Eco Sensitive Areas-Indian Coast June 11

8/6/2019 Eco Sensitive Areas-Indian Coast June 11

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3. Gahirmatha 19

4. Puri & Konark 19

IX. WEST BENGAL

1. Sunderbans 20

2. Digha 21

X. ANDAMAN & NICOBAR ISLANDS 21

XI LAKSHADWEEP ISLANDS 22

B. DEVELOPMENT OF OIL SPILL MODELS AND IMPACT OF OIL

SPILL ON MARINE ORGANISMS

1. Introduction 23

2. Behaviour and Effects of oil 23

3. Role of contingency plans 25

4. Response and Contingency planning

A case study Gulf of Kachchh

28

5. Response Management System 34

6. Conclusions and Recommendations 36


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Introduction

India has a coastline of about 5500 km in the mainland and about 2000 km in its

offshore islands. The coastal area of the country is blessed with vast network of back waters,

estuaries, creeks, lagoons and specialized ecosystems like mangroves and coral reefs. It has

vast beaches all along the coast. The biodiversity in the coastal waters, Gulf of Mannar and

Kutch, in the waters of Andaman, Nicobar and Lakshadweep islands and in the specialized

ecosystems like chilka lake, mangroves along east coast are significantly high. More than

5000 species of marine flora and fauna have been recordered so far the coastal and marine

waters of the country. There is an urge to preserve, conserve and protect the coastal habitats

and the marine environment from all made activities. The country is blessed with vast

stretches of beaches along its coastline. The beaches and the adjoining land are being

extensively for recreation, relaxation and for creating attractions like amusement parks etc.

Oil spills that occur during the accidents of ships/tankers, their grounding, rupture of seabed

and onshore oil pielines, offshore oil production and exploration platforms etc, do affect these

habitats,beaches and their adjoining land and cause irreversible damage to the biodiversity as

well as create an unaesthetic appearance.

The present section identifies locations of ecologically sensisitive areas, beaches of

commercial and recreational importance, historical and pilgrimage sites along the coastline of

the country for protecting them against oil spills. Names and locations of these areas

indicated in Fig 1. The degree of sensitivity of these areas in terms of oil spill risks and

development of a model to understand the movement of oil during oil spills and their likely

impact on flora and fauna have also been described.

Fig.1. Map showing the ecologically sensitive and other areas need to be proctected from oil spills


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A. SENSITIVE AREAS ALONG THE COASTLINE OF INDIA

I. GUJARAT

1. Gulf of Kachchh

Gulf of Kachchh, the largest coastal habitat in the West coast of India in the state of Gujarat

(20 15 to 23 35 N and 60 05 to 70 22 E) is encompassing over 1000 km long shoreline

covering an area of 7350 sq.km (Fig.VI.2). It is a shallow water body with depth extending

from 60 m at the mouth to less than 20 m at the head of the Gulf. While the average depth is

30 m, the minimum depth is upto 5 m, around Lushington island. The Gulf is delimited in the

north by the Kachchh region and in the south by the Saurashtra region. The Marine NationalPark and Marine Sanctuary are situated along the southern shore of the Gulf from Okha

(2230N, 6900E) eastwards to the vicinity of Khijadia (2230N, 7040E). This include 42

islands and a complex of fringing reefs backed by mudflats and sandflats, coastal salt marsh

and mangrove forests, sand and rocky beaches which support a great diversity of fauna and

flora. The area also has many islands fringing with corals and mangroves which provide a

disturbance free habitats for many species of nesting birds. Besides these islands there are a

number of wavecuts, eroded shallow banks like the Pirothan, Deda, Donna, Sankhodhar Beyt,

Paga, Adatra and Boria, which accounts for coral islands. The tidal amplitude is from 3-5m.

The spectacular Gulf of Katchchh is the home for more than 800 species of

organisms; 32 hard (Scleractinia) and 12 soft (Alcyonaria) corals, 150-200 species of fishes,

more than 100 species of algae, great diversity of sponges and worms, brittlestars, marine

turtles and other reptiles, over 200 species of migratory and resident bird species and also the

rare and endangered marine mammal, the dugong. The Gulf of Kutch produces 95% of the

salt requirements of the country. Salt pans are located close to inter-tidal area and deep into

the land.

The area is home for intermediate and major ports like Kandla, Adani, Okha and

Salaya. Kandla is one of the major ports that receives imported oil from ships and tankers.

Besides, there are 4 Single Point Moorings where oil is drained from large tankers through

under sea pipelines for landward transport of oil. The Asias largest oil refinery is located at

Jamnagar in the Gulf of Kutch. Considering the quantity of oil handled and transported, the

area is most vulnerable for oil spills. A few minor incidences of oil spill have occurred in the

past.


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Oil Spill Risk

Since the area has major and intermediate Ports, has four SPMs and located along

the shipping line, the risk on oil spill is very high.

2. Beach of South of Dwarka

Dwarka, a submerged port city of historical and Mahabharata fame, is said to have

been founded by Lord Krishna on the ruins of an earlier settlement known as Kusasthali after

reclaiming from the sea. The identification of the remains of a 15th century BC township

destroyed by the sea in the Dwarkadish temple complex overlooking the Arbian sea,

increased the possibility of finding the submerged remains of the city in the sea. The temple of

the Sea God (Samudra Narayana or Varuna Devata) near the junction of the Gomti river with

the sea, marks the entrance to the ancient harbour of Dwarka. Pilgrims regularly visit the

temple and the beach. The area is in the vicinity of shipping route and therefore any oil spill

occurring will affect aesthetics of the beach.

Oil Spill Risk

Since the area is away from the shipping line, the risk on oil spill is moderate.

Gulf of Khambat

Patches of mangrove formation is found at most of the locations along the Gulf of

Khambat. However, prominent and significant mangrove formation is found in the Piram

island.

Oil spill Risk

Due to location of minor and intermediate ports at Bhavnagar, Dahej, etc., the risk of

oil spill is present. However, as most of them are small to medium cargo ships, the threat is

less considering the quantity of oil handled. As the tidal current velocity is high, the movement

of oil slicks towards mangrove areas especially during high tides is significant and a matter of

concern.

II. MAHARASHTRA

The state having a coastline of 653 km is blessed with vast beaches and very few

ecologically sensitive zones. The details are:


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1. Beaches of Mumbai

Mumbai has beaches like Juhu, Versova which attract a number of day visitors. Oil

spills caused by ships and tankers calling at Mumbai and Jawaharlal Nehru Ports will affect

aesthetics of the beach.

Oil Spill Risk

Since the area is close to Mumabi and JN Ports and located along the shipping line,

the risk on oil spill is high.

MALVAN COAST

The Malvan coast occupies in Sindhudurg district, a part of Konkan coast along the West

coast of India. The coastal features of Malvan are rocky, dissected mainland with rias and lava

promontories, occasional presence of overhanging cliffs, projecting headlands, stacks and

reosion platforms, rocky shoals, several submerged coral reefs and boulders in a ria type

coast particularly towards south. The Sindhudurg fort constructed by King Shivaji is located

on the coast. The area is regularly visited by tourists.

Environmental Sensitivity

The area is of ecological, historical and tourism importance by the presence of intertidal corals

and the fort. Movement of oil due to spills occurring in the offshore will affect the ecology of

area.

