Pulicat Lake, Thiruvallur
Pulicat Lake is the second largest brackish water lake or lagoon in India, after Chilika Lake. Pulicat Lagoon is considered to be the second
largest brackish water body in India measuring 759 Sq. Kms. The Lagoon is one
the three important wetlands to attract North-East Monsoon rain clouds during
October to December season to Tamil Nadu. The lagoon comprises the following
regions, which adds up 759 km2 according to Andhra Pradesh Forest
Department: 1) Pulicat Lake (Tamil Nadu-TN & Andhra Pradesh-AP) 2)
Marshy/Wetland Land Region (AP) 3) Venadu Reserve Forest (AP) 4) Pernadu
Reserve Forest (AP).
The lagoon was cut across in the middle the Sriharicota
Link Road, which divided the water body into lake and marshy land. The lake
encompasses the Pulicat
Lake Bird Sanctuary.
The barrier
island of Sriharicota separates the lake from the Bay of Bengal and is home to the Satish
Dhawan Space Centre. Major
part of the lake comes under Nellore district of Andhra Pradesh.
The lagoon has rich flora and fauna diversity, which
supports active commercial fisheries and a large and varied bird population.
The International Union for the Conservation of Nature and Natural Resources
(IUCN) declared the Pulicat lagoon system a Ramsar site of international
importance and the World-Wide Fund for Nature declared it a protected area. This
shallow lake is famed for a variety of aquatic birds and is an important
destination for tourists. Boating facilities are available.
History
In the 1st century, the anonymous mariner who
wrote Periplus
of the Erythraean Sea listed
Podouke (Pulicat) as one of the three ports on the east coast of India. In
the 2nd century, Ptolemy’s list of ports on this coast included Podouke
emporion. In the 13th century, Arabs migrated to the shores
of the lake after they were banished from Mecca for refusing to pay
tributes to a new calif. Streets with dilapidated masonry houses once
occupied by these Arabian Muslims are still found in the area and resident
families claim records in Arabic testifying the migration.
Portuguese colonized the lake in 16th century followed by
the Dutch. The Dutch drifted to the
lagoon as their ships got stuck on the shores of Karimanal village on the
opposite side of the mouth of the lake. During the Dutch occupation, Pulicat
was known by the name Pallaicatta. Fort Geldria dating to 1609, a church, a cemetery with
tombs and mausoleums constructed by the Dutch are protected by the Archaeological
Survey of India (ASI).
The Dutch transacted business with the British
East India Company and
other countries in the region.
A scientific study of the palynological characteristics of the lagoon was conducted by
taking sedimentary soil samples from four
test pits. It shows that the vegetational reconstruction from peat beds at 4.98 metres (16.3 ft) a.m.s.l. and 1 meter
(3.3 ft) (a.m.s.l.) in the west at Sullurpeta and Kasdredinilem, respectively, is indicative
of a palaeo shoreline. The sea level reached its
maximum around 6650 plus or minus 110 yrs BP in Sullurpeta, 18 Kms (11 mi) west from
the present shoreline. The radiocarbon dates of peat bed at Kasdreddinilem
reveals an age of 4608 plus or minus 122 yrs BP, indicating the shift in
mangrove line eastwards during the regressive phase.
Geography
and Topography
The lagoon’s boundary limits range between 13.33° to
13.66° N and 80.23° to 80.25°E, with a dried part of the lagoon extending up to
14.0°N; with about 96% of the lagoon in Andhra Pradesh and 3% in Tamil Nadu.
The lagoon is aligned parallel to the coast line with its western and eastern
parts covered with sand ridges. Area of the lake varies with the tide; 450
square Kms (170 sq. mi) in high tide and 250 square Kms (97 sq. mi)
in low tide. Its length is about 60 Kms (37 mi) with width varying from
0.2 Kms (0.12 mi) to 17.5 Kms (10.9 mi). Climate of the lagoon coast
line is dominated by Tropical monsoons. Air temperature varies from 15 °C
(59 °F) to 45 °C (113 °F).
