 2.64/10 sq.m. 2.56 23 66

17 Manoliputti 2.16/10 sq.m. 2.60 22 54

18 Poomarichan 1.52/10 sq.m. 1.46 19 38

19 Pullivasal 0.60/10 sq.m. 0.76 10 15

20 Krusadai 1.24/10 sq.m. 1.24 17 31

21 Shingle 2.00/10 sq.m. 2.81 20 50

Source : Resources Information System for Gulf of Mannar (India), GOI, DOD,

Integrated

Coastal and Marine Area Management Project Directorate, Chennai, April 2001

Page 249: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.25

Commercially Important Species Contributing to Fishery in the Gulf of Mannar and the Palk Bay

Silver belles : Rays :

Leioganthus bindus Dasyatis bleekeri Leioganthus dussumeiri Dasyatis uamak Leioganthus jonesi Dasyatis sephen Leioganthus brevirostris Rhinotera javanica Leioganthus berbis Amphiotistius imbricatus Leioganthus equulus Amphiotistius kuhni Gazza minuta Aetobatus narinari Gazza achlamya Aetobatus flagellum Secutor insidiator Gymura poecilura Secutor ruconius 7 Carangids :

Sardines : Seleroides leptolepis Sardinells fimbriata Caranx ignobilis Sardinells gibbosa Atule mate Sardinells albella Carangoides malabaricus Sardinells sirm Carangoides sexfasciatus

Mackerel : Prawns : Rastrelliger kanagurta Penulirus ornatus

Tunas : Lobsters : Auxis thazard Panulirus ornatus Euthynnus affinis Panulirus homarus Sarda orientalis Panulirus versioclor Thunnus tonggol Thenus orientalis

Seerfishes : Sharks Scomberomorus commerson Carcharhinus sorrah Scomberomorus guttatus Rhizoprionodon actus

Perches : Scoliodon laticaudus Lenthrinus nebulosus Loxodon macrorhinus Siganus canaliculatus Sclaenids : Lutjanus spp. Otolithes rubber Epinephelus spp. Johnius maculates Plectorhynchus spp. Johnius dussumieri Diagramma spp. Johnieops aneus Upeneus spp. Protonibea diacanthus Plotosus spp. Threadfin Breams : Psammoperca waigiensis Nemipterus delagoae Theropon spp. Nemipterus japonicus Serraus spp. Goatfishes : Chaetodon spp. Parupeneus indicus Acanthurus spp. Parupeneus cinnabarius

Whitebaits : Upeneus sulphures Stolephorus indicus Upeneus vittatus Stolephorus batabiensis Upeneus sundaicus Stolephorus devisi

Source : CMFRI, Kochi (1998)

Page 250: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.26

Major Fishing Gears used in the Gulf of Mannar and the Palk Bay

Gear Types of Fishes

Shoreseines (Kara valai type) - Operated with the help of thony (palnkbuilt Tuticorin type) fitted with outboard engine, targeting the small pelagics

Shoreseines (Ola valai0 - Operated with the help of vaththai )plankbuilt Tuticorin type) non-motorized boat, targeting mainly the shrimps anf the pelagics

Boatseine - Operated with vallom (plank-built Tuticorin type boat with inboard engine) and fiberglass boat with outboard engine

Gillnets

Chalavalai or koolabalai - Mainly small pelagics

Vala valai or podivalai - Mainly small pelagics

Paravalai -

Thirukkaivalai - Raya

Namduvalai - Crabs, lobsters, Drepane spp. etc.

Chanku madi -

Paruvalai - Perches, oceanic tuna

Hooks & lines

Longlines - Perches, catfishes, sharks etc.

Trawl lines - Seerfishes, tunas, sharks, carangids etc.

Trawlers - Demersals

Kalamkatti valai - Operated utilizing the tides, smaller inshore fishes prevented escaping with recording tide

Traps - Reef fishes, lobsters

Handpicking - Macro algae, holothurians

Source : CMFRI, Kochi (1998)

Page 251: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.27

Marine Fish landings in the Gulf of Mannar during 1992-96 (In Tonnes)

Year Name of Group

1992 1993 1994 1995 1996 Average (1992-96)

5 of Total (Average)

PELAGIC 30826 30770 35872 57226 58759 42691 54.38

DEMERAL 17256 25756 30760 29107 33844 27364 34.85

CRUSTACEANS 2546 2887 7878 4777 4265 4471 5069

MOLLUSCS 4697 1627 3699 3871 6028 3985 5.08

TOTAL 55325 61141 78210 94981 102897 78511 100

Max. sustainable yield for Pelagic (A) - 44600 tonnes Current production - 42700 tonnes Max. sustainable yield for Demersal (B-D) - 35200 tonnes Current production - 37900 tonnes Exploitation in excess of sustainable yield - 800 tonnes GOM production in Tamil Nadu - 20% Production rate - per sq. km - 14 tonnes Production rate - per fishermen/yr - 0.683 tonnes Production rate - per sq. km - 14 tonnes Production rate - per active fishermen/yr - 2.24 tonnes

Source : CMFRI, Kochi (1998)

Page 252: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.28

Composition of Different Groups in Marine Fish Landings in the Gulf of Mannar (Catch in Tonnes)

Name of Fish 1992 1993 1994 1995 1996

ELASMOBRANCHS Sharks 1855 1401 992 929 600 Skates 194 61 10 62 191 Rays 1960 3200 2399 2989 2509

EELS 0 1 1 5 43 CATFISHES 411 575 180 313 553 CLUPEIDS

Wolf herring 810 1245 771 590 1014 Oil Sardine 7 26 0 1288 1419 Other Saridnes 11680 14383 15124 29052 31059 Other Shads 109 97 383 641 487 Stolephorus 2464 1042 1699 1601 2225 Thryssa 1180 1495 2473 2337 1812 Other Clupeids 1724 1297 3615 2209 2941

BOMBAY DUCK 0 17 0 7 0 LIZARD FISHES 704 1461 1288 2100 1527 HALF BEAKS] & FULL BEAKS]

366 342 343 452 824

FLYING FISHES 8 2 1 2 7 PERCHES

Rock code 656 1264 1108 779 659 Shappers 467 649 677 636 491 Pig-face breams 2291 4393 5184 4432 6266 Threadfin breams 1443 1540 1955 2571 2165 Other Perches 984 1641 1439 3204 2707

GOATFISHERS 1238 1085 1103 1097 732 THREADFINS 101 44 286 152 42 CROAKERS 1225 949 1736 1951 2133 RIBBON FISHES 1383 561 91 26 312 CARANGIDS

Horse Mackerel 0 0 25 16 91 Scads 2 4 1 39 74 Leather-jackets 115 61 141 443 552 Other Carangids 3178 2827 4098 4556 4131

SILVERVELLIES 3776 7228 11024 6548 42354 BIG-JAWED JUMPER 140 81 44 325 64

Page 253: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.28 (Contd…)

Name of Fish 1992 1993 1994 1995 1996

POMFRETS Black pomfret 15 2 54 3 21 Silver pomfret 43 27 85 134 73

MACKERELS 0 3 0 0 0 India makerel 213 1145 556 4620 3711 Other mackerel 0 0 0 3 0

SEER FISHES S. commersoni 774 1052 1209 2174 1797 S. guttatus 33 16 75 157 3 S. lineolatus 13 11 19 18 13 Acanthocybium spp. 2 0 0 0 0

TUNNIES E. affinis 1376 482 511 285 582 Auxis spp. 279 11 62 52 27 K. pelamis 3 4 7 1 0 Other tunnies 16 6 15 20 19

BILL FSIHES 137 148 78 34 135 BARRACUDAS 1142 1666 1487 2467 2763 MULLETS 11 14 105 40 335 FLAT FISHES

Halibut 40 259 130 95 5 Flounders 0 0 17 0 0 Soles 49 23 27 46 112

CRUSTACEANS Penaeid prawns 1562 1558 4278 3034 2529 Non-penaeid prawns 6 157 2347 643 108 Lobsters 252 257 309 191 132 Crabs 726 914 944 891 1017 Stomatopods 0 0 0 18 479

MOLLUSCS Bivalves 10 1 2 28 0 Gastopods 13 18 137 109 261 Cephalopods 4674 1606 3560 3734 5766

MISCELLANEOUS 3151 2838 3959 4417 2812 TOTAL 55325 61141 78210 94981 102897

Source : CMFRI, Kochi (1998)

Page 254: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.29

Composition of Trawl Catches in the Gulf of Mannar

Types of Fishes Percent

Elasmobranches a. Sharks 0.002 b. Rays 7.717

Catfishes 0.959 Clupeids a. Wolf herring 0.021 b. Oil sardine 0.059 c. Other sardines 1.321 d. Hilsa shad 0.375 e. Other shads 0.375 f. Anchovies

Colilia 0.004 Stolephorus 0.578 Thryssa 7.594

Other clupeids 0.463 Rock cods 0.031 Pig-face breams 0.036 Threadfin breams 0.033 Other perches 2.035 Snappers 0.002 Goatfishes 1.097 Threadfins 0.159 Croakers 5.630 Ribbon fishes 0.008 Caraginds 3.371

a. Leather jackets 0.004 b. Other carangids 0.496

Silver bellies 38.331 Big jawed jumper 0.010 Pomfrets

a. Black pomfret 0.010 b. Silver pomfret 0.073 c. Chinese pomfret 0.002

Indian mackerel 0.025 Seerfishes 0.396 Barracuda 0.241 Mullets 0.017 Flatfishes

a. Soles 0.438

Crustaceans a. Penaeid prawns 11.913 b. Non-penaeid prawns 0.004 c. Crabs 3.373 d. Stomatopods 0.433

Cephalopoda 0.611 Miscellaneous 12.115

Total 100.00

Source : CMFRI, Kochi (1998)

Page 255: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.30

Composition of the Trawl Catches at Pamban, Rameswaram and Tuticorin

Component Pamban and Rameswaram (%) Tuticorin

Silver bellies 44.0 28.0

Penaeid prawns 12.0 12.0

Thryssa 0.1 21.0

Rays 12.0 0.1

Carangids 1.0 10.0

Croaders 7.0 3.0

Crabs 5.0 0.01

Perches 2.0 2.0

Sardines 2.0 0.3

Goatfishes 2.0 0.0

Stolephorus 0.02 2.0

Catfishes 1.5 0.02

Seerfishes 0.0 1.0

Others 11.38 20.57

Source : CMFRI, Kochi (1998)

Page 256: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.31

Pearl Oyster Paars in the Gulf of Mannar and the Palk Bay

Group Paars 1. Pamban karai I Inner Pamban group 2. Pamban velangu

II Pamban Periya paar group 3. Pamban periya paar

4. Musal tivu paar III Musal Tivu group 5. Cholava karai paar

6. Vallai malai karai paar 7. Vallai malai velagu paar

IV Keelakkarai group

8. Anna paar

9. Valinukam paar 10. Valinukam thundu paar

V Valinokkam group

11. Nalla tanni tivu paar

12. Uppu tanni tivu paar 13. Vemabar karai paar

VI Inner Vemba group

14. Kumulam paar

VII Outer Vembar group 15. Vembar periya paar

VIII Outer Vaipar group 16. Vaipar periyar paar

17. Devi paar 18. Parnanthu paar 19. Paduthamarikan paar

IX Inner Vaipar group

20. Paduthanmarikan paar

21. Cruxian paar 22. Tuticorin kuda paar 23. Cruxian thundu paar

X Cruxian group

24. Vantivu arupagam paar

25. Nagarai paar 26. Uttipaar 27. Petha paar 28. Uduruvi paar 29. Kilathi paar 30. Athuvai aurpagam paar

XI Utti paar group

31. Patharai paar

32. Attonbotu paar XII Pasi paar group 33. Pasi paar

34. Tholayiram paar XIII Tholayiram paar group 35. Koothadiyar paar

36. Thundu paar XIV Kanna tivu group 37. Kanna tivu arupagam paar

Source : CMFRI, Kochi (1998)

Page 257: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.32

Distribution of Seagrass in the Islands of Gulf of Mannar Sr. No.

Species

Van

Kasu

war

Vilan

guch

alli

Kara

ichall

i Up

putha

nni

Puliv

inich

alli

Nalla

thann

i An

aipar

Va

limun

ai Po

ovar

asan

patti

Appa

Talai

ri

Valai

Mu

lli Mu

sal

Mano

li Ma

nolip

utti

Poom

arich

an

Pulliv

asal

Krus

adai

Shing

le

1 Cymodocea serrulata

+ + + + + + + + + + + + + + + + + + + +

2 Cymodocea rotundata

+ + + + + + + + + + + + + + + +

3 Syringodium isoetifolium

+ + + + + + + + + + + + + + + + + + + + +

4 Halodule uninervis

+ + + + + + + + + + + + + + + +

5 Halodule ovalis + + + + + + + + + + + + + + + + + + + +

6 Halophila ovata

+ + + + + + + + + + + + + + + + + + + + +

7 Thalassia hemprichii

+ + + + + + + + + + + + + + + + + + + + +

8 Enhalus acoroides

+ + + + + +

9 Halophila stipulacea

+ + + + + + + + + + + + + + + + + + + + +

10 Halophila decipiens

+ + + + + + + + + + + + + + + + + + + + +

11 Halophila beccarii

+ + + + + + + + + + + + + + + + + + + + +

12 Halodule pinifolia

+ + + + + + + + + + + + + + + + + + + + +

Source : Resources Information System for Gulf of Mannar (India), GOI,

DOD, Integrated

Coastal and Marine Area Management Project Directorate, Chennai, April 2001

Page 258: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.33

Maximum diversity index values of Seagrass in 21 islands of Gulf of Mannar

Sr. No Name of island Maximum diversity index

1 Shingle 2.39

2 Krusadai 2.48

3 Pullivasal 2.48

4 Poomarichan 2.48

5 Manoliputti 2.48

6 Manoli 2.48

7 Musal 2.48

8 Mulli 2.39

9 Valai 2.39

10 Talairi 2.39

11 Appa 2.19

12 Poovarasanpatti 2.19

13 Valimunai 2.19

14 Anaipur 2.39

15 Nallathanni 2.39

16 Pulivinichalli 2.39

17 Upputhanni 2.3

18 Karaichalli 2.39

19 Vilanguchalli 2.39

20 Kasuwar 2.07

21 Van 2.19 Formula : Maximum Diversity Index (MD) = log2 (TT)

Where TT is total taxa Source: Evaluation of Fourteen Trophic State Indices for Phytoplankton

of Indian Lakes and Reservoirs Environmental Pollution (Series A) 27 : 143-153 Editor : Sullivan P.I and Carpenter S.R (1982)

Page 259: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.34

Maximum diversity index values of Mangroves in 21 islands of Gulf of Mannar

Sr. No Name of island Maximum diversity index

1 Shingle 2.48

2 Krusadai 2.56

3 Pullivasal 2.39

4 Poomarichan 2.48

5 Manoliputti 2.48

6 Manoli 2.56

7 Musal 2.48

8 Mulli 2.3

9 Valai 1.79

10 Talairi 2.07

11 Appa 0.69

12 Poovarasanpatti 0

13 Valimunai 1.61

14 Anaipur 1.79

15 Nallathanni 1.79

16 Pulivinichalli 1.69

17 Upputhanni 1.94

18 Karaichalli 1.38

19 Vilanguchalli 0

20 Kasuwar 1.79

21 Van 1.79 Formula : Maximum Diversity Index (MD) = log2 (TT)

Where TT is total taxa Source: Evaluation of Fourteen Trophic State Indices for Phytoplankton

of Indian Lakes and Reservoirs Environmental Pollution (Series A) 27 : 143-153 Editor : Sullivan P.I and Carpenter S.R (1982)

Page 260: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.35

Mangrove Species in Coasts of Palk Bay and Gulf of Mannar

Name Type

Rhizophora apiculata True mangrove (Tree)

Ceriops tagal True mangrove (Shrub)

Avicennia marina True mangrove (Tree)

Derris trifoliate Mangrove associate (Tree)

Cyanometra ramiflora Mangrove associate (Shrub)

Acanthus iliciformis Mangrove associate (Shrub)

Myriostachya wightiana Mangrove associate (Grass)

Phoenix paludosa Minor Mangrove (Plam)

Page 261: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.36

Distribution of Mangrove Vegetation in the Islands of Gulf of Mannar

Sr. No.

Species

Van

Kasu

war

Vilan

guch

alli

Kara

ichall

i

Uppu

thann

i

Puliv

inich

alli

Nalla

thann

i An

aipar

Va

limun

ai Po

ovar

asan

patti

Appa

Ta

lairi

Valai

Mulli

Musa

l

Mano

li Ma

nolip

utti

Poom

arich

an

Pulliv

asal

Krus

adai

Shing

le

1 Avicennia marina

+ + + + + + + + + + + + + + +

2 Rhizophora mucronata

+ + + + + + + + +

3 Ceriops tagal + + + + + + + +

4 Bruguiera cylindrica

+ + + + + + + +

5 Lunmitzera racemosa

+ + + +

6 Pemphis acidula

+ + + + + + + + + + + + + + + + + + +

7 Excoecaria agaloocha

+ + +

8 Aegiceras corniculatum

+

9 Rhizophora apiculata

+ + +

ASSOCIATED SPECIES

10 Salvadora persiea

+ + + + + + + + + + + + + + + + + + +

11 Pandanus sp. + + + + +

12 Sesuvitun sp + + + + + + + + + + + + + + + + +

13 Scaevola plumieri

+ + + + + + + + + + + + + + + + +

14 Suaeda sp. + + + +

15 Salicornia brachiata

+ + + +

16 Thespesia populnea

+ + + + + + + + + + + + + + + + + +

Page 262: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.37

Annual Primary Productivity (Gross) in Certain Marine Environments as Grams Carbon per square meter Sea Surface

Locality Production gC/m2/year

Barents Sea 170-330

English Channel 60-98

Georges Bank 309

North Sea 57-82

Long Island Sound 470

Off Hawaii (open ocean) 21

Off Hawaii (inshore) 123

Turtle grass bed (Florida) 4650

Hawaiian coral reef 2900

Shelf waters off New York (shallow coastal region) 160

(Continental slope) 100

North Central Sargasso Sea 78

Temperature oceans 100-150

Equator 110-146

Barren tropical oceans 50

Cochin back water 281

West coast of India (within 50 m depth) 434

East coast (continental shelf) 230

Kavaratti lagoon (Laccadives) 2250

Minicoy reef 3000

Mandapam reef 2500

Andaman reef (Port Blair) 1200

Gulf of Mannar (inshore within 10 m depth) 745

Source : Bull. CMFRI, No. 22 (1970)

Page 263: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.38

Coral fauna around the Mandapam Group of Islands

Species of Coral Fauna Observed around Mandapam Group of Islands

Genus : Pocillopora :

P. damicornis p. danae

Genus : I. Acropora

A. formosa A. nobilis

A. erythraea A. corymbosa (Lamarck) . surculosa (Dana) A. hyacinthus (Dana)

Genus : III. Montipora

M. foliosa M. divaricata (Briiggemann)

M. digitata (Dana)

Genus : IV. Porites :

P. solida (Forskal) P. fragosa (Dana)

P. thurstoni (Pillai) p. alveolata (Milne Edwards and Haime)

P. exserta (Pillai) P. compressa (Dana)

P. (svnaraea) convexa P. nodifera (Klunzinger)

P. lutea P. mannarensis

Genus : V Favia

F. pallida

Genus : VI Favites

F. abdita (Ellis and Sollander)

Genus : VII Goniostrea. Spp.

Other coral species observed :

Platygyra lamellina (Ehrenberg) Leptoria phrygia (Ellis and Sollander)

Hydrophora spp. Leptastrea transversa (Klunzinger)

Leptastrea purpurea (Dana) Cyphastrea spp.

