pondicherry tamil nadu beach erosion
DESCRIPTION
Man-induced coastal erosion along Pondicherry - Tamil Nadu (India) coastline.TRANSCRIPT
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Pondicherry Beach Disaster Pondicherry Beach Disaster
ManMan--Made TsunamiMade Tsunami
ManMan--Induced Coastal Erosion at Pondicherry Induced Coastal Erosion at Pondicherry and neighboring beaches of Tamil Naduand neighboring beaches of Tamil Nadu
Pondy Citizens’
Action Network
(PondyCAN)
August 2008
www.pondycan.org
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Once upon a time …Pondicherry had a beautiful beach (1986)
Pondy Citizens’ Action Network – August 2008
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Nature’s gift to the citizens of Pondicherry (1986)
Pondy Citizens’ Action Network – August 2008
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• Protects us from cyclones and tsunamis
• Prevents ground water from becoming saline
• Supports the livelihood of fishermen
• Provides a natural recreational space
• A unique and indispensible habitat for wildlife (sea turtles)
• Part of our heritage - used during festivals (Masimagam, Vinayaga Chaturthi)
THE BEACH… an essential part of the ecosystem
Pondy Citizens’ Action Network – August 2008
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Then a harbour was built (1986-1989)……and neglected
Harbour entrance Pondy town 2 kms
Pondy Citizens’ Action Network – August 2008
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Pondy was never the same …a precious gift was lost (2000)
Pondy Citizens’ Action Network – August 2008
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How did we lose our beach?
Pondy Citizens’ Action Network – August 2008
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Understanding The Coastal Environment
of the Pondicherry –
Tamil Nadu
(Coromandel) Coastline
Pondy Citizens’ Action Network – August 2008
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The Pondicherry and Tamil Nadu coastlines are composed of sandy beaches, dunes and estuaries:
Rivers bring sand to the sea and feed the beaches.
Sand deposited along coast forms Estuaries, dunes, beaches.
The Cauvery Delta brings large amounts of sediment.
DunesBeachesEstuaries
Images: source Google Earth
Pondicherry
Pondicherry(Karaikal)
Tamil Nadu
Pondy Citizens’ Action Network – August 2008
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Typical Profile of a sandy beach
Pondy Citizens’ Action Network – August 2008
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South Pondy beaches – 1986-87 (Harbour construction
just started)
Pondy Citizens’ Action Network – August 2008
Vegetated dunes
Wide sandy beaches
Estuaries
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PONDICHERRY TOWN’S COASTLINE – BEFORE - 1989
Sand bar
Beach
Dune – Beach Road is over an old dunePondy Citizens’ Action Network – August 2008
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Coastal Processes along
Pondicherry –
Tamil Nadu Coastline
The most dominant process is: The Long Shore Drift (LSD):
the Natural Transportation of Sand
Pondy Citizens’ Action Network – August 2008
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Mechanisms of sand transportation
Cross-shore movement
Pondy Citizens’ Action Network – August 2008
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Mechanisms of sand transportation
Long-shore movement
Pondy Citizens’ Action Network – August 2008
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Mechanisms of sand transportation along Pondicherry Coastline
During NE monsoon
During SW monsoon
Swell orientation
Swell orientation
=
Direction of sand
movement
Image: source Google EarthPondy Citizens’ Action Network – August 2008
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Images: source Google Earth
swellswell
Mechanisms of sand transportation along Pondicherry Coastline
Pondy Citizens’ Action Network – August 2008
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During SW Monsoon (9 months):
6,00,000 cu.m
sand move North
During NE monsoon (3 months):
1,00,000 cu.m
sand move South
Mechanisms of sand transportation along Pondicherry Coastline
Pondy Citizens’ Action Network – August 2008
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Net long-shore drift =
6,00,000 cu.m
(North -
SW)
-
1,00,000 cu.m
(South -
NE)
= 5,00,000 cu.m
move North
each year
Mechanisms of sand transportation along Pondicherry Coastline
Pondy Citizens’ Action Network – August 2008
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500,000 Cu.m per
year!