Oil Spill Risk

The area is away from the Ports. However, located along the shipping line and

therefore, the risk on oil spill is moderate.

III. GOA

Goa is the tourists paradise with clean beaches throughout its 105 km coastline.

With natural forestry in adjoining hills of Western ghat, it attracts 11 million tourists every year.

The Marmagao port which handles iron ore and small quantum of oil is visited by ships and

tankers.


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Environmental sensitivity

The coastal waters are clean and extensively used for beach tourism and regularly

visited by locals and tourists. A few oil spill incidences that occurred in the past have affected

the aesthetics of the beaches.

Oil Spill Risk

The oil spill risk of beaches close to Marmagao port is high. It is moderate in other

areas.

IV. KARNATAKA

1. Coastal Area of Gokarn

Gokarn, famous for ancient temples, is an important coastal town located along this coastline.

An interesting feature of this coast is that the Western ghat (hill ranges) run almost parallel to

the coast and form cliffs in several places. Near Mahabaleswara temple close to estuarine

mouth (north of Gokarn), the coast is characterized by rocky edges. The area is likely to be

affected by drifting oil from offshore which occur in the event of oil spills.

2. Beaches of Karnataka

The state has long virgin beach areas close to Malpe, Karwar and Mangalore which are

enjoyed by local residents.


The beaches are regularly visited by the local population. Oil spills affect the

aesthetics of these beaches

Oil Spill Risk

Since the area are away from the Ports except Mangalore and located along the

shipping line, the risk on oil spill is moderate. The risk of oil spill on beaches of Mangalore

coast is high.


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KERALA

Kerala coastal zone is famous for its beautiful beaches, backwaters and lagoons.

The coastal belt, a narrow strip of lowland, is the most picturesque region of Kerala,

interspersed with extensive backwaters, lagoons and canals and flanked by luxuriant

coconut groves and green rice fields. The lagoons and backwaters are never far from the

sea and at several places they have established a permanent connection with it. The

backwaters, rivers and the canal system form a navigable waterway of about 1,920 km.

This offers an unique ecological niche with great potential for brackish water fish farming

in the state. The sea off Kerala is one of the most productive zone for marine fish. Kochi is

the major port located along the coast.


The entitre coastline is of natural beauty with vast beaches. The tidal implications are

felt deep into inland areas through the network of backwaters. They have high utility for

fishing, navigation and boating. Since the oil spills may cause extensive damage to beaches,

the entire coast requires protection from oil spills.

Oil Spill Risk

Except Kochi the area is away from the Ports and located along the shipping line, the

risk on oil spill is moderate. The risk on oil spill for Kochi backwaters and beaches are high

VI. Tamil Nadu

Tamilnadu with a coastline length of 906 km has a number of sensitive areas like

mangroves, coral reefs, bird sanctuaries, historical sites, pilgrimage areas and beaches. The

most that need protection from oil spills are:

1. Kanyakumari

It is one of the most popular destinations for tourists in the country. The Vivekananda rock

memorial which is 1 km offshore and the beaches of the area are the major attractions. It is

visited throughout the year by tourists from all over the country. The area has rocky shore

and extensive beaches with temples nearby. The area is of historial importance.



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The waters of the coastal areas are regularly used by the tourists for bathing and the

beach for recreation. Oil spills will affect the water quality thereby prohibiting bathing and it will

provide unaesthetic appearance to the beaches.

Oil spill risk

The area is close to the international tanker routes and oil spills will damage the rock

memorial and the beaches. It can be categorized as a high risk area.

2. Thiruchendur

Thiruchendur is an important pilgrimage areas in the state of Tamil Nadu. It is

regularly visited by the devotees who take bath in the sea.


Being known for pilgrimage, the beach the sea is in constant use for bathing by

visitors. The tidal amplitude around 80cm. The littoral drift governs near coast circulation. In

the event of oil spills occurring close to the coast in the months of March to September, the

tidal and long shore currents will transport the oil along the shore affecting the beaches and

contaminating sea water.

Oil Spill Risk

The area is away from the Ports and however, being located along the shipping line,

the risk on oil spill is moderate.

3. Tuticorin

Tuticorin is situated 607 kms south of Chennai (Lat. 845- 900 N and Long. 7815

E) on the eastern coast of southern Tamil Nadu. It has a major port and reasonably

industrialized. There is a thermal power plant on the coast with a generation capacity of 3 x

600 MW. The sea is part of the Gulf of Mannar.

Ecological Sensitivity

Tuticorin and adjoining sea areas have following biologically important aspects:

Pearl Banks: The maximum concentration of pearl banks is found in the region off

Tuticorin. The region between Tuticorin and Kanniyakumari have extensive pearl banks.


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There are about 10 pearl banks. The most preferred species of pearl oyster is Pinctada

fucata. There are about four species of pearl oysters. P. fucata is the most abundant

variety found off Tuticorin coast. The other common species is P. chemnitzi. In the region

near Tuticorin their concentration is found even at depths of about 37 mts at 847 N and

7825 E. The maximum concentration is along the depth contour of about 16 to 20 mts.Nearabout Van Thivu and Koswari Thivu there are pearl banks at depths of 11mts to 15mts.

The pearl oyster fishery yields easily about Rs.4 - 6 lakhs as gross revenue per annum when

fishery is in operation. Pearl fishing operation is conducted throughout the year. The usual

season is between November and May. The pearl culture industry using artificial seeding of

oyster for propagation of pearls is catching up.

Corals: The reef framework is complex. The coral reefs and patches that are found around

the various islands off Tuticorin are as follows:

a. Kariyashuli island 16 kms off Tuticorin coast has coral reef around the island upto a

distance from 500 m to 1 km.

b. Koswari Island 7 kms off Tuticorin has live corals in the southern side 500 mts to the

shore.

c. Hare Island now connected to the mainland 6 kms from Tuticorin has

fringing reef on eastern side upto 0.5 kms.

Chank Beds: The sacred chank Xancus pyrum is found in fine or soft sandy substrates.

The chank beds are very productive. The industrial uses of chanks are many. The

Valampuri chanks which have sinistral coiling fetch more than Rs.20,000/- for a perfect

chank of 65 mm or greater diameter. This sinistral form is used in worship in the Hindu

temples.

The water quality in the marine environment around the coral reef areas except the

one close to the Thermal power plant are good. Any oil spill by ships visiting the port will affect

the corals, chank and pearl oyster beds and cause immense damage to ecology and local

economy.

Oil Spill Risk

Since the area is close to the Tuticorin Port, the risk of oil spill is very high.

4. Gulf of Mannar

The Gulf of Mannar is situated between India and Sri Lanka. It runs on its Indian

side, at its head from Pamban Islands southern coastline which includes the famous pilgrim

centre of Rameswaram to Kanniyakumari along the mainlands coast, to a distance of

about 170 nautical miles. The Gulf of Mannar is spread on the Indian side along longitude


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from 7808E to 7930 E and latitude from 835 N and 925 N. There are about 21 islands

that extend from Pamban area to Tuticorin (Fig 2.). The Gulf of Mannar has been declared as

a Marine Biosphere reserve by the Government of India. The biological wealth of Gulf of

Mannar has been studied in detail since 1903.