Symphyllia spp. Echinopora lamellosa

Source : Resources Information System for Gulf of Mannar

(India), GOI, DOD,

Page 264: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Integrated Coastal and Marine Area Management Project Directorate,

Chennai, April 2001

Page 265: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.39

Summary of Underwater Observations on Shelter and Food of Various Coral Reef Associated Fauna in the Mandapam Group of Islands

Family Name Species Shelter Food items

Holocentridae Sargocentron spp. (silver spot squirrel fish) Myripristis spp. Violet soldier fish

RE & RF URS

Benthic crustanceans Plankton

Pomacanthidae Pomacanthus imperator Abudefduf saxatilis (Sergeant major)

RE & URS URS

Sponges and encrusting Organisms Zooplankton

Pomacentridae Amphiprion clarkii RE & Omnivorous associated with sea anemone

Chaetodontidae Chaetodon collaris C. melanotus C. meyeri C. auriga

RE & URS RE & URS E & URS RF & URS

Coral polyp soft corals coral polyp small Invertebrates

Serranidae Anyperodon leucogrammicus

RE & URS Fish and crustacean

Scaridae Scarus sordidus S. gibbus scarus ghbus

RF & RE RE RE

Algae Algae Algae

Lutjanidae Lutjanus bohar L.Monostigma

URS URS

Fish and crustacean Fish and crustacean

Lethrinidae Lethrinus spp. RF & URS Benthic Invertebrates

Note: RF-Reef flat, RE-Reef edge, URS-Upper reef slope

Source : Resources Information System for Gulf of Mannar

(India), GOI, DOD,

Integrated Coastal and Marine Area Management Project Directorate,

Chennai, April 2001

Page 266: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.40

Marine Water Quality in Palk Bay (Latitude 9O44′)

Parameters Sample Location & Distance from shore

1 0.5 km (depth 2 m)

2 5.0 km (depth 4 m)

3 10.0 km (depth 6 m)

4 15 km (depth 7 m)

Temperature, OC Surface 29.00 29.00 29.00 29.50 Bottom 28.50 28.00 28.00 28.80

Surface 28.50 30.00 28.00 30.40 Suspended Solids, mg/l Bottom 34.00 26.00 34.00 23.00

pH Surface 8.20 8.20 8.10 8.20 Bottom 8.20 8.20 8.10 8.10

Salinity, ‰ Surface 30.68 31.15 31.60 31.50 Bottom 32.10 30.60 32.50 30.50

Surface 4.60 4.27 4.48 50.00 Dissolved oxygen, ml/l Bottom 4.10 4.18 4.08 4.18

Surface 2.20 1.10 1.60 0.80 Total phosphorus, µmol/l Bottom 1.19 1.00 2.40 -

Surface 28.80 30.30 32.10 30.8 Total nitrogen, µmol/l Bottom 23.10 35.30 34.00 29.70

BOD, mg/l Surface 2.88 3.10 2.43 1.37 Bottom 2.55 1.35 0.08 0.31

PHC, µg/l Surface 9.10 9.80 13.30 8.20 Bottom - 1.50 - -

Cadmium, µg/l Surface 0.70 0.10 0.68 0.22 Bottom 0.14 0.24 0.68 0.62

Lead, µg/l Surface 1.28 ND 2.64 2.02 Bottom 3.00 2.40 3.94 2.18

Mercury, µg/l Surface 0.48 0.10 0.21 0.46 Bottom 0.70 0.27 0.19 0.63

Source : COMPAS report prepared by CECRI

Page 267: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.41

Distribution of Zooplankton in Palk Bay near the Proposed Channel

Parameters Levels Observed

Biomass, ml/100m3 0.48-1.92

Population no/100m3 6065-36837

Total groups no. 8-12

Major groups, %

Copepoda 47-70

Foraminifera 5.66-17.79

Ostracoda 1.4-3.8

Polychaeta 1.6-1.89

Cumacea 0.6-1.89

Amphipoda 1.09-3.77

Mysids 1.14-1.89

Decapod larvae 2.27-5.43

Stomatopod Larvae 0.61-5.43

Fish Eggs 3.68-7.95

Fish Larvae 0.61-2.27

Euphasids 1.14-1.60

Source : COMPAS report prepared by CECRI

Page 268: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 2.42

Distribution of Decapods in Palk Bay

Penaeus indicus +++

P. latiulcatus +

Metapenaeus affinis ++

Parapenaeopsis maxillipedo +

P. cornuta ++

P. tenella +

Macrobrachium rosenbergii ++

M. aemulium ++

Hippolyty ventricosa +

Page 269: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 2.43

Distribution of Desmospongiae and Corals in Palk Bay

Species Distribution

Demospongiae

Spongia officinalis ++

Heteronema erecta +

Hyattella cribriformis +

Ircinia fusca +

Fasciospongia cavemosa ++

Dysidea herbacea +

Dendrilla nigra ++

Psammaplysilla purpurea +

Haliclonia exigua +

Iotrochota baculifera ++

Sigmadocia fibulata +

Taxadocia fibulata +

Orina sagittaria +

Damiria simplex +

Callyspongia diffusa ++

Echinodictyum gorgonoides ++

Damiriana schmidti ++

Rhabderemia indica +

Endectyon thurstoni +

Tedania anhelans +

Acarnus thielei +

Aulospongus tubulatus ++

Clathria, frondifera ++

C. indica +

Mycale grandis ++

Mycalecarmia monanchorata +

Zygomycale parishii +

Toxemna tubulata +

Biemna fortiis +

Axinella tenuidigitata +

Higginsia mixta +

Myrmekioderma granulata ++

Trachyopsis halichondroides ++

Page 270: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 2.43 Contd…

Species Distribution

Spirastrella coccinea +

Timea stellata ++

T. stelligera +

Page 271: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Suberites carnosus +

Laxosuberites cruciatus ++

Aaptos aaptos ++

Placospongia carinata ++

Cliona celata ++

C. vastifica +

Prostylyssa foetida +

Stellettinopsis simplex +

Epipolasis topsenti +

Tethya robusta +

T. diploderma +

Echionemia acervus +

Myriastra purpurea +

Aurora globostellate +

Geodia perarmata ++

Geodia lindgreni +

Cinachyra cavemosa +

Paratetilla bacca +

Lophacanthus rhabdophorus +

Dercitopsis minor +

Pachamphilla dendyi +

Corticium candelabrum +

Corticium acanthastrum +

Page 272: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Plakina monolopha +

Plakina acantholopha +

Chondrilla sacciformis +

Page 273: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.44

Distribution (kg/hr) of Various Fishery Resources along Palk Bay SE Coast of India during 1985-90

Groups 10O/80O Elasmobranchs 0

Carrangids 6.62

Nemipterids 0

Epinephelus sp. 7.43

Lethrinus sp. 10.05

Lutjanus sp. 5.48

Lutianus sp. 0

Pomadasys sp. 17.14

Diagramma sp. 2.74

Pentaprion sp. 1.37

Other perches 2.05

Cat fishes 0

Sciaenids 0

Lizard fishes 0

Goat fishes 2.45

Leiognathus sp. 11.22

Sphryaena sp. 0

Seer Fish 0

Mackeral 0

Dussumieria sp. 0

Psenes indicus 0

Psenopsis cyaena 0

Priacanthus sp. 0

Balistids 0.59

Miscell. Fish 15.7

Jelly fish 0

Crustaceans and Cephalopods 6.97

Total catch 89.71

Page 274: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.45

Abundance of Demersal Finfish Resources (kg/hr) in SE Coast of India EEZ

Major groups/Species Area 10O/80O

51-100 m depth Sharks -

Skates -

Rays -

Carangids 451

Rastrelliger Kanagurta 227

Silver bellies -

Threadfin breams 1

Lizard fish 1

Upeneus sp. -

Sphyraena sp. -

Priacanthus sp. -

Perches 303

Platycephalus sp. -

Flat fish -

Trichiurus sp. -

Cat fish -

Other finfish 5

Miscell. Fish 41

Total 1035

Page 275: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 3.46

Perches Abundance in kg along S.E. Coast (Palk Bay)

Depth (m)

Latitude Lutjanus Lethrinus Serranids Plectorhynchus Other Perches

Total

0-50 10O 3 - 29 - 18 50

51-100 10O 93 193 17 264 270 837

101-150 10O 14 - - - - 14

4. Land Environment

The objective of the present study is to evaluate the environmental impacts

on various land and ocean features in the project area as a result of dredging

operations to be carried out in Adam Bridge area, parts of Gulf of Mannar and Palk

Bay to create the navigational channel. The dredged material is required to be

assessed both qualitatively and quantitatively to arrive at option for its disposal either

on land or in sea. It is therefore imperative to accurately define the baseline status of

various environmental parameters pertaining to both land and the sea and to carefully

examine the environmental impacts on them. The option of disposal of dredged

Page 276: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

material has to be selected in such a manner so that impacts on Biosphere Reserves

can be prevented/minimized.

Satellite remote sensing data has proved to be highly reliable in delineating

the landuse and land cover of any region in a very limited time and in a cost-effective

manner due to its capability of providing very high spectral and radiometric integrity

and consistency. Satellite remote sensing data also facilitates accurate detection of

any change in the landuse pattern. The delineation of correct landuse pattern forms an

integral component of environmental impact assessment.

4.1 Objectives

The objectives of the present study are as follows :

• Delineation of various landuse and land cover classes in the study region

and estimation of their areal coverage through the analysis and digital

classification of satellite data

• Identification of potential dumping sites for dredged materials disposal

4.2 Data Used

Satellite data obtained in 1998 and 2002 has been used for delineation of

landuse pattern and identification of dumping sites. The data obtained in 2002 was

mostly used to study change in landuse pattern and to select suitable dumping site

close to Adams Bridge provided the quality of dredged materials is suitable for

nourishment of soil.

1. Remote Sensing Data : In keeping with the climate of the area the following

cloud free satellite data were chosen and the quality was checked for cloud

and haze cover, striping, line drop out etc. The following data at the latitude

(09°05’00"-09°25'00") N longitude (79005'00"-79035'00") E were used:

A. Satellite data

Merged data PAN sharpened LISS III

IRS 1D LISS III scene

Path: 102 Row: 67 dated 02 Jun 2002

IRS 1D PAN

Path: 102 Row: 67 dated 08 May 2002

Page 277: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

B. Collateral Data

Detailed location map IRS 1D LISS-III multispectral data and PAN offer very high spatial resolution

of 23.5 m x 23.5 m and 5.8 m x 5.8 m with a swath width of 127 x 141 kms

and orbital cycle period of 24 days. The data is sensed in four spectral bands

viz., band 2 (0.52-0.59 µ), band 3 (0.62-0.69 µ), band 4 (0.77-0.86 µ) and

band 5 (1.55-1.76 µ) with 8-bit radiometric resolution providing a dynamic

display range of 0 to 255 which facilitates distinct representation of the

various classes and also enables subtle tonal and textural discrimination

among them. The spatial, spectral and radiometric resolutions of the remotely

sensed data are the three primary governing factors in the correct estimation of

various landuse and land cover classes through digital analysis and

classification of the data. The discriminability among the various classes can

be further increased using the different image interpretation keys of the

existing geomorphic and cultural features in the scene such as size, shape,

tone, colour, texure, pattern, association etc.

2. Toposheets and Thematic Maps : Relevant toposheets in 1:50,000 scale of

the Survey of India and landuse map in 1:1,000,000 scale published by the

National Atlas and Thematic Mapping Organization (NATMO) were used for

registration of the satellite data. These were also used as collateral data in the

digital analysis and classification of the satellite data.

3. Field Visit : In order to strengthen the classification scheme, field information

plays major role in clarification of IRS LISS III imagery. This filed visit

mainly includes collection of ground truth sample to establish ground control

points which are required to reference the satellite imageries to a known map

projection.

4.3 Hardware and Software Used

1. A highly configured computer was used for the digital image processing. The

system offers an integrated platform to carry out complex tasks necessary for

digital image processing.

2. Remote Sensing data was analyzed using EASI/PACE V 7.0 and Geomatica V

8.2 software loaded in a highly configured computer. The software package is

Page 278: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

a collection of image processing functions necessary for pre-processing,

rectification, band combination, filtering, statistics, classification etc. Apart

from contrast stretching, there are large number of image processing

functions, that can be performed on this station. Further analysis was

performed in GIS (MAP INFO Professional 6.2 and ARC/INFO software)

environs.

4.4 Selection of Study Sites

Keeping in view the objectives of the study pertaining to land environment,

three different subscenes were extracted from the satellite data in order to map the

various landuse and land cover classes with finer detail. The study sites are as

follows:

1. Pamban island alone

2. Pamban island and the coastal wedge of Mandapam

3. Pamban island and an approximately 25 km. coastal buffer land stretching

along the Palk Bay and the Gulf of Mannar (1998 imagery)

4.5 Methodology

Landuse refers to man’s activities on land, which are utilitarian in nature,

whereas land cover represents the vegetation and other natural features such as

barren land, stony land, water bodies, marshy areas etc. The remote sensing data

records information essentially on land cover from which information on landuse has to

be inferred. The landuse/land cover classification system standardised for mapping

different agro-climatic zones by the Department of Space has been adopted. The

classification system has six major landuse classes at level I and 28 at level II (Table 4.1). These are listed below:

1. Urban or built-up land : This comprises mostly cultural

features including commercial and industrial areas

2. Agricultural land : This includes cropped areas, fallow lands

and plantation

Page 279: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

3. Forest: This includes all lands administered as forests such as

dense, sparse, and degraded forests, mixed forest, scrub, forest

plantations, agriculture in forests etc.

4. Wastelands: Lands which have potential for the development

of vegetative cover but not being used due to different constraints are

classified under this category. This includes salt affected land,

gullied/eroded land, waterlogged area, marshy and swampy area, sandy

area and rocky outcrops etc.

5. Water bodies : Areas persistently covered by water such as

rivers/ streams, reservoirs/ tans, lakes/ponds, canals etc. are included

under this category

6. Others: Shifting cultivation, grassland, snow cover etc. are

included in this class.

The task of delineation of various landuse and land cover classes and site

selection for dumping of dredged materials was accomplished with recourse to the

step-wise methodology described as under.

Landuse and Land Cover Mapping

i. Preliminary analysis and reconnaissance study of the raw band data and false colour

composites (FCCs) generated in different band combinations with a view to

understanding the spectral signatures of the various spectral classes occurring on the

scene. This task was also supplemented through use of available toposheets and

other thematic maps such as landuse map published by NATMO. The FCCs were

stretched between 0 to 255 to utilise the full dynamic range of the display unit in

order to use the complete gray level range and optimise the contrast between various

features. It was felt that interpretation up to level II of the Department of Space is

not possible with consistent accuracy using FCC alone.

ii. Acquisition of representative ground truth samples from the field by means of a

Global Positioning System (GPS), providing a geometric accuracy which is

sufficient for accomplishing the task of digital image analysis successfully. The

ground truths were used for selecting the training pixels of different classes on the

FCCs with high geometric accuracy.

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iii. Selection of representative training signatures for various landuse/land cover classes

on the basis of their spectral discriminability and ground truths.

iv. Digital classification of the multispectral satellite data using maximum likelihood

classifier using the training signatures extracted for the respective classes. All the

four spectral band data have been used in the classification. Reject classes, and

underrepresented and overrepresented classes have been minimised by interactive

iteration through careful selection of the training area based on the a-priori

probabilities of different classes.

Identification of Dumping Sites for Dredged Materials

Subsequent to the generation of classified images of the study sites, dumping

sites for the dredged materials were identified on the images by resorting to various

criteria discussed in detail later.

4.6 Data Interpretation

Analysis of False Colour Composites (Merged FCCs)

Using the imagery analysis program, merged false colour composites were

generated using IRS 1D LISS III and PAN, for the different study regions viz., Pamban

island and the coastal wedge of Mandapam, Pamban island alone in Red (band 3),

Green (band 2) and Blue (band 1) combination as shown in Plate I and Plate II respectively. The interpretation of the FCCs was carried out using various image

interpretation keys such as tone, colour, size, shape, texture, pattern, and association

of the various landuse and land cover classes present in the study regions. In each

composite, the dark red colour represents dense vegetation, moderately red colour

represents moderately dense vegetation, and light reddish white colour represents

sparse vegetation. The plantations mainly comprise coconut and palm, which are

identified on the basis of both their reddish signature and characteristics pattern, and

the sparse plantations are displayed in reddish yellow colour. The dense scrub mostly

comprising Prosopis juliflora, a very common vegetation species occupying vast

stretches of land in the study areas in dark blue colour. Marshy land, backwater and

waterlogged areas appear in different shades of black. Water bodies appear in cyan

wherever they contain water, otherwise they are whitish in appearance. The barren

sandy areas are distinct by their characteristic white colour throughout the FCCs. The

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interpretation of the FCCs was made easier using the ground truths and also, the

collateral data such as toposheets and landuse maps.

Morphologically the area is a coastal plain. The area is characterized by the

formation of coastal alluvium, sand and clay. There are patches of shrub forest in the

close vicinity of the project site and mostly towards the southern part of the Pamban

Island, seen brownish red in the FCC. Also, general vegetation area mainly includes

cropland or shrub forest. The shrubs are random and appears in different shades of

brown tone. Fringe vegetation and sand bar is prominently seen along the coastline in

the island. The central portion of the imagery is indicating the presence of barren

sandy area as interpreted from characteristic whitish tone of the sand. The imagery

also indicates the presence of turbid water towards northern part of the island and

appears in cyan or dull green colour. The degraded barren land is also present

towards the south-eastern part of the island as prominently seen in the FCC. Road

network was visible in the monitor while performing image-processing though not

visible in the FCC paper print, however the road network is colour coded in the

classified image (Plate III).

Analysis of Classified Images

The colour coded output of supervised classification and maximum likelihood

algorithm for Pamban Island and its surroundings is depicted in Plate III. In this

image, different colours are assigned to various classes as given in the legend. The

fringe areas of the inland shallow and deep sandy areas i.e. areas located close to the

sea are prone to flooding due to backwater intrusion in most part of the year.

The area statistics of the different feature classes present on the classified

image is given in Table 4.2 for the study region. The landuse/ landcover classification

indicates 4.772 % area covered by turbid water, 53.328 % vegetation cover (crop land,

shrubs, forests), 8.084 % fallow land etc.

Different classes are identified, alongwith the corresponding area. Most of the

water bodies are shallow containing turbid water. Few agricultural activities occur in

the area. The yellow colour in the landuse map indicates the cropland. The fallow is

found to be associated with agricultural lands. The shrub land is found to be present

inside the forest as well as outside and is reported an area of 8.331 %. and is

assigned by reddish colour. Small patches of water bodies are mainly concentrated

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towards north-eastern part of the area and are assigned by the cyan colour in the land

use map. The degraded land is present towards the south-eastern part of the Island

and is assigned as deep brown colour. Road network as visible in full resolution is

represented as red lines in the colour coded output.

4.7 Identification of Dumping Sites for Dredged Materials

The following criteria were used to identify potential sites for dumping of the

dredged materials:

i. Areas which are close to the proposed ship navigational route

ii. Areas which presently are not in use for any significant activity (commercial

or other)

iii. Shallow and deep areas which otherwise can be reclaimed for productive

utility

iv. Barren sandy areas which do not contain any vegetation cover and are also

classified as unproductive

v. Areas which are devoid of vegetation and areas which are not in close

proximity to the dense vegetation

vi. Areas which are not in proximity to the water bodies such as river, pond, back

water etc. to ensure prevention of erosion and siltation of dumped materials

into them so that their natural pristine status is conserved

vii. Areas which are easily accessible and trafficable

A detailed and thorough examination of the classified images of the satellite

data was carried out using the above mentioned criteria and the following sites were

proposed for dumping of dredged materials based on 1998 imageries.

i. The shallow and deep sandy areas lying in the Pamban island since most of these

areas are located in the narrow strip of the island through which the navigational

channel is proposed to be constructed. Likewise, the barren sandy areas occurring

in the island can also be used as dumping sites. The shallow and deep areas cover

20.32 sq.km. i.e. 2032 hectares which comprises 20.67% of the island whereas the

barren sandy areas alone stretch over 21.76 sq.km. i.e. 21.76 hectares which covers

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22.13% of the island. In other words, nearly 42.8% of the island alone which covers

an area of 42.08 sq.km. i.e 4208 hectares can be selected for dumping sites. Even

effective utilization of 50% of the available area would serve as major dumping

sites within the island alone (i.e. nearly 20 sq.km. or 2000 hectares).

ii. Barren sandy areas occurr in the Pamban island and in the coastal wedge of

Mandapam area. The shallow and deep areas in this region are nearly same as that

of the Pamban island alone because these areas are dominantly confined to the

island only. However, an extensive barren sandy area is available in the coastal

wedge of the Mandapam region (over 140 sq.km. or 14000 hectares). Effective

utilization of a nominal 25% of the available area means that 35 sq.km. area is

available for dumping of the dredged materials.

Keeping in view the reduction in quantity of dredged material due to

realignment of route using navigational depths available in Gulf of Mannar, the

dredging activity will be restricted to an area in the vicinity of Adams Bridge over a

length of about 5 km and a width of about 500m. The quantity could depend on

bathymetry charts and the depth of dredging. It is proposed to dispose sand portion

into sea at a suitably identified location and the silt and clay can be disposed on

degraded land in Pamban island. The Plate IV shows proposed location for disposal of

dredged material as indicated in the marked area spreading over 753 hectares. The

area is degraded land and can be converted into cultivable land through nourishment

by dumping silt and clay with some portion of sand from dredged material.

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Table 4.1

Land use/ land Cover Status in Pamban Island, Based on the Satellite data of May, 2002

Inventory by IRS 1D LISS III + PAN May, 2002 Category

Area, (ha) % to Total

Vegetation Cover 1 717.835 7.438

Vegetation Cover 2 2758.664 28.585

Fringe Vegetation 866.136 8.974

Turbid Water 460.603 4.772

Mud Flats 97.185 1.012

Sand bar 1261.951 13.076

Fallow land 776.699 8.048

Shrub 804.056 8.331

Barren sandy 427.754 4.432

Degraded land 1479.719 15.332

Total 9650.602 100

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Table 4.2

Landuse/Land Cover Classification System

Sr. No. Level - I Level - II

1. Built-up Land 1.1 Built-up land

1.2 Road

1.3 Railway

2. Agricultural Land 2.1 Crop land

2.2 Fallow (Residual)

3. Forest 3.1 Evergreen/Semi-evergreen forest

3.2 Deciduous forest

3.3 Degraded/Scrub land

3.4 Forest blank

3.5 Forest plantation

3.6 Mangrove

3.7 Cropland in forest

4. Wasteland 4.1 Salt affected land

4.2 Waterlogged land

4.3 Marshy/Swampy land

4.4 Gullied/Ravinous land

4.5 Land with or without scrub

4.6 Sandy area (coastal and dessertic)

4.6 Barren rocky/Stonywaste/sheetrock area

5. Water bodies 5.1 River/Stream

5.2 Lake/Reservoir

5.3 Tank/Canal

6. Others 6.1 Grassland/Grazing land

6.2 Shifting cultivation

6.3 Snow cover/Glacial area

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5. Socio-economic Environment

Along the coast in the Gulf of Mannar and the Palk Bay, there are 127 villages

and towns spread over 5 districts. Summary data on population area number of households

etc. is presented in Table 5.1. Detailed information for each one of these villages/ towns is

presented in Table 5.2 and 5.3.