The large spindle-shaped barrier island named Sriharicota separates the lake from the
Bay of Bengal. The sandy barrier islands of Irkam and Venad and smaller islands
in the north are aligned north–south and divide the lagoon into eastern and
western sectors. The morphology of the lagoons is categorized under four types
with large areas under mudflats and sandflats. The fishing village
of Pulicat is at the south end of the lake. The Satish
Dhawan Space Center is located on the north end of the island. Pulicat, Dugarājupatnam and Sullurpeta are villages located on the periphery of the
lagoon.
Hydrology
Two rivers which feed the lagoon are the Arani river at the southern tip and the Kalangi River from
the northwest, in addition to some smaller streams. The Buckingham Canal, a navigation channel, is part of the lagoon on its
western side. The lagoon's water exchange with the Bay of Bengal is through an
inlet channel at the north end of Sriharicota and out flow channel of about 200
metres (660 ft) width at its southern end, both of which carry flows only
during the rainy season.
The lake acts as buffer to retain the accumulated
flood water till the flood water is discharged gradually to the sea during the
monsoon period and cyclones. The lake and its river basins are located both
in Andhra
Pradesh and Tamil Nadu states. The lake and its drainage river basins
become interstate river basin as per Interstate
River Water Disputes Act 1956.
Most of the lake area including its water outlet to the sea is located in
Andhra Pradesh.
The water quality of the lake varies widely during
various seasons – summer, pre–monsoon, monsoon and post–monsoon – as the depth
and width of the lake mouth varies causing a dynamic situation of mixing and
circulation of waters. The resultant salinity variation and DO (dissolved oxygen) affects the primary production, plankton,
biodiversity and fisheries in this lake. Salinity values vary from zero during
the monsoon to about 52,000 ppm (hyper saline) during post and pre–monsoon
seasons. Adjustment to this wide variation is difficult for sessile and
sedentary species in the lake.
However, euryhaline species still dwell in the lake. The benthic or the bottom habitat of this lagoon is
classified into three zones. The southern zone, the first zone, is dominated by
sand with some admixture of mud. The second zone at the northern region is
wholly muddy. The third zone with sand and mud in equal parts is overgrown with
patches of weeds and is reported to be rich in benthic biodiversity. Toxicity levels of heavy metals such as magnesium,
lead, zinc, nickel, cadmium, aluminum and copper and chemicals such as ammonia,
sulphate and fluoride in the lake are well within permissible limits.
Flora and Fauna:
The lagoon has rich flora and fauna diversity, which
supports active commercial fisheries and a large and varied bird population.
Limnology:
Fishing is the major occupation in the many villages
located around the lake periphery and on the islands. The lake has rich
fish diversity, mostly marine species, some truly brackish water and a few
freshwater species. Mullets and Catfish are the major brackish water fish, which have
supported sustenance fishing for the lake fishermen. The lake is a nursery for
several species of fish. Two thirds of the settlements in the lake area are in
Tamil Nadu and the balance in Andhra Pradesh. 12,370 fishermen live on
full-time fishery in the lake (6,000 in Andhra Pradesh and 6,370 in Tamil
Nadu). An average 1200 tonnes of fish and crustaceans are harvested annually,
of which prawns constitute 60%, followed by mullets.
Seafood exports of white and tiger prawns,
jellyfish, finfish and live lagoon green crabs are also economic benefits from the
lagoon. 168 total fish species are reported. The frequently found ones are
the mullets: M. cunnesius, M. jerdoni, M.
dussumieri, M. cephalus, M. bornensis and blowfish T.
nigropunctatus, T. leopardus, Barbus dorsalis, catfish Macrones vittatus, sardines, Sardinella fimbriata and milk fish. Finfish, green crabs, clams and prawns are the most commercially exploited fishes of
the lagoon. Endangered green sea turtles are found on
the beaches of Sriharikota beach. Apart from prawns, salt is also produced
from the lagoon.
