Coastal Processes and Shoreline Management – Initiatives of ICMAM/MoES Scientist-F & Head (Coastal Processes & Shoreline Management Group)
Coastal Process studies and Shoreline management (Since 2003 onwards...) 1. The coastal areas have been experiencing a number of changes: 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) 2. Careful understanding and estimations of coastal processes i.e. Tide, Current, Wave Tsunami, Storm Surges, Sediment transport, Shoreline evolution, etc, is very important 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
Shoreline Management Programme during X and XI th plan- First project of this nature in India WEST BENGAL MADHYA PRADESH ORISSA Gopalpur Ratnagiri BAY Gangavaram OF Vengrala ANDHRA PRADESH BENGAL BENGAL ARABIAN SEA NIO, Goa Karwar Chennai Honnanar Kundapur Objectives Malpe Assessment of coastal erosions (Monitoring of Shoreline changes, beach profile, LEO etc) Kozikode CESS, Trivandrum Understanding coastal processes through TAMIL NADU During X plan: desk, field data and mathematical modelling Panathura(Kerala) Vadanapally Ennore (TN) studies. Muthalapozhi Kayamkulam-Munambam Preparation of Shoreline Management plan. Paradip Ullal (Karnataka) 16 locations (2003-12) + 2 Loc (2012-17) Vellar (TN) INDIAN OCEAN ICMAM had lead role in implementing these projects in association with various institutes NCESS, NIO, IITM, NITK, BU, AU etc
Implementation of partial SMP for coastal Implementation of partial SMP for coastal protection at protection at Panathura Panathura 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) Predicted shoreline evolution Predicted shoreline evolution over 25 years over 25 years Performance now being monitored Model studies predicted beach formation north of groin But beach formed south of groin Monsoon erosion is mostly storm profile erosion – the data was not there and included in the model Beach developed Beach developed after groin after groin construction construction
Morphological modelling to arrive conceptual coastal measures along Tidal Inlet at Mangalore Sequence of modelling 6.5 Wave transformation Currents 6.0 Sediment Transport 5.5 (kilometer) Shoreline evolution 5.0 S [m] (meter) Above 0.4 4.5 0.3 - 0.4 0.2 - 0.3 0.1 - 0.2 0.1 - 0.2 0 - 0.1 4.0 -0.1 - 0 Various Coastal Engineering Solutions were -0.2 - -0.1 -0.3 - -0.2 tested for prevailing tidal, wave conditions to Nearshore Wave interaction with structures -0.4 - -0.3 3.5 Below -0.4 arrant the erosion in monsoon 8.0 8.5 9.0 9.5 10.0 10.5 11.0 (kilometer) Recommended submerged reef 11/02/2006 14:00:00 Scale 1:32580 0.30 0.30 0.28 4 1.2 2 . 0.28 2.4 0 . 4 0.26 0.26 Groyne 4 2 . . 0 2.4 4 T-Groyne 0.8 0.24 0.24 2.4 8 0.22 . 0 0 . 4 0.22 @3.5m depth 2 @3.5m depth 0.20 2.4 1.6 0.20 2.4 0.18 0.18 Spacing/Length=1.5 (kilometer) 2.4 0.4 0.16 (kilometer) 2.4 0.16 1.2 0 . 4 0.14 2 0.8 0 0.14 . . 5 meter 4 4 0.12 2 5 meter 0.12 H [m] (meter) 0.10 . 4 1.2 2 H [m] (meter) Above 2.8 0.10 2.4 0.08 2.4 - 2.8 Above 2.8 2.4 0 2 - 2.4 2.4 - 2.8 . 8 0.08 1.6 - 2 2 - 2.4 0.06 2.4 1.6 . 4 1.2 - 1.6 0 1.6 - 2 0.06 2 0.8 0.4 0.8 - 1.2 1.2 - 1.6 0.04 . 4 0.4 - 0.8 0.8 - 1.2 0.04 0 - 0.4 2 0.02 0.4 - 0.8 2 1.6 -0.4 - 0 . 8 0 - 0.4 Below -0.4 0.02 0.00 -0.4 - 0 2.4 0.00 0.05 0.10 0.15 0.20 Below -0.4 0.00 (kilometer) 0.00 0.05 0.10 0.15 0.20 06/01/2000 08:00:00 Scale 1:12555 (kilometer) 06/01/2000 08:00:00 Scale 1:2555 0.30 0.30 0.28 2.8 2 0 . Groyne 4 0.28 2.4 1.6 0.26 4 0 . 8 @4.5m depth 0.26 . 0.24 2 Submerged 2.4 2 . 