Fig.2. Gulf of Mannar and its 21 islands

The islands have been divided into Mandapam, Keelakarai, Vembar and Tuticorin

groups due to their proximity to these places and also the population in and around these

areas depend on the waters of these islands to meet their livelihoods. The islands are banned

for inhabitation.

Coral Reefs

On Gulf of Mannar both fringing and patch coral reefs occur. With the help of

calcareous algae in shallow sea, the Hermatypic corals build primary reef formation with

secondary detrital reefs in deeper water. The corals occur from a distance of 200-600 mts

from the outer edges of these islands. The depth at the outer edge of the reef is about 5 mts.

The density of corals vary from 0.3 sq km to 18 sq.km. For eg. Distribution of coral reefs in

the Mandapam group of islands is given in Fig.3.

Nallathanni

Pulivinichalli

Upputhanni

Karaichalli

Kasuwar

Anaipar

Palliyarmunai

Poovarasanpatt i

Appa

MusalThalayari

Vaalai

Mullai

Poomarichan

Pullivasal

Kurusadai

Shingle

MANDAPAM GROUP

KEZHAKARAI GROUP

VEMBAR GROUP

TUTICORIN GROUP

BAY OF

BENGAL

Vaan

Manoliputti

Manoli

Velanguchalli


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Fig.3. Distribution of corals in the Mandapam group of islands. Red colour are areas of livecorals; Yellow colour areas of dead corals and Green colour are areas of Sea grass.Numbers in the depth contour line indicate the depth.

In the Gulf of Mannar Islands, the eastern side of the islands would appear to

have a greater expanse of living coral reefs. The human exploitation of the coralline

stones is concentrated on the northern and western sides. Hence the eastern sides

remain now relatively free of human influence and interference and so exploitation is less.

Recently the Government of Tamil Nadu has prohibited quarrying of corals after considerable

loss of reefs to the point of extinction.

The coral genera of Gulf of Mannar and their status

Genus Status No. of Species recorded

Acropora xxx h 12

Astraeopora x h 1

Balanophyllia x a 1

Culucia x a 4

Cycloseris x a 1

Cyphastrea xx h 2

Dendrophyllia x a 2

Echinopora x h 1

Endopsammia x a 1 (single record)

Favia xx h 6

Favites xx h 6

Galaxea x h 1

Goniastrea xx h 2

Goniopora xx h 3

Heterocyathus xx a 1

Heteropsammia xx a 1 (deep water)

Hydnophora x h 2Leptastrea xxx h 2


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Leptoria x h 1

Madracis Deep water 1

Merulina x h 1

Montipora xxx h 17

Mycedium x h 1 (single record)

Ooscinaraea x h 1

Pachyseris x h 1

Paracyathus x a 1

Pavona x h 4

Platygyra xx h 1 or 2

Pocillopora xxx h 3

Polycyathus xx a 1

Porites xxx h 6

Psammocora x h 1

Pseudosiderastrea x h 1

Siderastrea x h 1

Symphillia x h 1

Tubastraea x a 1

Turbinaria x h 3

x - rare / xx - common / xxx - most common / h - hermatypic / a - ahermatypic

Algal Resources

The Gulf of Mannar area is well known for its algal wealth. A number of seaweeds

are found in abundance in this area. The total productive area estimated is around 10,000 ha.

with a standing of more than 18,000 tons. The mean algal density varies from as high as 1.16

Kg/l to 0.38 Kg/l. The common seaweeds found here are Ulva, Sargassum, Gelidiella,

Gracilaria, Caulerpa, Halimeda, Padina, Hypnea, Turbinaria, Chondrococcus, etc. About 160

species of algae have been recorded so far from this region. Out of which some 30 species

form the edible seaweeds.

Seagrass Ecosystem

The Gulf of Mannar area is also very rich in seagrasses. The species composition of

seagrasses is as follows: A. Hydrocharitaceae (Enhalus acoraides, Halophila ovalis, H. ovata,

H. beccari, H. stipulacea, Thalasssia hemprichii); B. Potamogetonaceae (Cymadocea

serrulata, C. rotundata, Halodule uninervis, Syringodium isoetifolium)

Mangrove Vegetation


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The Gulf of Mannar islands possess unique mangrove vegetation, consisting of

species belonging to Rhizophora, Avicennia, Bruguiera, Ceriops, Lumnitzera etc. Many

halophytes belonging to Suaeda, Arthocnemum, Sesuvium, Atriplex are also present. The

mangrove trees are not very tall, perhaps the height is curtailed due to strong winds prevailing

here.

Sacred Chank Beds

The sacred chank,Xancus pyrum also occurs in the Gulf of Mannar. The chank beds

are productive and form a potential fishery in this area.

Pearl Banks

The pearl banks are concentrated in the Pandiyan tivu, Van tivu, Upputhanni tivu and

Nallathanni tivu. Normally they occur in depths between 10 - 20 m. The pearl culture industry

for artificial propagation of pearls has been established. The other molluscs found in

abundance are Perna viridis, Meretrix, Katelysia, Anadara, Donaxand Dentalium.

Other Fauna

A variety of marine invertebrates are found in abundance in this area. The Krusadai

island in this region is commonly known as The Paradise of Biologists. The seacow

Dugong dugongis found in abundance in this area. It is an endangered species and has to be

conserved. Gorgonids are very valuable marine resources because of their pharmacological

values. Common forms belong to the following genera, Echinogorgia, Thessia, Juncella,

Subergorgia, and Leptogorgia.

Environmental Status

The Gulf of Mannar Marine National Park was established in the year 1983 to

conserve and restore the ecosystems of Palk Bay and Gulf of Mannar. Generally the coastal

waters are relatively unpolluted. Eventhough the shipping lines are far away from the gulf

area, considering the wind direction esp from June to Sep, any oil spill occurring from

ships/tankers moving from Indian Ocean towards Colombo or Tuticorin, would result in

movement of the oil towards the Gulf of Mannar. Since the volume of traffic in that area is not

significant, no major incident of oil spill has been reported so far. However, this would not be


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scenario all the times especially when the volume of traffic are proposed to increase in the

ports of Tuticorin and Colombo.

Oil Spill Risk

Since the area is close to the Tuticorin and Colombo ports in the eastern side of the

Gulf, the risk of oil spill is very high.

5. Vedaranyam :

Vedaranyam is one of the Coastal blocks of Thanjavur district. It is located along the

coastal shipping line moving towards Chennai port. It is situated 102 km east of Thanjavur. It

falls within the co-ordinates of 1015N to 1035N and longitude 7920E to 7955E.

Vedaranyam or Point Calimere is one of the six major wild life sanctuaries in

Tamil Nadu extending over an area of 17.29 Km2. It is the migration place of birds. It is one

of the major wintering grounds for the migrant birds from North India, Europe, Asia and Africa.

November to January is the peak migratory period. Twenty to thirty thousand Flamingoes

can be seen at a time during season. The sanctuary includes reptiles like monitor lizard,

chameleon, sharred tortoise, cobra, saw scaled viper, green viper snake and olive ridley

(sea) turtle.