5.1 Socio-economics of the Fishing Community

The project area contains a rich mix of people of different religions and castes.

There are 23,000 fisher-folk households with a population of 115,000 in about 70 fishing

villages/ hamlets. There are about 35,000 active fisher-folk and about 70% of them are

involved in direct fishing, 21% in fishing related activities and 9% in other activities.

The literacy rate among the communities living along the coast of Gulf of Mannar is

only 31%, far less than the state average (64%). While most of them (54%) do not have a

dwelling of their own and live in huts along the sandy beaches, 25% have semi permanent

and only 21% have concrete or tiled roof houses. Though majority (56%) of the fishermen

still depend on traditional catamaran for their fishing activities, 95% of them could not

operate continuously due to non-availability of net and other equipment. Only 10 percent of

the fisherfolk have ownership of means of production above Rs. 1,00,000 indicating the most

of the commercial trawlers are from outside the area. Hardly, 37% of the fisherfolk

households in the region have ownership on some sort of means of production. Per capita

income of a fishermen is just Rs. 3,943/- (1990-91), far less than the state average.

During this study a review of fishing activities in Ramnathpuram Dist. was taken up

based on 2000 census data. The number of male population involved in fishing is 29570

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whereas who are involved in trade, marketing, net making and other allied activities those

are around 2200. The population of fisherwomen involved in fishing is about 1657 and

women involved in allied activities including trade are about 5500. Income status of

fisherfolk in 2000 census has shown a positive trend as compared to 1991 census where per

capita income was Rs. 3943/-. The per capita income according to 2000 census varies from

Rs. 3000 to Rs. 15000/- as per 2000 census data. Income status of fisherfolk in Dist.

Ramnathpuram shows 7849 people in less than Rs. 3000/- range, 13083 people in Rs. 3001-

6000 range, 19425 people in Rs. 6001-12000 category and about 2000 people in Rs. 12001-

15000 range. As per 2000 census data the fishing crafts comprise mechanised boats (1804

no.) and non-mechanised boats (5078 no.).

Currently the Gulf’s fishery is truly an open access resource. No property regime is

in place to manage or control access to this resource and as a result it is under heavy,

unsustainable pressure. Approximately 45,000 fisherfolk are currently fishing along the

Gulf’s waters. Ninety percent of them are artisanal fisherfolk (using small wind or small

engine powered craft) and 10% of them are mechanised trawler fishermen. Any person who

desires to take-up commercial fishing need only register with the Fisheries Department.

There is no limit on the number of fishing society in their local village or town. These

societies serve primarily as a savings-type of institution, and do not provide the fisherfolk

with the benefits of cooperative marketing, processing and management of the local fishing

areas for the common good.

The introduction of mechanised fishing to the region in the last 40 years has

gradually led to the breakdown of the specialised artisanal fishing community (some fishing

exclusively for prawn, others for sea cucumber, etc.) and has resulted in most fisherfolk

fishing for whatever they can find.

One of the serious problems in the area is the increasing human population at rates

considerably faster than that occurring in metropolitan areas of India. The rate of increase in

some villages could exceed 4% per annum, which is equivalent to a doubling of the

population within about 30 years. Unless the population is stabilized it is unlikely that the

ecosystems in the proposed reserve and surrounding areas will be sustainable. This problem

will be aggravated by the inevitably greater demands on resources from individuals as

economic development proceeds.

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Currently there are very few, if any, income generating options for local fisherfolk.

There are no organised programs to provide local fisherfolk with technical and business

expertise in order to develop alternative livelihoods and income generating activities.

Existing research programs in the area are developing appropriate technologies for seaweed

farming, and pearl oyster farming, but they lack the mandate and expertise to transfer this

technology to local people.

5.2 Sample Survey

As part of the present study, a rapid survey was conducted on the socio-economic

aspects of the population in the project area, and to assess the public opinion on the proposed

canal project. The details of this survey alongwith the views expressed by the fishermen, the

officials of the Fisheries Department, Rameswaram, Naval Staff of Coast Guard Station,

Mandapam, and officials engaged in R&D work in the Gulf of Mannar and the Palk Bay on

the project are presented hereunder.

The Assistant Director of Fisheries, Govt. of Tamilnadu at Rameswaram was

contacted for information on fishermen settlements in the project area that might be affected

by the Sethusamudram Ship Canal Project. Based on the information obtained, the following

areas were visited for personal/group interviews on the ‘Socio-economic Component’ of the

project. This survey represents a sample of 8000 to 10,000 fishermen from Pamban,

Natarajapuram, Ramakrishnapura, Kothandaramar Koil Nagar (near the temple) and Moonru

Eruppu Chathram in the study area.

Natarajapuram, a village on the way to Kothandaramar Temple, is situated at a

distance of about 6 km from Rameswaram. The population of the village is about 4000, and

fishing is the only occupation of the villagers. There is a Registered Fishermen Co-operative

Society with Shri Chelladurai as the President of the Society. About 100 numbers of Vallam

(non mechanized boat with outboard motors of less than 14 H.P.) are used for fishing per day.

Each Vallam is manned by 5 people and so about 500 people are engaged in fishing per day.

Since these villagers are dependent upon non-mechanized boats (Vallam) they can go for

fishing only upto 3 km from the shore. The fish landing area of these people comprises the

shallow waters in the vicinity of the shore. Eral, nethil varieties are more only in the

Northern side and especially during June, July and August.

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Nearly 25 people belonging to the fishing group were interviewed for their views

about the Sethusamudram Ship Canal Project, popularly known among the local people as

“Sethu Calvai Thittam”. For the past 100 years the Government of India/ Tamil Naud have

been talking about the project, and therefore, the people in this area are well aware of the

project. The residents of Natarajapuram village were originally living in Dhanushkody

island. When Dhanushkody was engulfed by the severe cyclone of 1964, these people shifted

their residence to Natarajapuram. A large number of them are occupying Government land,

and have not been issued ‘pattas’ because of the proposed ‘Sethu Calvai Thittam’. Even

though the Government has the intention to issue pattas to these people, it is not able to do so

as the area required for the Sethu Calvai has not yet been identified and earmarked. Under

these circumstances, the people of Natarajapuram village anxiously look forward to the

fruition of the project at an early date, so that they will get the pattas for their lands. The

people are in one voice in favour of the Sethu Calvai Thittam.

Ramakrishnapuram village is in the vicinity of the proposed alignment of the

Sethusamudram Ship Canal. There is a Fishermen Co-operative Society in this village. As

per Shri Kumaresan, the President of the Society, there are 1432 registered mechanized

boats on both the islands. Out of these on an average 750 boats are used in a day for fishing

operations in the islands. Since these people use mechanized boats (upto a H.P. of 114) they

go for deep sea fishing thrice a week. The peak season lasts 5 months in a year. Here also

the people are well aware of the project because of the century old propaganda by the elected

representatives about implementing the project. While the people welcome the project, they

have an apprehension that deepening the canal might result in a reduction in the fishery

potential leading to a direct impact on the fishermen’s economic development. They also

expressed concern that their fishing nets could be damaged during ship navigation when the

canal comes into being. The fishermen suggested that, if the project comes into operation,

they need a separate boat jetty in a convenient place to anchor their boats. Not withstanding

the above, they all are in favour of the project.

The settlement called ‘Kothandaramar Koil Nagar’ near the Kothandaramar temple

has about 200 huts with a population of nearly 800. This village is very near the proposed

alignment and the local fisher folk have no ‘Vallarns’ or ‘Thonis’ for fishing. They go for

fishing to the Dhanushkody island by bus/walk. According to them fish is available in the

shallow (2 to 3 feet) waters in the Dhanushkody island. The fish catch is transported to the

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market by bus or as head loads. When interviewed, the people were of the opinion that the

Sethu Canal project would severely affect their economic development. The proposed land

cutting for the navigation channel between Kothandaramar Koi and Dhanushkody island,

near ‘Moonru Eruppu Chathram’, will cut off the road transport facility between their

dwelling places and Dhanushkody island, their only place of fishing. None the less, they are

in favour of the project in the overall national interest and with the hope that they will get

their ‘pattas’ from the Government once the project comes into operation.

The Government of Tamilnadu permits fishing by licensed fishermen in the islands

throughout the year. There seems to be competition between the fishermen having

mechanized boats on one hand and non-mechanized boats on the other resulting in over

exploitation of fishing in both the islands. Since the Sri Lankan Government has banned the

fishing operation for three months in a year, a sustainable fish potential is maintained near

‘Kachcha Thivu’ just two kms beyond the International Border Line (IBL) between India and

Sri Lanka. The over exploitation of fishing in the Indian islands tempts the Indian fishermen

to cross the IBL and get involved in fatal accidents by Sri Lankan Naval Staff. Under these

circumstances, the Sethu Samudram Ship Canal Project may not have any direct adverse

impact on fishing potential in both the islands.

The Naval Staff of the Coast Guard Station at Mandapam are of the view that the

implementation of the project will increase the potential for oil spill in the navigation canal.

They also suggested that the above problem could be overcome by enanting a low by which

any ship navigating through the canal and causing oil spill would not be allowed to use the

canal in future. Otherwise, they are much in favour of the project as it would provide free

protected access to fisherman between the Gulf of Mannar and the Palk Bay, illegal and

clandestine activities in the project area and also improve the socio-economic status of the

people living in Ramanathapuram, Rameswaram, Mandapam and Tuticorin.

Some of the Government staff directly involved in R&D in the Gulf of

Mannar and the Palk Bay were of the opinion that currently the increased activities in

both the Gulf of Mannar and Palk Bay have been depleting the reserves of the 'Bio-

Paradise of the Gulf of Mannar'. They further observed that there were more of dead

coral reefs than live ones. Under these circumstances, the proposed project with the

canal alignment far away from the marine parks (islands) would not have any

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significant adverse impact on the bio-sphere reserves of the Gulf of Mannar. They

also are in favour of the project.

5.3 Existing Status

The entire GOMBR area comprises of 99 panchayats spread over

approximately 1600 sq. km area. The area has around 466 villages, varying in size

and population. A population of around 2.79 lakhs live in the area depending on the

sea, agricultural and allied livelihoods.

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The Sub-programme Area and the Households:

Name of the Block No. of Panchayats

No. of Villages

Total households

Total Population

Ramnathpuram District

Mandapam 22 146 15,930 74648 Thirupulani 22 130 11,038 53554 Kadaladi 25 100 20,385 80855 Ramnad 3 22 3,241 14707 Tuticorin District Vilathikulam 20 50 7,843 35193 Ottapidaram 7 18 4,450 20274

Total 99 466 62,887 279231 (Source : Compilation from Census 1991)

The socio-economic development of the region is poor and requires intensive

efforts for developing it. The reserve area as demarcated is predominantly dependent

upon sea based activities which includes fishing and salt making. There however,

exist opportunities for palm-based occupations and other incidental activities related to

fishing. Agriculturally the area is characterized by severe drought with agriculture

dependant on the monsoons. The yields of crops are generally low and risk-prone due

to complete absence of irrigation facilities. The major source of irrigation is through the

village tanks, which are solely dependent upon the rainfall. The existing sea based

resources have become constrained and prone to conflicts and forcing the people in

the reserve area into despair.

Conflicts between intensive and artisanal fishers regarding equitable access to marine resources: The mode of fishing in the reserve area is through

traditional fishing through catamarans and mechanised trawlers. There are many

instances of conflicts between these two sectors, namely the traditional and

mechanised sectors on the one hand, and also within the sectors, on the other,

because of unequal opportunities. These lead to violent clashes in the open sea,

cutting of nets setting boats on fire. The mechanised boats, which allegedly cross the

international boundary line are often exposed to gunfire from the other side leading to

loss of life and seizure of boats.

The conflicts that arise in the fisheries sector are essentially due to the

economic disparity that has developed between the fishermen who continue to use the

age-old traditional crafts and gear to catch fish and the mechanised boat owners who

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have been able to adopt and invest in modern technologies such as trawling. Artisinal

fishers have a narrow range of operations closer to the coastline with propulsion

depending on human muscle power and wind energy and passive gears where the

fish should reach the gear for capture. The mechanised boat owners have a longer

range for capture and operations away from the coastline and operate active fishing

gear which goes after the fish for capture.

This latter group goes for high value shrimps and fish and, because of their

efficiency cause problems for conservation of the target resources. Due to shrinking

economic returns, the former (artisanal fishermen), unable to meet their daily livelihood

needs, resort to unsustainable activities such as coral mining, dynamite fishing,

juvenile fishing, sea cucumber collection, intensive seaweed harvesting, and even

attack protected and endangered species. They thus come into conflict with the law

enforcement machinery.

Almost every fishing village has a Fishermen Co-operative Society; some

have more than one. There are also Fisher Women Co-operative Societies in most of

the villages. Every fisherman is a member of a society. The main function of these

societies seems to be implementation of government welfare and subsidy schemes for

the fishing community. Marketing is left entirely to the merchants/ middlemen/ agents

and auctioneers. In some cases fisherwomen undertake retail marketing.

The Department of Fisheries plays an important role in dealing with issues

related to fishing, regulations, conflict resolutions and welfare schemes. However, the

content and character of marine fisheries have changed a great deal since the advent

of mechanisation as also the opening up of export market for several of the marine

products. On the one hand, the present marine resource use is becoming more and

more unsustainable and, on the other, the livelihood security of traditional fishermen is

getting eroded due to diminishing income. In such a trend, conflicts are bound to

increase and become widespread.

Marine-based livelihoods: The livelihoods of people in the coastal buffer

zone partly depend on coastal and marine resources. However, agriculture and allied

activities still play a major role in providing livelihoods for the poor. The activities of

coastal-based people include fishing, salt making, seaweed collection or other marine-

based activities are gaining importance. Ninety percent of these fisherfolk are artisanal

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(using wind or small engine powered craft) and 10% are mechanized trawler

fishermen. (Source: Paragraph 8 of GEF project brief)

The mechanisation of fishery has displaced women from their traditional roles

in processing, marketing and making of nets; forcing them to take up alternative

livelihoods. As women play a major role in supporting the sector, they would be the

primary beneficiaries. Existing livelihoods related programmes in the buffer zone area

do not provide adequate economic alternatives and in particular do adequately

address the needs of women fisher-folk. As a result, people’s only alternative

livelihood option has been harvesting of wild seaweed or coral, which they have been

over harvesting. (Source: Paragraph 9 of GEF project brief)

As a result of the complexity of the types and efficiency of fishing craft and

gear and the fluctuations in the available fishery resources, there are wide variations in

the catch and income to the fishermen. More than 70% of the active fishermen work as

labourers in the boats owned by others on share-basis or for wages. The fishermen

working in the country crafts such as catamarans, vathai, thoni and vallam (not

motorized) earn a daily income in the range of Rs.20-30, except on a few days during

the peak fishing season.

The fisherwomen are more burdened and try to supplement the family income

through fishery related trades such as dry fish preparation and marketing, seaweed

collection and net-making and mending, and non-fishery activities such as working as

labour in salt pans, and beedi making. These activities are seasonal and possible only

in certain areas and do not add much to the family income.

The GOMBR coastal belt has a very large proportion of country crafts, about

87%, against the mechanised boats, about 13%, in the total crafts of about 1573. Thus

a very large segment of traditional fishermen population has to work closer to the

shoreline in shallow waters where the resources are poor and thereby their income also

is poor. There are increasing number of instances where, due to poor catches and

diminishing economic returns, the owners are selling the mechanized boats.

The fishermen and fisherwomen, during discussion, expressed the desire for

guiding them and training them in income generating vocations that will improve their

socio-economic conditions. In respect of fishery technological options, Fish

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Aggregating Devices (FAD's) for men and net making/ mending and fish by-products

for women stand out significantly.

In addition to fishing many are involved in various supplementary activities for

their livelihoods viz., charcoal making, salt making, mat weaving, coir making and

agriculture and allied activities. Availability of timely and adequate credit from the

formal system and lack of support systems for marketing are the two main problems

faced by the people. The detailed discussions on the calculations are given in the

annexures.

Agriculture-based livelihoods: In the buffer zone area, agriculture also

plays an important role in the life of the people. The major part of agriculture thrives

based on the irrigation available through the village tanks. These tanks are traditional

water harvesting structures and provide ample scope for enhancing their existing

livelihoods if rehabilitated and maintained properly. As per the recent statistics (1994)

in the Ramnad region near the Reserve there exist around 71 tanks irrigating 3,750

ha. This constitutes around 21 % of the tankfed area near the Reserve. As the region

is devoid of any other form of agriculture, tanks irrigate around 80 % of the lands under

cultivation. Almost all the tanks in the reserve area are in need of rehabilitation.

On the other hand, it is also reported that farm workers from hinterlands

mainly tankfed agriculture farmers are leaving and joining as trawler workers. Though

this is a seasonal activity the trend seems to be on the increase. The major reason

attributed is due to lack of proper irrigation facilities like tanks, which are mostly under

disrepair in the region. Any meaningful development of the Reserve should also

include the development of tank irrigation and dependent agriculture.

Financial services for poor: Existing livelihood related programmes in the

buffer zone continue to ignore the development of sustainable alternatives. In a

majority of the cases, people would continue to be forced to seek credit from the

moneylenders at prohibitively high rates of interest, resulting in more pressure on the

resource to repay the interest.

Majority of the poor in this area depend on the indigenous systems and have

least access to formal institutions providing these services. Predominant among

savings systems include local chits, friends and relatives. People are involved in a

local practice called ‘Seimora’ (offering of money to relatives on a social function)

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which involves outflow of funds. Though this practice is a socially accepted mutual

support system, people find it difficult to meet these commitments and depend on

money lenders.

A variety of local lending practices are in use and the interest rates range

from 5-10% per month. In case of small consumption and emergency loans, the rates

are as high as 10-20%. The formal financial institutions primarily rely on collateral and

the procedures are lengthy resulting in undue delay in sanctioning of loans. Even if

formal credit is available, banks provide credit only for selected economic activities,

while the poor need credit for both income generation and social security. In order to

sustain the economic activity and to insulate the liquidation of assets in times of

emergency, the poor require continuous line of credit support for small consumption

and emergency needs.

As the livelihood of the poor in this area depends on the sea, there is a high

risk of accidents and often leading to death of family members. This causes great set

back to the whole family and affects their livelihoods. Though government sponsored

social security schemes are in existence, this does not cover and reach all the needy

in time. Incomes earned are high in cases of the marine or coastal-based activities but

due to the problem of alcoholism, the income does not reach the family and is drained

out of the system, keeping the families in perpetual debt leading to poverty. The

programme related to building up financial services should also include insurance

against the risks due to death, sickness and other calamities.

Existing status of Fishing Activities in Rameshwaram

The survey team had held discussion with general secretary of fishermen

association at Rameshwaram. It is revealed that about 50000 fishermen are involved

in fishing operation at Rameshwaram including all the villages in Pamban Island.

Fishing is done in both Palk Bay and Gulf of Mannar. Some times fishermen go upto

Lankan waters as prawn fishing in Palk Bay is not conducive due to rocky base. It

was informed that fish catch in Palk Bay has decreased over last 10 years.

Approximately 900 boats operate from Rameshwaram on alternate days. The fishing

is done both by mechanised and non-mechanised boats. Prawn catch is 20-25

kg/boat whereas fish catch is 600 kg per boat.

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Table 5.1

Summary of Coastal Villages/Towns in the Study Area

Number of Sr. No. District/Taluka No. of

Villages/ Towns

Population (1991

Census)

Area (Ha) Houses House-

holds

Population Density (Range)

District : Nagapattinam

1. Sirkali 8 48170 7874.46 10601 10776 2.97-17.26

2. Tharagamabadi 5 31324 3759.03 2811 2829 3.09-19.22

3. Nagapattinam 8 119442 11520.91 24105 24818 3.72-58.44

4. Vedaranyam 7 52523 6021.45 5442 5448 2.54-33.99

5. Thiruthuraipoondi 3 21997 2090.01 776 797 5.76-11.27

6. Nannilam 1 1225 311.48 265 266 3.93

Total population in Dist. (in 2000) (1487055)

District : Thanjavur

7. Pattukottai 14 36030 11386.44 7946 8034 0.56-22.01

8. Peravoorani 10 11349 3633.16 2202 2255 -

Total population in Dist. (in 2000) (2205375)

District : Pudukottai

9. Avudaiyar Kovil 17 49854 8664.38 9823 10003 0.05-21.54

Total Population in Dist. (in 2000) (1452269)

District : Ramanathapuram

10. Thiruvadanai 13 55626 7389.99 5567 5602 0.27-24.69

11. Mudukulathur 8 33379 13201.95 6549 6685 0.13-4.13

12. Ramanathapuram 22 137812 30651.39 22016 22073 0.5-29.84

13. Rameswaram 2 56522 624.92 4656 4688 52.36

Total Population in Dist. (in 2000) (1183321)

District : Tuticorin

14. Vilathikulam 2 9548 5024.3 1818 1854 0.51-1.07

15. Ottapidaram 2 6793 4118.61 1344 1358 0.78-2.65

16. Tuticorin 5 237419 20841.77 1157 1180 4.08-35.73

Table 5.2

Page 303: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Details of Coastal Towns/Villages in the Study Area (Palk Bay)

Sl. No.

