Sagar Island Research Articles

Very High Prevalence of Thinness Among Rural Bengalee Preschool Children of Integrated Child Development Service (ICDS) Scheme of Sagar Island, South 24 Parganas, West Bengal, India

Very High Prevalence of Thinness Among Rural Bengalee Preschool Children of Integrated Child Development Service (ICDS) Scheme of Sagar Island, South 24 Parganas, West Bengal, India

Study on the Impact of Grid Electricity in Powering the Expansion of Healthcare Services and Facilities in Sagar Island

Sagar Island, also known as 'Gangasagar' in commoners' parlance is one of the populous islands that falls under the Sundarban Biosphere Reserve in the State of West Bengal. The Island articulates the faith and sentiments of teeming billions of this country in a transcendental and sublime manner since time immemorial. Despite the age-old religious and cultural connotations, the island's socio-economic growth was contained to a certain extent due to non-availability of grid electricity. Islanders had to depend primarily on energy supplied in an intermittent manner through solar photovoltaic cells, diesel generator sets, kerosene-fed implements used for illumination or otherwise along with fuelwood. Situation in Sagar Island had started changing dramatically from 2012 onwards with the rolling out of 100 per cent household electrification programme under 'Integrated Coastal Zone Management Project.' Resonance of grid electricity is palpable cutting across all geographic, social and economic heterogeneities in Sagar Island. The execution of the entire component did have a kaleidoscopic impact through spurting of multiple socio-economic activities in Sagar Island. The present paper deliberates on the impact of grid electricity vis-a-vis the improvements that have taken place with respect to healthcare services and facilities in Sagar Island. The study shows that the initiatives, that are propelled either due to distribution of grid electricity through government-owned healthcare centres or through private healthcare enterprises, are quite impressive. Quantitative and qualitative assessments of 17 units, instrumental in providing healthcare services and facilities of varied nature in Sagar Island, have proved beyond doubt that grid electricity is not only a demand-driven project initiative whence it was conceived but in real terms is a game-changer that accelerates the pace of sustainable development.

Body Composition among Rural Bengalee Preschool Children of Integrated Child Development Service (ICDS) Scheme of Sagar Island, South 24 Parganas, West Bengal, India

The present study was carried out to studyage and sex variations in body composition characteristics among preschool children of Integrated Child Development Service (ICDS) Scheme from Sagar Island...

Climate change vulnerability to agrarian ecosystem of small Island: evidence from Sagar Island, India

The present study assessed climate change vulnerability in agricultural sector of low-lying Sagar Island of Bay of Bengal. Vulnerability indices were estimated using spatially aggregated biophysical and socio-economic parameters by applying principal component analysis and equal weight method. The similarities and differences of outputs of these two methods were analysed across the island. From the integration of outputs and based on the severity of vulnerability, explicit vulnerable zones were demarcated spatially. Results revealed that life subsistence agriculture in 11.8% geographical area (2829 ha) of the island along the western coast falls under very high vulnerable zone (VHVZ VI of 84–99%) to climate change. Comparatively higher values of exposure (0.53 ± 0.26) and sensitivity (0.78 ± 0.14) subindices affirmed that the VHV zone is highly exposed to climate stressor with very low adaptive capacity (ADI= 0.24 ± 0.16) to combat vulnerability to climate change. Hence, food security for a population of >22 thousands comprising >3.7 thousand agrarian households are highly exposed to climate change. Another 17% area comprising 17.5% population covering 20% villages in north-western and eastern parts of the island also falls under high vulnerable (VI= 61%–77%) zone. Findings revealed large spatial heterogeneity in the degree of vulnerability across the island and thus, demands devising area specific planning (adaptation and mitigation strategies) to address the climate change impact implications both at macro and micro levels.

Concentrations of Heavy Metals in Edible Dominant Oyster (Saccostreacucullata) Inhabiting Sagar Island, West Bengal

The heavy metals from the ambient environment enter the tissues of marine molluscs very frequently as they feed on the plankton of marine and estuarine water. Sagar island, situated in the northeast coast of Bay of Bengal, is the habitat of three major species of oysters namely Saccostrea cucullata, Crassostrea cuttackensis and Crassostrea madrasensis. By virtue of their sedentary nature, these species are exposed to all categories of pollutants, which have put them in the domain of indicator species. In this present paper, the concentrations of zinc, copper and lead were assessed in Saccostrea cucullata inhabiting Sagar island, Indian Sundarbans. A unique seasonal variation is observed in the accumulation of the selected heavy metals. A more detailed study is needed to establish the species as indicator of heavy metals.

