coastal processes and shoreline management –initiatives of

Coastal Processes and Shoreline Management – Initiatives of ICMAM/MoES

Scientist-F & Head

(Coastal Processes & Shoreline Management Group)

1. The coastal areas have been experiencing a number of changes:

2. Careful understanding and estimations of coastal processes i.e. Tide, Current, Wave Tsunami, Storm Surges, Sediment transport, Shoreline evolution, etc, is very important

Coastal Process studies and Shoreline management(Since 2003 onwards...)

accelerated changes in shoreline: loss of beaches and closures of inlets, degradation /changes of coastal habitats and land use- land cover increased coastal erosion & flooding due to extreme events and sea level rise changes in sediment transport pattern and islands, including coral islands Pressures of developmental activities along the shoreline (ports, harbours etc)

Tsunami, Storm Surges, Sediment transport, Shoreline evolution, etc, is very important to deal with various long-term variations in the coastal zone.

3. ICMAM has invested its energy in deal with these processes in small way at local scale through scientific experiments using monitoring, measurements, modelling, Mapping and Management (5 M approach)

4. Management solutions provided by ICMAM are partially implemented at few locations

5. Currently ICMAM focus is to i) assess the sediment transport rates at selected locations and ii) Long term and annual shoreline changes along Indian coast

ANDHRA PRADESH

ORISSA

MADHYA PRADESH

WESTBENGAL

BAYOFBENGAL

Gopalpur

Gangavaram

Shoreline Management Programme during X and XIth

plan- First project of this nature in India

Vengrala

Ratnagiri

TAMIL NADU

ARABIAN SEA

BENGAL

INDIAN OCEAN

Karwar

Kozikode

Vadanapally

Kundapur

Muthalapozhi

Honnanar

Malpe

NIO, Goa

CESS, Trivandrum

Chennai

ICMAM had lead role in implementing these projects in association with various institutes NCESS, NIO, IITM, NITK, BU, AU etc

Objectives Assessment of coastal erosions (Monitoring

of Shoreline changes, beach profile, LEO etc)

Understanding coastal processes through desk, field data and mathematical modelling studies.

Preparation of Shoreline Management plan.

16 locations (2003-12) + 2 Loc (2012-17)

During X plan:Panathura(Kerala)Ennore (TN)Kayamkulam-MunambamParadipUllal (Karnataka)Vellar (TN)

Implementation of partial SMP for coastal Implementation of partial SMP for coastal protection at protection at PanathuraPanathura

Predicted shoreline evolution Predicted shoreline evolution over 25 yearsover 25 years

Close grid nearshore bathymetry & Wave, current and sediment

Numerical modeling for Shoreline Evolution based upon historic data

Design of ‘T-groin field’, Implementation by Irrigation Dept. (Kerala Govt)

Performance now being monitored

Model studies predicted beach formation north of groin But beach formed south of groin

Beach developed Beach developed after groin after groin

constructionconstruction

Monsoon erosion is mostly storm profile erosion – the data was not there and

included in the model

Sequence of modelling Wave transformation Currents Sediment Transport Shoreline evolution

S [m] (meter)

Above 0.40.3 - 0.40.2 - 0.30.1 - 0.2

4.5

5.0

5.5

6.0

6.5

(kil

omet

er)

Morphological modelling to arrive conceptual coastal

measures along Tidal Inlet at Mangalore

0.1 - 0.2

0 - 0.1-0.1 - 0-0.2 - -0.1-0.3 - -0.2-0.4 - -0.3

Below -0.4

11/02/2006 14:00:00 Scale 1:32580

8.0 8.5 9.0 9.5 10.0 10.5 11.0(kilometer)

3.5

4.0

2.4

2

2.4 1.6 0.4

2.4

2

2.4 1.2 0.4

2.4

2

2. 4 0.8

2.4

0. 4

5 meter

H [m] (meter)

Above 2.82.4 - 2.8

2 - 2.41.6 - 21.2 - 1.60.8 - 1.2

0.4 - 0.80 - 0.4

-0.4 - 0Below -0.4

06/01/2000 08:00:00 Scale 1:2555

0.00 0.05 0.10 0.15 0.20(kilometer)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

0.22

0.24

0.26

0.28

0.30

(kilo

mete

r)

2.8 2

2.4

1.6

0.8

2.4

1.2

2.4

1.6

2. 4

1.6

0.8

2.4 1.2

2.4

1.6

2. 4

1.6

2.4

1.2

2.4

1.6

5 meter

H [m ] (meter)

Above 2.82.4 - 2.8

2 - 2.41.6 - 21.2 - 1.60.8 - 1.2

0.4 - 0.80 - 0.4

-0.4 - 0Below -0.4

06/01/2000 08:00:00 Scale 1:2555

0.00 0.05 0.10 0.15 0.20(kilometer)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