Avifauna:
The shallow lake is known for its diversity of
aquatic birds and is an important stopover on migration routes and is reported
to be the third most important wetland on the eastern coast of India for
migratory shorebirds, particularly during the spring and autumn migration
seasons. In view of the rich avifauna of the lagoon, two bird sanctuaries are
established in the lagoon, one in each of the two states of Andhra Pradesh and
Tamil Nadu. The Andhra Pradesh portion of Pulicat
Lake Bird Sanctuary,
established in September 1976, has an area of 172 Sq. Kms (66 sq. mi)
within the lagoon’s total area in the state in the Tada Taluk of Nellore district.
The Wildlife Division of the state has listed 115
species of water and land birds in the sanctuary. Nelapattu
Bird Sanctuary is
also located nearby in its catchment area. The Tamil Nadu part of the lagoon of
60 Sq. Kms (23 sq. mi) area, extending over the Ponneri and Gummidipoondi taluks of Thiruvallur
district was
declared a Bird Sanctuary in October 1980. Every year approximately
15,000 greater
flamingos are
reported to visit the lake along with pelicans, kingfishers, herons, painted storks, spoonbills and ducks.
The highest concentrations of flamingo are found in
the periphery of the lagoon where the water level is below 40 Cms (16 in).
The concentrations of flamingos are also associated with high algal, fish and
benthic diversity. Other water birds in the area include spot-billed
pelican, seven
species of herons and egrets, painted stork, greater flamingos, ducks, 20 species of shorebirds, gulls, terns, little grebe, Indian cormorant, little cormorant, Asian
openbill stork, black-headed ibis, Eurasian
spoonbill, lesser
whistling teal, spotbill duck, great thick-knee and stone curlew.
Several species of wintering waterfowl have been
noted including bar-headed goose, ruddy shelduck, Eurasian wigeon, common teal, northern pintail, garganey, northern
shoveller, common pochard, brown-headed gull, black-headed gull, whiskered tern, gull-billed tern and Caspian tern. Birds of prey which appear in winter are
the: white-bellied
sea eagle,
harriers and peregrine falcons. The largest concentrations of flamingos occur
in the Andhra Pradesh part of the sanctuary, around the islands of Venadu and
Irukkam.
Aquatic Vegetation:
Aquatic vegetation reported are 59 species,
including eight Cyanophyceae,
seven Chlorphyceae and two Rhodophyceae. Patches of residual, dry, ever green forest
and large areas of littoral scrub in woodlands in fishing villages bordering
the lagoon are seen. Invasive phytoplankton species of Prosopis
juliflora, Spirulina major, Oscillatoria spp., Anabaena spp., Rhizosolenia castracanei, Eucampia
cornuta and Climacodium frauenfeldianum in the plains on the
periphery of the lake have been recorded.
Threats
and Issues
In the Andhra Pradesh part of the lake several
threats to the lagoon have been identified. These are: pollution from sewage,
pesticides, agricultural chemicals and industrial effluents – from Arani and
Kalangi rivers draining into the lake that bring in fertilizers and pesticides
with the run off from the agricultural field in to the drainage basin, domestic
sewage, effluents and wastes from numerous fish processing units; oil spills
from the mechanized boats; release of 4,780 hectares (11,800 acres) of the
sanctuary for a marine chemicals and salt-manufacturing industry and shrimp
farming in more than 1,000 acres (400 ha) on the eastern part of the
lagoon have affected the Pulicat Bird Sanctuary; livelihood of 30,000 fishermen
and 20,000 agricultural labourers (for whom fishing is an off-season economic
activity) have also been disturbed. This activity is also reported to have
serious impact on aquaculture development.
Siltation and periodic closure of the bar mouth due to
the dynamic process of sediment
transport has
caused reduction of size and seasonal closure of the mouth of the lake has
reduced fresh sea-water exchange and made the lake shallow and turbid. It is
reported that average depth of 1.5 metres (4.9 ft) in the early 20th
century, has reduced to less than about 1 meter (3.3 ft) now, in the
lagoon. This has caused difficulties such as mouth getting silted up and
getting closed during the summer season (June–July to Oct–Nov); raise in flood
level occurs during the rainy season; the lake acts as a large evaporating
basin when the bar is closed resulting in salinity levels remaining low or high subject to the
flood discharge into the lake during the north east monsoon; fluctuation of
water level in the lake (above or below the sea level) is affecting flora,
fauna and fisheries; siltation has caused variation of the lake mouth resulting
in reduction of tidal inflows and consequent decline in stocking of
commercially important species of prawns and mullets.
