Sagar Island Research Articles

Estimation and counter- validation of LISS-III derived leaf area index in Deltaic vegetation

Leaf area index (LAI), a dimensionless biophysical variable is considered as one of the most important factors in characterizing canopy structure. It estimates the amount of foliage area per unit of ground area and helps indirectly to assess biomass and energy balance in an ecosystem. Remote sensing techniques established a strong correlation between the vegetation reflectance characteristics in red and near infra-red bands and LAI. Good number of image derived vegetation indices has been applied so far to estimate LAI successfully. In this paper correlation is established between field-collected LAI and three soil adjusted vegetation indices, i.e., SAVI, MSAVI and OSAVI derived from IRS-LISS-III data in deltaic ecosystem in Sagar Island of West Bengal, India. LAI was estimated from OSAVI for the whole island as OSAVI yielded best result (R2= 0.92). Coarse resolution MODIS LAI (MOD 15A3) product was counter-validated with respect to the LISS-III derived LAI image following the upscale validation approach. Out of the six best-fit models applied, the logistic regression showed strong positive correspondence between the two products (R2 = 0.71). Uncertainty of the model was also assessed and probable reasons were identified.

A Hooghly head‐scratcher

A Hooghly head‐scratcher

Variations of surface water quality in selected tidal creeks of Sagar Island, Indian Sundarban eco-region: a multivariate approach

Sagar Island in Indian Sundarbans is bestowed with numerous tidal creeks providing a suitable home to its inherent aquatic biota. The present study investigated the variation in the surface water quality in selected tidal creeks of Sagar Island, Indian Sundarbans to understand the present status of water quality for wildlife propagation and fisheries. Ten water parameters were taken into consideration for analysis on monthly basis from four stations (tidal creeks) from September 2015 to August 2016. One-way ANOVA showed five parameters (water temperature, salinity, dissolved oxygen, turbidity and chemical oxygen demand) varied significantly between seasons (p ≤ 0.05). Factor analysis exhibited four factors explaining 53.21% total variance in the observed data. Salinity and turbidity showed a maximum annual range of variations followed by dissolved oxygen. The fluctuations of physicochemical parameters throughout the year hinted toward the ever-changing nature of the estuarine ecosystem with possible human-induced impacts. Pronounced variation in turbidity seemed to be the effect of ferrying/transportation, monsoonal runoff and other human-induced activities. In the present study, water parameters viz., water temperature, dissolved oxygen and turbidity were the deterministic parameters influencing the variables in the system. The other important parameters were found to be COD, BOD3 and nitrate concentrations during the study period. The study shall provide baseline information in formulating the management measures in terms of water quality in wildlife propagation and fisheries.

Comparative Assessment of Livelihood Vulnerability of Climate Induced Migrants: A Micro Level Study on Sagar Island, India

The effects of climate change are causing large scale human displacements over the past few decades. Climate refugees are putting the biggest challenges to the geophysical biological and social system all over the world. This paper attempts to assess and compare the vulnerability of the climate-induced migrants and regular settlers of selected mouzas of Sagar Island, south 24parganas, India. People are witnessing their lands vanishing under their feet in these constantly sinking and shrinking deltaic estuaries of Sundarban. Findings of LVI and LVI-IPCC analysis indicate that the climate-induced migrant communities are more exposed to climatic variability due to the poor adaptive capacity. Moreover, poor access to food, water, health facilities is making them extremely vulnerable with lower resilience as these mouzas are facing frequent flooding, severe coastal erosion, embankment breaching and higher storm surge on annual basis. The outcomes of this study could be beneficial ineffective on-site risk management and planning propositions.

A Multi-decadal Comparative Analysis of a Set of Physicochemical and Nutrient Parameters in the Tropical Tidal Creeks of Indian Sundarban Mangrove Biosphere Reserve