Detecting shoreline changing trends using principle component analysis in Sagar Island, West Bengal, India

Sagar coastline is a major attraction site for tourist and also source of income for the local peoples. However shoreline has been changing due to erosion. The shoreline position is difficult to predict but the trend of erosion or accretion can be determinate by statistical techniques. The study aims to assess the shoreline changes and prediction in Sagar Island, a delta of Ganges, situated in West Bengal, India. This study sought to find the trend of shoreline changes and factors. Shoreline can be detected by using PCA and non-directional edge techniques from Landsat images. The shoreline mapping of Sagar Island during (1975–2015) using geospatial techniques. The present study focuses the shoreline change and in future prediction from satellite derived multi-temporal Landsat MSS, Landsat TM, Landsat ETM+, Landsat OLI data using GIS; it is used to determinate or to estimate the change rate of shoreline in Sagar Island by End Point Rate, and Linear Regression models.

Study on Sustainable Hybrid Off-grid Power Supply System for Isolated Sagar Island

This paper deals with the feasibility study of Solar-Wind hybrid system of generation of electrical energy for Sagar Island. To study the prospect of a hybrid system of electrical energy generation, a MATLAB/Simulink model of Lanco Solar LSP 250-260M-60 and BWC XL.1 wind turbine based hybrid system has been built and study the feasibility with the help of Solar irradiance, wind speed and load data of a particular location of Sagar Island. The constraint due to the environment, grid-connected electrical energy supplying to the Sagar Island is cost effective and difficult to implement. At the present diesel and kerosene engine is the only option to generate electrical energy and mitigate the electrical load demand of Sagar Island. As the non-renewable source of energy diminishes day by day and it produces harmful Greenhouse Gases during the generation of electricity, researchers have a prime interest in renewable energy sources which does not produce harmful gases during the generation of electricity and save our environment. So far research has been carried out on the Solar Photovoltaic (SPV) system for the electrification of Sagar Island. Electricity generated from only Solar PV array is not reliable and not cost effective because of the availability of the solar energy all the year. Hence, in this paper, an attempt has been made to compensate the electrical energy requirement of Sagar Island through a solar wind hybrid system of power generation with the practical data of Sagar Island, obtain from NASA and Ministry of Non-conventional Energy sources. The analysis shows that the hybrid system of solar and the wind are much more reliable and cost effective compared to single units of SPV system. Beside them, the environmental effect related to Greenhouse Gases (GHG) also estimated and compared with the diesel engine generated electrical energy.

Soil organic carbon stock explored by geo-spatial modeling at Sagar Island, India

Soil organic carbon (SOC) and organic carbon density (OCD) is an active indicator of soil fertility and productivity, and it fluctuates spatially and temporally. The main objective of the present study is to evaluate the spatial variability of SOC and OCD using geostatistics model as well as field methods at Sagar Island (Sundarban), India. Soil samples at the depths of 0–20 cm were collected from twenty plots at different season to estimate organic carbon concentrations and carbon density in the laboratory. Spatial distributions of SOC and OCD concentrations were estimated using ordinary kriging method. Remote sensing imagery and ground truth helped in identifying different features as well as land use/land cover correctly. Landuse are characterized by coastal water, sand, coastal wetland, salt marsh, agricultural fallow land, sparse vegetation, crop/paddy field, and mixed settlement area. The average value SOC were recorded as 2.80, 1.83, and 2.069 % in post-monsoon, pre-monsoon and monsoon season respectively. Semivariograms models of SOC and OCD in all seasons illustrated strong positive nugget values indicated short scale variability and sampling error. The coefficient of determination (R2) of the SOC model denoted as 0.71, 0.68 and 0.74 and for OCD calculated as 0.78, 0.67 and 0.83 at pre-monsoon, monsoon and post-monsoon season respectively. The results illustrated that mangrove forest portrayed highest amount of SOC concentration in both the pre-monsoon (1.05 kg/m2) and post-monsoon (0.94 kg/m2) season.

