Socioeconomic Vulnerability Assessment of Coastal Villages and Buildings along Andhra Pradesh East Coast of India
Authors
Mahendra, R.S., Mohanty, P.C., Francis, P.A., Sudheer Joseph, Balakrishnan Nair T. M. and Srinivasa Kumar T.
Source
Environment, Development and Sustainability, httpsdoi.org10.1007s10668-023-03955-x
Abstract
Climate change is a global phenomenon that has enhanced sea-level rise and aggravated the
prevailing coastal hazards that make coasts more vulnerable. The socioeconomic vulnerability
of villages for the entire Andhra Pradesh state and buildings at the selected locations
along the Andhra Pradesh coast is estimated to understand the level of risk due to exposure.
This study attempts to understand the reality of grassroots communitieshouseholds and
derive vulnerability indicators that affect coastal communities. In this regard, 1 the exposure
index EI, 2 coastal cumulative vulnerability index CCVI, and 3 socioeconomic
vulnerability indexes are calculated. EI is calculated based on oceanogenic multi-hazard
zones MHZ estimated using the long-term extreme water levels, shoreline change rate,
sea-level change rate, and high-resolution topographic data. The cumulative coastal vulnerability
index CCVI and socioeconomic vulnerability index SEVI are calculated for all
villages and buildings in the selected villages. A total of 16 socioeconomic risk indicators
from the village census of 2001 and ten indicators from the survey at the building level
are used in the study. The current study suggests 23 villages comprising 6000 households
associated with 0.022 million people under the very high SEVI category. Four villages
comprising 1000 households associated with 3000 people are in the very high cumulative
vulnerability index category. Nineteen hundred eighty-five buildings in the selected parts
of the study area had a very high SEVI. One hundred and forty-five buildings in the village
chosen had very high SEVI. The brief policy interventions and alternate livelihood options
are discussed in this paper. The decision matrix generated at the village and building levels
will help decision makers identify the contributing risk indicators for each villagebuilding
for appropriate resilience interventions.
Paper No
2
Publication ID : 865 & Year : 2023
Title
Characteristics of Astronomical Tides and Their Modulation on Sea Level Extremes Along the Indian Coast
Authors
Mohanty P.C., Mahendra R.S., Nayak R.K., Manche S.S., Joseph S., Balakrishnan Nair T.M., Srinivasa Kumar T.
Source
Ocean and Coastal Management, 231, 106398.
httpsdoi.org10.1016j.ocecoaman.2022.106398
Abstract
In this study, long-term hourly sea-level records from 18 tide gauge stations during 1972⿿2007 were analyzed to study the characteristics of astronomical tides, sea-level trends, and extremes around Indias mainland. The de-tided signals were used to estimate these parameters and study tide and surge interaction. The observed sea level depicts significant variability in daily, seasonal, and inter-annual time scales. Semidiurnal tides are the most dominant among the high-frequency tides, with an amplitude of up to 2.5 m for M2 and 0.75 m for S2 tides in the northwestern and northeastern continental shelf and reduced to 0.25 m in the south. The amplitude of diurnal tides O1 and K1is relatively weak 0.25m at all the stations. The annual harmonics dominate the seasonal cycle, with an amplitude of 0.7 m at Garden Reach in the northeastern continental shelf, decreases to 0.15 m at Tuticorin in the south, and remains small 0.1 m along the west coast of India. The amplitude of lunar nodal and perigee tides are significantly high up to 25 mm at several stations compared to the long-term global mean sea level trend ⿼3.3 mmy. The sea level trend is significantly positive up to 4 mmy for Sagar Island, Diamond Harbor, Haldia, and Mangalore negative up to ⿿3 mmy for Garden Reach and Okha, and in-significant 0.5 mmy for Mumbai, Vishakhapatnam, and Paradip. Interaction between the semidiurnal tides and surges was intense at most stations, with a high probability of surge peaks during the fall-tide conditions in the northern continental shelf, at rising-tidal conditions for the south-eastern and western peninsula, and co-occurring at high tide for southern stations. The degree of tide-surge interaction increases from south to north with an increase in tidal range and significant nodal and perigee tidal modulation.
Paper No
3
Publication ID : 864 & Year : 2022
Title
Wave induced coastal flooding along the southwest coast of India during tropical cyclone Tauktae
Authors
Ramakrishnan, R., Remya, P.G., Mandal, A., Mohanty P.C., Arayakandy, P., Mahendra, R.S. Balakrishnan Nair, T.M.
Source
httpsdoi.org10.1038s41598-022-24557-z
Abstract
The coastal flood during the tropical cyclone Tauktae, 2021, at Chellanam coast, Kerala, India, has
invited wide attention as the wave overtopping severely affected coastal properties and livelihood.
We used a combination of WAVEWATCHIII and XBeach to study the coastal inundation during high
waves. The effect of low-frequency waves and the rise in the coastal water level due to wave setup
caused the inundation at Chellanam, even during low tide with negligible surge height. Wave setup
raised the water level at the coast with steep slopes to more than 0.6 m and peaked during low tide,
facilitating wave breaking at the nearshore region. The coastal regions adjacent to these steep slopes
were subjected to severe inundation. The combined effect of long and short waves over wave setup
formed extreme wave runups that flooded inland areas. At gently sloping beaches, the longwave
component dominated and overtopped the seawalls and damaged households along the shoreline.
The study emphasizes the importance of longwave and wave setup and its interaction with nearshore
bathymetry during the high wave. The present study shall lead to the development of a coastal
inundation prediction system for the low-lying hot spots using the combination of WAVEWATCHIII and
XBeach models.
Paper No
4
Publication ID : 802 & Year : 2021
Title
Persistence of marine heat waves for coral bleaching and their spectral characteristics around Andaman coral reef.
Authors
Mohanty, P.C., Kushabaha, A., Mahendra, R.S., Nayak R.K., Sahu, B.K., Rama Rao, E.P., Srinivasa Kumar, T.
Source
Environmental Monitoring and Assessment 193, 491. httpsdoi.org10.1007s10661-021-09264-y
Abstract
Coral reefs are fragile and endangered ecosystems in the tropical marine and coastal environment. Thermal stress due to marine heat waves MHW could cause significantly negative impacts on the health conditions, i.e., bleaching of the coral ecosystem. The current study is an attempt to quantify the intensity of coral bleaching in the Andaman region in recent decades using the intensity of marine heat wave IMHW estimated from satellite measured sea surface temperature SST. A linear regression model was developed between IMHW and in situ observations of percent coral bleaching PCB which has the slope 7.767 of IMHW unit and intercept â¿¿â¿¿141.7. Further, an attempt was also made to establish the relationship between PCB and the ratio between the remote sensing reflectance Rrs at 443 and 531 nm to upscale the percentage of coral bleaching at synoptic scales. A significant positive correlation between the PCB and band ratio index was found R2â¿¿=â¿¿0.72. This approach can be used for the operational monitoring of coral reef beaching in this region.
Paper No
5
Publication ID : 807 & Year : 2021
Title
Effect of Sea Surface Temperature Variation on Productivity and Fisheries off Karnataka, West Coast of India.