Sand movement is a significant natural process and a factor which plays a major role.
Net Littoral Drift
Images: source Google Earth
Mechanisms of sand transportation along Pondicherry Coastline
Pondy Citizens’ Action Network – August 2008
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Interfering with the Littoral Drift
Pondy Citizens’ Action Network – August 2008
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Source: unknown
Pondy Town
Tamil Nadu
Satellite image of Pondicherry coastline (Year 2000)
Pondy Harbour
Ariyankuppam Estuary
Pondy Citizens’ Action Network – August 2008
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Eroding coastline
Accreting coastline
Profile of the Pondicherry coastline (year 2000)
PondyHarbour
Source: unknownPondy Citizens’ Action Network – August 2008
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Pondicherry Harbour (built in 1986-1989)
Pondy Harbour mouth
Pondy town 1.5 kms
Pondy Citizens’ Action Network – August 2008
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Breakwaters obstruct littoral drift
Sand depletion
Sand accumulation
Original shoreline
BreakwatersLittoral drift
Pondy Citizens’ Action Network – August 2008
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Existing sand by-pass system at Pondy harbour
Original
shoreline
Submarine tunnel
Dredger
Sand nourishment
Proposed by: Central Water & Power Reasearch Station (CWPRS), Pune, 1978.
Designed by: Consulting Engineering Services (CES), New Delhi, 1981.
Pondy Citizens’ Action Network – August 2008
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Dredging
&
Sand Nourishment
Sand by-pass system at Pondy Harbour
FAILED BECAUSE IMPROPERLY AND
SELDOM USED.
Pondy Citizens’ Action Network – August 2008
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Consequences of disrupting
the Littoral Drift along Pondicherry –
Tamil Nadu
Coastline
Pondy Citizens’ Action Network – August 2008
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Before (1986)
After (2002)
Pondy New Pier beach
Pondy Citizens’ Action Network – August 2008
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Before (1986)
After (2000)
Pondy town beach
Pondy Citizens’ Action Network – August 2008
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Before (2001)
After (2002)
Kottakuppam (TN) beach
Pondy Citizens’ Action Network – August 2008
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Affected villages in Pondicherry & Tamil Nadu (2002)
Pondy Citizens’ Action Network – August 2008
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1st August ‘02 … a week later
A house and trees… …turned into rubble and lost.
Parking space for traditional fishing crafts….is lost.
Pondy Citizens’ Action Network – August 2008
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Widespread destruction
Homes…. livelihoods … and nature
Pondy Citizens’ Action Network – August 2008
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Since the construction of the Harbour in 1989:- 8 kms of shoreline completely eroded- More than 30 km affected
Satellite image of Pondicherry and Tamil Nadu coastline (2006)
8 kms
PondyTamil Nadu
PondyHarbour
Blocked sand
Seawall
Pondy Citizens’ Action Network – August 2008
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Further disruption of the Littoral Driftcaused by
“hard” coastal protection measures:
Pondy Citizens’ Action Network – August 2008
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1989 – 2007: Instead of nourishing the beaches, rocks were dumped along the coast.
Pondy
Tamil Nadu
Pondy Citizens’ Action Network – August 2008
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Seawall ends in Pondy… the problem shifts to Tamil Nadu
Sea WallPondy
Tamil Nadu
Pondy Citizens’ Action Network – August 2008
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3 short groynes
POND
Y
TAMIL NADU
Seawalls & later groynes built in Tamil Nadu. 2002 – 2006.