Disappearance of the New Moore Island from the Southernmost Coastal Fringe of the Sundarban Delta - A Case Study

Loss of two small estuarine islands, Lohachara and Suparibhanga has been reported earlier from the Indian Sundarban lying adjacent to the northern Bay of Bengal. The present paper reports the loss of another offshore island, New Moore, popularly known as Purbasha at the border of India and Bangladesh. The island came into existence after a cyclone in 1970. This study reveals the loss of New Moore Island within the time period of 1985 to 2000 from the analysis of multi-temporal satellite images. The rate of erosion, of two other offshore islands, Jambu Dwip (0.187 sq. km yr.−1) and Maya Dwip (0.508 sq. km yr.−1) situated along the same latitude of New Moore, were also estimated within the same time period. A close relationship was observed between the rate of erosion of small islands and the rate of rising sea level in this region as measured from the tide data at the Sagar Island and other observatories during the study period. The sea surface temperature analysis from the year 1990 to 1998 showed a slight increase (~ 0.8 °C increase), indicating the thermal expansion of the sea surface. Moreover, the sea surface height analyzed during the period 1993–2000 using satellite altimeter data of TOPEX/POSEIDON revealed a steady increase of 1.23 cm yr.−1 sea level acceleration.

Shoreline shifting and its prediction using remote sensing and GIS techniques: a case study of Sagar Island, West Bengal (India)

The shoreline position is difficult to predict but the trend of erosion or accretion can be determined by geospatial and statistical techniques which may help in reducing the loss of property. The study aims to assess the shoreline changes and prediction in Sagar Island, a delta of the Ganges, situated in West Bengal, India. Shorelines have been delineated by using Tasseled Cap Transformation techniques from the Landsat MSS (1975), Landsat TM (1989, 1991) and Landsat ETM+ (1999, 2002, 2005, 2008, and 2011) images. The uncertainty was calculated for every year for assessing the positional error related to shoreline extraction. Total shoreline change rate/year has also been calculated and the uncertainty of total shoreline change rate was found ±3.20 m/year. In the present study, End Point Rate (EPR) and Linear Regression (LR) methods have been used for shoreline change rate calculation and prediction of shoreline. Long term (1975–2002) and short term (2002–2011) erosion and accretion rates were calculated for the study area. Sagar is the biggest island of the Sundarban region; so, it was divided into three segments in order to analyze the change on a segment basis. It was observed that the most of erosion occurred in the Segment B (south Sagar). The rate of erosion was −7.91 and −7.01 m/year for the periods 1975–2002 and 2002–2011 respectively. The mean shoreline change rate was high in Segment B (South Sagar) with values of −6.46 m/year (1975–2002) but the rate was decreased into −5.25 m/year during the later period (2002–2011). The study reveals that most of the southern part of Sagar Island is vulnerable to high rate of shoreline erosion.

Tidal Analysis and Prediction for the Gangra Location, Hooghly Estuary in the Bay of Bengal

The Hooghly estuary located in the head Bay of Bengal region is a part of the highly dynamic deltaic environment. Tidal variations are pre-dominant in this estuary, and tides propagate considerable distance through a complex network of various riverine systems, inlets, bays and creeks having vital implications on water mass exchange, reworking of deltaic sediments and the mixing process. The Hooghly River houses two major ports of national importance, viz. Kolkata Dock System and Haldia Dock Complex. Tidal forcing is primarily semi-diurnal in nature and with the presence of complex riverine morphology, the tidal characteristics are substantially modified causing various tidal constituents of compound tides. The present study performs location-specific tidal analysis and prediction utilizing one-hourly tide data with SLPR2 harmonic tidal analysis tool for Gangra situated upstream of the Hooghly River. In a geomorphologic perspective, the water-level elevation at Gangra results from natural tidal flow, as well as refracted effects from cross-flow due to the presence of two natural island barriers, namely Sagar Island situated southward off Gangra and Nayachara in the east. The Hooghly channel comprises of complex bathymetric features and tidal analysis at Gangra reveals the presence of Msf (luni-solar synodic fortnightly) tidal constituent. Very few locations in India have reported on the existence of the Msf tides, and Gangra is one among them. This study also performs a comprehensive validation between the computed monthly tidal prediction from SLPR2 and measured water level at Gangra. The skill level of prediction exhibits a good match. This study also investigates the influence of atmospheric effects on sea-level pressure variations and the resultant water-level elevation from extreme weather events such as depressions and severe cyclonic storms that occurred during 2013. The study signifies the importance of tidal analysis and prediction for operational needs.