Authors
Kumari, P.V., Thomas, S., Mohanty, P.C. Jayappa, K.S., Mahendra R.S. and Gupta, A.
Source
J Indian Soc Remote Sens. httpsdoi.org10.1007s12524-021-01447-x
Abstract
Variations of chlorophyll-a chl-a, sea surface temperature SST and net primary productivity NPP along with fish catch
were studied along the coastal waters off Karnataka, west coast of India from January 2007 to December 2016. These
variations are linked with the Indian Ocean Dipole and El Nin˿oSouthern Oscillation⿿Nin˿o3.4 SST index. NPP was
estimated by using vertically generalized production model. Change in NPP values over the decade 2007â¿¿2016 was
studied in context of global reports of decline in productivity over the period. It is very important to understand the pattern
of NPP variability as well the interrelationship with SST over a long period to study its impact on distribution of the fishery
resources. Trend showed that there is reduction in productivity after 2012 and this trend continued in subsequent years.
During the study period, an increasing trend in SST is observed along the Karnataka coast. The present study shows that a
strong El Nin˿o event was seen in 2015, along with declined productivity in the coastal waters off Karnataka by 24 and
increase in SST by 1 from the average of 10 years 2007â¿¿2016. Increased SST and low ocean productivity resulted
in reduced fish catch with the decline of 6.7 in total fish catch along the Karnataka coast from 2014 to 2015. In 2016, 5.29
lakh tones of fish catch, was estimated resulting in 19.6, increase compared to 2015. During southwest monsoon, sea
surface height anomalies SSHa showed negative anomaly trend and increased Ekman pumping resulted in upwelling over
the study area.
Paper No
6
Publication ID : 806 & Year : 2021
Title
Spatio-temporal changes of Mangrove cover and its impact on bio-carbon flux along the West Bengal coast, Northeast coast of India.
Authors
PC Mohanty, RS Mahendra, RK Nayak, LK Sharma, and E Pattibhi Rama Rao
Source
European Journal of Remote Sensing, 541, 524â¿¿536. httpsdoi.org10.108022797254.2021.1977183
Abstract
The present study assesses patio-temporal variability of the greenness index of Indian mangroves
of the Sundarban forest with bio-carbon flux during 1990-2020. The analysis of NDVI
derived using Landsat data reveals the mangrove stress level was very high during the years
1990, 2006, 2007, 2009 and 2011, with 2011 km2 mangroves were severely affected out of a
total 2215 km2. The improved and healthy condition prevailed during 1999, 2000, 2001, 2015,
2016 and 2019 and normal condition during 2002, 2005, 2008 and 2010. The net change in
mangrove cover during 1990-2020 shows distinct loss and gain regions across the study region.
The shoreline change analysis shows that nearly 90 km2 of mangroves were lost on the seaward
side due to coastal erosion. Whereas, 50 km2 of newly developed mangroveswere observed in
western parts of Southern Parganas due to accretion and no lossgain was recorded in the rest
of the areas. A significant positive correlation coefficients 0.76 at p=0.01 was recorded
between the increase in the extent of the mangrove region and bio-carbon fluxes for the
years of normal and high-stress level condition as the dominant classes. Conversely, correlation
is insignificant for the years dominated by healthy conditions.
Paper No
7
Publication ID : 803 & Year : 2021
Title
Holistic approach to assess the coastal vulnerability to oceanogenic multi-hazards along the coast of Andhra Pradesh, India.
Authors
Mahendra, R.S., Mohanty, P.C., Francis, P.A., Sudheer Joseph, Balakrishnan Nair T. M. and Srinivasa Kumar T.
Source
Environ Earth Sci, 80, 651. httpsdoi.org10.1007s12665-021-09920-z
Abstract
The coastal vulnerability to multi-hazard study aims to assess the coastal zones of Andhra Pradesh that really are vulnerable to various oceanogenic hazards. Using high-resolution coastal elevation, the maximum extent of coastal inundation during extreme high waves of cyclones tsunamis, shoreline change, and sea-level rise can be computed. Vulnerability impact up to the village level was assessed based on future projection return period of multi-hazard impact using a holistic approach with geospatial techniques. The current study results revealed that 706 villages and 8 towns that are completely falling under CMZ are at risk. A total of 9682 km2 of coastal zones of Andhra Pradesh coast are exposed and prone to inundation as recorded under CMZ. Krishna, Godavari, Guntur and Prakasham districts comprise 70 of the total CMZ area are large low-lying areas exposed to ocean hazards. CMZ area along Andhra Pradesh coast recorded a significant negative correlation of â¿¿ 0.65 with coastal elevation and a positive correlation of 0.34 with coastal exposure index. Shoreline change assessed from 1972 to 2019 across the study area reveals the 7 under high erosion along the headland and low-lying area of Krishna-Godavari delta. The outputs and maps produced in this study provide vital input for coastal disaster management and necessary policy interventions.
Paper No
8
Publication ID : 804 & Year : 2021
Title
Spatio-temporal changes of Mangrove cover and its impact on bio-carbon flux along the West Bengal coast, Northeast coast of India.
Authors
P.C. Mohanty, S. Shetty, R.S. Mahendra, R.K. Nayak, L.K Sharma and E. Pattbhi Rama Rao
Source
European Journal of Remote Sensing, Accepted
Abstract
The coastal vulnerability to multi-hazard study aims to assess the coastal zones of Andhra Pradesh that really are vulnerable to various oceanogenic hazards. Using high-resolution coastal elevation, the maximum extent of coastal inundation
during extreme high waves of cyclones tsunamis, shoreline change, and sea-level rise can be computed. Vulnerability
impact up to the village level was assessed based on future projection return period of multi-hazard impact using a holistic
approach with geospatial techniques. The current study results revealed that 706 villages and 8 towns that are completely
falling under CMZ are at risk. A total of 9682 km2
of coastal zones of Andhra Pradesh coast are exposed and prone to inundation as recorded under CMZ. Krishna, Godavari, Guntur and Prakasham districts comprise 70 of the total CMZ area
are large low-lying areas exposed to ocean hazards. CMZ area along Andhra Pradesh coast recorded a signifcant negative
correlation of â¿¿ 0.65 with coastal elevation and a positive correlation of 0.34 with coastal exposure index. Shoreline change
assessed from 1972 to 2019 across the study area reveals the 7 under high erosion along the headland and low-lying area
of Krishna-Godavari delta. The outputs and maps produced in this study provide vital input for coastal disaster management
and necessary policy interventions.