Seawall
SoudanikuppamNadukuppamThandirayan
kuppam
Pondy Citizens’ Action Network – August 2008
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Groyne construction work at Tandhirayankuppam, TN 4th May 2007
Pondy Citizens’ Action Network – August 2008
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Groyne built North of Thandiyankuppam Village in Tamil Nadu May 2007
≈
120 m
Erosion
Pondy Citizens’ Action Network – August 2008
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Erosion at Quiet Beach, Thandhirayankuppam, TNas a result of groyne construction
April 2007 9th May 2007
Pondy Citizens’ Action Network – August 2008
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Erosion at Quiet Beach, Thandhirayankuppam, TN
April 2007 6th June 2007
Pondy Citizens’ Action Network – August 2008
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Erosion at Quiet Beach, Thandhirayankuppam, TN
April 2007 28th June 2007
Pondy Citizens’ Action Network – August 2008
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Erosion at Quiet Beach, Thandhirayankuppam, TN
April 2007 18th July 2007
Pondy Citizens’ Action Network – August 2008
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Erosion at Quiet Beach, Thandhirayankuppam, TN
April 2007
9th May 2007
6th June 200728th June 2007
Erosion in 3 month’s time
18th July 2007
Pondy Citizens’ Action Network – August 2008
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Dumping rocks and similar hard measures are not a solution
• Increases and transfers erosion down the coast
• Work has to continue forever as rocks keep sinking
• Requires huge sums of public money
• Does not protect us from big waves
• Mountains have to be destroyed
• Natural habitats for wildlife are destroyed
• The coastline is transformed and degraded
Is this sustainable?Pondy Citizens’ Action Network – August 2008
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March 2002
Coastal erosion is advancing northwards at more than 350 m/year (1 m/day)
Kottakupam
…3 months later!
Pondy Citizens’ Action Network – August 2008
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Challenges & Threats:
Proposed developments along SE coastline
that disrupt the Littoral Drift such as:
- Commercial Ports- Fishing harbours- “Hard” coastal structures- Artificial channels in seabed
Pondy Citizens’ Action Network – August 2008
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Proposed Deep Water Port at Pondicherry
Existing harbour Proposed Deep Water Port.
Existing Harbour Proposed Harbour
• Land area: 150 acres.• Cargo handling capacity: 1.5 MTA.• Actual capacity: 0.05 MTA (average).• Breakwaters: 250 m long.• Depth: Max. 4 m.
• Land area: 400 acres (min.)• Cargo handling capacity: 20 MTA.• Breakwaters: 750 m long.• Depth: Max. 14 m.
Pondy Citizens’ Action Network – August 2008
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Coastal erosion caused by disruption of littoral driftPotential situation in Pondy:
Potential erosion
Situation in Chennai:
Original shoreline
Original shoreline
Existing erosion
Chennai Harbour
Proposed Pondy
Harbour(similar to Chennai harbour)Pondy Citizens’ Action Network – August 2008
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Proposed Port developments likely to disrupt of littoral drift
Cheyur Port
Cuddalore Port
Karaikal Port
Nagapattinam Port
Pondicherry Port
Pondy Citizens’ Action Network – August 2008
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IMPACTS OF COASTAL EROSION
• Destruction and loss of property
• Destruction and loss of natural habitats and wildlife
• Increased water salinity and scarcity
• Loss of livelihoods for fishermen
• Degradation of fertile agricultural land
• Exposes the coastline to cyclones
Pondy Citizens’ Action Network – August 2008
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Do we need coastal developments that will:
• Increase coastal vulnerability
• Create water scarcity
• Damage the environment
• Endanger wildlife
..And ruin the quality of life of present and future generations
Pondy Citizens’ Action Network – August 2008
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Concluding remarks:
• The disruption of the littoral drift is likely to be oneof the greatest challenges for coastal protectionand restoration.
• Unless we demonstrate that the littoral drift can be restored once disrupted, future coastal developmentswill result in greater damage to the coast.
• The restoration of the affected Pondicherry and TamilNadu coastline could present an opportunity for establishing coastal restoration practices for otherparts of this coast.
Pondy Citizens’ Action Network – August 2008
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THANK YOU!
Pondy Citizens’ Action Network – August 2008