Name of Viallage/Town

Taluk Population Area (Ha) No. of Houses

House-holds

Density

District : Nagapattinam

1. Perunthottam Pandaravadai

Sirkali 4270 607.57 984 989 7.03

2. Pudupattinam Sirkali 7444 1530.28 1722 1756 4.04

3. Thandavakulam Sirkali 4130 1022.20 1059 1059 4.04

4. Vedankudi Sirkali 4646 1563.00 1022 1022 2.97

5. Thirumullaivasal (Urban Panchayat)

Sirkali 11551 669.24 2299 2395 17.26

6. Thennampattinam Sirkali 4138 784.33 898 914 5.28

7. Kilaiyur Sirkali 6643 896.76 1453 1477 7.41

8. Vanagiri Sirkali 5348 801.08 1164 1164 6.68

9. Kalamanathur Tharagambadi 2805 811.26 658 658 3.46

10 Marudampallam Tharagambadi 2802 502.16 617 617 5.58

11. Pillaiperumal Nallur Tharagambadi 2593 839.25 626 626 3.09

12. Manikkapangu Tharagambadi 4243 624.00 910 928 6.80

13. Taragambadi (Urban) Tharagambadi 18881 982.36 N.A. N.A. 19.22

14. Nagore Nagapattinam 970 - 211 211

15. Prathiba Ramapuram Nagapattinam 5779 1553.96 1315 1315 3.72

16. Thiruppundi Kilobotti Nagapattinam 4490 936.05 1136 1136 4.80

17. Therkupovur Nagapattinam 3600 660.94 864 864 5.85

18. Vilandawadevi Nagapattinam 5071 929.05 1164 1165 5.46

19. Vellankanni Nagapattinam 6155 428.24 1301 1301 14.37

20. Vettaikaran Iruppu Nagapattinam 6888 1168.82 1794 1795 7.96

21. Nagapattinam Nagapattinam 86489 5843.85 16320 17029 58.44

22. Kodiyakadu (Kodikarai)

Vedaranyam 1762 694.71 384 384 2.54

23. Kovilpattu Vedaranyam 2747 567.00 682 682 4.84

24. Vellapallam Vedaranyam 5311 937.17 1241 1243 5.67

25. Naluvedampatti Vedaranyam 4938 959.69 1217 1219 5.15

26. Pushpavanam Vedaranyam 5700 1370.31 1405 1407 4.16

(Contd…)

Page 304: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 5.2 (Contd…)

Sl. No.

Name of Viallage/Town

Taluk Population Area (Ha) No. of Houses

House-holds

Density

27. Periyaguttagai Vedaranyam 2233 614.90 513 513 3.63

28. Vedaranyam Vedaranyam 29832 877.67 - - 33.99

29. Muthupet (Rural) Thiruthuraipoondi 18826 1670.45 11.27

30. Muthupet (Urban) Thiruthuraipoondi 421 73.12 111 111 5.76

31. Thuraikkadu Thiruthuraipoondi 2750 346.44 665 686 7.96

32. Panagudi Nannilam 1225 311.48 265 266 3.93

District : Thanjavur

33. Thambikku Nallavankottai Maravadakku

Pattukottai 2575 2531.2 623 623 0.68

34. Thambikku Nallavankottai Vadakku

Pattukottai 3522 1293.02 896 896 2.72

35. Thamarankottai Pattukottai 10277 2309.60 2433 2442 2.27

36. Palanjur Pattukottai 2092 1476.20 494 494 1.42

.37. Adirampattinam Pattukottai 1591 987.40 241 241 1.51

38. Briparakkarai Pattukottai 2504 329.40 530 530 3.02

39. Vaullivayal Pattukottai 579 175.60 126 126 3.30

40. Sarabendiraravanp attinam

Pattukottai 4563 207.34 780 850 22.01

41. Rajamadam Pattukottai 2094 625.20 513 513 3.35

42. Kollukkadu Pattukottai 1795 505.00 368 368 3.48

43. Pudupattinam Pattukottai 1300 242.20 251 251 5.37

44. Andikkadu Pattukottai 1409 366.80 324 324 3.84

45. Kollivoyal Pattukottai 65 115.60 15 15 0.56

46. Karisavayal Pattukottai 1664 221.88 354 354 5.02

47. Rowthanvayal Peravoorani 793 129.48 128 128 -

48. Villunniyoyal Peravoorani 96 391.21 27 27 -

49. Adikadevan Peravoorani 611 335.221 27 27 -

50. Sendalaivayal Peravoorani 1167 186.14 212 212 -

51. Nadiyam Peravoorani 2093 707.82 454 454 -

52. Sedubavachattram Peravoorani 1225 94.10 237 237 -

53. Marakkavalasai Peravoorani 1443 404.31 286 286 -

(Contd...)

Page 305: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 5.2 (Contd...)

Sl. No. Name of Viallage/Town Taluk Population Area (Ha) No. of Houses

House-holds

Density

54. Ariyakuttithevan Peravoorani 24 115.09 5 5 -

55. Thiruvathevan Peravoorani 1922 725.16 410 417 -

56. Kuppathevan Peravoorani 1975 544.63 416 431 -

District : Pudukottai

57. Melastanam (3 part) Avudaiyar Kovil 246 386.96 56 56 0.64

58. Manamelkudi Avudaiyar Kovil 13627 1135.24 2705 2710 7.63

59. Kodikulam Avudaiyar Kovil 10737 1028.64 2178 2304 10.44

60. Kizhamanjakkudi Avudaiyar Kovil 2081 594.50 413 413 3.50

61. Nattanipurasakudi Avudaiyar Kovil 7719 916.21 1418 1436 8.42

62. Alaganvayal Avudaiyar Kovil 2627 238.45 498 498 11.02

63. Enadi Avudaiyar Kovil 298 331.53 63 63 0.90

64. Subrahmanyapuram Avudaiyar Kovil 3092 239.96 504 528 12.89

65. Revuthanvayal Avudaiyar Kovil 169 36.87 40 40 4.58

66. Pillaiyartidal Avudaiyar Kovil 295 168.37 69 69 1.75

67. Munpalai Avudaiyar Kovil 1616 873.69 312 312 1.85

68. Avadaiyarpattinam Avudaiyar Kovil 390 18.11 65 65 21.54

69. Thandalai Avudaiyar Kovil 1494 598.54 324 324 1.58

70. Periamadaipayachal Avudaiyar Kovil 2995 778.30 652 652 2.66

71. Seyyanam Avudaiyar Kovil 1203 761.35 239 239 1.58

72. Mimisal Avudaiyar Kovil 1244 124.74 282 289 9.97

73. Palangulam Avudaiyar Kovil 21 432.92 5 5 0.05

District : Ramanathapuram

74. Marungur Thiruvadanai 5221 564.78 924 924 -

75. Uppur Thiruvadanai 3574 670.85 713 713 4.46

76. Tiruppalaikudi Thiruvadanai 7078 286.63 1273 1273 24.69

77. Vattanam Thiruvadanai 1780 464.37 380 380 0.33

78. Muthuramalingapattinam Thiruvadanai 254 144.46 49 49 1.63

79. Valangudi Thiruvadanai 218 81.78 41 41 2.67

80. Pudupattinam Thiruvadanai 3641 115.38 674 705 11.08

81. Chitturuvadi Thiruvadanai 2145 589.88 472 472 3.64

82. Valamavur Thiruvadanai 384 273.66 79 79 0.27

83. Thondi Thiruvadanai 19240 1554.12 N.A. N.A. 12.38

(Contd...)

Page 306: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 5.2 (Contd…)

Sl No. Name of Village/Town Taluk Population Area (Ha) No. of Houses

House-holds

Density

84. Nambuthalai Thiruvadanai 6908 816.55 N.A. N.A. 8.46

85. Kaliyanaguri Thiruvadanai 1978 326.27 427 431 6.06

86. Kanathankundu Thiruvadanai 3205 1501.26 535 535 2.13

87. Mandapam Ramanathapuram 5709 2263.92 1145 1145 0.50

88. Devipattinam Ramanathapuram 8350 1520.79 1634 1658 5.02

89. Chittrakkottai Ramanathapuram 6667 2106.82 1331 1337 3.16

90. Theruvadi Ramanathapuram 5162 1054.97 899 899 2.82

91. Alagankukam Ramanathapuram 13364 2294.47 2636 2637 2.78

92. Attangarai Ramanathapuram 2854 814.76 601 616 3.50

93. Enmahamkundan Ramanathapuram 5159 481.17 1141 1151 10.72

94. Pirappanvalasai Ramanathapuram 3991 1070.61 918 918 2.40

95. Sattakkonvalasai Ramanathapuram 2108 1332.92 405 406 1.58

96. Nochivurani Ramanathapuram 2331 1305.20 550 550 0.57

97. Kalimankundu Ramanathapuram 5476 1190.04 1254 1254 2.09

98. Tiruppullani Ramanathapuram 6599 2929.02 1255 1255 0.63

99. Kanjirahgudi Ramanathapuram 5431 1586.48 1049 1049 3.42

100. Rameswaram rameswaram 32721 624.92 - - 52.36

Note : N.A. – Not Available

Page 307: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 5.3

Details of Coastal Towns Villages in the Study Area

SI No.

Name of Village/Town

Taluk Population Area (Ha) No. of Houses

House-holds

Density

District : Ramanathapuram

1. Pudumadam Ramanathapuram 6940 783.19 1461 1461 8.86

2. Attiyuthu Ramanathapuram 2407 1162.58 445 445 2.07

3. Kilnagachchi Ramanathapuram 2328 954.12 502 502 2.44

4. Karan Ramanathapuram 3164 1231.40 693 693 1.73

5. Rettaiyurani Ramanathapuram 5446 1382.33 1300 1300 0.65

6. Periyapattinam Ramanathapuram 7762 931.75 1459 1459 6.63

7. Keelakarai Ramanathapuram 32834 2199.13 598 598 29.84

8. Mayakulam Ramanathapuram 3107 1374.12 601 601 2.26

9. Pattennedal Ramanathapuram 623 681.60 139 139 0.91

10. Pamban Ramanathapuram 23801 N.A. 4656 4688 N.A.

11. Kannirajapuram Mudukulathur 4139 1002.06 779 783 4.13

12. Narippaiyur Mudukulathur 6214 1798.07 1157 1178 3.46

13. Kudiraimoli Mudukulathur 637 262.84 136 136 2.42

14. Periyakulan Mudukulathur 5470 2898.76 1101 1122 0.13

15. Vallindokkam Mudukulathur 3482 1133.98 544 568 3.07

16. Ervadi Mudukulathur 7334 2300.95 1590 1644 3.19

17. Mukkaiyur Mudukulathur 1820 1766.33 333 336 0.66

18. Mariyur Mudukulathur 4283 2038.96 909 918 1.87

District : Tuticorin

19. Vembar Mudukulathur 5122 1323.35 918 940 1.07

20. Vaippar Mudukulathur 4426 3700.95 900 914 0.51

21. Kila Arasaid Ottapidaram 1368 1315.43 303 306 1.04

(Contd…)

Page 308: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 5.3 (Contd...)

SI No.

Name of Village/Town Taluk Population Area (Ha) No. of Houses

House-holds

Density

22. Pattanamarudur Ottapidaram 838 1071.88 165 165 0.78

23. Taruvaikkulam Ottapidaram 4587 1728.30 876 887 2.65

24. Sankarapperi Tuticorin 5376 1317.94 1157 1180 4.08

25. Mullakkadu Tuticorin 2271 120.86 N.A. N.A. 18.79

26. Tuticorin (Rural + Town) Tuticorin 205766 17574.01 N.A. N.A. 15.63

27. Milavittan Tuticorin 10679 298.88 N.A. N.A. 35.73

28. Mappilaiurani Tuticorin 13327 1530.08 N.A. N.A. 8.71

Note : N.A. – Not Available Source : Coastal Zone Management Plan for Tamil Nadu, Environmental &

Forest Department, June 1996

6. Assessment of Environmental Impacts

6.1 General

The major step involved in the process of environmental impact assessment

is the identification of impacts as it leads to other steps such as quantification and

evaluation of impacts. In order to identify and evaluate the impacts associated with the

project, it is necessary to establish a general checklist and describe the existing

environmental quality in the area under development, and the activities of the

proposed project which may cause environmental impacts.

While a number of techniques are available for identification of impacts, in the

present case, the “Network Method” which involves understanding of the cause-

Page 309: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

condition-effect relationship between an activity and environmental parameters has

been adopted. This method has been basically advantageous in recognizing the

impacts that would be triggered by the proposed activities and provides a “road map”

type of approach for the identification of second and third order effects. The purpose is

to account for the project activities and identify the type of impacts which would initially

occur. The next step is to select each impact and identify the secondary and tertiary

impacts which will be induced as a result. This process is repeated until all possible

impacts are identified. The major advantage of this approach is that it allows

identification of the impacts by selecting and tracing out the events as they are

expected to occur.

6.2 Impact Networks

In the backdrop of data collected during the site visits, information provided by

the concerned authorities and the list of project activities described earlier in the

report, the ‘cause-condition-effect’ networks for various components and activities of

the project have been delineated as depicted in Fig. 6.1 through 6.2. In these

illustrations, the lines are to be read as “has an effect on”.

Pre-construction activities are those taken up prior to start up of the actual

construction of the project and may include resettlement and rehabilitation. They may

not have any direct impact on environment as such but may lead to socio-economic

impacts on the local inhabitants who are likely to be displaced and relocated.

Construction activities would cause land alternations in accordance with the

project design and a variety of physical, chemical, ecological, aesthetic and socio-

economic impacts of varying duration and magnitude. Physico-chemical changes

occur mainly due to dredging, and clearing of vegetation cover at the site and

earthwork excavation thereby causing soil erosion resulting in turbidity in surface

runoff. Ecological impacts occur due to loss of marine resources, removal of trees and

shrubs and field habitats which result in destruction of terrestrial organisms. Socio-

economic impacts that occur during construction relate to generation of employment,

displacement of families, removal of natural resources of the site etc.

Operation phase involves various maritime and shipping activities all of which

can cause impacts (positive or negative) on marine water quality, ecology, aesthetics

and socio-economics of the project affected population.

Page 310: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

6.3 Impacts due to Land Based Facilities

The project envisages construction of shore facilities to cater to needs of

canal in Adam’s Bridge area, viz. service jetties, slipways, buoy yard, repair workshop

as also staff and administration buildings for facilitating regulated traffic in the vicinity

of Adam’s 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 these

project related activities will be firmed up once the modus-operendi of traffic regulation

in canal portion is finalized. Hence, the extent of land acquisition, the need for

resettlement and rehabilitation of affected population, if any, could not be assessed at

this juncture. However, given that the canal will pass through Adam’s Bridge area, the

pressure on land based facilities would be negligible in comparison to that envisaged

in earlier studies where land locked canal cutting through Pumban Island was

proposed.

During the construction of the ship canal, it is anticipated that considerable

sea-borne activity in the form of logistic and support services would take place. This,

coupled with the dredging activity, would have significant adverse impact on the

traditional fishing activities by the licensed fisher folk and consequently on their income

levels.

6.4 Impacts due to Dredging

The major activity during construction phase of project comprises capital

dredging along the proposed alignment of the ship channel in Adam’s Bridge and Palk

strait area. The area which require intensive dredging to achieve depth of 12 m across

the Adam’s Bridge area is over a length of 20 km and in Palk Bay Strait area is about

54 km. The areas have been studied for its actual bathymetry, seabed characteristics

and hydrography.

Page 311: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

The study area near the Adam’s Bridge is depicted in Fig. 6.3 and the

borehole data for this region has been collected in March 2004 and is show in

Fig. 6.4. Sediments of different grain sizes mainly consists of sand silt and clay. The

data is presented in Chapter 2 under geological strata. Bathymetry data computed for

5 different alignments in Adam’s Bridge area is shown in

Tables 6.1 to 6.5 and Figs. 6.5 to 6.9. Regressional coefficient for each graph was

computed to arrive at actual quantity of dredged material generation for 12.0 m depth

profile. The quantities of dredged material along each line are shown in Fig. 6.10.

Total area under dredging in Adam’s Bridge section for 12 m deep,

300 m wide channel will be about 600 ha. The quantity of capital dredge material

including slope and tolerance is approximately 38 x 106 m3 for 12 m deep channel.

Requirement of capital dredging in Palk Bay/Palk Strait area have been

computed. The proposed alignment in Palk Bay/Palk Strait is shown in Fig. 6.11. The

Bathymetry along the alignment is presented in Fig. 6.12. The quantity of dredged

material will be about 44 million m3 for 12 m deep 300 m wide channel as per

bathymetry data collected by National Hydrography office, Dehradun

(Fig. 6.12).

The proposal envisaged by Ministry of Shipping was for creation of navigation

channel to suit different draught requirement viz. 9.15, 10.7 and 12.8 m requiring

dredging depths of 10 m, 12 m and 14 m respectively. For 12.8 m draught channel

width will be 500 m whereas for 9.15 and 10.7 m draughts, channel width will be 300

m. Based on hydrography data collected by NHO

(Fig. 6.12) it is observed that navigation depths in Palk Bay are restricted to about 12

m only. The total length from Adam’s Bridge to Palk Strait is about 145 km. Based on

the bathymetry data, requirements of dredging and quantity of dredge spoil likely to be

generated have been computed for various options viz. 9.15 m draught (10 m deep),

10.7 m draught (12 m deep) and 12.8 m draught (14 m deep) channel with respective

widths. The data is provided in Tables 6.6-6.8. It could be observed that quantity of

dredged/spoil will reduce with the depths to about 39, 82 and 313 million m3

respectively besides reduction in length of channel to be dredged. In the event of

proposal for 12.8 m draught requiring 14 m depth, dredging will require to be carried

out in entire Palk Bay area to create a channel of 500 m width generating 313 million

Page 312: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

m3 of dredge spoil. Dredging all along the length of the channel in Palk Bay will be

detrimental to ecologically sensitive area of this region. It would also involve heavy

additional expenditure on dredging and disposal of dredge spoil. Thus keeping in view

environmental sensitivity and economic viability the proposal for 14 m depth (12.8 m

draught) is not considered. Thus channel depth of only 10 m and 12 m are considered

for studying environmental and economic impacts. The channel will be dredged with a

bottom width of 300m to a depth of -10mCD or -12mCD in Palk Strait and adjoining

parts of Palk Bay to achieve the required depth over a stretch of 36 and 18km

respectively. In the Gulf of Mannar, navigational depths (more than 12 m) will be used

from Tuticorin Port to Adam’s Bridge Area. A 20 km long channel with a bed width of

300 m. will be dredged to a depth of -10mCD or -12 mCD catering to vessels drawing

a draught of 9.15 or 10.7m respectively.

Though option for both 9.15 m and 10.7 m draught were evaluated, study

carried out by shipping corporation of India for estimating traffic potential at 7, 9 and 11

draught recommended that a minimum draught of 10.7 m be kept to make channel

viable. The savings based on expected number of transits through proposed channel

for various considered draught is given in Table 6.9.

The proposed channel will have a bed width of 300m which will provide a safe

width for navigation of two way channel. The channel will have side slopes of 1:3. A

cross section of channel is shown in Fig. 6.13.

Besides capital dredging, annual maintenance dredging of about 0.1 million

m3 is envisaged in Adam’s Bridge area based on data available for sediment transport

across Palk Bay and Gulf of Mannar. The studies carried out by NSDRC signifies that

the region around Adam’s Bridge forms an significant sink for littoral drift. The

prolonged accumulation in this area may lead to emergence of new Island. In case of

occurrence of cyclone in Gulf of Mannar, such prolonged deposition of sediments

move north and enter Palk Bay through Pamban Pass and Adam’s Bridge. Once the

sediment enter Palk Bay, the environmental condition favours immediate deposition.

Hence the occurrence of cyclone in Gulf of Mannar and the associated northerly

waves might, exchange more sediment from southern part of Peninsular India to

Northern part of east coast. Thus the quantity of maintenance dredged spoil will

increase in the channel across Adam’s Bridge in the event of cyclone.

Page 313: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

The dredging of sea bed would result in increase of turbidity due to silt & clay

both during dredging and disposal. Higher silt load in seawater prevents penetration of

sunlight in water body and ultimately affect primary productivity.

Page 314: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Primary productivity, the only means of synthesis of organic matter is the

basis to trophic web. Any damage to the lower trophic level would reflect into higher

trophic including fish. If sunlight does not penetrate into the sea for days together,

darkness would prevail on the bottom, which adversely affect the photosynthetic

activity of the symbiotic algae in the molluscs and corals. Further when silt gets

deposited on all living organism especially on sedentary biota - viz. pearl oysters,

corals, algae, gorgonids, other molluscs, annelids, prochordates, echinoderms, the

egg mass of many free swimming animals, etc, they get destroyed since these

organisms have no / little locomotive power to move away from the dredging zone.