Paper No
9
Publication ID : 801 & Year : 2021
Title
Vulnerability assessment of coastal fishing communities for building resilience and adaptation Evidences from Tamil Nadu, India,
Authors
Thavasiyandi Umamaheswari, Gopalrajan Sugumar, Pandian Krishnan, Pachampalayam Shanmugam Ananthan, Arur Anand, Jeyapaul Joyson Joe Jeevamani, Ranganalli Somashekharappa Mahendra, John Amali Infantina and Cherukumalli Srinivasa Rao
The coastal communities are the most vulnerable to climate vagaries, which affect their habitat and livelihood alike. Vulnerability assessments undertaken using quantitative or qualitative methods at macro- or micro-level need to capture the location and context so as to be able to use them towards improving mitigation and resilience strategies at the community level, where the impact is felt. The characteristics of the marine fishing villages differ from those of other villages in any coastal block district in a State, making a strong case for a marine village-specific vulnerability assessment as well as intervention planning. This work, capturing this grassroots reality and deriving vulnerability indicators that affect fisheries and coastal households, pilots a novel socio-economic vulnerability SEVIPH and cumulative vulnerability CVIPH framework in marine fishing villages of Thoothukudi, a coastal district of Tamil Nadu in India, and compares it with an existing framework SEVISV that relies on secondary data. A set of 54 indicators reflecting vulnerability components such as exposure, sensitivity fishery and social and adaptive capacity economic, development drivers and alternate livelihood activity has been developed. Primary data were collected from 1741 households residing in all the 24 marine fishing villages in Thoothukudi district to estimate various sub-indices and indices of SEVIPH, SEVISV and CVIPH. Significant differences p 0.01 in sensitivity index SI and adaptive capacity index ACI were observed among the fishing villages, which however, got masked at taluk and district level due to aggregation, underscoring the importance of household based village level assessment of vulnerability. Overall, 42 of the fishing villages were socio-economically highly vulnerable, while about 71 of the villages had high cumulative vulnerability index. While the overall social and economic status of fishing households were lower compared to non-fishing population, it could be ascertained that there was relatively less inequity among them. The study also found significant disparities and differences p 0.05 across the villagestaluks in terms of exposure, sensitivity as well as socio-economic capabilities to respond, adapt and develop resilience. The two dimensional decision matrix plotted against SI and ACI median threshold values presented a greater contrast and helped in identifying the key drivers or contributing factors and buffers or ameliorating factors for coastal vulnerability of marine fishing villages to aid in location-specific intervention planning. The study also highlighted the need for imparting need-based location-specific training programmes at the village and taluk level for vulnerability reduction.
Paper No
10
Publication ID : 800 & Year : 2020
Title
Earth Observation Technique-Based Coastal Vulnerability Assessment of Northern Odisha, East Coast of India.
Authors
Barik KK, Mohanty PC, Nanda S, Ramasamy A and Mahendra RS
Source
Jor. Ind. Soc. of Rem. Sen., 49, 293â¿¿303. httpsdoi.org10.1007s12524-020-01216-2
Abstract
The coastal zones of northern Odisha coast, western Bay of Bengal, are highly exposed to natural forcing. These regions are vulnerable due to natural hazards such as cyclones, tsunamis, floods, shorelinebeach erosion and sea-level rise. Further, the increased intensity and density of the extreme events in the recent decades have contributed more to the coastal vulnerability, thereby causing floods and inundation. Therefore, there is a need of sustainable use of the coastal zone with proper management practices. In this context, coastal vulnerability index CVI has been proved as an effective method for assigning the vulnerability status to any coastal zone. The present research work aims to develop a CVI by integrating risk values of nine input variables and to segment them into low, moderate, high and very high vulnerability categories as per their degree of vulnerability. The study area exhibits a long 273.8 km coastal tract, and about 9.6 of the coastal tract is under very high vulnerability category, followed by 29.7 under high vulnerability, 46.3 under medium vulnerability and rest 14.3 under low vulnerability.
Paper No
11
Publication ID : 798 & Year : 2020
Title
Storm Surge Hazard Assessment Along the East Coast of India Using Geospatial Techniques.
Authors
HC Prince, R Nirmala, RS Mahendra, PLN Murty
Source
DOI httpsdoi.org10.21203rs.3.rs-56384v1
Abstract
The present study is to estimate the inundation extent and depth to estimate the extent of damage using geospatial technique caused due to a storm surge. This is achieved by selecting a worst-case cyclone track Super Cyclonic Storm scenario for three Indian states, Andhra Pradesh, Odisha and West Bengal based on the historic data. Over 1300 cyclones are observed to have hit the east coast of India in the past 173 years, which is about an average of more than 7 cyclones per year. Geospatial model results for Orissa cyclone 1999 suggests that over 2,150 km2 of land is submerged due to storm surge. The inundation was observed up to an extent of 45 km inland upright to the shoreline with over 1,100 km2 area submerged 1-2m from ground level. This is the worst cyclone with peak speed 140 knots of the country known so far to have caused maximum damage. The storm surge model of Andhra cyclone 1996 suggests that about 450 km2 of area inundated due to storm surge where majority of the area is submerged up to1m of water pile. The most affected place is Mummidavaram. Whereas, the results of storm surge model for the state of West Bengal is carried out using a synthetic track passing through West Bengal coast with wind speed of 155 knots worst case. The model result shows 5,400 km2 of land submerged up to 1m of water and about 2,700 km2 of area submerged under 1-2m of water. The most affected area is South 24 Parganas and parts of Bangladesh. The results of the current study are useful for the coastal cyclone disaster management in order to make decisions on preparedness and disaster risk reduction. These results can also be used for the coastal future development purposes.
Paper No
12
Publication ID : 799 & Year : 2020
Title
Geospatial-Based Coastal Risk Assessment of Gujarat Coastline.
Authors
Abraham M., Mahendra R.S., Mandla V.R., Merugu C.S., Peddinti V.S.S.
Source
In Saride S., Umashankar B., Avirneni D. eds Advances in Geotechnical and Transportation Engineering. Lecture Notes in Civil Engineering, vol 71. Springer, Singapore. httpsdoi.org10.1007978-981-15-3662-5_5
Abstract
Nowadays due to the change in climatic conditions and proliferation in sea level, the coastlines are under high threat. The Gujarat coastline is studied in the current work. It is the longest coastline in India and is highly vulnerable to cyclones, earthquakes, floods, landslides, etc. These facts show the relevance of the present research. The parameters based on which the coastal vulnerability index is laid include seven physical parameters and one social parameter. The seven physical parameters are rate of shoreline change, coastal slope, coastal elevation, geomorphology, significant wave height, tidal range, sea level rise, and the social parameter is population density. The additional parameters used in this study, to increase the accuracy of the vulnerability index are coastal elevation, rise in sea level, and population density. The study is done using geospatial data and various other models and is analyzed with the help of geospatial tools. The high-resolution Cartosat DEM data is used to analyze the coastal elevation and makes this study stand out from the previous studies. Using the risk rating of each parameter, the coastal vulnerability index is prepared and it divides the coast into four zones, that is, very highly vulnerable, highly vulnerable, moderately vulnerable, and low vulnerable. According to the analysis, about 43.5 of the coastline is under highly vulnerable zone and about 1 is under very highly vulnerable zone. The study shows that the area under high erosion is basically tidal flats and mangroves.