Salinity, pH, dissolved oxygen (DO), dissolved inorganic nitrate (DIN), dissolved inorganic phosphate (DIP), and reactive silicate (DSi) concentrations were measured in three tidal creeks in the Sagar Island (situated within the Sundarban Biosphere Reserve, India) during 2016–17, once in a month throughout an annual cycle. The present observations were compared with a study carried out three-decade ago in the same locations during 1988–89. There was no significant difference in salinity between the years 1988-89 and 2016-17. Compared to the 1988–89 scenario, pH reduced considerably during 2016–17, indicating the dominance of heterotrophic activities over autotrophic processes. The comparative analysis shows that DO varied between 3.8 mg l− 1 and 5.4 mg l− 1 during 1988–89, which went to hypoxic levels (< 2 mg l− 1) during 2016–17. Such hypoxic conditions can lead to direct mortality of several marine biotas that thrives in these creeks. DIN and DSi concentrations reduced significantly. Compared to the 1988–89 scenario, DIN and DSi concentrations reduced by three times and ten times, respectively, in the year 2016-17. DIP concentration showed an increase in annual mean concentration, which was statistically not significant. Despite that DIN:DIP ratio reduced significantly during 2016–17 compared to that of 1988–89, which can lead to changes in the primary productivity potential of the phytoplankton community. Such changes in concentrations of the physicochemical and nutrient parameters can adversely affect the sustenance of several aquatic life forms and lead to changes in species composition or total abandonment.

Micro-level Assessment of Rural Societal Vulnerability of Coastal Regions: An Insight into Sagar Island, West Bengal, India

Most of the villages in coastal blocks of West Bengal, India, are prone to both cyclones and coastal and river flooding. Very severe cyclones in recent time (e.g., Sidr, Aila, Fani, Bulbul, and Amphan) exposed the coastal population livelihood at stake. Displacement and migration are very much evident due to such extreme events. However, the existing study examines the nature of societal vulnerability mainly for the coastal villages that focus on the biophysical components. An ‘integrated approach’ was adopted to assess the societal vulnerability which is viewed as a function of exposure, sensitivity and adaptive capacity. A number of proxy indicators were considered to represent these components and a normalisation procedure was adopted in order to aggregate them into a single value. Three key observations emerged. First, components such as sensitivity and adaptive capacity were found to act as the major determinants of vulnerability. Second, eight mouzas were found to have a higher vulnerability score, and surprisingly, some of the mouzas are non-coastal. Third, factors such as demography, agriculture and economic capacity emerged as the major cause for increasing vulnerability. These results have policy implications in the context of prioritising limited resources among the vulnerable villages and determinants through the disaster risk management programme at the district and block levels.

Spatio-temporal modelling of shoreline migration in Sagar Island, West Bengal, India

Sagar Island is a very popular pilgrimage destination located in the western part of Indian Sundarbans. This study employs Digital Shoreline Analysis System (DSAS) extension tool in ArcGIS platform to study and analyse the shoreline dynamics of Sagar Island by utilizing satellite images extending 40 years (1975–2015). 44 transects with 100 m spacing were laid and divided into six littoral cells (LCs). End Point Rate (EPR) and Linear Regression (LR) models were utilized to analyze the shoreline change patterns and also for predicting the future shoreline positions. It was observed that almost the entire southern portion of Sagar Island is susceptible to high rate of shoreline erosion. Most of the erosion occurred in Dhablat (LC 4 (a)) in the south eastern part at a rate of 11.695 ± 2.1 m/year. The mean shoreline change rate was also high in LC5 (±23.525 m/year). However, the overall shoreline change rate for the island was 4.94 m/year and uncertainty of total shoreline change rate was ±4.4 m/year. The study shows the usefulness of DSAS as a scientific tool for shoreline change studies and highlights state of erosion in the study area.

Data article on soil site suitability analysis using geostatistical and visualization techniques for selected winter crops in Sagar island, India.

We assessed soil site suitability for selected winter crops in the coastal saline agro-ecological environment of Sagar Island, India by integrating land limitation and crop suitability evaluation framework of FAO. Grid based (1 km by 1 km) soil sampling and estimation of important soil quality attributes were measured in the laboratory following standard procedures. Geo-statistical and visualization methods were applied to match the soil suitability for selected crops. The weights of crop specific soil parameters have been assigned through PCA analysis. The inverse distance weighting interpolation and reclassification methods were adopted for generation of spatial layers of those soil attributes. Nearly 61% area (14,618 ha GA) of the Island is under agricultural landuse (AL), mostly dominated (>75% of AL) by lowland rice-fallow mono-cropping. Soils are highly suitable (S1) for growing sunflower while moderately suitable (S2) for growing chilli, mustard and potato crops. The grid-wise georeferenced soil data information generated in this study will help in periodic monitoring of soil quality in spatio-temporal dimensions for devising location specific soil health managements in the Island. The methodology used in estimating soil quality index and crop specific soil suitability analysis in spatial format will help in replicating such studies in other such coastal Islands of Indian Sub-continent.