0.24 1 0.22 2.4 2 0 . 8 0.22 2 1.6 Reef@3.5m . Spacing/Length<1.5 4 0.20 0.20 2.4 1.6 0.18 2.4 1 depth . 6 0.18 (kilometer) 2.4 0.16 1.2 0 . 8 (kilometer) 1 0.16 2.4 . 2 0.14 2 1.6 0.14 . 4 5 meter 1.6 0.8 0.12 2.4 5 meter 0.12 H [m] (meter) 2.4 0.10 2 H [m] (meter) Above 2.8 0.10 2.4 1 . 6 Above 2.8 2.4 - 2.8 0.08 2 - 2.4 0.08 2.4 - 2.8 2.4 8 1 . 2 0 . 1.2 2 - 2.4 1.6 - 2 2 0.06 . 4 1.6 - 2 1.2 - 1.6 0.06 1.2 - 1.6 2 1.6 0.8 - 1.2 0.04 . 4 1.6 0.8 - 1.2 0.4 - 0.8 0.04 2 0 . 4 . 8 0.4 - 0.8 0 - 0.4 0.02 0 - 0.4 0.02 2.8 1.2 -0.4 - 0 8 -0.4 - 0 Below -0.4 . 2 0.00 2 Below -0.4 0.00 0.00 0.05 0.10 0.15 0.20 0.00 0.05 0.10 0.15 0.20 (kilometer) (kilometer) 06/01/2000 08:00:00 Scale 1:2555 06/01/2000 08:00:00 Scale 1:2555
Shoreline Management (2003-2012): lessons learned Plans are conceptual solutions & subjective Lack of information / Generation of quality data Understanding the nature, causes Coastal Erosion for coastal protection– holistic approach therefore 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 Monthly shoreline & Foreshore slope survey for Erosion & Shoreline changes are site specific and Positional Uncertainty Human interventions and Distinct Morphology positional uncertainty for a geomorphic systems depend on human interventions. shoreline changes Shoreline processes depend on I. Seasonal Error (E s ), morphology Rocky Cliffs Earth Cliffs Tidal Inlets Wide Pocket Beaches II. Tidal Fluctuation Error (E td ), Beach Measurement Uncertainty I. Digitizing Error (E d ), II. Pixel Error (E p ), III. Rectification Error (E r ), E 2 s + E 2 td + E 2 c + E 2 d + E 2 p + E 2 r + E 2 E t = ± ts 300 LRR LRR Distance from Baseline (Meters) Distance from Baseline (Meters) y = 2.610 y = 2.610 250 R² = 0.923 200 150 100 50 0 1989 1994 1999 2004 2009 2014 EPR Shoreline Date (Years) Distance in m between WLR oldest and youngest shoreline (EPR) = Time no of yrs) between oldest and youngest shoreline Plan view of uncertainty in data Plan view of uncertainty in data
Protocols adopted for Geometric Correction to Shoreline studies: 2 nd 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 edge mismatch between the two or more images. RMSE maintained within pixel. 6-8 Check used for verifying rectification (Check point error ~ less than a pixel). 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 Change (1990 Shoreline Change (1990- -2016) 2016) GJ Coastline Length : 1400 km Districts : 14 + 2 (UT) Khambhat 1:25000 grid : 136 Jamnagar Kuchadi Marsh land SHORELINE TREND High Accretion Moderate Accretion Low Accretion Suvali Beach Stable Porbandar protected Low Erosion Moderate Erosion Beach High Erosion Adri Rocky Coast Cumulative Shoreline Change (%) Cumulative Shoreline Change (%) Class 1990-2012 1990-2013 1990-2014 1990-2015 1990-2016 Vanakabara Beach (Diu) Jafarabad Rocky Cliffs 3.2 3.4 2.9 2.7 2.3 High Erosion 4.9 5.4 4.6 3.9 3.4 Moderate Erosion 34.4 35.5 34.4 34.5 33.0 Low Erosion 29.7 26.5 26.8 28.2 29.3 Stable 22.0 23.3 25.9 25.1 26.4 Low Accretion 3.3 3.4 3.3 3.5 3.7 Moderate Accretion 2.5 2.5 2.2 2.0 2.0 High Accretion
Shoreline changes Odisha coast over 25 years: Examples of natural and human-induced erosion Pentha coast SHORELINE STATUS BETWEEN 1990 & 2016 Legend SHORELINE 1990 SHORELINE 2016 58 60 31 50 40 Gopalpur 30 10 20 10 0 EROSION STABLE ACCRETION
Short term changes Short 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. 12 th June 2014 24 th May 2013 22 nd June 2012 11
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