Human-induced ecological changes in western part of Indian Sundarban megadelta: A threat to ecosystem stability

The study first illustrates a comprehensive account of large-scale changes in water quality characteristics and plankton community structure due to occurrence of Annual Gangasagar Festival (AGF) at Sagar Island, western part of Indian Sundarban megadelta for 3-year duration (2012–2014; n=36). About 1 million pilgrims across India converge to take their holy bath at the confluence of Hooghly estuary and Bay of Bengal during January each year. This mass scale bathing results negative impact on water quality due to high turbidity (14.02±2.34 NTU) coupled with low chlorophyll a (1.02±0.21mgm−3) and dissolved oxygen (3.94±1.1mgl−1). A marked decrease in abundance (from 4140 to 2997cellsl−1) and diversity (H′=2.72–1.33) of phytoplankton and microzooplankton tintinnids (from 450 to 328 ind l−1; H′=4.31–2.21) was recorded. The festival acts as multiple stressors modifying natural functions of the delta. Sound and sustainable management strategies are to be adopted to maintain the protection-usage equilibrium.

Variations in Primary Sedimentary Structures along a coastal profile: Gangasagar, Sagar Island, West Bengal

Variations in Primary Sedimentary Structures along a coastal profile: Gangasagar, Sagar Island, West Bengal

Monsoon variability, crop water requirement, and crop planning for kharif rice in Sagar Island, India.

In the Sagar Island of Bay of Bengal, rainfed lowland rice is the major crop, grown solely depending on erratic distribution of southwest monsoon (SM) rainfall. Lack of information on SM rainfall variability and absence of crop scheduling accordingly results in frequent occurrence of intermittent water stress and occasional crop failure. In the present study, we analyzed long period (1982-2010) SM rainfall behavior (onset, withdrawal, rainfall and wetness indices, dry and wet spells), crop water requirement (CWR, by Food and Agriculture Organization (FAO) 56), and probability of weekly rainfall occurrence (by two-parameter gamma distribution) to assess the variability and impact on water availability, CWR, and rice productivity. Finally, crop planning was suggested to overcome monsoon uncertainties on water availability and rice productivity. Study revealed that the normal onset and withdrawal weeks for SM rainfall were 22nd ± 1 and 43rd ± 2 meteorological weeks (MW), respectively. However, effective monsoon rainfall started at 24th MW (rainfall 92.7 mm, p > 56.7 % for 50 mm rainfall) and was terminated by the end of 40th MW (rainfall 90.7 mm, p < 59.6 % for 50 mm rainfall). During crop growth periods (seed to seed, 21st to 45th MW), the island received an average weekly rainfall of 65.1 ± 25.9 mm, while the corresponding weekly CWR was 47.8 ± 5.4 mm. Despite net water surplus of 353.9 mm during crop growth periods, there was a deficit of 159.5 mm water during MW of 18-23 (seedling raising) and MW of 41-45 (flowering to maturity stages). Water stress was observed in early lag vegetative stage of crop growth (32nd MW). The total dry spell frequency during panicle initiation and heading stage was computed as 40 of which 6 dry spells were >7 days in duration and reflected a significant (p < 0.05) increasing trend (at 0.22 days year(-1)) over the years (1982-2010). The present study highlights the adaptive capacity of crop planning including abiotic stress-tolerant cultivars to monsoon rainfall variability for sustaining rainfed rice production vis-à-vis food and livelihood security in vulnerable islands of coastal ecosystem.