Soil site suitability analysis using geo-statistical and visualization techniques for selected winter crops in Sagar Island, India

The present study comprehensively assessed soil site suitability for selected winter crops in the coastal saline agro-ecological environment of Sagar Island, India by integrating land limitation and crop suitability evaluation framework of FAO. Soil properties (e.g. texture, pH, organic carbon; SOC, electrical conductivity; EC and available macronutrients- NPK) were obtained through extensive grid based (size: 1 km by 1 km) soil sampling and estimation in the laboratory following standard procedures. Geo-statistical and visualization methods were applied to match the suitability for selected crops based on their essential soil quality requirements. The weights of the soil parameters have been assigned through PCA analysis, based on the relative importance of soil properties sensitive to crop specific growth and development. The inverse distance weighting (IDW) interpolation and reclassification methods were adopted for generation of spatial layers of those soil properties. Results revealed that, nearly 61% of the geographical area (14618 ha GA) of the Island is under agricultural landuse (AL), mostly dominated by lowland rice-fallow based mono-cropping system (76% of AL) followed by rice-rice double cropping (in 14.8% AL). Soil suitability analysis for growing winter crops within agricultural area revealed that 38.4% (5607 ha) of AL is highly suitable (S1) for sunflower, 11.9% of AL (1739 ha) for chilli, 6.8% (987 ha) of AL for potato and only 1% (150 ha) of AL is considered to be highly suitable for mustard crop cultivation. However, the predominant fine textured soils of the Island falls under moderately suitable (S2) category for growing chilli (85.1% of AL), mustard (64.6% of AL), sunflower (55.7% of AL) and potato (53.0% of AL) crops. More than one third of the soils within the agricultural landuse were found not optimum for growing potato, sunflower and mustard. Findings from the study can be harnessed in increasing crop area diversification and intensification with appropriate irrigation and crop management practices in Sagar Island and similar such coastal Islands.

Development of a Grid Connected Solar-Wind Hybrid System With Reduction in Levelized Tariff for a Remote Island in India

Abstract Sagar Island which is located in the world's largest delta, the Sunderban, in the eastern coast of India faces severe power crunch. Due to its isolated location, the power infrastructure is underdeveloped. This has led to very unreliable power supply and frequent power cuts. The island being economically weak, power is inaccessible to most of its residents. Thus, the per unit energy consumption of the area is low and it has led to the lowering of the human development index of the area. However, Sagar Island, owing to its location, has huge solar and wind power potential. This paper discusses the prospect of developing a solar-wind hybrid power plant to supply power to the area. The developed hybrid renewable energy system (HRES) power plant will provide uninterrupted power to the island. Results show that the levelized cost of electricity (LCOE) from the proposed power plant is 0.03707 $/kWh, which is lower than the LCOE from the available grid. Lowering the cost of electricity will make electricity accessible to most of the inhabitants of the island. This will, in turn, increase the per unit energy consumption and hence the human development index. The proposed power plant will also help the environment by reducing CO2 emissions by 1894.08 tonnes annually. It will also save 587.39 tonnes of coal in its lifetime. Hence, the HRES power plant will make power accessible and also help Sagar Island to become a renewable fed “Green Island.”

Micro-level coastal vulnerability assessment in relation to post-Aila landscape alteration at the fragile coastal stretch of the Sagar Island, India

After the Aila cyclone on May 25, 2009, the fragile coastal environment of the Sagar Island is facing harsh impacts associated with coastal erosion, landscape degradation and alarming socioeconomic pressure. The present micro-level study focuses on the shoreline dynamics and associated landscape alteration rate of different land use/land cover patterns over 2.24 km2 area, along about 3 km coastline at low-lying (1.45 m) fragile land-shorefront stretch of the Sagar Island, India using multi-temporal satellite images of pre-Aila (2006) and post-Aila (2010 and 2017) periods. The embankment and shoreline shifting trends and predicted positions are estimated through the digital shoreline analysis system (DSAS) considering multiple shoreline/embankment positions over the period of 2006 to 2017. About 0.64 km2 area of productive land is exposed to marine action due to the rapid rate of shoreline retreat (28.48 m/y) within the decade. The coastal vulnerability index (CVI) is estimated after considering the 14 parameters from physical and socioeconomic variables. The result reveals that the shorefront zones (3 and 5) are highly vulnerable with CVI of 1 and 0.494 than the interior zones (2 and 4). The estimated vulnerability divulges that in the near future, the entire area will ruin due to high rate of land erosion with triggered effects of the local sea level rise (SLR) and associated hazards. The adopted multi-criterion CVI estimation method can also be applied over a large area in the other coastal stretch of the tropical regions.