Deposition of silt bury many small living organisms. Silt enters into the gills of the

animals and impairs respiration. Silt also affects the planktonic life. siltation affects the

solubility of oxygen and gas exchange due to mineralisation and pH changes and,

thus, the amount of dissolved oxygen in the water is reduced. Owing to the destruction

of seagrass and seaweed beds, larger animals such as dugongs, turtules and

herbivorous fishes are also affected. It is true that the dissolved components of the silt

would enrich the algal growth and trigger the planktonic bloom. But this blooming may

not be of much use since the benthic and other fauna, which mainly feed on them, are

either not available or destroyed owing to silt deposition.

It is known that seabed strata is only sand hard pane and blasting which

could adversely affect flora and fauna due to shock waves emanating from the blast is

not required for excavation/dredging.

Whatever may be the method of dredging that is employed, a part of

sediments removed from the sea bottom would get spread to adjacent dredging area.

This would form as a mat and bury the entire fauna and flora into it. Adverse effects

are also to be expected from pollution owing to the use of machinery for construction

and operating units. Spillage of oil and grease, rust and metallic wastes due to wear

and tear, marine litter, float, including plastic bags, discarded articles would be the

major pollutants.

To minimize impacts due to dredging and disposal of dredged material,

options for both land and sea disposal are considered. Suitable location on land as

well as in sea are to be selected based on environmental viability. Likely impacts due

to both the options are discussed in following section :

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6.4.1 Dredged Material Disposal

6.4.1.1 Disposal on Land

Based on recent remote sensing imageries for landuse and landcover,

degraded areas in Pumban island have been identified (Plate IV referred in Chapter 4) for disposal of part quantities of dredged material. Visual inspection of the project

site has revealed that a long stretch in Pumbam island between Kodandaramasamy

temple and Dhanushkody could be one of the potential sites for dredged material

disposal. Based on the analysis and interpretation of satellite data under the present

study, a few sites including the above have been identified for land disposal of the

dredged material. The suitability of these sites has been confirmed after detailed

groundtruth verification of the sites. Composition of dredged material plays vital role in

deciding its suitability for disposal on land. The degraded areas identified in Pumban

island near Dhanushkody are sandy in nature. The dredged material has content of 5-

8% clay and silt hence the spoil can be used for nourishment of degraded land for

reclaiming it and promoting life and vegetative growth. However the site will require

proper embanking/protection to prevent erosion due to wave action during cyclonic

conditions.

Keeping in view the reduction in quantity of dredged material due to

realignment of route using navigational depths available in Gulf of Mannar, the

dredging activity will be restricted to an area in the vicinity of Adams Bridge over a

length of about 20 km and width of 300 m. The quantity of dredged spoil generated

upto a depth of 12 m is 38 million m3 in this area. It is proposed that the top protion of

the sea bed containing silt and clay (Approx. 7-8 million m3) be disposed on degraded

areas of Pamban Island subject to approval under CRZ. The rest of the dredged

material containing mainly sand with particle size varying from 125 µm to 600 µm is

proposed to be disposed into sea (Gulf of Mannar) at a location varying from 30-40 m

depth. The Plate IV referred in Chapter 4 shows proposed location for disposal of

dredged material as indicated in the marked area spreading over 753 hectares. The

area is degraded land and can be converted into cultivable land through nourishment

by dumping silt and clay with some portion of sand from dredged material.

The maintenance dredge spoil will mainly comprise silt / clay and will be used

for reclaiming degraded areas in the vicinity of Pamban island / Mandapam.

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6.4.1.2 Disposal in Sea

Disposal of dredged spoil generated during capital dredging containing sand

is proposed to be disposed in sea in the proximity of dredging activity where potential

adequate dilution and dispersion is available. It is observed from the bathymetry data

that a depth of 30-40 m is available about 25-30 km away from Adam’s Bridge in GOM

area. An exercise using dispersion modelling was carried out to study impact of

dredged spoil on turbidity of sea water.

The Cornell Mixing Zone Expert System (CORMIX), evaluation version

represents a robust and versatile computerized methodology for predicting both the

qualitative features (e.g. flow classification) and the quantitative aspects (e.g. dilution

ratio, plume trajectory) of the hydrodynamic mixing processes resulting from different

discharge configurations and in all types of ambient water bodies, including small

streams, large rivers, lakes, reservoirs, estuaries, and coastal waters.

The methodology provides answers to questions that typically arise during the

application of mixing zone regulations for both conventional and toxic discharge. More

importantly, this is accomplished by utilizing the customary approaches often used in

evaluating and implementing mixing zones, thereby providing a common framework

for both applicants and regulatory personnel to arrive at a consensus view of the

available dilution and plume trajectory for the site and effluent discharge

characteristics.

Three different subsystems for discharge conditions are available in CORMIX.

The model predicts the geometry and dilution characteristics of the effluent flow

resulting from a submerged single port diffuser discharge, of arbitrary density

(positively, neutrally, or negatively buoyant) and arbitrary location and geometry, into

an ambient receiving water body that may be stagnant or flowing and have ambient

density stratification of different types.

To predict dilution and plume trajectory of discharged effluent, CORMIX

typically combines the solutions of several simple flow patterns to provide a complete

analysis from the efflux location all the way into the far field.

The logic processing elements of CORMIX identify which solutions should be

combined to provide the complete analysis. This process, called flow classification,

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develops a generic qualitative description of the discharge flow and is based on known

relationships between flow patterns and certain calculated physical parameters.

PARAM is the program element that computes relevant physical parameters

including the various length scales, fluxes, and other values needed for the execution

of other program elements. Length scales are calculated measures of the length of

dynamic influence of various physical processes.

At the heart of CORMIX is a flow classification system contained in the

program element CLASS. It provides a rigorous and robust expert knowledge base

that carefully distinguishes among the many hydrodynamic flow patterns that a

discharge may exhibit. These possibilities include discharge plumes attaching to the

bottom, plumes vertically mixing due to instabilities in shallow water, plumes becoming

trapped internally due to density stratification, and plumes intruding upstream against

the ambient current due to buoyancy and many others. Theoretically based

hydrodynamic criteria using length scale analysis and empirical knowledge from

laboratory and field experimentation are applied in a systematic fashion to identify the

most appropriate flow classification for a particular analysis situation. For all three

subsystems, a total of about 80 generic flow configurations or classes can be

distinguished.

Once a flow has been classified, CORMIX assembles and executes a

sequence of appropriate hydrodynamic simulation modules in the program element

HYDRO1, 2 or 3. HYDRO consists of : (a) control programs or "protocols" for each

hydrodynamic flow classification and (b) a large number of subroutines or "simulation

modules" corresponding to the particular flow processes, and their associated spatial

regions, that occur within a given flow classification. The simulation modules are

based on buoyant jet similarity theory, buoyant jet integral models, ambient diffusion

theory and stratified flow theory, and on simple dimensional analysis. The basic tenet

of the simulation methodology is to arrange a sequence of relatively simple simulation

modules which, when executed together, predict the trajectory and dilution

characteristics of a complex flow. Each of the simulation models uses the final values

of the previous module as initial conditions.

For simulating discharge of dredge material in sea (tentative location shown

in Fig. 6.14a), single submerged port discharge is used for predicting the movement of

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suspended solids (Silt) in the ocean. Table 6.10 shows the calculation of silt produced

during dredging operation and its concentration in the discharged water. The scenario

is generated for steady state discharge of silty water having a concentration of

1,20,000 mg/l. The flow rate is taken to be 1.099 m3/s. The density of the discharged

water is taken to be 1047 kg/m3 and the effluent is discharged having discharge depth

of 25 m. The ambient water body is sea in which the effluent is discharged and is

taken to be unbounded. The wave currents or velocity are taken to be 0.3 m/s and

surface wind velocity have been taken as 5 m/s. Fig. 6.14 shows the three-

dimensional plume showing the movement of suspended solids (Silt). Fig. 6.15 shows

the variation of the Centerline Concentration along the direction of ambient current

velocity for Near Field and Fig. 6.16 shows for Far Field. Fig. 6.17 shows the dilution

vs. centerline distance. It can be inferred from these graphs that the effect of the silty

water when discharged will be localized and restricted to about 1500 meter from the

discharge point. However the plume will not surface immediately and the

concentration of suspended solids in sea water will return to normal after 1500 m in

the line of advection.

The capital dredging envisaged in Palk Strait area is 44 million m3 over a

stretch of about 54 km including some portion in Palk Bay in proximity to shallow areas

in Palk Strait. The quality of dredge spoil has been studied by NHO Dehradun.

Depending on the quality, disposal options can be decided. In the event of higher silt

content land disposal in proximity to dredging area avoiding sensitive locations viz.

Point Calimer sanctuary will be thought off. As this area is close to Bay of Bengal

where depth more than 25 m is available, disposal in sea would be a preferred option.

However concerns of transboundary migration of sand and pollutant will govern the

selection of site. The tracer studies have been initiated for further studies to select

suitable location. In no case dredged spoil will be allowed to be dispersed in Palk Bay.

Thus impact due to dredge disposal could be minimized by selecting option of

land disposal for dredged spoil containing higher percentage of clay and silt. Balance

dredged spoil containing sand could be disposed in sea. As sand particles have

discrete setting, rise in turbidity of sea water at disposal location is not envisaged

thereby minimizing impact on primary production. In the event of disposal of silt

containing dredged spoil the turbidity zone will develop at the disposal location,

however submerged disposal will not allow suspended solids plume to rise to surface

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immediately thereby providing adequate dilution before the plume surfaces in the

direction of current. However by the time the plume surfaces at about 1500 m,

concentration of suspended solids would return to background level.

The existing level of primary productivity in the project area will remain

practically unaltered during the construction and operation phases of the ship channel

as proposal for disposal of silt / clay on land should be the most preferred option. Even

during sea disposal care would be taken to dispose material well below the sea

surface so that plume of suspended solids will remain submerged and will not cause

alteration in surface turbidity and primary productivity. There would not be any

significant change in water quality including turbidity due to the proposed deployment

of trailor suction hopper dredgers for capital and maintenance dredging. Moreover, the

envisaged dredging activities in the area are likely to cause much less turbidity than

the international threshold, and thus the likely risk to marine biota is going to be

minimal.

Disposal of sand (~30 million m3) in the form of dredge spoil will temporarily

after the structure of benthic community. However the benthos will restructure and

recover to original status after the capital dredging activity is completed.

Due to dredging, the bottom flora and fauna on an area approximately

600 ha along the channel alignment in Adam’s Bridge 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 Reserves.

6.5 Impacts due to Road and Rail Traffic

During the construction activity viz. creating infrastructure base on Pamban

island to support dredging activity, the shore-based structures, there will be

considerable increase in rail and road traffic to and from the island for transportation of

men, material, machinery and equipment. These would inevitably lead to congestion in

traffic and increased levels of air and noise pollution with their associated impact on

normal public life. This scenario may continue during the operation phase of the canal

due to increased trade and commerce.

6.6 Impacts on Productivity and Ecology in GOM/Palk Bay

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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 Adam’s 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 µm to 600 µm) 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

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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.

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 will 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.

A potential source of pollution of the marine environment during the operation

phase of the project relates to ship discharges – oily ballast, bilge water and sewage,

and accidental spills. Likewise, the effects of anti-fouling paints on bottom dwelling

marine organisms, particularly clams and oysters, when the depth is relatively shallow

and there are a number of crafts moored in the location, can be significant.

Presently, stray turtles and marine mammals suffer from propeller cuts, ghost

fishing, and death due to ingestion of jetsam and floatsam. Such instances may

increase unless strict control is enforced in maintaining the canal litter-free, and

shipping speed is under regulatory control.

Despite significant shipping activities, it has been reported that Olive Ridley

turtles from the deep seas migrate to Gahirmatha beach in northern Orissa via

northern Sri Lanka and Paradeep Port for mass nesting during November-February

each year. Reported mass killing of turtles in this region is primarily due to their getting

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entangled in gill netters and also due to poaching by local people for turtle flesh. This

observation indicates that the proposed canal project may not have any significant

adverse impact on the migration and mass nesting of turtles.

During the operational phase, the frequent ship movements in the channel,

maintenance dredging of the canal which could increase turbidity, oil spill, bilge water,

marine litter etc. may have negative impacts if they are allowed to travel to the Gulf of

Mannar Biosphere Reserve which supports a very fragile ecosystem.

Excavation of the channel in the Adams Bridge sector would provide a deeper

passage in the sector, which is shallow at present, and serve only as a barrier.

Underwater currents play a significant role, not only in the transportation of large

marine organisms, plankton biota, fish eggs and larvae but also on shore dynamics,

especially of the islands, reef and paars. Strong current would erode the banks of the

canal and carry the sediments from one sector to another, which ultimately results in

accretion of sand in one sector and erosion in another sector. Once the canal is

deepened, the passage would greatly increase the movement of fishes and other large

animals from Bay of Bengal to Indian Ocean and vice-versa. Hence, the entry of

oceanic and alien species into Palk Bay and Gulf of Mannar and also dispersal of

endemic species outside Palk Bay and Gulf of Mannar would be facilitated.

6.7 Impacts on Hydrodynamic Conditions

Because of the deepening of the channel, the course of water currents and

their speed as related to the prevalent biomonsoonal conditions may be altered.

Currents play a vital role not only in the movement of large marine organisms,

planktonic biota, the juvenile, larvae and eggs, but also on shore dynamics especially

of islands, reefs and paars. Current related sediment transport might level up, bury or

elevate certain locations, and yet other benthic sites may be eroded and deepended.

This would play havoc on the benthic animals including pearl oysters.

Hydrodynamic modelling was carried out to study the baseline spatial tidal

current distributions in the Gulf of Mannar and the Palk Bay, and to estimate the

changes that could be brought about due to the proposed ship navigation canal. The

focus has been to predict the change in direction and magnitude of the vector currents

due to the change (increase) in bathymetry resulting from dredging. The geographical

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domain considered for modelling is shown in

Fig. 6.18.

A two dimensional (Ocean) Model, DIVAST (Depth Integrated Velocity and

Solute Transport) has been used for the hydrodynamic modelling. The model

simulates two dimensional distributions of currents, water surface elevations and

various water quality parameters within the modelling domain as function of time

taking into account the hydraulic characteristics governed by the bed topography,

surface wind effects and boundary conditions. It is assumed that the flow (in the study

region) is predominantly horizontal and nonstratified, and hence the two dimensional

depth integrated representation of the system is adequate. The solute transport

processes viz. advection, diffusion and dispersion are included. The temperature

distribution is taken to be governed by air-water heat exchange.

The finite different scheme used in DIVAST is based on the Alternating

Direction Implicit Technique which involves the sub-division of each time step into two,

for obtaining solutions in X and Y directions separately, using Gauss elimination and

back substitution methods.

The boundaries due to coastline or adjacent to structures are treated through

closed boundaries conditions and water surface elevations are treated through open

boundary conditions. The numerical treatment of flooding and drying in the tidal base

is incorporated through iterative checks on the wet and dry cells. The numerical model

allows for variable grid sizes in different zones allowing for better representation of

discontinuities in the neighbourhood of locations of interest.

6.7.1 Tidal Current Distributions - Before and After Dredging

The modelling exercise has been carried out on a HP Workstation under HP-

UNIX 10.1 Operating System. The source code of the model has been suitably

compiled, and configured for modelling, after incorporating boundary conditions. The

simulations have been carried out for 42 hours, for each case of ‘before dredging’ and

‘after dredging’ conditions.

The present bathymetry is assumed to be not significantly different from the

bathymetry data depicted in Naval Chart 317. For the purpose of model mapping, the

bathymetry data was interpolated for the entire modelling domain in grid sizes of 358

m x 358 m.

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Current (tidal stream) measurements, with the assistance of the staff of Chief

Hydrographic Surveyor of India, were carried out at 10 locations in the study domain

for spring tide conditions. The locations, and their latitudes and longitudes are shown

in Fig. 6.19. The current measurements at a few representative locations in the Palk

Bay and the Gulf of Mannar are depicted graphically in Figs. 6.20 - 6.21. The graphs

depict the relative intensities of currents and directions and their variations over the

tidal curve. The values of maximum speed at a few locations in the Palk Bay and the

Gulf of Mannar are given in Table 6.11. The tidal variations with respect to time

measured at a location close to Rameswaram Jetty are shown in Fig. 6.22. The

proposed ship navigation alignment considered for modelling is shown in Fig. 6.23.

The depth, width and draft along the proposed alignment for modelling the

hydrodynamic conditions is taken as 12 m, 300 m and 10.7 m respectively.

The model has been calibrated and the calibration curves for tide and

currents are shown in Figs. 6.24-6.25. The curves show good match between the

measured and the model predicted values. The spatial distributions of tidal currents

have been modelled for two conditions :

i) with the present bathymetry ii) with the increased depths along the proposed alignment

The currents predicted by the model for a new patches (sub areas) within the

study domain are shown in Figs. 6.26-6.27. The sub areas are chosen for being

geographically close to the coral reefs and the proposed alignment. The sub areas are

referred as Patch I, Patch II, Patch III and Patch IV in the Figs. 6.24-6.25. The

magnitudes and angles of the current vectors for each sub area are given in Table 6.12 through 6.15. The directions are with respect to the model axis. The model axis is

assumed to be North-South direction and the angles (in degrees) are measured in

clock wise direction from the model axis starting from North.

The arrows on the tidal curves in Figs. 6.24-6.25 indicate the time point on

the tidal curve for which the current vectors are shown.

Patch I is spatially located close to the coral reefs which are shown in Figs. 6.28-6.29 (Source of Data-Digitized from SAC Maps). It is seen that there is no

significant change in the magnitude and direction of current velocities.

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Patch II and Patch III are close to the alignment in the South Approach

Channel in the Gulf of Mannar. As in the case of Patch I, it is seen that there is no

significant change in the magnitude and directions of current velocities.

Patch IV is in the Palk Bay close to the approach channel. There is a

significant change in magnitude and direction of current velocities near the proposed

alignment. However, west of the proposed alignment the directions remain the same.

6.7.2 The Salient Conclusions

Current vectors predicted by the model at the sensitive sub areas for highest

spring water height point out the following :

6.7.2.1 Gulf of Mannar

• There is no significant change in the current vectors due to dredging

• The current directions remain nearly the same after dredging

- The average current direction is between 270O–350O, with respect to

model axis, and geographically this represents approximately North-

West direction (Model axis is South-North Direction, same as

geographical South-North)

• The maximum current speed is 0.7 m/sec

• Speed and directions do not vary significantly with geographical locations

close to the proposed alignment

6.7.2.2 Palk Bay (Near Adams Bridge)

For the sub region close to approach to the Channel from Palk Bay :

• There is a significant change in magnitude and directions for major portions

near the proposed alignment

- Average direction before dredging is between 270o to 340o, towards

North-West

- The current directions in the channel alignment change due to dredging.

Average direction after dredging is 90O to 180O towards South-East

• However, to the west of proposed alignment there is no significant change in

current directions

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• The maximum current observed is 0.31 m/sec

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6.8 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

400 nautical miles and voyage time of about 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.

During the construction of the channel, 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 Rameshwaram

consequently reducing the load and congestion on railways and roadways.

Once the channel is in place the clandestine and illegal activities presently in

vogue in the Palk Bay and the Gulf of Mannar will be minimised due to constant

vigilance and regulation of movement of ships and vessels.

6.9 Analysis of Alternatives for Route Alignment

The various proposals considered for the alignment of the Sethusamudram

Ship Canal including the one recommended as a channel in current study are depicted

in Fig. 6.30. Between 1860 and 1922, as many as 9 proposals were formulated to

connect the Gulf of Mannar with the Palk Bay in order to shorten the sea route

between the west and east coasts of India. Most of these proposals envisaged cutting

through Pamban Channel. But none of these materalised for want of financial

resources.

After independence, the Government of India in 1955 constituted the

Sethusamudram Project Committee under the Chairmanship of Sir A. Ramaswamy

Mudalidar. The Committee made detailed investigations and recommended a crossing

through the mainland in keeping with the following : i) the site is directly in line

between Tuticorin and Palk straight, ii) the sea rout will be entirely west of medial line,

iii) this will obviate the use of vulnerable railway bridge at Pamban, iv) this alignment is

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set to have little sign of hard material and v) scope for development due to its location

in main land is more. The Committee further recommended the implementation of both

the Tuticorin Port and Sethusamudram Canal as an integrated project. However, the

Government sanctioned only the Tuticorin project.

A high level Committee under the chairmanship of (late) Venkateswaram

appointed by the Government of India conducted further investigations and submitted

its report in 1968 recommending an alignment across the Rameswaram island in

keeping with the following advantages : i) short crossings requiring less length of

pilotage, and so less cost of pilotage, ii) quick transit of ships due to shorter length of

channels, iii) greater number of ships can be handled, iv) less maintenance dredging

of channels as the length of three channels is only 8 miles for this crossing as against

28 miles for the mainland crossing and v) no reef in this alignment of south approach

channel while the south approach channel of Mandapam alignment has reef which is

very difficult to dredge. The technical Committee, based primarily on cost and

economic considerations, recommended the Rameswaram alignment (DE alignment)

with an estimated cost of Rs. 37.46 crores for detailed investigation to cover all

seasons w.r.t. tide littoral drift etc. The proposal was reviewed from time to time and

the cost was updated in 1980 to Rs. 110 crores.

The Laxminarayanan Committee, constituted in 1981 by the GoI, reviewed

the above proposal and, on detailed inspection, noted that there was heavily built up

residential area in the Rameswaram alignment. It examined an alternative alignment

across Dhanushkody east of Rameswaram temple. After a study of the coastal

morphology in relation to the latest hydrographic chart, the Committee recommended

the K-alignment across Dhanushkody west of Kodandaramaswamy Koil with an

estimated project cost of Rs. 282 crores (1983 prices). For the same alignment and

associated quantities of work, the proposal has been updated for its economic viability

by PTCS Ltd. in March 1996.