Evolution of an Alluvial Tidal Creek – A Case Study

The Bhagirathi-Hugli, a major distributor of the Ganga river, traverses a distance of about 550km in the state of West Bengal, India and falls into the Bay of Bengal. The river is the principle drainage artery of the state, and together with its tributaries forms one of the major river systems in the Indo-Gangetic Delta. The river is non- tidal for about 231km and tidal over the remaining 319km. In the tidal part, again, the estuarine portion, i.e. about 180km from Diamond Harbour downwards is very much dominated by tides and waves.The Hugli estuary has braided itself into a number of channels in its estuarine part where it has fanned in an exponential manner. The estuary is dynamically very much active and complicated because of its continued evolutionary changes. A number of islands and submerged sand –bodies within the flow system create the total flow phenomenon complicated and continually changing. It is observed over a short period that a number of islands and sand- bodies disappeared such as Bedford sand and new ones are coming up at different places where the physico-chemical environments are favouring for their formation. The Sagar island is the largest island at the mouth of the Hugli estuary, dividing the total flow into two parts- the major portion flows along the western part leading to Haldia Dock Complex and Kolkata Dock System and minor one flows along the eastern part which is popularly known as the Muriganga river or the Channel Creek. From hydrological observations, it was observed that about 20%-25% of total flows (Flood+ Ebb) would flow along this channel in early nineties but very recent morphological development clearly depicts that a number of submerged sand bodies have developed alarmingly resulting in a drastic fall of capacity of the channel and a reduction of flows to about 8%-10% of the total flows within a span of about 20 years. This channel has its own importance not only due to serving as the main water way connecting Sagar island with main land but also it plays a very important role in this dynamic estuary. For decades, this channel has undergone many changes, and this changing pattern has been studied using Remote Sensing and Geographical Information System (GIS). Change Detection Study has been made using supervised classification of yearly satellite imagery. The ground- truth has been acquired by extensive survey works using HYPACK software and by conventional survey method. All these studies lead to reveal the fact that the entire tidal creek, i.e. Creek Channel area is shoaling alarmingly. From the satellite image analysis, growth of several sand bars of this channel are detected. The total areas of zero-contours are increasing very rapidly, and these are clearly indicated by the infamous phenomenon of sedimentation in the main connecting waterways between Sagar Island and main land i.e. Kachuberia and Lot-8, a lot of bars generated in this very important waterways causing blockage of both the flood and ebb flows in this channel. This phenomenon casts adverse effects in (a) total flow of the main Hugli estuarine regime (b) navigation within Creek (c) drainage in the surroundings and also (d) in the flow –dynamics of the adjacent creek, i.e. Hatania-Doania river.If the present trend of sedimentation in this tidal creek continues, it is apprehended that within few decades it will be silted up.

Utilization of Carbon in NPZ Model of Hooghly Estuarine System, India

Hooghly estuary along with the luxurious mangroves of the Sundarbans is one of the important estuaries of India. A quite rich mangrove patch in association with the creeks is visible at Sagar Island, the largest island in the row. Degradation and leaching of litter provides nutrient for the growth and development of phytoplankton which in turn strengthens the grazing food chain from zooplankton to fish. Phytoplankton growth is influenced by solar radiation, nutrient and temperature. The model incorporates light acclimation by algae, self-shading, photosynthetic production and nutrient uptake. Water quality changes with seasons. The model uses the functional relations among the three state variables as observed in response to the changeable environment throughout the year there. The model is calibrated and validated taking carbon as the currency of the model. Dissolved inorganic carbon as nutrient, water temperature, surface solar irradiance, and salinity of upstream and downstream of the estuary are collected from the field. Model results indicate that the growth of zooplankton and phytoplankton are enhanced by increasing nutrient input in the system. The predicted temporal distribution and trends of plankton biomass, inorganic carbon is in general agreement with field observations. Sensitivity analysis has been done. The model captures the dynamics of plankton population, which serve as major food source for fish species of the estuary. This model could be predictive in search for the role of mangrove in estuary and its control on nutrient and plankton dynamics of this region which will be helpful in management aspect.