Climate Change and Livelihood Vulnerability of the Local Population on Sagar Island, India

This paper attempts to assess the vulnerability to climate change of human communities in selected mouzas of Sagar Island, South 24 Parganas District of India. A primary household survey has been conducted to collect data on socio-demographic profile, livelihood strategy, health, food, water, social network, natural disaster and climate variation indicators, were selected for Livelihood Vulnerability Index (LVI) and Livelihood Vulnerability Index-Intergovernmental Panel on Climate Change (LVI-IPCC) analyses to measure and compare the vulnerability of mouzas (administrative unit) currently suffering from frequent flooding, coastal erosion and embankment breaching on an annual basis. Secondary data collected from the Indian Meteorological Department, the Water Resources Information System of India and the Global Sea Level Observing System have been used to identify dynamics of climate change by employing statistical and Geographic Information System (GIS) techniques. A GPS survey has been conducted to identify locations of embankment breaching, and satellite images obtained from the National Aeronautics and Space Administration and U.S. Geological Survey (NASA USGS) Government website have been applied to shoreline and land use change detection, using a supervised maximum likelihood classification. The results indicate that the study area has experienced increasing temperature, changing precipitation patterns, rise in sea level, higher storm surges, shoreline change, constant land loss, embankment breaching and changing land use, which have had impact on vulnerability, particularly of poorer people. The LVI (0.48 to 0.68) and LVI-IPCC (0.04 to 0.14) scores suggest that the populations of Dhablat, Bankimnagar, Sumatinagar, Muri Ganga and Sibpur mouzas are highly vulnerable (LVI scores of 0.60 to 0.68 and LVI-IPCC scores of 0.11 to 0.14) to climate change both because the communities are more exposed to it, and because poor access to food, health facilities and water makes them extremely sensitive to it and lowers their adaptive capacity. The findings of this study could be crucial to framing further development and adaptation strategies relating to climate change, and to safeguarding the estuarine ecosystem and the vulnerable population.

Feasibility Assessment of Distributed Generation Systems in Sagar Island, West Bengal, India

Feasibility Assessment of Distributed Generation Systems in Sagar Island, West Bengal, India

Impact of environmental factors on the dependency of litter biomass in carbon cycling of Hooghly estuary, India

Litterfall of the mangroves and its subsequent decomposition is an important mechanism in terms of productivity and nutrient cycle of that ecosystem. Present study emphasizes on the significance of litter biomass and role of environmental factors impacting this process. Mangrove litter undergoes degradation and decomposition and serves as the main source of carbon in different forms within the system, mangrove forests adjacent to the creeks at Sagar Island of the Hooghly–Matla estuarine ecosystem. This system receives a major load of carbon from adjacent mangrove forest in the form of litterfall throughout the year. Keeping in view the effect of environmental factors on litterfall and dynamics of carbon, machine learning method has been applied for this study. Different forms of carbon and environmental factors like temperature, salinity, pH, dissolved oxygen are estimated following standard procedure. Correlation, redundancy analysis and LASSO (Least Absolute Shrinkage and Selection Operator) regression are done in order to know the impact of environmental variables on carbon pool dynamics and effect of litterfall on the carbon pools in soil and water. The results reflect a strong correlation among the studied environmental factors and carbon pool dynamics. It has been revealed from the LASSO prediction results that each carbon pool is sensitive to a separate set of environmental factors.