0.22

0.24

0.26

0.28

0.30

(kilo

mete

r)

2.8

1.6

2. 4

0.8

0.4

2. 4 0.8

2.4

1.2

2.4

0.8

0.4

2.4 0.4

2.4

1.6

2.4

0.8

0. 4

2.4

0.4

2.4

1.2

5 meter

H [m] (meter)

Above 2.82.4 - 2.8

2 - 2.41.6 - 21.2 - 1.60.8 - 1.20.4 - 0.8

0 - 0.4-0.4 - 0

Below -0.4

06/01/2000 08:00:00 Scale 1:12555

0.00 0.05 0.10 0.15 0.20(kilometer)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

0.22

0.24

0.26

0.28

0.30

(kilo

mete

r)

2.8

1.2

2.4

1.6

2.4 1.2 0.8

2.4

2

2.4

1.6

2.4 1.2 0.8

2.4 1. 6

2.4 2

0.8

2.4 0.8

2.8 2

0.4

5 meter

H [m] (meter)

Above 2.82.4 - 2.8

2 - 2.41.6 - 21.2 - 1.60.8 - 1.2

0.4 - 0.80 - 0.4

-0.4 - 0Below -0.4

06/01/2000 08:00:00 Scale 1:2555

0.00 0.05 0.10 0.15 0.20(kilometer)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

0.22

0.24

0.26

0.28

0.30

(kilo

mete

r)

T-Groyne @3.5m depth

Groyne

@3.5m depth

Submerged [email protected]

depth

Groyne @4.5m depth

Spacing/Length=1.5

Spacing/Length<1.5

Various Coastal Engineering Solutions were tested for prevailing tidal, wave conditions to

arrant the erosion in monsoon

Nearshore Wave interaction with structures

Recommended submerged reef

Plans are conceptual solutions & subjective Lack of information / Generation of quality data Understanding the nature, causes Coastal Erosion for coastal protection– holistic approachtherefore

Shoreline Management (2003-2012): lessons learned

The project was reviewed by high level committee in 2012 and recommended to focus on Coastal Processes studies and Shoreline vulnerability assessment ( 2013 onwards…)

Ongoing activities: Shoreline change mapping - a coastal service on shoreline changes Coastal Processes & Transport modelling- Understanding of the system & to provide

technical support to coastal states and other user agencies Coastal Change System- extent of coastal changes, classification & vulnerability assessment

Approach for Shoreline Monitoring for Indian Coast: Remote Sensing + Field Monitoring

Wide Beach

Distinct MorphologyShoreline processes depend on

morphology

Tidal InletsEarth CliffsRocky CliffsPocket Beaches

Erosion & Shoreline changes are site specific anddepend on human interventions.

Human interventions and shoreline changes

Et = ± E2s + E2

td + E2c + E2

d + E2p + E2

r + E2ts

I. Seasonal Error (Es),II. Tidal Fluctuation Error (Etd),

Positional Uncertainty

I. Digitizing Error (Ed),II. Pixel Error (Ep),III. Rectification Error (Er),

Measurement Uncertainty

y = 2.610300

Dis

tan

ce f

rom

Bas

elin

e (M

ete

rs)

Monthly shoreline & Foreshore slope survey for positional uncertainty for a geomorphic systems

LRR

Plan view of uncertainty in dataPlan view of uncertainty in data

EPR

Time no of yrs) betweenoldest and youngestshoreline

Distance in m betweenoldest and youngestshoreline

(EPR) =

WLR

y = 2.610R² = 0.923

0

50

100

150

200

250

1989 1994 1999 2004 2009 2014

Dis

tan

ce f

rom

Bas

elin

e (M

ete

rs)

Shoreline Date (Years)

LRR

2nd Order polynomial is preferable (requires minimum of 6 GCPs).- used 10-12 GCPs – collected from field (90%)

GCP’s spread evenly over the image, covering the whole image, and GCP were also placed in overlapping region to avoid edgemismatch between the two or more images.

RMSE maintained within pixel. 6-8 Check used for verifying rectification (Check point error ~ less than a pixel).

