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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
Erosion Stable Accretion
%
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
Erosion Stable Accretion
%
0
10
20
30
40
50
Erosion Stable Accretion
%
Goa
0
10
20
30
40
50
Erosion Stable Accretion
%
Karnataka
010203040506070
Erosion Stable Accretion
%
Kerala
0
10
20
30
40
50
Erosion Stable Accretion
%
Tamil Nadu
01020304050607080
Erosion Stable Accretion
%
Puducherry
0102030405060
Erosion Stable Accretion
%
Andhra Pradesh
01020
Erosion Stable Accretion
%
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)
Web Application