Pondicherry Tamil Nadu Beach Erosion

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

Once upon a time …Pondicherry had a beautiful beach (1986)

Pondy Citizens’ Action Network – August 2008

Presenter

Presentation Notes

Beach not at its widest. Size of beach varies seasonally. Waves breaking on sand bar is visible.

Nature’s gift to the citizens of Pondicherry (1986)


• 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


Then a harbour was built (1986-1989)……and neglected

Harbour entrance Pondy town 2 kms


Pondy was never the same …a precious gift was lost (2000)


How did we lose our beach?


Understanding The Coastal Environment

of the Pondicherry –

Tamil Nadu

(Coromandel) Coastline


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


Typical Profile of a sandy beach


South Pondy beaches – 1986-87 (Harbour construction

just started)


Vegetated dunes

Wide sandy beaches

Estuaries

PONDICHERRY TOWN’S COASTLINE – BEFORE - 1989

Sand bar

Beach

Dune – Beach Road is over an old dunePondy Citizens’ Action Network – August 2008

Presenter

Presentation Notes


Coastal Processes along

Pondicherry –

Tamil Nadu Coastline

The most dominant process is: The Long Shore Drift (LSD):

the Natural Transportation of Sand


Mechanisms of sand transportation

Cross-shore movement


Mechanisms of sand transportation

Long-shore movement


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


swellswell



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



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



500,000 Cu.m per

year!

Sand movement is a significant natural process and a factor which plays a major role.

Net Littoral Drift




Interfering with the Littoral Drift


Source: unknown

Pondy Town

Tamil Nadu

Satellite image of Pondicherry coastline (Year 2000)

Pondy Harbour

Ariyankuppam Estuary


Presenter

Presentation Notes

Erosion visible north of harbour – Pondy town bulges into the sea. Accretion visible south of harbour – wide beach.

Eroding coastline

Accreting coastline

Profile of the Pondicherry coastline (year 2000)

PondyHarbour

Source: unknownPondy Citizens’ Action Network – August 2008

Presenter

Presentation Notes

Erosion visible north of harbour – Pondy town bulges into the sea. Accretion visible south of harbour – wide beach.

Pondicherry Harbour (built in 1986-1989)

Pondy Harbour mouth

Pondy town 1.5 kms


Breakwaters obstruct littoral drift

Sand depletion

Sand accumulation

Original shoreline

BreakwatersLittoral drift


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.


Dredging

&

Sand Nourishment

Sand by-pass system at Pondy Harbour

FAILED BECAUSE IMPROPERLY AND

SELDOM USED.


Presenter

Presentation Notes

The current engineering thinking the world over is for soft rather than hard engineering solutions – they try to replicate natural processes rather than fight them. In the case of Pondicherry the most sustainable long term solution that comprises sand nourishment by dredging . But this comes at a cost – Rs. 50-100/cubic metre of sand dredged or Rs. 2.5 – 5.0 crores per annum, for as long as the Port exists. Without capital derdging. The rabour was meant to provide shelter to about 300 mechanized fishing vessels, but ended up taking away the livelyhood of traditional fisherfolk who use catamarans from the beach, it endangered the town of POndicherry which now lies exposed to cyclones and the town being at or even slightly below sea-level Since the Port appears to be economically unviable with a constant recurring financial, social and environmental cost, it has essentially achieved next to nothing.

Consequences of disrupting

the Littoral Drift along Pondicherry –

Tamil Nadu

Coastline


Before (1986)

After (2002)

Pondy New Pier beach


Presenter

Presentation Notes


Before (1986)

After (2000)

Pondy town beach


Presenter

Presentation Notes


Before (2001)

After (2002)

Kottakuppam (TN) beach


Presenter

Presentation Notes


Affected villages in Pondicherry & Tamil Nadu (2002)


1st August ‘02 … a week later

A house and trees… …turned into rubble and lost.

Parking space for traditional fishing crafts….is lost.


Widespread destruction

Homes…. livelihoods … and nature


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


Further disruption of the Littoral Driftcaused by

“hard” coastal protection measures:


1989 – 2007: Instead of nourishing the beaches, rocks were dumped along the coast.

Pondy

Tamil Nadu


Presenter

Presentation Notes

Cost of harbour about 20 crores. Cost of dumping rocks for shore protection – about 20 crores upto date. This cost will keep going up as it is a recurring cost – rocks sink into the soft sand. Length of seawall at present: 8 km. It is extending northwards every couple of years.

Seawall ends in Pondy… the problem shifts to Tamil Nadu

Sea WallPondy

Tamil Nadu


3 short groynes

POND

Y

TAMIL NADU

Seawalls & later groynes built in Tamil Nadu. 2002 – 2006.

Seawall

SoudanikuppamNadukuppamThandirayan

kuppam


Groyne construction work at Tandhirayankuppam, TN 4th May 2007


Groyne built North of Thandiyankuppam Village in Tamil Nadu May 2007

≈

120 m

Erosion


Erosion at Quiet Beach, Thandhirayankuppam, TNas a result of groyne construction

April 2007 9th May 2007


Erosion at Quiet Beach, Thandhirayankuppam, TN

April 2007 6th June 2007



April 2007 28th June 2007



April 2007 18th July 2007



April 2007

9th May 2007

6th June 200728th June 2007

Erosion in 3 month’s time

18th July 2007


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

March 2002

Coastal erosion is advancing northwards at more than 350 m/year (1 m/day)

Kottakupam

…3 months later!


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


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.


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

Proposed Port developments likely to disrupt of littoral drift

Cheyur Port

Cuddalore Port

Karaikal Port

Nagapattinam Port

Pondicherry Port


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


Presenter

Presentation Notes

The current engineering thinking the world over is for soft rather than hard engineering solutions – they try to replicate natural processes rather than fight them. In the case of Pondicherry the most sustainable long term solution that comprises sand nourishment by dredging . But this comes at a cost – Rs. 50-100/cubic metre of sand dredged or Rs. 2.5 – 5.0 crores per annum, for as long as the Port exists. Without capital derdging. The rabour was meant to provide shelter to about 300 mechanized fishing vessels, but ended up taking away the livelyhood of traditional fisherfolk who use catamarans from the beach, it endangered the town of POndicherry which now lies exposed to cyclones and the town being at or even slightly below sea-level Since the Port appears to be economically unviable with a constant recurring financial, social and environmental cost, it has essentially achieved next to nothing.

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


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.


THANK YOU!


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Pondicherry Tamil Nadu Beach Erosion