Protocols adopted for Geometric Correction toShoreline studies:

About ~35-38% of shoreline is experiencing erosion based upon 1990-2015 Accretion is leading to closure of creek /inlet mouths Existing ~200 harbours & ports, Sea level rise also has impact on coast

SHORELINE TREND

High Accretion

Moderate Accretion

Low Accretion

Stable

Low Erosion

Moderate Erosion

High Erosion

GJ Coastline Length : 1400 kmDistricts : 14 + 2 (UT)1:25000 grid : 136

Shoreline Change (1990Shoreline Change (1990--2016)2016)

Khambhat

Suvali BeachPorbandar protected Beach

Jamnagar Kuchadi Marsh land

Cumulative Shoreline Change (%)Cumulative Shoreline Change (%)

Jafarabad Rocky CliffsVanakabara Beach (Diu)

Adri Rocky Coast

Class 1990-2012 1990-2013 1990-2014 1990-2015 1990-2016

High Erosion 3.2 3.4 2.9 2.7 2.3

Moderate Erosion 4.9 5.4 4.6 3.9 3.4

Low Erosion 34.4 35.5 34.4 34.5 33.0

Stable 29.7 26.5 26.8 28.2 29.3

Low Accretion 22.0 23.3 25.9 25.1 26.4

Moderate Accretion 3.3 3.4 3.3 3.5 3.7

High Accretion 2.5 2.5 2.2 2.0 2.0

SHORELINE STATUS BETWEEN 1990 & 2016

SHORELINE 1990

Legend

Pentha coast

Shoreline changes Odisha coast over 25 years: Examples of natural and human-induced erosion

0

10

20

30

40

50

60

EROSION STABLE ACCRETION

31

10

58

SHORELINE 2016

Gopalpur

Short term changesShort term changes-- No trend, human intervention No trend, human intervention

Poompuhar region is an eroding site for past few decades.

8 groins structures were constructed after 2013 along Poompuhur region.

11

12th June 201424th May 201322nd June 2012

Coastal Processes studies and Shoreline vulnerability assessment ( 2013 onwards…)

Ocean to Coast: Ocean to Coast: Wind Wave+ Current + Nearshore+ shoreline Model

Hydrodynamic and Sediment Transport Modelling (South Maharashtra coast- Vangurala- Ratnagiri)

Global model-regional-Local Model.: Wave Watch III & SWAN implemented to capture realistic local wave features for LST MIKE platform ( Wave, Tide, and current model) – for Suspended sediment transport

(Coarse, 1.0 x 1.0)-Indian Ocean

(Mod, 0.1 x 0.1) -Arabian Sea

(Fine, 0.03 x 0.03)-South Maha.

SWAN / MIKE21 MODEL

WAVEWATCH IIIMODEL

(a) Large scale Wave Modelling

Model validation for of Hs, T &Dir

EMPIRICAL ESTIMATION

Offshore

LITPACK MODEL

(Fine, 100x100m) (Fine, 10x10m)

Near shore

(b) Regional Hydrodynamic modelling (100-500m grid): Integrating tide, wave, and wind influence to generate the composite energy regime in shallow waters

(c ) Local scale wave model (5-10 m grid) to capture wave breaking, refraction, diffraction fine scale processes for sediment transport

1000 2000 3000

X coordinate in m

1000

2000

3000

4000

5000

6000

7000

Y c

oo

rdin

ate

in m

On

e ye

ar

N

Ten

yea

rs

Longshore Sediment Transport and Shoreline prediction modelling for Vengurla coast

Modelling for sediment transport estimations and Prediction of Shoreline Changes for 10 years

Location Net (m3/yr) Gross (m3/yr)

Average -8511 1.18 * 105

On

e ye

arT

en y

ears

Longshore Sediment Transport and Shoreline prediction modelling for Vengurla coast

0102030405060

Erosion Stable Accretion

%

Gujarat, Daman & Diu

2030405060

%

Maharashtra

2030405060

%

Odisha

010203040506070


%

West Bengal

Arabian Sea Bay of Bengal

INDIA1990-2015 Pentha

(Sea wall)

KothapalayamRatnagiri

Jafarabad(Wavecut notch)

Fore shore

Bermline

Back shore

Sediment characteristics

Coastal changes System for Indian coast(on information needed for coastal development & management)

01020


%

0

10

20

30

40

50


%

Goa

0

10

20

30

40

50


%

Karnataka

010203040506070


%

Kerala

0

10

20

30

40

50


%

Tamil Nadu

01020304050607080


%

Puducherry

0102030405060


%

Andhra Pradesh

01020


%

Sl. No State Km 1:25,000 scale grid

1 Tamil Nadu & Puducherry 1055 81

2 Andhra Pradesh 978 89

3 Odisha 474 47

4 West Bengal 422 30

5 Karnataka & Goa 340 34

6 Maharashtra 734 45

7 Gujarat, Daman & Diu 1404 136

8 Kerala 542 55

Total 517Kizhunnapara beach

(Tombolo morphology)

Kothapalayam(Sand dunes)

Solai Nagar(Sea wall)

Kodimunai(Sea wall)

Ratnagiri(Rocky terrace)

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coastal processes and shoreline management –initiatives of

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