A small part of the area is protected in the Point Calimere Wildlife Sanctuary gazetted

in March 1968, but the most important wetlands are unprotected. However the wetland has

been proposed for designation as wetland of international importance under the RAMSAR

Convention. The area is free from major settlements and industrialization. The water quality

of sea area is good. Since it is located along the shipping route, oil spills will affect the water

quality and in turn will affect the feeding of birds which depend on aquatic fish for nutrition.

Oil Spill Risk

The area is away from the Ports . However as it located along the shipping line, the

risk on oil spill is moderate.

6.Pitchavaram Mangroves

The Pitchavaram mangrove realm (Lat. 11 26 N; Long. 79 48

E) near Parangipettai,

is situated on the South East coast of the peninsular India and represents a heterogenous


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mixture of mangrove elements. It lies in between the Northern Vellar and Southern Coleroon

estuarine systems and along with Killai lagoon, is referred to as the Vellar Coleroon estuarine

complex. Covering an area of approximately 1,100 hectares, it is represented by 51 islets,

waterways, channels, gullies and rivulets and account for 40% of the total area of the

mangrove, of this 50% is forest and the remaining part consists of mud flats and sandy plains.This ecosystem is well known for its luxuriant growth of mangrove plants with high productivity

and diversity of fauna and is provided with rich detritus, nutrient salts, vitamins, trace elements

etc.

Aquatic Fauna and Flora

The aquatic fauna comprise of juveniles and adults of finfishes, shrimps, molluscs,

crabs and benthic invertebrates. Seaweeds such as Enteromorpha, Cladophora,

Chaetomorpha, Padina, Gracilaria and Hypnea occur in the vicinity of mangroves. The

seagrasses, Halophila and Halodule also occur near here and gross production of the

seagrass community ranges from 0.313 to 1.380 g C Sq.m/day. The flouristic survey during

the study period revealed 81 species of Angiospermic plants belonging to 39 families in the

mangrove islets. Another 5 species belonging to 4 families are recorded in the mudbank

regions of the mangrove forest. Of the 86 species, 24 are trees, 21 shrubs, 28 herbs, 7

climbers, 3 creepers and 3 parasites. The plants are distributed in varying degree of

abundance in the mangrove forest. By the degree of abundance,Avicennia marina is the most

common species. Followed by it are Rhizophora apiculata, R. mucronata, Bruguiera cylindricaandAegiceras corniculatum in that order.Xylocarpus granatum is the rarest species. Prawns,

crabs, molluscs and fishes are abundant in the mangrove area


The Coleroon estuary forms as a major source of sea/brackishwater for the

Pichavaram mangrove. The estuary being located along the shipping line from Tuticorin to

Chennai, any oil spill occurring or moving close to Coleroon mouth will affect the mangroves

by way of way blocking pores of mangrove plant roots. The water quality of the area is good.

Eventhough, the mangroves are located about 1-3 km away from the coast, any oil spill that

occur will affect the mangroves.

Oil Spill Risk




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7. Mahabalipuram

Mahabalipuram (Lat. 1237 N; Long. 8012 E) located 58 km south of Chennai,

covers an area of about 8 Km2. It was once a port of the Pallava dynasty. The Pallavas had

created many marvelous monuments at this place which attract tourists from all over the world

and about 500 tourists visit this place every day. The popular beach and holiday resort are

internationally renowned for their fabulous stone monuments dating back to the 8th century

A.D. Mahabalipuram otherwise known as Mamallapuram has been declared as a World

Heritage site by UNESCO. There is a shore temple which is protected from sea erosion by

dumping large boulders of stones on the seaward side.


The area has Archeological signifcance and beach is enjoyed by tourists. Since the

area is in the vicinity of shipping line towards Chennai port, any incident of oil spill will the

affect the beaches.

Oil Spill Risk



8. Sandy beaches in and around Chennai

The sandy beaches of East coast road from Mahabalipuram and upto Marine beach in

Chennai city is enjoyed by beach lovers, holidayers and is a major area of recreation. Oil spill

incidents in the area will immensely affect the dependent population and the tourists.

Oil Spill Risk

The beaches other than Marina are away from the Chennai Port and located along

the shipping line, the risk on oil spill is moderate. However, since the Marine beach is close

to the Chennai the risk of oil spill is high

VII. ANDHRA PRADESH

Andhra Pradesh has a coastline of 974 km. The coastal areas are blessed with

lagoons, mangroves and vast beaches. The mangrove Ecosystems of Krishna estuary


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(Nizampatnam and Machilipatnam), and Godavari estuary (Coringa areas) are the prominent

ones in the state.

1. Pulicat Lake

Pulicat lake is located 40 Km north of Chennai city and 1/3 of the lake belongs to Tamilnadu

and 2/3 to Andhra Pradesh. It is the second largest brackish water lake in India after Chilka

lake. Situated between 1324

and 1343 N latitude and between 80 03 and 80 18 E

longitude, the lake is about 60 km in length and 0.2 to 17.5 km in breadth. It has a high water

spread area of 460 Km2

and low water spread area of 250 km2. Due to deltaic deposits, the

lake is extensively shallow with an average depth of about 1.5 meters. The lake is separated

from the Bay of Bengal, by an inland spit called the Sriharikota island. The lake belongs to

both Tamilnadu and Andhra Pradesh. About 17,250 ha of the Andhra Pradesh portion of the

lagoon lies within the Andhra Pradesh Pulicat Lake Sanctuary (58,000 ha), established in

September 1976. The entire portion within Tamil Nadu (6000 ha) was declared as a

Sanctuary in October 1980. The lake is confluent with the Bay of Bengal across a bar of

about 3 Km from the Pulicat light house on the Tamil Nadu side. The resources of the lake

forms as a livelihood for nearly 40,000 fisherfolk.


The lake is an extremely important area for a wide variety of resident and migratorywaterfowl, notably pelicans, herons and egrets, storks, flamingos, ducks, shorebirds, gulls and

terns. Pulicat is the third most important wetland for migratory shorebirds on the eastern

seaboard of India, and is especially important during the spring and autumn migration

seasons. The water of the Pulicat lake is very rich in population diversity and density of

planktonic organisms. The rooted and submerged aquatic macrophytes and filamentous algae

constitute the benthic flora of this lake. They are generally seen in shallow regions and around

islands.

The area is in the vicinity of Ennore and Chennai ports. Any oil spill close to the area

may affect the water quality of the lake and the fauna. It may lead to a major socio-economic

problem.

Oil Spill Risk

Since the area is close to Ennore and Chennai ports the risk of oil spill is high

2. Mangrove ecosystems of Godavari and Krishna estuaries


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In Andhra Pradesh, the occurrence of mangroves is observed in East Godavari,

Krishna, Guntur and Nellore districts. The lower reaches of Godavari, Krishna and Penniar

rivers support these mangrove ecosystems. The Godavari-Krishna deltaic mangroves owing

to their geographical proximity have been treated together as they lend themselves admirably

for unity in approach and for our understanding and appreciation.

Machilipatnam (Krishna Delta)

The Machilipatnam mangrove area lies between latitude 16 0

- 1615

N and

Longitude 81 10- 81- 15 E. The northern distributory of the Krishna river drains in this area

and this tributary brings in a lot of sediments and freshwater which has enabled the luxuriant

mangrove growth.