In all the proposals listed as above, the only major criterion influencing the

final recommendation has been the economic viability of the proposal with very little

consideration to the environmental/economical aspects of the project. This can be

attributed to the fact that at that time even at the national level environmental concerns

of developmental projects were rarely addressed.

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While detailed information for the above enumerated alternatives are not

available, it would be apparent that any alignment of the proposed canal across the

main land would have not only proved expensive due to the longer lengths of dredging

and the associated socio-economic impacts particularly with respect to land

acquisition, resettlement and rehabilitation. These alignments would have also been

nearer to the 21 islands in the Gulf of Mannar (which have subsequently been

declared as national Marine Parks) with their associated ecological impacts.

The alignment proposed by the Venkateswaran Committee also suffers from

similar problems as above, though relatively less in magnitude. The K alignment

crossing the Rameswaram island cutting a land portion of only 800 m involves

minimum of social disruptions. Shifting the canal towards Dhanushkody by another 3-4

km as recommended by the Steering Committee constituted by Ministry of Surface

Transport, Govt. of India for the present study would further minimise the impact due

to the land canal portion, and also be farther away from the National Marine Parks with

the advantage of reduced cost of dredging without significantly increasing the total

length of the canal. The alignment across the Dhanushkody island would not only

require cutting across the coral reefs but perhaps also blasting during construction.

From navigational considerations, this alignment with sharp turns is not considered

desirable. Thus, from all considerations including environmental and ecological, the

alignment recommended by the Steering Committee farther away from the

Kodandaramasamy temple towards Dhanushkody and with the crossing of the land

portion more or less at Moonru Iruppu Chatram appeared to be a better choice.

The present study recommended the use of navigational depth in Gulf of

Mannar by the ships to approach Adam’s Bridge from Tuticorin port. It could be

observed that ships can reach Adam’s Bridge area, enter the channel in South-North

direction parallel to medial line between Sri Lanka and India. The route thus would be

around 20-25 km away from the GOM biosphere reserves. As most stringent

regulatory practice for discharge of wastes from ship are recommended, the impacts

due to operation of this route an GOM biosphere reserves will be insignificant. The

dredged material will also be disposed 20-25 km away from GOM biosphere, the

movement of silt toward the biosphere is not envisaged. Thus the route would become

environmentally viable only if the management plans and recommended measures are

strictly followed.

Page 330: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 331: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 332: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 333: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 6.3 : Study Area for Route Alignment in Adam’s Bridge Area

Page 334: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

\\

Fig. 6.4 : Borehole Data in Adam’s Bridge Area

Page 335: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

y = 1E-07x2 - 0.0019x + 12.544R2 = 0.6954

0

2

4

6

8

10

12

0 5000 10000 15000 20000

Distance (m)

Dep

th (m

)

Fig. 6.5 : Bathymetry Along Line 1

y = material to be dredge x = length R2 = regretion wett

Page 336: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

y = 9E-08x2 - 0.0018x + 12.842R2 = 0.7058

0

2

4

6

8

10

12

14

0 5000 10000 15000 20000

Distance (m)

Dep

th (m

)

Fig. 6.6 : Bathymetry Along Line 2

Page 337: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

y = 1E-07x2 - 0.0021x + 14.129R2 = 0.7281

0

2

4

6

8

10

12

14

0 5000 10000 15000 20000

Distance (m)

Dep

th (m

)

Fig. 6.7 : Bathymetry Along Line 3

Page 338: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

y = 7E-08x2 - 0.0017x + 13.886R2 = 0.6426

0

2

4

6

8

10

12

14

0 5000 10000 15000 20000

Distance (m)

Dep

th (m

)

Fig. 6.8 : Bathymetry Along Line 4

Page 339: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

y = 6E-08x2 - 0.0017x + 14.224R2 = 0.6709

0

2

4

6

8

10

12

14

0 5000 10000 15000 20000 25000

Distance(meter)

Dep

th(m

eter

)

Fig. 6.9 : Bathymetry Along Line 5

Page 340: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

36.05

32.58

38.33

35.88

37.56

29

30

31

32

33

34

35

36

37

38

39

Mat

eria

l to

be d

redg

ed x

10

-6 m

3

Line 1 Line 2 Line 3 Line 4 Line 5Different Channels

q

Fig. 6.10 : Quantity Dredged Material along Various Tracks in Adam’s Bridge

Page 341: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 342: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 343: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.1

3 : C

ross

Sec

tion

of P

ropo

sed

Cha

nnel

Page 344: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 6.14 : 3D Plume of Disposed Silt

Page 345: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 6.15 : Near Field

Page 346: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 6.16 : Far Field

Page 347: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 6.17 : Central Line Dilution

Page 348: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fals

e C

olou

r C

ompo

site

Fig.

6.1

8 : G

eogr

aphi

cal D

omai

n C

onsi

dere

d fo

r M

odel

ling

Page 349: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 6.19 : Locations for Current Measurements

Location (Point)

Longitude Latitude

1. 79O21’03” 09O22’21” 2. 79O25’00” 09O16’15” 3. 79O00’00” 09O13’29” 4. 79O11’02” 09O15’38” 5. 79O13’10” 09O12’15” 6. 79O20’59” 09O11’50” 7. 79O13’10” 09O07’49” 8. 79O20’59” 09O08’25” 9. 79O13’10” 09O00’00” 10. 79O20’59” 09O00’00”

1

2

Page 350: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.2

0 : T

idal

Str

eam

Obs

erva

tions

PAM

BA

Pt.

2

O

CEA

N S

ITE

DA

TA C

OLL

ECTI

ON

DA

TE :

10/0

7/98

SA

CM

No.

: 01

4856

RD

U N

O :

0171

82

Spee

d (K

nots

)

POSI

TIO

N :

LAT

09O22

’21.

46N

LO

NG

79.

O21

’03.

76”E

Tim

e (h

rs.)

Speed (Knots)

Page 351: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

PAM

BA

Pt.

2

O

CEA

N S

ITE

DA

TA C

OLL

ECTI

ON

TI

DA

L ST

REA

M O

BSE

RV

ATI

ON

S

D

ATE

: 11

/07/

98

SAC

M N

o. :

0148

56 R

DU

NO

: 01

7182

Sp

eed

(Kno

ts)

PO

SITI

ON

: LA

T 09

O22

’21.

46N

LO

NG

79.

O21

’03.

76”E

Tim

e (h

rs.)

Speed (Knots)

Fig.

6.2

0 (C

ontd

….)

Page 352: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.2

0 (C

ontd

….)

Page 353: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.2

0 (C

ontd

….)

Page 354: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.2

1 : T

idal

Str

eam

Obs

erva

tion

Page 355: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

PAM

BA

Pt.

8

O

CEA

N S

ITE

DA

TA C

OLL

ECTI

ON

TI

DA

L ST

REA

M O

BSE

RV

ATI

ON

S

D

ATE

: 10

/07/

98

SAC

M N

o. :

0169

26 R

DU

NO

: 01

6552

D

irect

ion

(Deg

rees

)

POSI

TIO

N :

LAT

09O08

’25N

LO

NG

79.

O20

’59”

E

Fig.

6.2

1 (C

ontd

….)

Page 356: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

PAM

BA

Pt.

8

O

CEA

N S

ITE

DA

TA C

OLL

ECTI

ON

TI

DA

L ST

REA

M O

BSE

RV

ATI

ON

S

D

ATE

: 11

/07/

98

SAC

M N

o. :

0169

26 R

DU

NO

: 01

6552

D

irect

ion

(Deg

rees

)

POSI

TIO

N :

LAT

09O08

’25N

LO

NG

79.

O20

’59”

E

Fig.

6.2

1 (C

ontd

….)

Page 357: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

PAM

BA

Pt.

8

O

CEA

N S

ITE

DA

TA C

OLL

ECTI

ON

TI

DA

L ST

REA

M O

BSE

RV

ATI

ON

S

D

ATE

: 11

/07/

98

SAC

M N

o. :

0169

26 R

DU

NO

: 01

6552

D

irect

ion

(Deg

rees

)

POSI

TIO

N :

LAT

09O08

’25N

LO

NG

79.

O20

’59”

E

Fig.

6.2

1 (C

ontd

….)

Page 358: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Lo

catio

n : R

AM

ESH

WA

RA

M (N

D) R

-J

Dat

e : 1

0/07

/98

Fig.

6.2

2 : T

idal

Obs

erva

tions

Page 359: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Hyd

ro-d

ynam

ic M

odel

ling

Fig.

6.2

3 : P

ropo

sed

Ship

Nav

igat

ion

Alig

nmen

t Con

side

red

for M

odel

ling

Page 360: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.2

4 :

Cal

ibra

tion

Tide

Hei

ghts

Lo

catio

n : 2

0, 2

0

Water Heights (above Datum) in Mtrs.

Tim

e (h

rs)

Page 361: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.2

5 : C

alib

ratio

n C

urre

nts

Loca

tion

: 8

Page 362: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.2

6 :

Spat

ial C

urre

nt P

redi

cted

by

the

Mod

el –

Bef

ore

Dre

dgin

g

Page 363: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.2

7 :

Spat

ial C

urre

nt P

redi

cted

by

the

Mod

el –

Afte

r Dre

dgin

g

Page 364: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.2

8 :

Loca

tions

of C

oral

Ree

fs in

the

Mod

ellin

g D

omai

n (A

djoi

ning

Man

dapa

m a

nd P

amba

m Is

land

s)

Page 365: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig.

6.2

9 :

Loca

tions

of C

oral

Ree

fs in

the

Mod

ellin

g D

omai

n (D

hanu

shko

di P

ortio

n of

Pam

bam

Isla

nd)

Page 366: EIA Full Report of Neeri on Sethusamudram Ship Channel Project
Page 367: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.1

Bathymetry along Line: 1

S. No. Distance (km) Depth (m)

1 1 8.7

2 2 8.0

3 3 7.7

4 4 7.4

5 5 6.9

6 6 6.8

7 7 5.8

8 8 4.6

9 9 2.7

10 10 1.4

11 11 0.9

12 12 1.3

13 13 3.7

14 14 4.5

15 15 5.9

16 16 7.2

17 17 10.4

18 18 12.3

Page 368: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.2

Bathymetry along Line: 2

S. No. Distance (km) Depth (m)

1 1 9

2 2 8.6

3 3 8.3

4 4 8

5 5 7.5

6 6 6.9

7 7 6.1

8 8 4.8

9 9 3

10 10 2.2

11 11 4.1

12 12 1.5

13 13 3.3

14 14 3.6

15 15 5.2

16 16 7

17 17 6.3

18 18 12.2

Page 369: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.3

Bathymetry along Line: 3

S. No. Distance (km) Depth (m)

1 1 9.2

2 2 9.3

3 3 8.9

4 4 8.4

5 5 7.9

6 6 7.6

7 7 6.7

8 8 5.1

9 9 2.9

10 10 2.5

11 11 1.6

12 12 1.1

13 13 0.5

14 14 2.5

15 15 3.3

16 16 5.7

17 17 7.7

18 18 7.2

19 19 11.7

20 20 11.7

Page 370: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.4

Bathymetry along Line : 4

S. No. Distance (km) Depth (m)

1 1 9.5

2 2 9.3

3 3 9.5

4 4 9.1

5 5 7.59.1

6 6 9

7 7 8.3

8 8 7.3

9 9 5.6

10 10 2.8

11 11 2.4

12 12 1.1

13 13 0.8

14 14 1.1

15 15 2.7

16 16 3.4

17 17 6.1

18 18 6.7

19 19 8.3

20 20 8.3

Page 371: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.5

Bathymetry along Line : 5

S. No. Distance (km) Depth (m)

1 1 10.2

2 2 9.6

3 3 9.1

4 4 9.2

5 5 8.8

6 6 8.7

7 7 8.5

8 8 7.6

9 9 6

10 10 4.4

11 11 2.1

12 12 0.7

13 13 0.9

14 14 0.2

15 15 1.7

16 16 2.2

17 17 3.7

18 18 6.6

19 19 7.6

20 20 7

Page 372: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.6

Dredging Requirement for 10 m Depth (9.15 m draught)

and 300 m Width Channel

Quantity : million cu.m.

Section (See Fig. 6.12)

Bed Width Quantity

Slope Quantity

Tolerance Quantity

Total Quantity

Adam’s Bridge

A-B (CSD)

7.0 0.70 - 7.70

A-B (TSHD)

3.9 0.39 0.60 4.89 say 4.9

B-C (TSHD) 9.6 0.96 1.3 11.86 say 11.9

Total 24.45 say 24.5 Palk Strait E1-E2 2.4 0.24 1.79 4.43 say 4.45 E2-E3 8.2 0.82 1.29 10.31 say 10.35

Total 14.74 say 14.80

Page 373: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.7

Dredging Requirement for 12 m Depth (10.7 m draught) and 300 m Width Channel

Quantity : million cu.m.

Section (See Fig. 6.12)

Bed Width Quantity

Slope Quantity

Tolerance Quantity

Total Quantity

Adam’s Bridge

A-B (CSD)

7.0 0.70 - 7.70

A-B (TSHD)

7.5 0.75 0.60 8.85 or say 8.9

B-C 18 1.80 1.3 21.1

Total 37.7 or say 38 Palk Strait E-E1 1.72 0.17 1.29 3.18 or say 3.2 E1-E2 14.25 1.43 1.79 17.47 or say 17.5 E2-E3 16.84 1.68 1.29 19.81 or say 19.8 E3-E4 2.43 0.24 0.49 3.16 or say 3.2

Total 43.7 or say 44 CSD : Cutter Suction Dredger TSHD : Trailor Suction Hopper Dredger

Page 374: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.8

The Quantity of Dredged Material for 14 m Deep 500 Wide Channel

Quantity : million m3

Section (See Fig. 6.12)

Bed Width Quantity

Slope Quantity

Tolerance Quantity

Total Quantity

Adam’s Bridge

A-B (CSD)

11.66 1.16 - 12.82

A-B (TSHD)

18.48 1.85 1.0 21.33

B-C (TSHD) 44.00 4.40 2.17 50.57

Total 84.72 say 84.7 Palk Strait C-D 33.25 3.32 5.70 42.27 D-E 39.00 3.90 6.00 48.90 E-E1 17.52 1.75 2.19 21.46 E1-E2 43.56 4.36 2.97 50.89 E2-E3 42.48 4.25 2.16 48.89 E3-E4 13.06 1.31 1.62 15.99

Total 228.4 Grand Total 313.1

Page 375: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.9

Expected Number of Transits through Sethusamudram Channel

Rs. in Crores

7m Draught 9m Draught 11 m Draught

Cargo Transits (Per year)

Savings (Rs.)

Transits (Per year)

Savings (Rs.)

Transits (Per year)

Savings (Rs.)

POL & Specialized Cargo 282 39.39 366 51.97 522 75.75

Dry Bulk Cargo 120 11.92 120 11.92 120 11.92

General Cargo 1,306 16.82 1,306 16.82 1,362 19.81

Total 1,708 68.13 1,792 80.71 2,004 107.48

Page 376: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.10

Inputs to Model for Dredged Material Disposal

(12 m deep Channel)

Dredge Material Disposal in Gulf of Mannar Water

Volume of dredged material = 38x106m3

Composition of dredge = 95% sand and 5% silt

Volume of Silt = 19,00,000 m3

Total nos of day = 200 day

Per day silt disposal = 19,00,000/200 = 9500 m3/d

Silt disposed per sec = 9500 /(24*60*60) = 0.1099 m3/s

Assumed solution of silt = 10%

Volume of silt solution = 0.1099/0.1 = 1.099 m3/s

Density of solution = 0.1*1.2 +0.9*1.03 = 1.047 g/cc

Concentration of silt = 0.1*1200 = 120kg/m3

= 1,20,000 mg/l

Page 377: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.11

Maximum and Minimum Tidal Current (Speed) at Locations in

Palk Bay and Gulf of Mannar

Location Latitude Longitude Maximum speed in knots

Minimum speed in knots

Palk Bay

1 09o 22’ 21”.46 N 79o 21’ 03”.76 E 0.42 0.04

2 09o 16’ 15”.1 N 79o 25’ 40”.0 E 0.62 0.03

Gulf of Mannar

3 09o 13’ 29”.0 N 79o 00’ 00”.0 E 0.31 0.02

4 09o 15’ 38”.0 N 79o 11’ 02”.0 E 0.36 0.02

8 09o 08’ 25”.0 N 79o 20’ 59”.1 E 0.29 0.06

Page 378: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.12

Speed and Direction of Currents for Patch-I Before Dredging

Currents Patch-I Speed in cms/sec

5 6 7 8 9 10 11 12 13 14 15 55 31.26 17.03 13.42 25.63 23.41 22.56 22.02 24.19 17.89 15.81 15.30 56 27.29 24.02 19.03 22.00 24.08 22.36 22.02 22.09 18.44 17.46 16.12 57 26.48 24.19 20.02 21.00 25.00 17.12 19.03 19.10 18.25 17.12 17.03 58 24.02 23.19 22.09 23.00 24.08 18.49 17.12 16.00 19.03 17.03 18.00 59 30.15 19.24 22.02 22.00 21.00 18.03 17.03 17.00 17.00 16.00 16.00 60 26.08 23.02 22.00 21.00 20.00 19.00 18.00 17.00 17.00 16.00 15.00 61 25.18 24.08 22.02 21.02 21.02 20.02 18.03 17.03 17.03 16.03 16.03 62 24.33 24.19 22.20 21.10 21.10 20.02 18.03 17.03 17.03 16.12 16.12 63 23.35 23.35 22.36 21.21 21.21 20.10 18.11 17.12 18.25 17.26 15.13 64 23.54 22.56 21.38 21.38 20.40 20.22 19.24 18.44 18.25 17.26 16.28 65 22.80 21.59 21.59 20.62 19.42 20.40 19.42 19.42 18.44 17.46 16.49 66 22.14 21.84 20.88 20.62 19.65 20.88 19.65 19.65 18.68 17.72 16.49 67 22.14 21.19 20.88 20.62 19.65 19.92 20.25 19.92 18.68 17.72 17.72 68 21.19 20.62 18.97 22.85 21.02 21.19 18.97 18.97 18.97 18.97 18.03 69 21.93 18.36 23.77 22.47 19.31 18.97 18.97 18.97 18.97 18.03 18.03 70 21.47 17.89 22.85 21.93 18.38 18.97 18.03 18.03 17.72 18.03 17.72

Direction in Degrees

5 6 7 8 9 10 11 12 13 14 15 55 277 183 297 291 290 283 273 187 207 198 191 56 278 272 183 270 275 280 273 185 193 193 187 57 281 277 273 270 270 187 183 186 189 187 183 58 182 277 275 270 185 194 187 270 273 273 270 59 276 189 183 270 270 183 183 270 270 270 270 60 274 272 270 270 270 270 270 270 270 270 270 61 277 275 273 273 273 273 273 273 273 274 274 62 279 277 278 275 275 273 273 273 273 277 277 63 280 280 280 278 278 276 276 277 279 280 278 64 282 283 281 281 281 279 279 283 279 280 281 65 285 283 283 284 282 281 282 282 283 283 284 66 288 286 287 284 285 287 285 285 286 286 284 67 288 289 287 284 285 288 290 288 286 286 286 68 289 293 288 293 295 289 288 288 288 288 289 69 294 299 292 291 288 288 288 288 288 289 289 70 298 297 293 294 292 288 289 289 286 289 286

Table 6.12 (Contd…)

Page 379: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

After Dredging

Currents Patch-I

Speed in cms/sec

5 6 7 8 9 10 11 12 13 14 15 55 28.28 15 12.53 24.17 21.54 20.62 20.1 22.09 16.55 14.87 14.14 56 25.32 22.09 18.03 20.02 22.09 20.4 20.02 20.02 16.28 15.3 15.13 57 24.74 22.36 19.1 19.03 23.02 16.03 17.03 17.03 16.12 15.03 15 58 22 21.38 20.1 20.02 22.02 14.32 15.03 14 17.12 14.04 16 59 27.17 17.12 19.03 19 19 16 15 15.03 15.03 14 14 60 23.09 21.02 19.03 19.03 18.03 17.03 15.03 15.03 14.04 14.04 13.04 61 22.2 21.1 20.1 19.1 18.11 17.12 16.03 15.03 14.04 14.04 13.04 62 21.38 21.38 20.22 19.24 18.11 18.11 15.13 15.13 14.14 14.14 13.34 63 21.59 20.4 19.42 18.44 18.44 18.25 16.12 15.3 16.49 15.3 13.34 64 20.88 19.65 19.65 18.44 17.46 17.46 17.46 16.49 15.52 15.52 14.32 65 20.25 19.92 18.97 17.72 18.68 17.72 16.76 16.76 17.76 15.81 14.87 66 20.25 19.31 18.03 18.03 17.09 18.03 18.03 16.76 16.76 15.81 14.87 67 19.7 18.38 18.38 17.72 18.03 17.09 18.38 17.09 17.09 16.16 15.23 68 18.79 17.89 17.46 20.12 17.89 17.46 16.16 16.16 16.16 16.16 16.16 69 19.72 16.64 21.47 20.12 17.89 17.46 16.16 16.16 16.16 16.16 16.16 70 18.87 16.64 20.12 19.72 17 16.55 16.55 16.16 15.23 15.23 15.23