Paper No
13
Publication ID : 726 & Year : 2019
Title
Framework for mapping the drivers of vulnerability and spatial decision making for climate change adaptation in coastal India A Case study from Maharashtra, India
Authors
18. P. Krishnan, PS. Ananthan, R. Purvaja, Joyson J. Jeevamani, J. Amali Infantina, Ch. Srinivasa Rao, A. Anand, RS. Mahendra, I. Sekar, K. Kareemulla, Amit Biswas, R. Kalpana Sastry, R. Ramesh
The impacts of climate change are of particular
concern to the coastal region of tropical countries like
India, which are exposed to cyclones, floods, tsunami,
seawater intrusion, etc. Climate-change adaptation
presupposes comprehensive assessment of vulnerability
status. Studies so far relied either on remote sensing-based
spatial mapping of physical vulnerability or on certain
socio-economic aspects with limited scope for upscaling or
replication. The current study is an attempt to develop a
holistic and robust framework to assess the vulnerability of
coastal India at different levels. We propose and estimate
cumulative vulnerability index CVI as a function of
exposure, sensitivity and adaptive capacity, at the village
level, using nationally comparable and credible datasets.
The exposure index EI was determined at the village level
by decomposing the spatial multi-hazard maps, while
sensitivity SI and adaptive capacity indices ACI were
estimated using 23 indicators, covering social and
economic aspects. The indicators were identified through
the literature review, expert consultations, opinion survey,
and were further validated through statistical tests. The
socio-economic vulnerability index SEVI was
constructed as a function of sensitivity and adaptive
capacity for planning grassroot-level interventions and
adaptation strategies. The framework was piloted in
Sindhudurg, a coastal district in Maharashtra, India. It
comprises 317 villages, spread across three taluks viz.,
Devgad, Malvan and Vengurla. The villages in Sindhudurg
were ranked based on this multi-criteria approach. Based
on CVI values, 92 villages 30 in Sindhudurg were
identified as highly vulnerable. We propose a decision tool
for identifying villages vulnerable to changing climate,
based on their level of sensitivity and adaptive capacity in a
two-dimensional matrix, thus aiding in planning location-specific interventions. Here, vulnerability indicators are
classified and designated as â¿¿driversâ¿¿ indicators with
significantly high values and intervention priority and
â¿¿buffersâ¿¿ indicators with low-to-moderate values at the
village level. The framework provides for aggregation or
decomposition of CVI and other sub-indices, in order to
plan spatial contingency plans and enable swift action for
climate adaptation.
Paper No
14
Publication ID : 797 & Year : 2019
Title
Geospatial assessment of flood hazard along the Tamil Nadu coast.
Authors
21. P C Mohanty, Satej Panditrao, R S Mahendra, H Shiva Kumar, Sai P Bharadwaj, R K Nayak, Pattabhi Rama Rao.
Source
Jour. Ind. Soc. Of Rem. Sen., 47, 1657-1669. httpsdoi.org10.1007s12524-019-01012-7
Abstract
During Novemberâ¿¿December 2015, very heavy rainfall caused severe flood in Southern Tamil Nadu that resulted in severe damages with huge economic losses as per news agency Times of India. Remote sensing data from Sentinel-1 synthetic aperture radar SAR and Landsat-8. Operational land imager OLI images together with ancillary information such as rainfall and demographic data were used in the current study to assess the extent and impact of flooding. The SAR data are used to map the flood or inundation zones. Landsat-8 OLI is used to extract built-up area affected by the flood employing three methods built-up area extraction method BAEM, BAEM with Enhanced Built-up and Bareness Index EBBI, and modified Normalized Difference Built-up Index NDBI approach. The classification accuracies obtained for these three approaches were 89, 83.5, and 78 for BAEM using EBBI, BAEM, and NDBI, respectively. Aerial comparison of built-up area extracted using BAEM using EBBI shows the best accuracy with respect to the built-up area obtained from very high-resolution imagery. This extracted built-up area BAEM using EBBI method was used to estimate the extent of inundation covering the built-up area. Further the flooding risk at village level was assessed using the population density and flooding area. Built-up area extracted was also overlaid with flooding area to highlight actual built-up areas under risk due to flood.
Paper No
15
Publication ID : 796 & Year : 2019
Title
Statistical Assessment of Long-term Shoreline Change along the northern coast of Odisha, East Coast of India
Authors
20. Barik, K. K., Annaduari R., Mohanty P C Mahendra, R S, J K Tripathy and D Mitra
Source
Ind. Jour. Geo Mar. Sci. Vol. 48 12, 1990-1998.
Abstract
Odisha, a coastal state on eastern seaboard of India possesses a ~450 km long coastline vulnerable to a multitude of
natural and anthropogenic threats. The present study reports a systematic assessment of rates of shoreline change over a
period of 25 years from 1990- 2015, using Landsat 5 and 8 series of Thematic Mapper and Operational Land Imager
satellite images. An analysis of rate of shoreline change was carried out along select regions of Odisha coast using Digital
Shoreline Analysis System DSAS. Linear Regression Method LRR was used to estimate net shoreline change at sub
decade time scale and End Point Rate EPR to estimate net shoreline change rate in between two consecutive years. The
highest erosion with a coastline length of 63 km was observed between Rajnagar around Satabhaya beach and
Mahakalapara near to Hukitola beach block of Kendrapara district and between Ersama around Paradeep port and
Balikuda blocks northern parts of Devi River mouth of Jagatsinghpur coastal district. The result suggest that both EPR and
LRR techniques were used to estimate shoreline change rate and the similar result of erosion by both EPR and LRR
technique indicated weaker cyclic trend in erosion.
Paper No
16
Publication ID : 685 & Year : 2018
Title
Coral bleaching pattern in Palk Bay and Gulf of Mannar unprecedented in India: an issue of concern or an indication of a resilient reef community?
Authors
Krishnan, P., Purvaja, R., Sreeraj, C.R., Raghuraman, R., Robin, S., Abhilash, K.R., Mahendra, R.S., Anand, A., Gopi, S., Mohanty, P.C., Venkataraman, K., Ramesh, R.
Source
CURRENT SCIENCE, VOL. 114, NO.3,10 FEBRUARY 2018
Abstract
The status of reefs in Palk Bay and Gulf of Mannar were investigated during Apr-May, 2016 following the bleach alert, as the sea surface temperature (SST) recorded a sudden increase from 30.5 to 34.0 deg. C in Gulf of Mannar. 71.48±8.9% of the corals in Palk Bay and 46.04±3.78% in Thoothukkudi group of Islands in Gulf of Mannar, were found bleached, showing a clearly decreasing trend from north to south, which could be attributed to the corresponding pattern to the intensity of SST recorded in the study sites. Observations of bleaching patterns among different life-forms showed 68% of the bleached corals were massive forms. It was observed that 22 out of the 26 massive forms observed were bleached, while the Acropora corymbose (ACC), digitate (ACD) and encrusting coral (CE) forms were not bleached in any of the study sites in Palk Bay and Gulf of Mannar. The study suggests that the ACC, ACD and CE forms have adapted to thermal stress, subsequent to the earlier mass bleaching events. The study highlights the need for understanding the molecular mechanism of the association between corals and the symbiotic algae, for further understanding on coral bleaching in Indian waters.
Paper No
17
Publication ID : 795 & Year : 2018
Title
Geospatial Analysis of Mangrove Environs changes due to tectonic disturbance A Case study in Havelock and Little Andaman Islands, India.