Coringa (Godavari Delta)

The Godavari- Gautami riverine systems form an extensive network of backwaters

leading to formation of luxurious growth of mangroves. The Coringa Wildlife Sanctuary

(23,570 ha) was established in the year 1978.

Ecological Sensitivity

32 species of mangrove and mangrove-associated plants belonging to 26 genera and 18

families are recorded in Godavari and Krishna mangrove ecosystems. Two species i.e.,

Scyphiphora hydrophyllacea (Godavari mangroves) and Aegialites rotundifolia (Krishna

mangroves) are regarded as rare species. The areas is rich in plankton, various types of

benthic organisms

Oil Spill Risk

The Krishna area is away from the Ports. However, located along the shipping line

and therefore, the risk on oil spill is moderate. In the case of Coringa mangroves, as it is

located close to the Kakinada port (an intermediate port), the risk of oil spill is high.

3. Beaches of Visakhapatnam

The port city has extensive beach areas covering a distance of 10km which is used

for reaction purposes. There are proposals for establishment of Amusment parks near the

city. Any oil spill incident occurring will affect the aesthetic state of the beach.


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Oil Spill Risk

Since the area is close to the Visakhapatnam port the risk of oil spill is high.

VIII. ORISSA

The state of Orissa having coastline length of 476 km, is blessed with ecologically

sensitive areas, lagoons and unexplored beaches. The industrially backward state, is

environmentally the richest. It has three ecologically important coastal areas. They are

(1) Chilka Lake, (2) Bhitarkanika mangroves and (3) turtle breeding grounds of Gahirmatha

coast. The historical site includes Konark and holy site is Puri. Both are located on the coast

and beaches are enjoyed by the tourists.

1. Chilka Lake

Chilka is the largest estuarine lake of the Bay of Bengal situated on the east coast of

Peninsular India. It lies between 19 30- 19 57

N latitude and 85 5

20

- 85 29

20

E

longitude. The lake normally covers an area of 1055 sq.km but swells to 1165 sq.km during

the rainy season and gradually shrinks to 906 sq.km during summer. Depth of the lake varies

from 1.73 to 3.7 meters during the rainy season and 0.93 to 2.6 meters during summer

months. The lake turns into a freshwater ecosystem from July to December due to

monsoonal rains.


The lake is rich in benthic plants, seagrasses, planktonic and benthic organisms, prawns and

fishes. The lake is also best known as a a bird sanctuary. Birds visit the lake during Oct-

December of every year. The nnual fish output of the lake on an average amounts to 6,500

tons. Percentage composition of commercially important prawns, large mullets, Bhekti and

Kontia are showing downward trend while Kundal, Balargiand Jagiliare on the rise. . There

are about 114 fishermen villages inside and adjacent to the lake. The fishermen are about

52,000 and derive their livelihood from the resources of the lake. Oil spills occurring in the

vicinity of the lake will affect the ecology and resources of the lake.

Oil Spill Risk

The Chilka area is away from the Ports. However, located along the shipping line and



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2. Bhitarkanika

Bhitarkanika sanctuary is located on the east coast of India, in the state of Orissa

(204 - 208 N and 8645 - 8750 E). It is one of the largest mangrove forest along the east

coast well known for salt water crocodile, olive ridley sea turtles and king cobra. This was

declared as a wildlife sanctuary by the State Government in the year 1975. It is situated near

Chandbali town which is about 50 km from Bhadrak.

There are 6 six major species of mangroves. Among vertebrate fauna, King Cobra,

Python, Kraits, salt water crocodile (Crocodylus porosus), Olive ridley sea turtle (Lepidochelys

olivacea) are noteworthy. Besides these, Leopard, Chital deer, Sambar and wild boar are also

seen in this sanctuary. Nesting colony of about 30,000 breeding pairs of open billed storks

( Anastomus oscitans) has been discovered in this sanctuary. They nest on Avicennia

officinalis trees in the midst of the sanctuary. This is assumed to be the largest colony on the

east coast. Night herons, cattle egrets, cormorants and grey herons constitute other species

of birds in the colony. Olive ridley turtles visit the coastal boundary area of the sanctuary in

large numbers (1 to 2 lakhs) during December to February every year to lay eggs .

Oil Spill Risk

The area is away from the Ports. However, located along the shipping line and


3. Gahirmatha

The 35 km long stretch of coastline along the Orissa coast, forming the coastal

boundary of Bhitar Kanika sanctuary in the Cuttack district of Orissa is the Gahirmatha beach,

well known for the nesting grounds of Olive ridley sea turtle (Lepidochelys olivacea).

Gahirmatha coast extends from Ekakulanasi muhana (20 52 N , 86 77 E) which marks the

northern extremity of Cuttack district to Barunei muhana (20 72 N, 87 5 E) along the coast

of India.

Mass nesting by the Olive ridley sea turtle takes place along 10 km of coastline from

Habialikhati upto Ekakulanasi of Gahirmatha coast. Arrival of half to one million female Olive

ridley sea turtle (Lepidochelys olivacea) is seen every year without fail during late December to

January and again from mid March to April. Rookery (nesting ground) at Gahirmatha coast

and another near Devi river estuary in Cuttack district together host one of the largest

aggregation of Olive ridleys in the world.


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1982. This region adjoins the Sunderban Wildlife Sanctuary of Bangladesh. The park and the

tiger reserve are situated among the estuarine mangrove forests which is most suited to the

tiger. It is also one of the most important Project Tiger areas and has the largest number of

tigers in India. Conservation of the ridley sea turtles has also been undertaken by Project

Tiger. The main wildlife include tiger, saltwater crocodile, estuarine and marine turtle,different species of birds and gangetic dolphin. The Lothian Islands cover an area of 3,885

ha and was established as wildlife sanctuary in the year 1976. The forest area of the

Sunderbans with an expanse of 4,264 sq.km of the core area.

The Sunderban supports a major inshore and estuarine fishery; the fishing season

lasts 4 or 5 months, and at least 10,000 fishermen are engaged in the fishing operations.

There are many brackishwater aquaculture farms (bheris) particularly in the northern part of

the delta. These are impoundments of naturally inundated areas, often of several hundred

hectares in extent.

The tidal waters of Hooghly penetrate deeply into Sunderbans. As the Sunderbans is located

in the vicinity of shipping and oil tanker line of Hooghly and the vessels call at Haldia and

Calcutta Ports. Any oil spill occurring in the Hooghly estuary will affect the mangrove areas

also.

Oil Spill Risk

Since the area is close to the shipping line, the risk on oil spill is high

2. Digha

Digha beach along the Bay of Bengal coast is one of the important tourist spots in

West Bengal. This area has a large number of beach resorts and hotels. The water quality is

very much influenced by the river Hooghly. Any oil spill occurring in the sea off Digha will

affect the tourism beaches.

Oil Spill Risk

Since the area is close to the shipping line, the risk on oil spill is high

X. ANDAMAN AND NICOBAR ISLANDS

The Andaman and Nicobar islands comprise about 348 islands of volcanic origin

situated between 6

to 14

N Lat. and 92

to 94

E Long. occupying an area of about 8249sq.km., in the Bay of Bengal. It has a coastline length of 1962 km. The area of Andaman


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group of islands is 6408 sq.km and Nicobar group of islands is 1841 sq.km (Anon, 1994). The

10 degree channel divides the above group of islands. The coastline is irregular and deeply

indented by innumerable creeks, bays and estuaries which facilitate the development of rich

and extensive mangrove forests. The coastal area is generally rocky and muddy but in several

cases sandy also. Mudflats with sand and coral rubbles promote the growth of mangroves andseagrasses. Enclosing the mangrove areas in the island are the elevated sandy beaches

varying from island to island and spread along the coastline.