Direction in Degrees

5 6 7 8 9 10 11 12 13 14 15 55 278 270 299 294 292 284 276 185 205 200 188 56 279 275 183 273 275 281 273 183 191 191 188 57 284 280 276 273 272 184 183 183 187 184 270 58 270 281 276 273 183 192 184 270 277 274 270 59 276 187 183 270 270 270 270 274 274 270 270 60 275 273 273 273 273 273 274 274 274 274 274 61 278 275 276 276 276 277 274 274 274 274 279 62 281 281 279 279 276 276 278 278 278 278 283 63 283 281 282 283 283 279 277 281 284 281 283 64 287 285 285 283 283 283 283 284 285 285 282 65 290 288 288 286 286 286 286 287 287 285 286 66 290 291 289 289 291 289 289 287 287 288 290 67 294 292 292 286 289 291 292 291 291 292 293 68 295 297 294 297 298 295 291 291 291 292 293 69 300 303 298 297 297 294 292 292 292 292 292 70 302 303 297 300 298 295 295 292 293 293 293

Table 6.13

Page 380: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Speed and Direction of Currents for Patch-II

Before Dredging

Currents Patch-II

Speed in cms/sec

30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

70 11 11 11 11 11 9.8 9.5 9.5 9.5 9.5 8.5 8.5 8.5 10 9.8 10

71 11 11 11 11 9.8 9.5 9.5 9.5 8.5 8.5 8.5 8.5 8.5 8.9 10 10

72 11 11 9.8 9.8 9.5 9.5 9.5 8.5 8.5 8.5 8.5 8.5 8.5 8.5 8.1 10

73 10 9.5 9.5 9.5 9.5 9.5 8.5 8.5 8.5 8.5 8.5 8.5 7.6 7.6 8.5 8.5

74 10 10 9.5 9.5 9.5 8.5 8.5 8.5 8.5 8.5 8.5 7.6 7.6 7.6 8.5 7.6

75 10 11 9.8 9.8 9.5 8.5 8.5 8.5 8.5 7.6 7.6 7.6 7.6 7.6 7.6 7.6

76 12 11 9.8 9.8 8.5 8.5 8.5 8.5 8.5 8.5 7.6 7.3 7.6 7.6 7.6 7.6

77 16 9.4 9.8 9.8 8.9 8.5 8.5 8.5 8.5 7.6 7.3 7.3 7.6 7.6 7.6 7.6

78 15 8.9 9.8 9.8 8.5 8.5 8.5 8.5 7.6 7.3 7.3 7.3 7.3 7.6 7.6 7.6

79 14 8.9 8.9 8.9 8.5 8.9 8.5 8.5 7.3 7.3 7.3 7.3 7.3 7.6 7.6 7.6

80 13 8.5 8.5 8.9 9.8 8.5 8.5 7.6 7.6 7.3 7.3 7.3 7.3 7.3 7.3 7.6

Direction in Degrees

30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

70 292 292 292 292 292 294 288 288 288 288 291 291 291 299 294 299

71 292 292 292 292 294 288 288 288 288 291 291 291 291 297 299 299

72 292 292 294 294 288 288 288 291 291 291 291 291 291 291 300 299

73 287 288 288 288 288 288 291 291 291 291 291 291 293 293 291 291

74 287 287 288 288 288 291 291 291 291 291 291 293 293 293 291 293

75 287 292 294 294 288 291 291 291 291 291 293 293 293 293 293 293

76 290 297 294 294 291 291 291 291 291 291 293 286 293 293 293 293

77 297 302 294 294 297 291 291 291 291 293 286 286 293 293 293 293

78 293 297 294 294 291 291 291 291 293 286 286 286 286 293 283 293

79 295 297 297 297 291 297 291 291 286 286 286 286 286 293 293 293

80 297 291 291 297 294 291 291 293 293 286 286 286 286 286 286 293

Page 381: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.13(Contd…) After Dredging

Currents Patch-II

Speed in cms/sec

30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

70 8.94 8.06 8.06 8.06 8.06 7.21 7.21 7.21 7.21 7.21 6.40 6.40 6.40 7.81 5.66 5.83

71 8.06 8.06 8.06 8.06 8.06 7.21 7.21 7.21 7.21 6.40 6.40 6.40 6.40 5.66 6.40 8.60

72 8.06 8.06 8.06 8.06 7.21 7.21 7.21 7.21 7.21 6.40 6.40 6.40 6.40 5.66 6.40 7.81

73 8.06 8.06 8.06 7.21 7.21 7.21 7.21 7.21 7.21 5.83 5.83 6.40 6.40 5.66 7.07 7.07

74 8.06 8.06 8.06 7.21 7.21 7.21 7.21 7.21 5.83 5.83 6.40 6.40 6.40 6.40 6.40 7.07

75 8.94 8.06 8.06 7.21 7.21 7.21 7.21 5.83 5.83 6.40 6.40 6.40 6.40 6.40 6.40 6.40

76 9.85 8.60 8.60 7.21 7.21 7.21 7.21 6.40 6.40 5.83 5.83 5.83 5.83 6.40 6.40 6.40

77 13.04 7.81 7.21 7.21 7.21 7.21 7.21 6.40 5.83 5.83 5.83 5.83 5.83 6.40 6.40 6.40

78 12.21 7.81 7.21 7.21 7.21 7.21 7.21 6.40 6.40 5.83 5.83 5.83 5.83 6.40 6.40 6.40

79 11.40 7.21 7.21 7.81 7.21 7.21 7.21 6.40 5.83 5.83 5.83 5.83 5.83 6.40 6.40 6.40

80 7.21 7.21 7.81 7.81 7.81 7.21 7.21 6.40 6.40 5.83 5.83 5.83 5.83 5.83 6.40 6.40

Direction in Degrees

30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

70 297 300 300 300 300 304 304 304 304 304 309 309 310 315 315 329

71 300 300 300 300 300 304 304 304 304 309 309 309 315 321 321 324

72 300 300 300 300 304 304 304 304 304 309 309 309 315 321 321 320

73 300 300 300 304 304 304 304 304 304 301 301 309 315 315 315 315

74 300 300 300 304 304 304 304 304 301 301 309 309 309 309 309 315

75 297 300 300 304 304 304 304 301 301 309 309 309 309 309 309 309

76 294 306 306 304 304 304 304 309 309 301 301 309 309 309 309 309

77 302 310 304 304 304 304 304 309 301 301 301 309 309 309 309 309

78 305 310 304 304 304 304 304 309 309 301 301 301 309 309 309 309

79 308 304 304 310 304 304 304 309 301 301 301 301 309 309 309 309

80 304 304 310 310 310 304 304 309 309 301 301 301 301 309 309 309

Page 382: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.14

Speed and Direction of Currents for Patch-III Before Dredging

Currents Patch-III

Speed in cms/sec

51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

70 13.42 11.66 12.53 13.42 11.66 9.22 10.82 8.00 0.00 0.00 0.00 0.00 0.00 0.00 3.00

71 12.53 11.18 11.18 11.18 11.18 12.53 12.08 10.00 10.82 7.00 0.00 0.00 0.00 0.00 0.00

72 9.85 9.85 9.85 9.85 9.85 10.77 11.18 11.66 9.22 8.54 7.00 0.00 0.00 0.00 0.00

73 9.85 8.54 8.54 8.54 8.94 10.30 11.18 12.53 13.42 14.32 13.00 8.49 10.63 7.00 0.00

74 8.94 8.54 7.62 7.62 8.06 8.94 10.30 11.18 11.18 11.18 10.30 10.82 8.49 77.31 10.00

75 8.06 7.62 6.71 6.71 6.71 7.21 8.06 9.43 9.43 9.43 10.00 10.00 9.90 15.81 15.00

76 8.06 8.06 7.21 6.71 6.71 7.21 7.21 7.21 7.81 9.22 9.22 9.22 10.82 10.00 10.00

77 8.06 7.21 7.21 7.21 6.40 6.40 6.40 6.40 7.07 7.81 7.81 9.22 9.90 8.49 8.49

78 8.06 7.21 7.21 7.21 6.40 6.40 5.66 5.66 5.66 5.66 5.66 8.49 8.60 7.81 7.81

79 8.06 7.21 7.21 7.21 6.40 6.40 5.66 5.66 5.66 5.66 5.66 6.40 7.21 8.06 8.06

80 6.71 8.06 7.21 7.81 7.07 7.07 6.40 6.40 6.40 5.66 5.83 5.83 7.21 8.06 8.06

81 8.06 8.06 7.21 7.81 7.81 7.07 7.07 6.40 6.40 6.40 5.83 5.83 6.71 7.62 7.62

82 8.06 8.06 8.60 7.81 7.81 7.81 7.07 7.07 6.40 6.40 6.71 6.71 6.71 7.62 7.62

Direction in Degrees

51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

70 297 301 299 297 301 311 326 0 0 0 0 0 0 0 270

71 299 297 297 297 297 299 294 307 326 0 0 0 0 0 0

72 294 294 294 294 294 292 297 301 311 339 0 0 0 0 0

73 294 291 291 291 297 299 297 299 297 295 293 315 319 0 0

74 297 291 293 293 300 297 299 297 297 297 299 304 315 315 0

75 300 293 297 297 297 304 300 302 302 302 307 307 315 305 307

76 300 300 304 297 297 304 304 304 310 311 311 311 304 307 307

77 300 304 304 304 309 309 309 309 315 310 310 311 315 315 315

78 300 304 304 304 309 309 315 315 315 315 315 315 324 320 320

79 300 304 304 304 309 309 315 315 315 315 315 321 326 330 330

80 297 300 304 310 315 315 321 321 321 315 329 329 326 330 330

81 300 300 310 310 310 315 315 321 321 321 329 329 333 337 337

82 300 300 306 310 310 310 315 315 321 321 333 333 333 337 337

Page 383: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.14 (Contd…) After Dredging

Currents Patch-III

Speed in cms/sec

51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

70 14.14 13.45 14.21 15.81 12.21 9.90 10.82 9.00 0.00 0.00 0.00 0.00 0.00 0.00 5.00

71 12.73 12.04 12.21 12.21 12.21 13.04 12.53 10.00 10.30 7.00 0.00 0.00 0.00 0.00 0.00

72 10.00 10.00 10.82 10.30 10.30 10.30 10.82 1.82 9.90 7.28 6.00 0.00 0.00 0.00 0.00

73 10.00 8.60 8.60 9.43 9.43 10.30 11.66 11.66 12.53 14.32 12.08 8.49 10.00 7.00 0.00

74 8.60 7.81 7.81 7.21 8.60 8.60 10.00 10.82 10.82 10.82 10.00 10.82 8.49 11.31 9.00

75 7.81 7.81 7.81 7.07 7.81 7.81 8.60 9.22 10.00 10.00 10.00 10.63 9.90 15.00 14.21

76 7.81 7.81 7.07 7.07 7.07 7.07 7.07 7.81 7.07 9.22 9.90 9.90 10.63 10.00 10.00

77 7.81 7.07 7.07 7.07 7.07 6.40 6.40 6.40 7.07 7.07 7.81 9.22 9.90 8.49 8.49

78 7.07 7.07 7.07 7.07 6.40 6.40 6.40 6.40 6.40 5.66 6.40 8.60 8.60 8.60 7.21

79 7.07 7.07 7.07 7.07 6.40 6.40 6.40 6.40 5.83 5.83 5.83 5.83 7.21 8.06 7.62

80 6.40 7.07 7.07 7.81 7.21 6.40 6.40 5.83 5.83 5.83 5.83 5.39 7.62 8.06 8.54

81 7.07 7.07 7.81 7.81 7.81 7.21 7.21 7.21 6.71 5.83 6.71 6.32 7.62 7.62 8.54

82 7.07 7.07 7.07 7.81 7.81 7.81 7.21 7.21 7.21 6.71 6.71 7.62 7.62 7.62 8.25

Direction in Degrees

51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

70 315 312 309 305 305 315 326 0 0 0 0 0 0 0 270

71 315 312 305 305 305 302 299 307 331 0 0 0 0 0 0

72 307 307 304 299 299 299 304 304 315 344 0 0 0 0 0

73 307 306 306 302 302 299 301 301 299 295 294 315 323 0 0

74 306 310 310 304 306 306 307 304 304 304 307 304 315 315 0

75 310 310 310 315 310 310 306 311 307 307 307 311 315 307 309

76 310 310 315 315 315 315 315 310 315 311 315 315 311 307 307

77 310 315 315 315 315 321 321 321 315 315 320 319 315 315 315

78 315 315 315 315 321 321 321 321 321 315 321 324 324 324 326

79 315 315 315 315 321 321 321 321 329 329 329 329 326 330 337

80 309 315 315 320 326 321 321 329 329 329 329 338 337 330 339

81 315 315 320 320 320 326 326 326 333 329 333 342 337 337 339

82 315 315 315 320 320 320 326 326 326 333 333 337 337 337 346

Page 384: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.15

Speed and Direction of Currents for Patch-IV Before Dredging

Currents Patch-IV

Speed in cms/sec

51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

45 23.35 13.60 6.08 0.00 0.00 0.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

46 13.34 13.00 8.06 7.07 3.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

47 13.00 9.85 5.39 1.41 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

48 13.93 9.49 4.12 1.41 2.00 1.00 2.00 2.00 2.00 2.00 2.00 2.00 1.00 1.00 1.00

49 13.00 10.20 7.07 3.00 9.06 2.00 2.00 3.00 11.40 19.24 18.25 19.24 16.12 16.12 12.17

50 13.93 13.34 13.04 11.00 25.02 28.07 27.17 15.30 10.44 19.24 19.24 22.20 11.40 12.17 12.17

51 15.23 18.11 23.00 32.02 30.07 29.15 28.16 18.25 14.32 18.25 19.10 24.08 11.40 12.37 12.17

52 18.03 21.10 24.08 27.17 27.17 26.17 24.19 21.10 19.24 20.22 21.10 24.08 13.15 12.37 12.17

53 21.19 22.80 24.33 25.71 26.31 25.32 21.21 20.22 21.10 22.09 22.09 23.09 16.12 11.18 13.15

54 23.41 24.35 24.19 25.71 26.48 26.31 12.65 13.60 28.28 22.09 22.09 21.10 19.10 12.17 14.14

55 25.63 25.30 25.08 27.46 31.26 17.46 13.00 24.52 22.56 22.36 22.20 24.08 16.12 15.13 15.13 Direction in Degrees

51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

45 350 343 351 0 0 0 90 90 90 90 90 90 90 90 90

46 347 337 353 352 0 90 90 90 90 90 90 90 90 90 90

47 337 336 338 315 0 90 90 90 90 90 90 90 90 90 90

48 339 342 346 225 180 90 90 90 90 90 90 90 90 90 90

49 337 349 352 0 84 90 90 90 90 90 90 90 90 90 90

50 339 347 356 0 88 86 84 79 73 81 81 82 75 81 81

51 337 354 0 88 86 84 84 81 78 81 84 83 75 76 81

52 341 355 85 84 84 83 83 85 81 82 85 85 81 76 81

53 341 345 81 77 81 81 82 82 85 85 85 85 83 80 81

54 340 341 83 77 79 81 72 73 82 85 85 85 84 81 82

55 339 342 85 80 83 77 67 78 77 80 82 85 83 82 82

Page 385: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Table 6.15 (Contd…) After Dredging

Currents Patch-IV

Speed in cms/sec

51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

45 4.47 4.00 3.16 0.00 1.00 1.00 1.41 1.41 2.24 2.24 2.24 3.16 4.12 4.12 5.10

46 3.16 5.10 2.24 1.41 0.00 1.00 1.41 1.41 2.24 2.24 3.16 3.16 4.12 4.12 5.10

47 5.39 4.12 2.83 2.24 1.00 1.41 1.00 1.41 2.24 2.24 3.16 3.16 3.16 5.10 5.10

48 5.39 3.16 1.41 3.16 3.00 2.24 2.00 2.24 2.83 2.83 3.61 3.16 4.12 5.10 5.10

49 5.39 2.00 1.41 5.00 4.12 3.61 2.24 3.16 3.61 3.61 4.24 4.47 4.47 5.39 6.32

50 6.40 3.61 1.00 6.00 5.10 4.47 3.61 3.00 3.16 3.16 4.24 5.00 5.83 6.32 7.28

51 7.81 3.61 1.00 8.06 6.32 5.00 3.61 3.00 3.61 3.61 3.61 5.00 5.83 6.71 7.28

52 8.49 5.39 4.47 9.49 7.62 5.00 3.61 2.00 4.24 4.24 4.47 5.39 6.32 7.62 8.25

53 8.60 10.00 10.77 10.82 8.06 6.40 4.24 3.00 3.61 3.61 4.47 5.39 5.39 6.32 8.25

54 12.04 16.12 15.30 10.82 7.81 5.66 5.00 4.00 4.47 4.47 5.39 5.39 5.39 6.32 8.25

55 13.45 17.00 20.10 10.30 7.21 5.66 5.83 5.00 5.66 5.66 5.83 5.39 5.39 5.39 8.25

Direction in Degrees

51 52 53 54 55 56 57 58 59 60 61 62 63 64 65

45 297 270 252 0 180 180 135 135 153 153 153 162 166 166 169

46 288 191 243 315 0 90 135 135 153 153 162 162 166 166 169

47 292 194 225 333 0 45 90 135 153 153 162 162 162 169 169

48 292 198 225 342 0 63 90 117 117 135 146 162 166 169 169

49 292 270 225 0 76 56 27 108 108 124 135 153 153 158 162

50 309 304 270 0 79 63 34 90 108 108 135 143 149 162 164

51 310 326 0 83 72 53 34 90 124 124 146 143 149 153 164

52 315 338 63 72 67 53 34 90 124 135 153 158 162 157 166

53 306 323 68 56 60 51 45 90 135 146 153 158 158 162 166

54 318 330 79 56 50 45 37 90 117 153 158 158 158 162 166

339 318 332 84 61 56 45 31 90 112 135 149 158 158 158 166

Page 386: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

7. Environmental Management Plan

7.1 Construction Phase

7.1.1 Acquisition of Land for Onshore Facilities

Requirement of land in coastal areas of Ramnathpuram and Rameshwaram

towns has been envisaged by Tuticorin Port Trust for construction of administrative

buildings, residential quarters, facilities for mobilizing and monitoring of construction

activities in Adams Bridge area. The majority of land in Pamban island belongs to

Govt.; however the fishermen inhabit the coasts in Dhanushkody and Arimunai area.

Though land requirement has been minimized due to shifting of canal alignment,

displacement of fisherman in Dhanushkody and Arimunai is envisaged during

construction phase. A proper rehabilitation plan will be drawn for fishermen during

construction phase and maximum land will be returned to users after the construction

activities are completed.

7.1.2 Dredging Activity

Major phase of construction will involve dredging in Adam’s Bridge area

resulting into generation of 38 million cu. m. of dredged spoil. From the shallow

seismic data, it is observed that 0.5 to 1 m sea bottom comprise clay and silt followed

by hard and soft sand upto a depth of 12.0 m below CD. It is proposed to use 7 to 8

million m3 of dredged spoil for nourishment of coastal area for its consolidation using

clay, silt and sand present in excavated material. The degraded areas of Pamban

island are proposed to be reclaimed using a portion of dredged spoil. The land thus

reclaimed will be developed for vegetation and partially for habitation. Tuticorin Port

Trust (TPT) in consultation with state authorities will identify area which can be

acquired for development. These areas after development will be used for habitation

and greenbelt plantation. A provision for budget to resettle the fishermen as well

vegetation will be made by TPT.

Balance dredged spoil, about 30 million cu.m. will be transported for disposal

to sea at a location having depths ranging from 30 to 40 m and atleast 20 km away

from Gulf of Mannar marine national park. Adequate distance from international medial

Page 387: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

line will also be maintained. This is to prevent impacts on ecologically sensitive coastal

areas in GOM and to minimize transboundary effects. About 44 million m3 of dredged

material generation is envisaged during dredging in Palk Bay and Palk Strait area

Dredge material will not be disposed in Palk Bay. It is proposed to dispose this

material in Bay of Bengal at suitable depth (more than 25 m bathymetry) in open sea

so as to avoid any impacts on coastal areas particularly in the vicinity of Point

Calimere. This would involve high lead distances (between 30 & 60 km) for disposal

vessel requiring higher investments on costs. During excavation and transportation of

dredged spoil, fishing communities will be informed about the schedule so as to

minimize impacts on fishing activities. During transportation of dredged spoil,

precautionary measures will be taken to avert collision of ships with fishing boats,

damage to fishing nets and also to marine animals crossing the path of the

vessel/barges.

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 Adam’s Bridge.

During dredging and disposal activities monitoring of marine environmental

quality be periodically done to assess the impact of dredging and disposal on water

quality with respect to suspended solids load.

It is also recommended that existing jetties at Rameshwaram 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. This would provide

fisherman with better facilities to operate during adverse tidal conditions.

Transportation of construction material in the vicinity of Adam’s Bridge will be by sea

route using the available navigational depths of heavy machinery.

Transportation

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.