Authors
Vybhav. K., Mahendra R. S., Lingadevaru M., Channabasappa K. and Madhuri Kalaskar
Source
International Journal of Research in Advent Technology, Vol.6, No.8, E-ISSN 2321-9637
Abstract
Conservation of mangroves is highly important due to the valuable services from mangrove ecosystem
such as, habitat for many faunflora, spawning ground for fishes, protects coastal zone against oceanic inundation
etc. The total mangrove cover in Andaman Island is about 616.2 Km2
. Andaman Islands experienced tectonic
disturbance due to Sumatra earthquake, which caused unprecedented impact on the mangrove environs. The analysis
of the mangrove changes in the south Andaman Islands of the Havelock and Little Andaman representing the
subsidence and uplift area of the land, and also reveals the degradation of the mangrove in both the areas. The
degradation of the mangrove environs in the subsided area, seaward side is attributed to increase in the saline
condition of the area. Whereas, the uplifted area landward side fringe is due to lack of brackish water in the
upstream area.
Paper No
18
Publication ID : 686 & Year : 2017
Title
Persistence of surface thermal fronts as an indicator of Potential Fish Zones using Remote Sensing along the coastal environs off Gujarat, west coast of India
Authors
Mohanty, P. C., Mahendra R. S., Nayak R. K., Nimit Kumar and Sirinivasa Kumar, T., R Dwivedi
Source
Regional Studies in Marine Science 16 (2017) 216â¿¿224, doi.org/10.1016/j.rsma.2017.09.010
Abstract
In this paper we demonstrate the persistence of sea surface thermal fronts based on the frequency of Sea Surface Temperature gradient satellite data, at seasonal and non-seasonal cycles. Prominent thermal fronts were observed in the northeast Arabian Sea between the 50m bathymetry contour and continental self break (~200 meter contour). A total of 45-75% of thermal fronts occurred at the annual time-scales whereas 20-30% occurred at the semi-annual time-scales. Maximum frequency occurrence was observed in the coastal waters south and southwest of Saurashtra peninsula during February and March. Primary productivity co-varies with the frequency of the thermal fronts with a time-lag of 2-4 weeks. This outcome can help on timely and reliable prediction of biologically productive zones.
Paper No
19
Publication ID : 684 & Year : 2017
Title
Impact of sea level rise and coastal slope on shoreline change along the Indian coast.
Authors
Mohanty P. C., Mahendra R. S., Nayak R. K and Srinivasa Kumar T.
Source
Natural Hazards, DOI 10.1007/s11069-017-3018-9
Abstract
Densely populated coastal zones of India are highly exposed to natural environment.
These are impacted by episodic natural events, continuous coastal process,
gradually rising sea levels and coexisting human interventions. The present study is an
attempt to assess the implication of the sea level rise and coastal slope in the coastal
erosion for entire mainland of India. In this regard, two methods were employed to estimate
the shoreline change rate (SCR): (1) satellite-derived SCR using the Landsat TM and
ETM? acquired during 1989â¿¿2001 and (2) SCR derived by Bruun Rule using the
parameters coastal slope and sea level trend derived from satellite altimetry. Satellitederived
SCR has been compared with the shoreline change estimated based on Bruun Rule,
revealing a better agreement with each other in terms of trend. Peaks of shoreline retreat
calculated using Bruun model and satellite-observed SCR offset by 25â¿¿50 km. Offset in
these peaks was observed due to net drift towards north in the east coast and south in the
west coast of India, revealing the applicability of the Bruun Rule along the Indian coast.
The present study demonstrates that coastal slope is an additional parameter responsible for
the movement of shoreline along with sea level change. The results of satellite-derived
SCR reveal the highest percentage of erosion along West Bengal coast with 70% followed
by Kerala (65%), Gujarat (60%) and Odisha (50%). The coastlines of remaining states
recorded less than 50% of coasts under erosion. Results of this study are proving critical
inputs for the coastal management.
Paper No
20
Publication ID : 683 & Year : 2017
Title
Coral Bleaching Along Andaman CoastDue to Thermal Stress During Summer Months of 2016: A Geospatial Assessment.
American Journal of Environmental Protection, 6(1), 1-6. doi: 10.11648/j.ajep.20170601.11
Abstract
Coral bleaching reported in the North Bay, Andaman Islands during the April last week of 2016 due to thermal
stress. The Coral Bleaching Alert System (CBAS) a service providing by Indian National Centre for Ocean Information
Services (INCOIS) has reported the warning and the bleaching has been confirmed from the field survey conducted on April
26, 2016. As coral reef is important fragile eco-system of the shallow marine environment suffers due to human and natural
impacts. Bleaching has been initiated as weather predictions of the various agencies have suggested the elevated temperatures
in the Indian subcontinent this year. We have put forward our remote sensing analysis of coral bleaching warning as Alert
Level-1 followed by the initiation of the coral bleaching in the in-situ observation at Andaman Islands enhances the credibility
of satellite observation and the service of INCOIS. These results were useful for the coastal management authority for taking
suitable measure and policy on important coral eco-system.
Paper No
21
Publication ID : 626 & Year : 2016
Title
Coastal Vulnerability Assessment for North East Coast of Andhra Pradesh, India.
Authors
Vivek G, Mahendra R.S., Mohanty P.C., Srinivasa Kumar T. and Sachikanta Nanda
Source
IJRSG, 5(2), 1-7
Abstract
Coastal areas of Andhra Pradesh in the north eastern part
of India are mostly vulnerable for accelerated erosion haz-ards. Along the 200 km of coastline most of the coastal are-as, towns and industries are threatened by reoccurring of
storms, flood events and sever coastal erosion. The east
coast of India is mostly affected by tropical cyclones origi-nating from northern and southern Bay of Bengal, where 1-2
tropical cyclones form every year along the coast. Recently
two tropical cyclones that formed in the Bay of Bengal are
Hudhud (October 13, 2014) and Phylin (October 11, 2013)
has caused devastating impact on the eastern coast. With this
study, it is an attempt to develop to develop a coastal vulner-ability index (CVI) for the Andhra Pradesh using eight rela-tive risk variables. Most of these parameter are dy-namic in nature and requires different data from diffe r-ent sources. The base data is from remote sensing satellites,
for others it is taken from long-term in situ measurements
and from numerical models. Zones of vulnerability to
coastal, natural hazards of different magnitude (high, medi-um and low) are identified and shown on map. In this study,
tsunami run-up has been considered as an additional physi-cal process parameter to calculate the CVI. In earlier studies,
tidal range are assumed to include both permanent and
episodic inundation hazards.
Paper No
22
Publication ID : 627 & Year : 2016
Title
Coastal Vulnerability Assessment for Eastern Coast of India, Andhra Pradesh by Using Geo-Spatial Technique
Authors
Basheer Ahammed K. K., Mahendra R.S. and Pandey A.C.