Impact of Environmental Factors on the Carbon Dynamics at Hooghly Estuarine Region

Degradation of litter from mangrove forests adjacent to the creeks at Sagar Island of the Hooghly-Matla estuarine ecosystem is one of the principal sources of nutrient to the estuary. 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 factor on the dynamics of carbon is studied through multivariate statistics. Essential environmental variables like soil carbon, dissolved carbon, temperature, salinity, pH, and dissolved oxygen are analyzed following standard protocol. Multivariate statistical analyses like correlation, regression, and centered PCA ordination are done in order to know the impact of environmental variables on carbon dynamics. The results reflect a close intercorrelation among the studied environmental variables and carbon. It also emphasizes the fact that soil and water temperature, and dissolved oxygen affect soil carbon dynamics, whereas salinity and pH of soil and water greatly regulate dissolved carbon dynamics. The variance pattern of these studied variables through seasons is also enumerated by PCA ordination studies.

Estimation and prediction of maximum daily rainfall at Sagar Island using best fit probability models

Sagar Island, setting on the continental shelf of Bay of Bengal, is one of the most vulnerable deltas to the occurrence of extreme rainfall-driven climatic hazards. Information on probability of occurrence of maximum daily rainfall will be useful in devising risk management for sustaining rainfed agrarian economy vis-a-vis food and livelihood security. Using six probability distribution models and long-term (1982–2010) daily rainfall data, we studied the probability of occurrence of annual, seasonal and monthly maximum daily rainfall (MDR) in the island. To select the best fit distribution models for annual, seasonal and monthly time series based on maximum rank with minimum value of test statistics, three statistical goodness of fit tests, viz. Kolmogorove–Smirnov test (K-S), Anderson Darling test (A 2 ) and Chi-Square test (X 2) were employed. The fourth probability distribution was identified from the highest overall score obtained from the three goodness of fit tests. Results revealed that normal probability distribution was best fitted for annual, post-monsoon and summer seasons MDR, while Lognormal, Weibull and Pearson 5 were best fitted for pre-monsoon, monsoon and winter seasons, respectively. The estimated annual MDR were 50, 69, 86, 106 and 114 mm for return periods of 2, 5, 10, 20 and 25 years, respectively. The probability of getting an annual MDR of >50, >100, >150, >200 and >250 mm were estimated as 99, 85, 40, 12 and 03 % level of exceedance, respectively. The monsoon, summer and winter seasons exhibited comparatively higher probabilities (78 to 85 %) for MDR of >100 mm and moderate probabilities (37 to 46 %) for >150 mm. For different recurrence intervals, the percent probability of MDR varied widely across intra- and inter-annual periods. In the island, rainfall anomaly can pose a climatic threat to the sustainability of agricultural production and thus needs adequate adaptation and mitigation measures.

Impact of multispecies diatom bloom on plankton community structure in Sundarban mangrove wetland, India

A multispecies bloom caused by the centric diatoms, viz. Coscinodiscus radiatus, Chaetoceros lorenzianus and the pennate diatom Thalassiothrix frauenfeldii was investigated in the context of its impact on phytoplankton and microzooplankton (the loricate ciliate tintinnids) in the coastal regions of Sagar Island, the western part of Sundarban mangrove wetland, India. Both number (15–18 species) and cell densities (12.3×103cellsl−1 to 11.4×105cellsl−1) of phytoplankton species increased during peak bloom phase, exhibiting moderately high species diversity (H′=2.86), richness (R′=6.38) and evenness (E′=0.80). The diatom bloom, which existed for a week, had a negative impact on the tintinnid community in terms of drastic changes in species diversity index (1.09–0.004) and population density (582.5×103 to 50×103indm−3). The bloom is suggested to have been driven by the aquaculture activities and river effluents resulting high nutrient concentrations in this region. An attempt has been made to correlate the satellite remote sensing-derived information to the bloom conditions. MODIS-Aqua derived chlorophyll maps have been interpreted.

Shifting shoreline of Sagar Island Delta, India

Shoreline mapping is extremely important in order to determine the dynamic nature of coastal areas. This paper presents shoreline mapping of the Sagar Island delta, Sundarban region, India. The island is part of mangrove ecosystem and is facing constant erosion and deposition from tidal action and cyclonic storms which have made this an area of unique importance. Mapping of shoreline has been performed 1951 to 2011 and change in the land-water boundary of the island calculated. Further shoreline prediction is performed on the basis of the extracted shorelines using the End point Rate model with a micro-level grid-based approach. The predicted maps have been validated using ground control points. Three images from 1951, 1990 and 2011 have been used for the mapping and detection of changes in the island area and shoreline over 60 years.