The flood plains reclamation
in Arani river basin for industrial and residential purposes is also increasing
lake maximum water level during the floods. The Arani and Kalangi rivers
carrying run off from agricultural fields in the drainage basin cause increase
in pollution load from fertilizers and pesticides into the lake; pollution from
domestic sewage being released to the lake; Petrochemical complex, power plant
and a satellite port on Ennore creek have further aggravated the
problem; there is threat of flooding of 14 island – villages of the lake; subsequent
to the tsunami in 2004, the number of fishing boats have
increased resulting in the `Catch Per Unit Effort' of fish, prawns and crabs
declined from 1000 tonnes to about 700 tonnes; and this has increased the
social and fishing rights conflicts between marine based fishermen and the
lagoon fishermen.
Due to the 2004 Indian
Ocean earthquake,
lagoon fishery was adversely affected, with many fishing communities losing all
means of livelihood until the middle of April 2005, as the loss of lives, homes
and boats prevented them from going fishing in the sea and the lake. They
subsisted on relief supplies provided by the government and other agencies.
Many people in fish related trades were also affected. However, a
beneficial effect of the tsunami has been the widening of the opening to the
lagoon.
Restoration
and Social Activities
Various groups and non-governmental organizations
are active in the area. AARDE Foundation maintains Pulicat-Museum at
Pazhaverkadu to create awareness among inhabitants and city dwellers. AARDE
Foundation represented Pulicat at United Nation's World Urban Forum and
HABITAT-III as an associate-partner. Annual PULICAT-DAY event as part of
RAMSAR's World Wetlands Day is celebrated every February by AARDE to bring
attention to this fragile environment. An expert plan on "Wildlife Action
Plan for Conservation Measures on the Pulicat Lake Sanctuary" has
envisaged to set up a hydro biological research station, visitor center,
provide shallow-bottomed boats to enable sanctuary staff to patrol the lagoon
and to prepare a management plan and conservation strategy for the entire area.
COPDANET is striving to implement traditional
"Paadu system" and regular desilting to ensure adequate salt and
fresh water mix in the lagoon which could enhance fish resources. Centre for
Research on New International Economic Order (CReNIEO) has been promoting
welfare of fishermen and management of the natural resources of the
lake. A research study by Loyola
College, Chennai reported in 2007 that the lake that bore the
brunt of industrial pollution has made an ecological turnaround, recording
toxicity levels well within permissible limits. Under the "Tsunami
Emergency Assistance Project" (TEAP), construction of a high-level bridge
across Pulicat lake along with approach roads on both sides of the lake has
been constructed providing a safe escape route for people residing on the
islands and also access for emergency response operations.
The southern part of the lagoon in Tamil Nadu 5 Kms
(3.1 mi) from the estuary is rich in fishes and the fishing is controlled
by a traditional Paadu system. Paadu is a traditional system of
getting entitlements to eligible members of a particular community for
undertaking specified fishing activity in certain designated areas. The fishing
grounds fall within a radius of 5 Kms (3.1 mi) from the mouth of the lake
with a salinity well maintained without much drying even during low tides.
However, this traditional practice is based on caste control of the access
rights to the high productive areas and is opposed by eastern fishermen and
ocean-side villages. As a result, conflicts leading to violence have been
reported.
Connectivity
Pulicat
Lake is located at about 500 meters from Pazhaverkadu Bus Stop, 1.5 Kms from Pulicat
Bus Stand, 9 Kms from Thirupalaivanam, 9 Kms from Karungali, 20 Kms from Ponneri,
20 Kms from Ponneri Railway Station, 74 Kms from Thiruvallur, 70 Kms from
Chennai Airport and 55 Kms from Chennai. Town buses are frequently available
from Ponneri and Red Hills.