Source
Geoinformatics & Geostatistics: An Overview, 4(3), DOI: 10.4172/2327-4581.1000146
Abstract
The study mainly deals with the physical vulnerability of eastern
coast India, Andhra Pradesh. It is one of the Indian states which
have a very vast coastal line. Andhra Pradesh is very important
to the whole economy, Vishakhapatnam is a major port situated
in the eastern coast of India. Andhra Pradesh coastal line about
972 Km long, is affected by Storm surge, Cyclone, Sea Level Rise
and Tsunami, etc. The method adopted for identifying the coastal
vulnerability mapping was Coastal Vulnerability Index (CVI). Seven
parameters were used for identifying Costal Vulnerability mapping
which are Historical Shoreline changes, Mean Sea Level Rice,
Significance of Wave Height, Mean Tide Range, Coastal Regional
Elevation, Coastal Slope and Geomorphology. The final results
of this study are in the form of a coastal vulnerability map which
shows the environmentally vulnerable areas. This map will give
general idea about the probability of an area to undergo coastal
hazards due to coastal erosion or sea level rise. According to this
study about 16% area of the coast of Andhra Pradesh is identified to
have high vulnerability which can harm the environment. The map
prepared of the Andhra coast under this study can be used by the
state and district administration involved in the disaster mitigation
and management plan.
Paper No
23
Publication ID : 242 & Year : 2015
Title
The admissible tsunamigenic source region of 24 September 2013 land-based earthquake â¿¿ application of backward ray tracing technique.
Authors
Ch. Patanjali Kumar, B. Ajay Kumar,E. Uma Devi, R. S. Mahendra, M. V. Sunanda, M. Pradeep Kumar, J. Padmanabham, S. Dipankar and T. Srinivasa Kumar
Source
Current Science: 108(9)
Abstract
A minor tsunami of about 50 cm was generated along
the coast of Qurayat near Makran subduction zone in
the Arabian Sea due to the 24 September 2013 Paki-stan earthquake of magnitude 7.6 Mw
(mB),althoughits
source was ~200 km far inland of the Makran trench.
The real-time sea-level observation network in the
Arabian Sea recorded minor tsunami arrivals. In an
attempt to explain the mechanismof this unusual tsu-nami, we use backward ray tracing technique to map
the admissible region of tsunamigenic source. Basi-cally, in this technique the ray equations are inte-grated starting from the specific locations of tsunami
observations, in all possibledirections. The known
travel time of the initial waves to the respective tide
gauges and tsunami buoys is used in this method.
Backward wave front is constructed by joining all
end-points of the rays from each of the locations. The
region where the envelope of all backward wave fronts
converges is considered as the source of the tsunami,
which is ~470 km from the earthquake epicentrewith
the location at 24.8 N and 61.5 E. The admissible re-gion identified is an undersea section between Chaba-har and Gwadar,where a mud island had appeared
subsequent to this earthquake. Convergence of the
tsunami source zone and location of the mud island
suggest that the sudden uplift must have caused the
tsunami
Paper No
24
Publication ID : 520 & Year : 2014
Title
Assessment of Tsunami Hazard Vulnerability along the coastal environs of Andaman Islands
Authors
Prerna, R., Srinivasa Kumar, T., Mahendra, R. S., Mohanty, P. C.
Source
Natural Hazards, DOI 10.1007/s11069-014-1336-8.
Abstract
The December 2004 Sumatra-Andaman earthquake emphasized consistent and comprehensive assessment of areas that are prone to the hazard of tsunami. It also focused attention on the hazards that could be posed by large subduction zone earthquakes and the tsunamis that could be further generated. Due to the extremely high vulnerability in the Andaman Islands in South East India, it is essential for planners to develop a comprehensive a priori information database in order to minimize the impact of these destructive situations. A similar effort has been done in this study wherein the entire Andaman Islands have been assessed and the ¿Tsunami Hazard Vulnerable areas¿ have been highlighted in accordance with the Maximum Wave Run-up heights and topography. These areas have been extracted from the total area keeping in mind the Run-up wave heights on the very day of the Sumatra Andaman earthquake i.e. on 26 December 2004. Also, the topographical variations in the region have been studied to establish a relation between the vulnerability of an area and its topography. The hazard of tsunami puts at risk, the lives of approximately 314084 people over an area of 5833.199 sq. km in the Andaman Islands. Out of the total area, 708.826 sq. km is the hazardous portion which is 12.15%. The islands have experienced a total of 386 earthquakes (above 5.0 Magnitude) from the time of Sumatra ¿ Andaman Tsunami till the end of 2009. These statistics clearly indicate the need for hazard preparedness and planning in order to minimize impact during unfortunate circumstances. This study thus aims at the preparation of Tsunami Hazard Vulnerability Map for the Andaman Islands which can be further used by administrative and disaster mitigation organizations as and when required.
Paper No
25
Publication ID : 519 & Year : 2014
Title
Consequence of cyclonic storm Phailinon coastal morphology of Rushikulya estuary: an arribada site of vulnerable Olive Ridley sea turtles along the east coast of India
Authors
Shiva Kumar H., Satej Panditrao, S.K. Baliarsingh, Prakash Mohanty, R. S. Mahendra, Aneesh A. Lotliker, T. Srinivasa Kumar
Source
CURRENT SCIENCE, 107(1).
Abstract
Scientific Correspondence
Paper No
26
Publication ID : 493 & Year : 2014
Title
Evaluation of various image classification techniques on Landsat to
identify coral reefs
Authors
Tarun T. K., Ravi Babu M. V., Mahendra R. S. and Srinivasa Kumar T.
Coral reefs are one of the prominent marine ecosystems in the world. Coral reefs
are facing threats from both natural and anthropogenic factors. Monitoring,
protecting and studying these ecosystems are considered as a complex process
because they are underwater features. Remote sensing can be quite useful in this
by providing huge amount of database of satellite images. Landsat series have
been providing satellite data for last 50 years and now it is one of the large
databases providing satellite imageries. Accurate processing of these images can
increase the accuracy of coral reef information extraction from these images.
Classification is one of the important processes that can give adequate and precise
information about coral reefs. This study is intended to compare various supervised
classification techniques available for extraction of information from the
image and to suggest best of them. Maximum Likelihood and Support Vector
Machine have proven to be good classification module that can be used to classify
Landsat Images to coral reef detection and monitoring.
Paper No
27
Publication ID : 518 & Year : 2014
Title
Geospatial assessment of Coral and Mangrove Environs of the Andaman Islands
Authors
Mahendra. R. S., Mohanty. P. C., Bisoyi. H. and Srinivasa Kumar. T.
Source
International Journal of Earth Sciences and Engineering: 7(1), 375-379.
Abstract
An archipelago island system of Andaman is consisting of several hundreds of islands. The coastal environs of these islands are rich in bio-diversity. Most of the islands rimed with fringing corals and healthy mangroves observed near the creeks/streams in the coastal zones. The Sumatra Earthquake occurred on December 26, 2004 recorded a 9.3 Mw not only generated devastating tsunami, but also created lot of tectonic disturbances in the Andaman region. As result of this, northwestern parts of the land got uplifted above a meter from the earlier position. This resulted in the lot of spatial disturbances in the coastal environment. The shallow depth corals were exposed and degraded permanently. Moreover, the mangroves in the up streams were also degraded. A case study from the Interview Island in the northern Andaman was selected to assess the changes. The study was carried out using the Landsat Enhanced Thematic Mapper (ETM) and Indian Remote Sensing (IRS) Linear Imaging Self Scanning Sensor (LISS)-III data were used to infer the spatial changes in the coral and mangrove environments. The assessment was carried out using the Remote Sensing and GIS techniques. The results of the study reveal that the total coral reef area of 17. 82 km2 degraded. The mangrove also showed the same tendency of degradation of total 4.48 km2 area. The techniques and the data were used in the study were given useful insight. The results help in understanding the spatial extent and the distribution of the damage caused due to this natural calamity on the coral and mangrove environment.