In the Andaman group of islands, North Andaman, Middle Andaman, South Andaman

and Little Andaman are the only big islands. All other islands are tiny ones. In Nicobar group of

islands, Great Nicobar, Little Nicobar, Katchel, Nancowrie, Triniket, Trerssa, Chowra,

Trilonchang and Car Nicobar are the big ones.. Until recently, these islands constituted an

almost undamaged and highly diversified natural environment, with luxuriant rain forests

extending down from the hills to deserted beaches, fringing reefs, and rich coastal waters

almost unpolluted by soil erosion and industrial activity.

The waters A &N islands are rich in biodiversity and fishery. The international tanker

route is located south of Indira point at Greater Nicobar. Few oil spill incidences have

occurred in the past in this area with major one during 1993. Considering the tanker traffic the

area is highly vulnerable for oil spills. The spills will affect corals, virgin beaches, fishery and

the mangroves.

Oil Spill Risk

Since the area except Greater Nicobar is away from the Ports and located along the

shipping line, the risk on oil spill is moderate. Due to its proximity to the international tanker

route, the risk of oil spill is very high for Greater Nicobar

XI. LAKSHADWEEP ISLANDS

Lakshadweep is an archipelago lying between 8-1230 N latitude and 71-74 E

longitude. It is a group of islands located about 300 km to west of the Kerala coast. It has 37

islands covering an area of 32 km2

, of which ten are inhabited. They are Androth, Amini,

Agatti, Bitra, Chetlat, Kadmat, Kalpeni, Kavaratti, Kiltan and Minicoy. Bangaram, uninhabitated

till recently, is now a tourist resort. Andrott is the largest with an area of 4.84 sq km. Minicoy

atoll (8 18N and 73E) is the southernmost atoll and the largest in the Lakshadweep. Bitra is

the smallest of the inhabited islands with an area of just 0.10 sq km.


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The islands are flat and scarcely rise more than two meters. The islands are coralline

in origin and made up of fine coral sand and boulders, compacted into sandstones. The

archipelago consists of 12 atolls, 3 reefs and 5 submerged banks. The coral reef area is

estimated at 4200 km2. Almost all atolls of this archipelago have a NE-SW orientation with the

island on the east, a broad well developed reef on the west and lagoon in channels. The shoreof the lagoon side of the atolls are characterized with sandy beach, having medium to coarse

coralline sand and beach rocks exposed during low tide. The coral growth in many islands is

luxurious and highly diverse.


Since all the islands have extensive coral reef, oil spills affect corals and associated

fauna especially the bite fish which is used for tuna fishing. Few oil spill incidences occurred

in the past have extensively damaged the corals and associated fauna and the sea grasses.

Oil Spill Risk

Due to its proximity to the international tanker route, the risk of oil spill is very high for

all the islands of Lakshadweep.


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B. DEVELOPMENT OF OIL SPILL MODELS AND IMPACT OF OIL SPILL

ON MARINE ORGANISMS

1. Introduction

The increase in density of marine traffic, especially oil tankers and petroleum based

installations in the proximity of Indian coast, are possible causes for occurrence of oil spills.

Spill can occur from blow out, collision, grounding of vessels and stranding. The developing

countries like India, should have capabilities to combat eventual oil spills.

The National Oil Spill Disaster Contingency Plan was prepared first time in India by

Coast Guard during 1996 with an objective to combat oil spill disaster in Maritime zones of

India. It has been updated in 2002. Coast Guard is the National Agency for coordinating

with various resource agencies in the event of oil spills ocurring in the seas around India. The

Coast Guard has a capability to deal with a major oil spill of approximately 20,000 tons in

Exclusive Economic Zone of India. (Coast Guard, 1996).

In the National Contingency plan the Department of Ocean Development has been

entrusted with tasks such as mapping of ecologically sensitive areas and carrying out scientific

research in effects of oil pollution.

2. The Behaviour and Effects of Oil Spill

2.1 Physical properties of Oil

The rate at which oil spill spreads will determine its effect on the environment. Most

of the oils tend to spread horizontally into a smooth and slippery surface, called a slick, on top

of the water. Factors which affect the ability of an oil spill to spread include surface tension,

specific gravity and viscosity.

2.2. Effects of oil on plants and animals

When the oil is spilled into an aquatic environment, it can harm organisms that live on

or around the water surface and those that live under water. Spilled oil can also damage parts


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of the food chain, including human food resources. The severity of the impact of an oil

spill depends on a variety of factors, including characteristics of the oil itself. Natural

conditions, such as water temperature and weather, also influence the behavior of oil in

aquatic environments. Various types of habitats have differing sensitivities to oil spills as well.

Some toxic substances in an oil spill may evaporate quickly. Therefore, plant, animal,

and human exposure to the most toxic substances is reduced with time, and usually limited to

the initial spill area. Although some organisms may be seriously injured or killed very soon

after contact with the oil in a spill, non-lethal toxic effects can be more subtle and often long

lasting. For example, aquatic life on reefs and shorelines is at risk of being smothered by oil

that washes ashore. It can also be poisoned slowly by long-term exposure to oil trapped in

shallow water on beaches.

Aquatic environments are made up of complex interrelations between plant and

animal species and their physical environment. Harm to the physical environment will often

affect one or more species in a food chain. The effects an oil spill is likely to have on an

organism is dependant on the coastal environment in which the organism spends most part of

its life in open water, near coastal areas, or on the shoreline.

In open water, fish and whales have the ability to swim away from a spill by going

deeper in the water or further out to sea, reducing the likelihood of they being harmed by even

a major spill. Aquatic animals that generally live closer to shore, such as turtles, seals, and

dolphins, risk contamination by oil that washes onto beaches or by consuming oil-

contaminated prey. In shallow waters, oil may harm sea grasses and kelp beds, which are

used for food, shelter, and nesting sites by different species. The most affected are the

submerged and sessile organisms like corals and the organisms habitating the inter-tidal area.

Both have richest biodiversity and density in terms of given area.

Spilled oil and clean up operations can threaten different types of aquatic habitats,

with varying degree of impact.

Coral reefs are important nurseries for shrimp, fish, and other animals as well

as recreational attractions for divers. Coral reefs and the aquatic organisms

that live within and around them are at risk from exposure to the toxic

substances in the oil as well as smothering.

Exposed sandy, gravel, or cobble beaches are usually cleaned by manual

techniques. Although oil can soak into sand and gravel, only a very few

organisms live full-time in this habitat, so the risk to animal life or the food

chain is far less as compared to other habitats, such as tidal flats.


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Sheltered beaches have very little wave action to encourage natural

dispersion. If timely clean up efforts are not begun, oil may remain stranded

on these beaches for years.

Tidal flats are broad, low-tide zones, usually containing rich plant, animal and

bird communities. Deposited oil may seep into the muddy bottoms of these

flats, creating potentially harmful effects on the ecology of the area.