Assessment of Nutritional Status Using Mid-Upper Arm Circumference Among Bengalee Preschool Children of Sagar Island, South 24 Parganas, West Bengal, India

Assessment of Nutritional Status Using Mid-Upper Arm Circumference Among Bengalee Preschool Children of Sagar Island, South 24 Parganas, West Bengal, India

Assessment of Nutritional Status Using Mid-Upper Arm Circumference Among Bengalee Preschool Children of Sagar Island, South 24 Parganas, West Bengal, India

Assessment of Nutritional Status Using Mid-Upper Arm Circumference Among Bengalee Preschool Children of Sagar Island, South 24 Parganas, West Bengal, India

Pollution and its consequences at Ganga Sagar mass bathing in India

Sagar Island is the largest island of Indian Sundarban, which hosts Ganga Sagar Mela (GSM). GSM is the second largest gathering (mass bathing) in India after Kumbha Mela. The total population of Sagar Island is more than 2.12 lakh. During GSM, another 20 lakh visit the island to take holy dip at the confluence of the River Ganges at Bay of Bengal. Physicochemical and bacteriological analysis of water and soil was carried out to estimate the pollution caused by this mass gathering. This is the first report addressing the relationship between the soil qualities and nearby canal water qualities during Post-GSM period regarding pollution. Study illustrates a massive change in water quality characteristics in Post-GSM period compared to the Pre-GSM condition. Results of different parameters like dissolved oxygen (DO), biological oxygen demand (BOD), nitrate, phosphate, fecal coliform and total coliform indicate extreme level of water quality degradation on the beach and canal water caused by untreated sewage, organic waste materials and fecal matters. Different parameters and water quality index indicated that pollution of beach water caused mainly due to direct discharge of enormous volume of canal water into the sea during the Post-GSM and worst water quality noticed at Sagar Canal just beside the Kapil Muni Ashram. DO, BOD and total coliform values suggest that beach water is not suitable for outdoor bathing in Post-GSM. Also, health survey indicates an increase in bacteriological diseases immediately after Post-GSM period in the nearby villagers. A real concern with sustainable management strategies can only address this issue to protect the people and the ecosystem.

Biomass fuel cell based distributed generation system for Sagar Island

Biomass fuel cell based distributed generation system for Sagar Island

Monitoring estuarine morphodynamics through quantitative techniques and GIS: A Case study in Sagar Island, India

Mapping of coastal areas, shorelines, estuarine islands are very important in order to determine the hydro dynamic and hydro meteorological behavior of coastal zone and estuarine deltaic tracts. This paper presents the spatio-temporal changes of morphological configuration of shorelines, river banks of deltaic Sagar Island situated in the mouth reaches of Hugli estuary in India. Passing through the western margin of Ganga delta the Hugli river is flowing to the Bay of Bengal in north south direction and it is dominated by strong tidal current. Being the largest island in Hugli estuary Sagar Island represent variety of inter tidal sub tidal sub-environment formed by estuarine erosional and depositional processes. The study aims to monitor and measure the quantitative changes of shorelines, island area, spatio-temporal variations of erosional and depositional processes and resultant landform assemblages by using shoreline change envelop (SCE), net shoreline movement (NSM) and end point rate (EPR). With the help of multi-temporal maps and image (District map, Police station map of 1912–29, SoI Topographical sheets 1967–69 and IRS P6 LISS IV satellite image of 2014), GIS techniques, mathematical modeling of hydro morphological parameters the present study has given a fruitful result. Measurement of shoreline dynamics clearly shows that coastal shoreline and estuarine bank line erosional processes are very active along south eastern coastal tract, south western part of Sagar Island and exposed concave river banks along the north eastern part of Sagar respectively. Finally is has found that intensity of erosion in Sagar Island is strongly controlled by estuarine exposure, sediment composition, channel flow direction, near bank channel depth, orientation of thalweg line, wave form velocity, long shore velocity, direction of longshore current, episodic cyclonic events with mean high tidal ranges and disturbance in estuarine equilibrium condition.

Invasion of Giant African Alien Land Snail &lt;I&gt;Lissachatina fulica&lt;/I&gt; (Férussac, 1821) in Sagar Island of India

The extremely high reproductive capacity of Lissachatina fulica (Férussac, 1821) caused serious effect on the local biodiversity and acts as a serious pest for agriculture, forestry and hamper the livelihood. The L. fulica from its route invasion from Kolkata has spread upto Himalayan region of India. Although, river Hooghly acts as a barrier for inland species, L. fulica now reported from the Sagar Island, most probably could be through sea transport or by human. Proper management and action plan for eradicate or control the population of L. fulica from Sagar Island is necessary for controlling further blowout of this invasive species.