Paper No
28
Publication ID : 243 & Year : 2014
Title
Assessment of Tsunami Hazard Vulnerability along the coastal environs of Andaman Islands.
Authors
Prerna, R., Srinivasa Kumar, T., Mahendra, R. S., Mohanty, P. C.
Source
Natural Hazards: DOI 10.1007/s11069-014-1336-8.
Abstract
The December 2004 Sumatraâ¿¿Andaman earthquake emphasized consistent and
comprehensive assessment of areas that are prone to the hazard of Tsunami. It also focused
attention on the hazards that could be posed by large subduction zone earthquakes and the
Tsunamis that could be further generated. Due to the extremely high vulnerability in the
Andaman Islands in South East India, it is essential for planners to develop a compre-hensive a priori information database in order to minimize the impact of these destructive
situations. A similar effort has been done in this study wherein the entire Andaman Islands
have been assessed to target â¿¿â¿¿Tsunami Hazard Vulnerable areasâ¿¿â¿¿ in accordance with the
maximum wave run-up heights and topography. These areas have been extracted from the
total area keeping in mind the run-up wave heights on the very day of the Sumatraâ¿¿
Andaman earthquake, i.e., on December 26, 2004. Also, the topographic variations in the
region have been studied to establish a relation between the vulnerability of an area and its
topography. The hazard of Tsunami puts at threat, the lives of approximately 314,084
people over an area of 5,833.1 km
2
in the Andaman Islands. Out of the total area,
708.8 km
2
is the hazardous portion which is 12.1 %. The islands have experienced a total
of 386 earthquakes (above 5.0 magnitude) from the time of Sumatraâ¿¿Andaman Tsunami
till the end of 2009. These statistics clearly indicate the need for hazard preparedness and
planning in order to minimize impact during unfortunate circumstances. This study thus
aims at the preparation of Tsunami Hazard Vulnerability Map for the Andaman Islands
Paper No
29
Publication ID : 494 & Year : 2013
Title
Assessment of the coral bleaching during 2005 to
decipher the thermal stress in the coral environs of the Andaman Islands using Remote Sensing
Authors
Prakash Chandra Mohanty, Ranganalli Somashekharappa Mahendra, Hrusikesh Bisoyi,
Srinivasa Kumar Tummula, George Grinson, Shailesh Nayak and Bijaya Kumar Sahu
Source
European Journal of Remote Sensing, 46: 417-430; doi: 10.5721/EuJRS20134624
Abstract
Sea Surface Temperature (SST) derived from the NOAA AVHRR satellite data were used to
generate the Degree of Heating Weeks (DHW) and Hot Spot (HS) products. Combination
of the cumulative temperature anomalies and the thermal stress studies were yielded to
synoptically identify the probable areas of bleaching. The bleaching status of the Andaman
region was assessed based on the DHW and HS for the bleaching event occurred in the
Andaman region in April/May 2005. The bleaching status up to Alert Level-1 was recorded
with the maximum HS of 3oC and DHW 6oC-week. Simultaneous in-situ reef observations
conducted in the Andaman Sea confirmed the coral bleaching event. The maximum mortality
in the region due to coral bleaching was shown by the Acropora species (43%) followed
by Montipora species (22%) and Porites species (14%). This study focused on detection of
coral bleaching warning based on the SST in compliment with the in-situ observations.
Paper No
30
Publication ID : 687 & Year : 2012
Title
Coastal Vulnerability Atlas of India
Authors
Shailesh Nayak, Srinivasa Kumar, T., Mahendra, R. S., Mohanty, P. C., Bisoyi, H.,
Source
INCOIS-ASG-CGAM-CV-201201. INCOIS, Hyderabad, India
Abstract
Atlas prepared in the current study depicts the Coastal Vulnerability on
1:1,00,000 scales. The work has been carried out at state level for all
coastal states of India. The methodology, data used and the area wise
statistics are presented. The overview of the results depicts that the parts
of West Bengal and Gujarat coasts are under the highly vulnerable when
compared to other parts in terms of the future sea level rise. Overall the
southern parts of the coasts are comparatively low vulnerable.
Paper No
31
Publication ID : 358 & Year : 2012
Title
Identification of hot spots and well managed areas of Pichavaram mangrove using Landsat TM and Resourcesat ¿ 1 LISS IV: An example of coastal resource conservation along Tamil Nadu Coast, India.
Authors
Srinivasa Kumar, T., Mahendra, R. S., Nayak, S., Radhakrishnan, K. R. and Sahu, K. C.
Source
Journal of Coastal Conservation, 16(1), 1-12, DOI: 10.1007/s11852-011-0162-3.
Abstract
The present work is a multi-temporal satellite based study on the spatial dynamic of an important coastal habitat, the Pichavaram mangrove ecosystem, over a period of 15 years. The Pichavaram mangrove forest near Chidambaram, South India is the second largest mangrove forest in the world. Unsupervised classification, the Iterative Self Organising Data Analysis Technique (ISODATA), has been used to classify the mangrove cover into the open and dense classes. The status of the classes has been monitored using Landsat TM of 1991, 2001, and Resourcesat¿1 LISS IV of 2006 satellite data. The study demonstrated that by classifying mangrove ecosystem into just the 3 classes using remote sensing data and by studying their temporal variations, it is possible to get a reasonably accurate picture of the extent and condition of the mangrove ecosystem. The total area of the Pichavaram mangrove showed a net increase of 2.51 km2 within a span of 15 years (1991 to 2006). The hot spots that are at a risk of being degraded, and on the other hand, the mangrove areas that are well managed are identified using Geographical Information System (GIS) tools for the restoration and conservation measures.
Paper No
32
Publication ID : 321 & Year : 2011
Title
Assessment and Management of Coastal Multi-hazard Vulnerability along the Cuddalore-Villupuram, East Coast of India using Geospatial Techniques
Ocean & Coastal Management
Authors
Mahendra,R. S., Mohanty,P. C., Bisoyi, H., Srinivasa Kumar, T. and Nayak, S.
The current study area is coastal zone of Cuddalore, Pondicherry and Villupuram districts of the Tamil
Nadu along the southeast coast of India. This area is experiencing threat from many disasters such as
storm, cyclone, flood, tsunami and erosion. This was one of the worst affected area during 2004 Indian
Ocean tsunami and during 2008 Nisha cyclone. The multi-hazard vulnerability maps prepared here are
a blended and combined overlay of multiple hazards those affecting the coastal zone. The present study
aims to develop a methodology for coastal multi-hazard vulnerability assessment. This study was carried
out using parameters probability of maximum storm surge height during the return period (mean
recurrence interval), future sea level rise, coastal erosion and high resolution coastal topography with the
aid of the Remote Sensing and GIS tools. The assessment results were threatening 3.46 million inhabitants
from 129 villages covering a coastal area 360 km2 under the multi-hazard zone. In general river
systems act as the flooding corridors which carrying larger and longer hinterland inundation. Multihazard
Vulnerability maps were further reproduced as risk maps with the land use information. These
risk caused due to multi-hazards were assessed up to building levels. The decision-making tools presented
here can aid as critical information during a disaster for the evacuation process and to evolve
a management strategy. These Multi-hazard vulnerability maps can also be used as a tool in planning
a new facility and for insurance purpose.