Salt marshes are found in sheltered waters in cold and temperate areas.

They host a variety of plant, bird, and mammal life. Marsh vegetation,

especially root systems, is easily damaged by fresh light oils.

Mangrove forests are located in tropical regions and are home to a diverse

plant and animal life. Mangrove trees have long roots, called prop roots, that

stick out well above the water level and help to hold the mangrove tree in

place. A coating of oil on these prop roots can be fatal to the mangrove tree

and because they grow so slowly, replacing a mangrove tree may take

decades.

Marshes and swamps with little water movement are likely to incur more

severe impacts than flowing water. In calm water conditions, the affected

habitat may take years to restore.

Other standing water bodies, such as inland lakes , are home to a variety of

birds, mammals, and fish. The human food chain can be affected by spills in

these environments.

Spills can happen on land or in water, at any time of day or night, and in any weather

condition. Preventing oil spills is the best strategy for avoiding potential damage to human

health and the environment.

3. Role of Contingency Plans

A contingency plan is a set of instructions that outlines the steps that should be taken

before, during, and after an emergency. A contingency plan looks at all the possibilities of

what could go wrong and contingent upon actual events, has the contacts, resource lists,

and strategies to assist in the response to the spill.

At a glance, an oil spill contingency plan may appear complicated because it provides

many details about the numerous steps required to prepare for and respond to spills. It also

covers many spill scenarios and addresses different situations that may arise during or after a

spill. Despite its complexity, a well-designed contingency plan should be easy to follow.

Although they are different in many respects, contingency plans usually have four major

elements in common, (EPA, 1999) viz:


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Hazard identification

Vulnerability analysis

Risk assessment

Response actions

Planners use hazard identification and vulnerability analysis to develop a risk

assessment. The risk assessment is then used as the basis for planning specific response

actions. Each of these four elements is described below:

3.1. Hazard identification

It is impossible to know when an oil spill is going to happen and how much oil is likely

to be spilled. However, it is possible to identify where oil is stored, the corridors through which

it travels, and the industries that use large quantities of oil.

Different situations can affect the ability of response personnel to contain and clean

up an oil spill, such as weather conditions, geographic isolation and spill size. Private

companies and local, state, and federal agencies design their contingency plans to address

spills from many locations and under different conditions. The following information is usually

collected as a part of hazard identification:

Types of oils frequently stored in or transported through that area.

Locations where oil is stored in large quantities and the mode of

transportation used to move the oil, such as pipelines, trucks, railroads, or

tankers.

Extreme weather conditions that might occur in the area during different times

of the year.

The location of response equipment and personnel trained to use the

equipment and respond to the spill.

3.2. Vulnerability/senstivity analysis

The vulnerability analysis section of a contingency plan provides information about

resources and communities that could be harmed in the event of a spill. This information

helps personnel involved in cleaning up a spill to identify reasonable, well-informed choices on

protecting public health and the environment. Vulnerability analysis information should include

the following:


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List of public safety officials in the community.

List of facilities such as primary health centres, nursing homes and hospitals

List of recreational areas, such as camp grounds

List of critical habitats that can be effected when spill occurs

Identification of parts of the environment that are particularly susceptible to oil

or water pollution.

3.3. Risk Assessment

Contingency planners compare the hazard and the vulnerability in a particular location

to see the kind of risk that is posed to a community. The plan then addresses those problems

by determining how best to control the spill, how to prevent certain populations or

environments from exposure to oil, and what can be done to repair the damage done by the

spill.

The previous section deals with vulnerable/sensitive areas and extent of risk involved.

3.4. Response actions

Response actions are developed to address the risks that are identified in the risk

assessment. A carefully designed contingency plan will describe major actions that need tobe taken when a spill occurs. These actions should take place immediately following a spill so

as to minimize hazards to human health and the environment. The following response actions

should be included in a contingency plan:

Notifying all private companies or government agencies that are responsible

for the clean up effort.

Getting trained personnel and equipment to the site quickly.

Defining the size, position and content of the spill; its direction and speed of

movement; and its likelihood of affecting sensitive habitats.

Ensuring the safety of all response personnel and the public.

Stopping the flow of oil from the ship, truck, or storage facility, if possible, and

preventing ignition.

Containing the spill to a limited area.

Removing the oil.

Disposing of the oil once it has been removed from the water or land.


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3.5. Improving Plans with Geographical Information System (GIS)

Contingency planners and other response organisations are now using Geographic

Information Systems (GIS) to make contingency plans better and easier to use. GIS makes

electronic maps that can focus attention on the location of things that are important to

planners and oil spill responders. GIS can also provide detailed information about each of the

items shown on a map, as attributes attached, such as how large an oil storage facility or

pipeline is, whether a road is paved, or the times of the year that sensitive species are in the

area. GIS can also help to determine the best way to get to potential spill sites and identify

areas that responders might have difficulty in accessing.

Having all these data easily accessible in one place and being able to see these

things in relation to each other can make planning more effective. It allows planners to know

where spills are most likely to occur and how bad they might be and lets them prioritize actions

to protect the most sensitive resources first. It can also help planners know what kind of

resources and how much of resources (booms, skimmers, vacuum trucks, etc.) they may

need in a given area.

4. Response & Contingency Planning- A Case Study of Gulf of Kachchh

4.1 Gulf of Kachchh

Gulf of Kachchh (GOK), (Fig.4) a semi enclosed water body, known for its rich bio-

diversity comprises vast inter-tidal zone with mudflats, beaches, flood plains, mangroves, coral

reef and associated fauna. The strategic location of the Gulf of Kachchh nearer to the oil

producing Gulf countries has attracted establishment of facilities for refining and piping of

petroleum products and related activities in the recent years to meet the growing demand for

the consumers of northern India. Four Single Point Moorings (SPMs) are already catering in

the Gulf waters to handle the crude and eight more are proposed by various agencies to serve

that extra demand. Projections are there to handle a traffic of 480 very large crude carriers

(VLCCs) with the crude oil handling capacity of 7 x 107

tons/y in the coming years, which is 6-7

times the present capacity. The incidence of oil spills resulting from tanker traffic, loading,

unloading and associated activities will increase in the years to come as the demand for

petroleum and its products continue to rise. The threat due to the oil spills on the ecology of

the Gulf and consequent economic losses need to be addressed through scientific techniques.

Prediction of the oil slick thickness and dynamics, distribution of oil in the water column and

atmosphere are of interest and the extent of areas of ecologically sensitive mangroves, corals,

mudflats, beaches, etc., affected by oil can be mapped from the Geographical InformationSystem in order to make a contingency planning and assessing environmental impact. An


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initiative in this direction has been made by the Department of Ocean Developments ICMAM

Project Directorate, Chennai.

Fig 5. Gulf of Kachchh and its Environment

4.2 Methods for Containing and Recovery of Oil following Spill

The various alternative measures for containing and cleaning up of oil spills are: (i)

recovery of oil from the sea surface with mechanical devices (boom, skimmer and sorbents),

(ii) sinking of oil with heavier-than-water materials, and (iii) dispersion of oil into the water

column with chemical and biological dispersants. All the above three methods are directed to

the removal of oil from the water surface, but only the first - removes the oil physically from the

marine environment. The second and third methods simply displace the oil from the water

surface to the seabed or the water column. In addition, both the second and third methods

require the addition of another compound to the water, which in some cases may cause

ecological damage itself. A careful environmental evaluation of the clean up methods must be

performed prior to their use. A numerical model may be used for the rapid simulation and

comparison of the various scenarios and it works as a decision support tool to find out where

the spilled oil will go.