Page 388: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

7.2 Operational Phase

7.2.1 Route Alignment

The proposed navigation route in Gulf of Mannar will be about 20 km from all

the 21 islands except Van Tiu which is about 9 km from Tuticorin Harbour. These

islands falling in marine national park are ecologically sensitive due to presence of

diverse flora and fauna. With a view to minimize impacts of developmental activity on

this marine national park, the canal alignment in Gulf of Mannar is suggested in such a

way that only navigational depths will be used hence no dredging activity will be

required. The alignment in this region will be at depths greater than 20 m and would

keep a distance of about 20 km from marine national park. The ships originating from

TPT will however be about 9 km away from Van Tiu and later take a designated

navigation route once out of Tuticorin harbour area. Ship traffic bypassing Tuticorin

Port will maintain a distance of more than 20 km from biosphere reserves throughout

the transit in Gulf of Mannar and Adam’s Bridge. In Adam’s Bridge area the 300 m

wide channel will be along line no. 2 for which bathymetry was studied (pl. refer Fig. 2.48)

7.2.2 Discharges from Ships

All the ships originating from Tuticorin Port will comply to Marpol Conventional

1973/78 and CPCB regulations for discharge of bilge, ballast, effluents etc. into sea.

However keeping in view the sensitivity of the region, ships will not be allowed to

discharge any effluents viz. bilge, ballast, treated sewage, deck washings, oily wastes,

spillages etc. into sea so that water quality and living organisms are not affected. The

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

possibility of spillage. Tuticorin port has been handling oil ships for last 25 years and

not a single incidence of oil spill has been reported. The oil spill contingency plan in

operation at TPT will be extended to navigation in new channel. It is suggested that a

pilot should board the vessel from Tuticorin to navigate ship through GOM area up to

Bengal Channel in Palk Bay. This will help in keeping vigil on discharges from ship as

well as ship movement so that it would not drift towards marine park area.

Traditional fishing using mechanised and non mechanised boats will not get

affected as width of canal will be 300 m and rest of the sea is available for fishing. The

channel will be properly marked by navigational light buoys. Accidents by collision of

Page 389: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

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. With

the deepening of channel in Adam’s Bridge area it would be possible for fishermen to

access fishing area in Gulf of Mannar from Palk Bay and Vice-Versa. No special

permission would be required by fishermen to use the transit. It is recommended that

TPT will provide a corridor both in terms of space and time to fishermen living in

coastal areas of Rameshwaram, Mandapam and Ramnathpuram to access the canal

for moving across the ridge from Palk bay to Gulf of Mannar and Vice-versa.

Tuticorin Port Trust, keeping in view the sensitive coastal ecology, would

ensure that there will not be any open sea accidents and ships will follow a defined

sea waterway and the national and international regulations on safe navigation to

avoid any oil spill. The defaulters will be punished with fines and imprisonment. An

environmental watcher will board every ship that will transit the canal along with the

pilot at Tuticorin to caution the ships about movement of fishes and marine animals,

particularly movement of mammals, dolphins, sea cow, turtles etc. to prevent any

damage to this biological wealth of Gulf of Mannar. Movement of fishing boats,

placement of fishing nets will be watched by both pilot who also will be responsible on

behalf of TPT to prevent any discharges from ships. The traffic management along the

canal will be controlled by TPT. The port currently handles 1600 ships per annum at

TPT. The traffic projected with 9.15 m draft will be 1792 whereas for 10.7 m draft it will

be slightly more. Hence there will be marginal increase in traffic. Management facilities

at TPT will be augmented to handle the increased traffic.

TPT will ensure following from the ships transiting the canal :

• Ships should not use paints, anti corrosive agents of toxic nature on ship

bottoms

• All the ships berthing at TPT will have sewage treatment facilities however no

ship will be allowed to discharge treated sewage in Gulf of Mannar area

Page 390: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

• Ships bypassing TPT and transiting the canal will also be inspected for its

navigational safety measures before it is allowed to enter the canal

alignment.

7.2.3 Maintenance Dredging

Maintenance dredging of about 0.1 million m3 per year is envisaged in the

Adam’s Bridge area and about 0.45 million m3 in Palk Bay area totalling to 0.55 million

m3 for centre 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. The studies carried out by NSDRC

signifies that the region around Adam’s Bridge forms an significant sink for the littoral

drift. The prolonged accumulation in the area may lead to the emergence of new

islands. In case of occurrence of cyclones in Gulf of Mannar, such prolonged

deposition of sediments move north and enter Palk Bay through Pamban Pass and

Adam’s Bridge. Once the sediment enter the Palk Bay, the environmental conditions

favours immediate deposition. Hence the occurrence of cyclones in Gulf of Mannar

and the associated northerly waves might exchange more sediment from the southern

part of Peninsular India to Northern parts of east coast. Thus the quantity of

maintenance dredged spoil will increase in the channel across Adam’s Bridge in the

event of cyclones.

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 Rameshwaram in

consultation with state authorities.

An oil spill contingency plan will be drawn by Tuticorin Port Trust with

preparedness to prevent spread of oil or any cargo spillage in Gulf of Mannar and Palk

Bay and its immediate recovery by deploying equipments and ships.

7.3 Summary of Environmental Management Plan

7.3.1 Construction Phase

• No dredging will be done in Gulf of Mannar except in Adam’s Bridge

area

Page 391: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

• Alignment of navigation route 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 to under CRZ regulation. Balance dredged spoil will be

disposed in sea at a depth 30-40 m, 20-25 km away from Gulf of

Mannar islands. Dredged spoil generated in Palk Strait / Palk Bay area

will be disposed in open sea in Bay of Bengal at depth more than 25-40

m, 30-60 km away from dredging area

• Safe distance 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 Adam’s Bridge

• It is also recommended that existing jetties at Rameshwaram 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

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• 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.

7.3.2 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 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 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

Page 393: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

and time be provided to fisherman to use the channel in Adam’s Bridge

area for moving across Palk Bay to GOM and vice versa for fishing

activity

• The jetties at Rameshwaram 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 from either from Rameshwaram 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

• A corridor both in terms of space and time will be provided to fishermen

living in coastal areas of Rameshwaram, Mandapam and

Ramnathpuram to access the channel for moving across the ridge from

Palk bay to Gulf of Mannar and Vice-versa

• 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

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• 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 Rameshwaram in consultation with state authorities.

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21. Jayasankar, P., Sillaginid fishes of Palk Bay and Gulf of Mannar with an account on

the maturation and spawning of Indian sand whiting, Sillago sihama (Forsskal).

Indian - J. Fish. 1991, 38, 1, 13-25.

22. Luther, G. food and feeding habits of the two species of Chirocentrus from

Mandapam. Indian - J Fish. 1985, 32, 4, 439-446.

23. Pillai, N. G. ; Dorairaj, K., Results of the trawling survey by an institutional boat

cadalmin II in the Palk Bay and Gulf of Mannar, Mandapam, during 1977-80.

24. James, P. S. B. R. ; Soundararajan, R.; Rodrigo, J. X., A study of the seed resource of

the Indian sand whiting Sillago sihama (Forskal) in the Palk Bay. Indian - J. Fish.

1984, 31, 3, 313-324.

25. Mallik T. K. , Shelf sediments and mineral distribution patterns off Mandapam, Palk

Bay. Indian -J. Mar. Sci. 1983.12, 4, 203-208.

26. Gandhi, V.; Mohanraj, G.: Thiagarajan, R., Biology and biometry of milkfish chanos

chai nos. (Forsskal). J- Mar. Biol. Assoc. India, 1986. 28, 1-2, 169-177.

27. Luther, G., Food and feeding habits of the two species of Chirocentrus from

Mandapam. Indian- J. Fish. 1985, 32, 4, 439-446.

28. Westheide, -W. New interstitial polyochaeta (Hesionidae, Dorvilleidae) from the

littoral of the Bay of Bengal, MICROFAUNA-MAR. 1992,7,147-157.

29. Arumugam, -G; Balasnbramadia, -T s.; Rajapackjam, -s. on the occurrence of

chimaeroid egg capsule of Tuticorin, Gulf of Mannar, INDIAN -J- FISH. 1990. 37,

2,167-168.

30. Rajamani, - M .; Manickaraja, - M. Observation on the seasonal prawn fishery of the

Periathlai coasl. In the Gulf of Mannar ,INDIAN -J- FISH. 1990. 37, 3, 183-188.

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31. Dorairaj,-K.; Mohanraj,-G.; Gandhi, -V.; Raju,-A,; Rengaswamy, -V.S. ; Rodrigo, -

J.X, On a potentially rich milkfish seed collection ground near Mandapam along with

the methods of collection and transportation, INDIAN-J.-FISH. 1984, 31,2, 257-271.

32. Hamsa, - K.M.S.A..; Arumugam, -G. A record of the snake mackerel Gempylus

Serpans cuvier from Gulf of Mannar. Indian J. Fish. 1982, 29, 1-2, 255-257.

33. Chellam, A.; Velayudhan, T. S.; Dharmaraj, S.; Victor, A. C. C.; Gandhi, A. D. A

note on the predation on pearl oyster Pinctada fucata (Gould) by some gastropods.

Indian-J. Fish. 1983, 39, 2, 337-339.

34. Manisseri, M. K., On the fishery of Juveniles of Penaeus semisulcalus along the

Tinnevelly coast, Tamil Nadu. Indian-J. Fish. 1982, 29, 1-2, 20-28.

35. Marichamy, r.; Rajapandian, M. E.; Srinivasan, A., The standing of rorqual whale

Balaenoptera musculus (Linnaeus) in the Gulf of Mannar. J. Mar. Biol. Assoc. India,

1984, 26, 1-2, 168-170.

36. Mahadevan, S.; Nayar, K. N. national Marine Parks (Gulf of Mannar). J. Mar. Biol.

Assoc. India, 1983, 25, 1-2, 71-77.

37. Thomas, P. A. Sponges collected aboard R. V. Skipjack from the southeast coast of

India. J. Mar. Biol. Assoc. India, 1984, 26, 1-2, 95-102.

38. Russell, B. C., On the validity of Nemipterus furcosus (Valenciennes) (Nemipteridae).

Cybium. 1991. 15, 1, suppl., 35-41.

39. Parthasarathy, N.; Ravikumar, K.; Ganesan, R.; Ramanurthy, K., Distribution of

seagrasses along the coast of the Tamil Nadu, Southern India. AQIAT. BOT. 1991.,

40, 2, 145-153.

40. Ganesan, M.; Kannan, R.; Rajendran, K.; Govindasamy, C.; Sampathkumar, P.;

Kannan, L., Trace metals distribution in seaweeds of the Gulf of Mannar, Bay of

Bengal. Mar. Pollut. Bull. 1991., 22, 4, 205-207.

41. Rao, C. B. ; Satyanarayana, C. Rao, D. V. ; Fahy, E.; Faulkner, D. J. , Metabolites of

Aplysia dactylomela from the Indian Ocean. Indian-J. Chbm., Sect. B. 1989, 28B, 4,

322-325.

42. Ray, S. B.; Rajagopalan, S. B.; Somayajulo, B. L. K., Radiometric studies of sediment

cores from Gulf of Mannar. Indian -J. Mar. SCI. 1990, 19, 1, 9-12.

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43. James, D. B., Research, conservation and management of edible holothurians and

their impact on the beache-de-mer industry. CMFRI-SPEC., Publ. 1988. 40, 97-98.

44. Mohan, R. S. L., Research needs for the better management of dolphins and dugong

resources of India. CMFRI - Spec. Publ. 1980., 40, 98-99.

45. Kasim, H. M.; Hamsa, K. M. S. A., Exploitation of seerfish resources in Gulf of

Mannar. CMFRI Spec. Publ. 1988, 40, 11-12.

46. Srinivasan, A.; Santhanam, R.; Jegatheesan, G., Biomass and seasonal distribution of

planktonic Binbinnids of Pullavazhi Estuary, Soulheasl coast of India. Indian-J. Mar.

SCi., 1988, 17, 2, 131-133.

47. Luther, G.; Dharma Raja, S. K.; Pollution studies on the fishes of the genus

Chirocentrus cuvier. J. Mar. Biol. Assoc. India. 1982. 24, 1-2, 118-128.

48. Radhakrishnan - Nair, P. N., Diurnal variation in the feeding habits of Dussumieria

acuta val. From the Gulf of Mannar and the Palk Bay. J. Mar. Biol. Assoc. India.,

1982, 24, 1-2, 112-117.

49. James, D. B., Ecology of Intertidal echinoderms of the Indian, seas. J. Mar. Biol.

Assoc. India., 1982, 24, 1-2, 124-129.

50. Uusitalo, J., Commercial seaweed collection and agar/alginate industries in Tamil

Nadu, India. Seaweed cultivation as a from a minor field study in November-

December 1986. Fish. Dev. Ser. Natl. Swed. Board Fish. 1987., 23, 61.

51. Mahalingam, R.; Gopinath, K., Ecological conservation of seagrass beds in the Gulf

of Mannar, India. Environ. Conserv. 1987, 14, 3, 265-268.

52. Nalluchinnappan, I.; Jeyabaskaran, Y.; Krishnamoorthy, S., Effect of temperature and

salinity on catches of "Choodai" at Tuticorin, Gulf of Manner. Matsya. 1982,11.

53. Sivakami, S.; Marichamy, P.; Livingston, P.; Gopakumar, G.; Thiagarajan, R.;

Vivekanandan, E.; Vidyasagar, K.; Selvaraj, G. S. D.; Muthusamy, S.; Pillai, N. G. K.

Khan, M. Z. , Distrubution of finfish resources along southeast coast of India in

relation to certain environmental parameters. Proceedings of the second workshop on

scientific results of Forv. Sagar, SAMPADA. Pillai, V. K.; Abidi, S. A. H. ;

Ravindran, Balachandran, K. K.; Agadi, V. V.eds. New Delhi India EPARTENT of

ocen development 1996, 315-330.

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54. Ramanujam, N. Mukesh, M. V. Preeja, N. B., Calcium carbonate accretion ,

mechanical properties and adaptive significance of the coral Acropora cervicornis in

the windward side of Karichalli Island, Gulf of Mannar. J. Indian, Assoc. Sedimentol.

1992, 11, 89-94.

55. Ganesan, M.; kannan, L., Seasonal distribution of intertidal seaweeds and seagrasses

at two selected places of the Gulf of Mannar. Phykos 1995, 34, 1-2, 135-144.

56. Balachandran, S., Shore birds of the Marine National Park in the Gulf of Mannar,

Tamil Nadu. J. Bombay. Nat. Hist. Soc. 1995, 92, 3, 303-313.

57. Ramanujam, N.; Mukesh, M. V.; Sabeen, H. M.; Preeja, N. B., Morphological

variations in some Islands in the Gulf of Mannar ,India. J. Geol. Soc. India, 1995, 45,

703-708.

58. Rao, B.; Trimurtulu, G.; Sreedhara, C.; Venkata Rao, D.; Bobzin, S. C.; Faulkner, D.

J., Diterpenes from the brown alga Dictyota bartayresiana. Phytochemistry 1994, 37,

2, 509-513.

59. Genesan, M.; Kannan, L., Seasonal variation in the biochemical constituents of

economic seaweeds of the Gulf of Mannar. Phykos 1994. 33, 1-2, 125-135.

60. Venkataramanujam, K.; Venkataramani, V. K.; Devaraj, M., A new solenostomid fish

solenostomus tuticoriensis sp. no. from Tuticorin Bay, South India. J. Mar. Biol.

Assoc. India. 1993, 35, 1-2, 201-204.

61. Thomas, P. A.; Ramadoss, K.; Vincent, S. G., Invasion of Cliona margaritifera dendy

and C. lobata Hancoock on the mollluscan beds along the Indian coast. J. Mar. Biol.

Assoc. India. 1993, 35, 1-2, 145-156.

62. Sastry, A. V. R.; Suresh, K. V.; Ramesh, M. V.; Kamalakaram,S., Sediment transport

from the outer shelf into the lower Bengal Fan. Recent geoscientific studies in the bay

of Bengal and the Andaman sea papers presented in the Seminar Held on October 9-

11, 1990, at Calcutta. Geological Surv. Of India, Calcutta. India Calcutta. India 1992

no 29, 189-195.

63. Rao, M. S., Some aspects of morphology and Quaternary sea level changes in

Coromandel coast of Tamil Nadu and Andhra Pradesh. Sea Level variation and its

impact on Coastal Environment Rajamanickam, G. V. ed 1990, 279-295.

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64. Loveson, V. J. Rajamanickam, G. V. Chandrasekar, N., Environmental impact of

micro details and swamps along the coast of Palk Bay Tamil Nadu, Inda. Sea Level

variation and its impact on Coastal Environment Rajamanickam, G. V. ed 1990, 159-

178.

65. Chandramohan, P., Distribution of longshore sediment transport along the Indian

coast based on empirical model. Third National Conference on Dock and Harbour

Engineering, 6-9 December - 1989 Proceedings, 1989, 501-508.

66. Angusamy, N; Rajamanickam, G. V., (1993), The distribution and nature of heavy

minerals along the beaches of Southern Tamil Nadu.

67. Ammer Hamsa, K. M. S.; Gandhi, V. Foraminifera collected off Mandapam (Gulf of

Mannar). J. Mar. Biol. Assoc. India. 1978 20, 1-2.

68. V.N. Pillai, N.G. Menon, Marine Fisheries Research & Development, CMFRI, 2000

69. Souvenir 2000, Mandapam Regional Centre of Central Marine Fisheries Research

Institute, Mandapam Camp

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Environmental Impact Assessment for Proposed

Sethusamudram Ship Channel Project

Executive Summary

1.0 Introduction 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 ‘Adam’s 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 Adam’s 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, 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.

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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.

2.0 Project 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 Adma’s 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

Adam’s 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 Adam’s 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

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Traffic Management System (VTMS) is proposed to be located at Rameshwaram

island between Dhanushkodi and Koil Nagar village to control navigation, besides

other infrastructure including administrative requirements.

3.0 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.

4.0 Key Findings 4.1 Environmental Status 4.1.1 Marine Environment

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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 Adam’s 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 Adam’s Bridge do not

exist though major groups of biological resources like sea fan, sponges, pearl oysters,

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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.

Biodiversity

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,

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Flamingoes, Teals, Gulls Tems, Plovers and Stilts, Dolphins and Turtles are seen

close to shore area.

4.1.2 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.

4.1.3 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.

4.2 Oceanographic Status

The hydrodynamic studies of the seabed in Adam’s 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

Page 407: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

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 Adam’s Bridge area shows soft and hard sand upto 12 m

with particle size varying from 65 to 600 µm. 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. Subbottom 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.

5.0 Impacts due to the Project 5.1 Impacts on Landbased Facilities

The project envisages construction of shore facilities to cater the needs of

channel in Adam’s Bridge area, viz. service jetties, slipways, buoy yard, repair

workshop as also staff and administration buildings for facilitating regulated traffic in

the vicinity of Adam’s bridge area. The locations of land-based structures, and the

Page 408: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

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 Adam’s 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 Pumban 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.

5.2 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.

Page 409: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

In Adam’s 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 µm to 600 µm) 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

Page 410: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

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

Adam’s 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.

5.3 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 Rameshwaram

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.

Page 411: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

6.0 Environmental Management Plan 6.1 Construction Phase

– No dredging will be done in Gulf of Mannar except in Adam’s Bridge

area

– Alignment of navigation route at Adam’s 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 Adam’s Bridge

– It is also recommended that existing jetties at Rameshwaram 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

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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.

6.2 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

Page 413: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

– 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

Adam’s Bridge area for moving across Palk Bay to GOM and vice

versa for fishing activity

– The jetties at Rameshwaram 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 Rameshwaram 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

Page 414: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

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 Rameshwaram in consultation with state authorities

10.5 m

8.1 m

9.6 m

11.6m

10.5 m

8.1 m

9.6 m

11.6m

B

D

E

C

E1

E2E3

E4

14.6 km

19.8 km14.4 km

5.4 km

Km : Distance between points m : average depth within a section

Page 415: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 6.12 : Bathymetry along the Proposed Channel

6.33

L E G E N : : :Numbers :

A1

A B

C

D

E E1

E2 E3 E4

Tirutturaippundi

Karryappattinam Topputtural

POINT CALIMER

North Channel

Muttupet Pattukkottai

Atirampattinam

Peravuruni

Tiruvayppadi

Manamelkudi

Kottaippattanam

Gopalapatnam Sundarapandiyanpattana

Tiruvadanai

Tiruvettriyur

Moreppanai

Uchipuli

Neduntivu Shoal

Delft Channel

Land End Mannar Island Near W

Talamannar

Vallaipadu

Vidattaltivu Parayanpiddy

Pooneryn

ChemNakarkoy

Point PedrPoint Pedro Shoa

Kalmunal Pt.

Karaitivu NW Point

PALK STRAIT

PALK BAY

GULF OF MANNAR

A E4 C E

Page 416: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 6.11: The Alignment of the Proposed Channel

Fig. 6.14a : Tentative Location for Disposal of Dredge Materials in Sea

6.36a

Proposed in 1961 Proposed in 1968 Proposed in 1996 Report Suggested by Steering Committee Considered by NEERI (1998) Present Proposal of NEERI

Page 417: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Fig. 6.30 : Plan Showing Various Alignments of Sethusamudram Ship Canal Project and the Group of Islands (Marine Parks) in Gulf of Mannar

6..58 4.10

Page 418: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

4.11

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4.12 4.13

Page 420: EIA Full Report of Neeri on Sethusamudram Ship Channel Project

Annexure I

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