Paper No
33
Publication ID : 316 & Year : 2010
Title
Applications of the Multi-spectral Satellite data from IRS-P6 LISS-III and IRS-P4 OCM to Decipher Submerged Coral Beds around Andaman Islands.
Authors
Mahendra R.S., Hrusikesh Bisoyi, Prakash C. Mohanty, Sumisha Velloth, Srinivasa Kumar T. and
Shailesh Nayak
Source
International Journal of Earth Sciences and Engineering: Volume03, Issue05, pp 626-631.
Abstract
The coral reef of AndamanSea is one of the least explored regions of the Indian Ocean. The coral reefs are the tropical fauna forming the important eco-system in the tropical ocean. The coral reefs grow in the suitable climatic conditions. The coral reef systems of Andaman region are unique from ecological perspective. The reefs found around Andaman region are fringing type of reef. Most of this reef is found in the shallow depths especially in the photic zone along the coast. There are even reef banks exist along some ridges in the offshore region away from the coast. Some areas are remaining unmapped due to isolated from the coast. The satellite data can able to detect the signatures of the submerged reef banks. Multi-spectral bands of IRS series P6 LISS-III and P4 OCM satellite data deciphering the information about submerged reef bank in AndamanSea. The shorter wavelength from OCM spectral band3 (480-500 nm) and LISS III band1 (520-590 nm) were found useful in mapping submerged reef bank. The spectral signatures of these areas are similar to the mapped/observed submerged reef banks. The depths of these areas are from 25-70 meters observed based on the NHO charts and GEBCO bathymetric data. The current study brought out the possible areas of the submerged reef banks in the environs of the AndamanIsland.
Paper No
34
Publication ID : 245 & Year : 2010
Title
Coastal Multi-Hazard Vulnerability Mapping: A Case Study Along The Coast of Nellore District, East Coast of India
Authors
Mahendra R.S., Mohanty P. C., Srinivasa Kumar T., Shenoi S. S. C. and Nayak S.
Source
Italian Journal of Remote Semsing: Volume 42, Issue 3, pp. 67-76.
available at: http://www.aitjournal.com/articleView.aspx?ID=179
Abstract
The study area coastal zone of Nellore district is experiencing frequent inundation by natural disasters. The current study is focused on generating Multi-hazard vulnerability map using the parameters historical storm surge heights, future sea level, future shoreline and high resolution coastal topography. The area is experiencing the severe coastal erosion up to 7 m/y along some stretches poses a threat. An area totalling 1708.36 sq. km. is found to fall under the multi-hazard zone and the coastal population are under threat due to future storms, erosion, accelerated sea level rise, etc. The image enhancement, interpretation and GIS overlay techniques along with data used here are effective to produce Multi-hazard vulnerability maps. These Maps are become vital tools for the coastal disaster management during an event and to take suitable decision on the future developments.
Paper No
35
Publication ID : 244 & Year : 2010
Title
Coastal Vulnerability Assessment for Orissa State, East Coast of India.
Authors
Srinivasa Kumar, T., Mahendra, R. S., Nayak, S., Radhakrishnan, K., and Sahu, K. C
Coastal areas of Orissa State on the northeastern part of the Indian peninsula are potentially vulnerable to accelerated erosion hazard. Along the 480-km coastline, most of the coastal areas, including tourist resorts, hotels, fishing villages, and towns, are already threatened by recurring storm flood events and severe coastal erosion. The coastal habitats, namely the largest rookeries in the world for olive Ridley sea turtles (extensive sandy beaches of Gahirmatha and Rushikulya), Asia¿s largest brackish water lagoon (the ¿Chilika¿), extensive mangrove cover of Bhitarkanika (the wildlife sanctuary), the estuarine systems, and deltaic plains are no exception to it. The present study, therefore, is an attempt to develop a Coastal Vulnerability Index (CVI) for the maritime state of Orissa using eight relative risk variables. Most of these parameters are dynamic in nature and require a large amount of data from different sources. In some cases, the base data are from remote sensing satellites; for others it is either from long-term in situ measurements or from numerical models. Zones of vulnerability to coastal natural hazards of different magnitude (high, medium, and low) are identified and shown on a map. In earlier studies, tidal range was assumed to include both permanent and episodic inundation hazards. However, the mean of the long-term tidal records tends to dampen the effect of episodic inundation hazards such as tsunamis. For this reason, in the present study, tsunami run-up has been considered as an additional physical process parameter to calculate the CVI. Coastal regional elevation has also been considered as an additional important variable. This is the first such study that has been undertaken for a part of the Indian coastline. The map prepared for the Orissa coast under this study can be used by the State and District administration involved in the disaster mitigation and management plan.
Paper No
36
Publication ID : 246 & Year : 2006
Title
Summer chlorophyll-a distribution in eastern Arabian Sea off Karnataka-Goa coast from satellite and in-situ observations
Authors
Raghavan, B. R., Mini Raman, Chauhan, P., Sunil Kumar, B., Shylini, S. K., Mahendra, R. S. Nayak, S. R., .
Source
Proceedings of the SPIE, Volume 6406, 64060W (2006); doi:10.1117/12.694232
Abstract
Chlorophyll-a maps derived from IRS-P4 Ocean Color Monitor (OCM) was used to study the distribution pattern of phytoplankton biomass in the eastern Arabian sea off Karnataka-Goa coast, southwest coast of India. The data was compared with in-situ measurements of chlorophyll-a concentration estimated for 100 stations covering an area of more than 4000 km^2 in the above region. The presence of dense algal blooms spread over an area of almost 100 km^2 representing Trichodesmium sp. 18km off Kumta-Gokarna in the eastern Arabian Sea depicts high value (30 to 40 mg/m^3) of chlorophyll concentration. Similarly, around the Nethrani Island, off Bhatkal, the surface concentration ranged from 5 to 10 mg/m^3. The secchi depth varied from 4 to 8 m near the island. The sea surface area enveloping this high bloom (around the island) depicts a normal distribution of chlorophyll-a ranging from of 0.1 to 5 mg/m^3. It is suggested here, that the low salinity value (35 to 35.2 %) around the Nethrani Island enhances the algal bloom due to enrichment of nutrients in the shallow marine environment through probable inputs of nutrient charged fresh water from the island aquifers. Near river mouths, the values are marginally high in the range of 3 to 5 mg/m^3, probably enforced by riverine nutrient inputs well depicted by the Tadri River. The satellite (IRS-P4 OCM) derived images of chlorophyll during summer also shows high values as a band parallel to the coast. During the occurrence of algal blooms this band, parallel to the coast, widens offshore and this phenomenon of widening is typically absent during non-bloom summer scenarios, as identified for summer 2005.