4.3 Possible scenario of accidental oil spill due to installation of SPMs

The crude oil is being transported by large tankers through sea route and unloaded

via SPM (A Single Point Mooring system) through a system of manifold pumping, floating

hoses, underwater hoses and sub-sea pipeline to onshore base storage tank. There is a


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possibility of oil spill due to leakage in valves, improper hose couplings, rupture of floating

hoses, underwater hoses or sea bed pipe line. Other unforeseen events such as severe

cyclone, earthquake or international third party interference can also damage the sub-sea

pipeline. In such cases, large spill of the order of 3000 m3

when a loaded tanker grounds or

collides with another ship, spill may vary from 7000 m3

to 10,000 m3

. The quantity of oil spillbased on various accidents/events can broadly categorized as:

Accidents/Events Oil Spilled (m3)

1) Advection of cast-off coupling 0.5

2) Rupture of under buoy hose 9.0

3) Minor rupture of sub-sea pipe line 100.0

4) Rupture of floating hose 200.0

5)Major rupture of sub-sea pipe line 3000.0

6) Tanker grounded 10,000.0

4.4 Oil Spill modelling

The movement of surface oil can be predicted temporally and spatially by changingwind and current fields, yielding a time history of the surface coverage of oil on water.

Additionally a numerical approximation of the weathering (fate) of each predicted portion of oil

released is carried out as the model progresses. Thus, for every time-step (several minutes to

one hour) the surface oil lots are advected (moved horizontally) by the wind and current field.

Also at every time-step each surface lot of oil has a predicted spreading, evaporation,

entertainment into the underlying water column, mousse formation and potential shoreline

stranding. The user interface enables the viewing of animations of the surface oil movement

and the summary oil weathering time history by environmental partition (air, water surface,

water column, ashore). It helps to find out the path of oil trajectories in the case of spill,

whether it will hit the coast or not and the time taken by the spill to reach the coast.


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Fig 6. Typical flow field for the Gulf of Kachchh.

The circulation in gulf is governed by tides and winds. A typical plot showing the flow

field during ebb is indicated in fig 6. After analysing the historical wind data available in Gulf of

Kachchh, three different wind conditions i.e., no wind, 5m/s constant wind speed from 240

degree N and 5 m/s constant wind speed from 330 degree north were used for the oil spill

simulations. An accidental instantaneous oil discharge of 100 m3

was specified at SPM

location and simulation was carried out for three cases- i) No wind, ii) 5 m/s wind from 240

degree North and iii) 5m/s wind from 330 degree north. The time exposition maps were

prepared to show how the oil is being transported with time on the water surface. The figures

7 indicates the oil movement at the end of 24 hours. It follows the path of the streamlines as

per the tidal flow and the oil is being transported through the advection in no wind condition.

During flood tide the oil is moving in the Pathfinder creek towards the IOC/KPT Vadinar jetty.

When the wind blows from 240 degree from north, the oil is moving towards the central

channel (NE) after 24 hour (fig 8). In 3rd

condition, it is found that the oil is being transported

towards the shore (fig 9). The first oil residues hit the coast at Narara reef in 12 hours.


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Fig 7. Oil Spill Movement after 24 hours when there is No Wind.

Fig 8. Oil Spill Movement after 24 hours when Wind is blowing from 2400

N .


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Fig 9. Oil Spill Movement after 24 hours when Wind is blowing from 3300

N .

4.5 Environmental Data requirement

The accuracy of the oil spill prediction depends on description of adequate wind and

current fields. The experiences of ICMAM-PD in application of Oil Spill modelling in Gulf of

Kachchh, shows that the temporal and spatial changes in the current field and wind play the

dominant role. Since reliable oil spill event data are not available in Gulf, a field data collection

programme is being organized by ICMAM-PD to collect data on various parameters

simultaneously at several locations. The parameters such as tide, current, wind, wave,

dispersion factors, temperature, salinity etc., will be monitored simultaneously to obtain

synoptic data. The locations where observation would be made are indicated in fig 10. These

measurements will be carried out in three phases to represent the annual conditions. Out of

three phases, the first observation covering 15 days has been completed. In addition to above

field data, remote sensing data from satellite (IRS 1C and OCM P4) will also be utilized for

regional scale modelling.

Wind speed - 5 m/sWind Direction - 330degree from N


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Fig 10. Map showing location of Monitoring Stations

5. Response Management System

The results of computer simulation such as trajoctory of oil spill and fate of model

were overlaid on GIS and knowledge base generated. Typical plot showing the overlay of oil

spills on resource map of Gulf of Kachchh is shown in fig 11. With this knowledge base, a

Decision Support System (DSS) will be prepared, where a decision maker can explore the

possibility of different strategies in an interactive manner. This system can be made as real

time system, when the data on wind and oil proportion are fed from time to time. The

Response Management System described above is partially completed. Data of two more

seasons are yet to be collected for calibration and validation of oil spill model.


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(b)

(c)

(a)

Fig 11. Ecological areas affected by Oil cover after 48 hrs of

spill in 3 wind scenarios (a) No wind, (b) 5 m/s from

240N and (c) 5 m/s from 330N


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6. Conclusions and Recommendations

It is evident from the above discussion that computer simulation models,

Geographical Information System and Decision Support System tools are very useful in oil

spill modelling and management. The effectiveness of response system depends on

knowledge base on various aspects such as physical oceanographic processes and

resources. Hence, a substantial knowledge base incorporating all parameters should be

generated and made available to the organizations/institutes who are responsible for Oil Spill

Management. Today tools are available to predict the surface movement of oil on the basis of

wind and current data, which may be incorporated into the underlying database of the spill

model system. Once the Oil Spill model is calibrated and validated for initial data set, by

changing the essential parameters such as wind and oil properties, the model can be operated

in real time model. It is likely that the validated model for the Gulf of Kachchh will be available

by March 2003. It is also possible to develop similar models for others mostly by using wind

data. This task can be entrusted to the DODs ICMAM Project Directoratre, Chennai.

ACKNOWLEDGEMENT

The report has been prepared based on inputs provided by Dr.S.Ramachandran, Institute for

Ocean Management, Anna University Chennai and inputs from the ICMAM Project Directorate

of Department of Ocean Development, Chennai

REFERENCES

1. Anon,1998, Manual and Reference guide for MIKE 21 of Danish Hydraulic Institute (DHI).

2. Environmental Protection Agency, USA., 1999, Understanding Oil Spills and Oil Spill

Response.

3. ICMAM-PD, 2002, Geographical Information system for Gulf of Kachchh.

4. Kankara,R.S and B.R Subramanian, 2001, Simulation of the movement and fate of oil

pollutants in Gulf of Kachchh, HYDRO 2001, CWPRS.

5. Studies on Coastal Fragile Areas. Central Pollution Control Board. June 2000.

(COPOCS/13/1998-99)


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