Shifting shoreline of Sagar Island Delta, India
TL;DR: Shoreline mapping is extremely important in order to determine the dynamic nature of coastal areas as mentioned in this paper, where the authors presented a shoreline mapping of the Sagar Island delta, Sundarban region, India.
Abstract: 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.
Citations
More filters
TL;DR: In this paper, the authors used end point rate (EPR) and linear regression (LR) methods to calculate the change rate of the shoreline in Sagar Island, a delta of the Ganges in West Bengal, India.
Abstract: 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.
86 citations
Cites methods from "Shifting shoreline of Sagar Island ..."
...In another study, Kundu et al. (2014) carried out shoreline mapping of the Sagar Island during the period 1951–2011 using geospatial techniques....
[...]
TL;DR: In this article, the authors investigated the independent and integrated impacts of climate and land use changes using SWAT model in a part of the Narmada river basin in Madhya Pradesh, India.
85 citations
TL;DR: In this article, the authors compared the precipitation trend from the gridded rain gauge data collected by India Meteorological Department (IMD) and Multisatellite High Resolution Precipitation Products (HRPPs) for the river basins of India.
67 citations
TL;DR: In this article, the spatial distribution of vulnerability to coastal hazards within the Sundarban Biosphere Reserve (SBR) in India was examined by using the square root equation to assess the exposure risk and vulnerability of local communities inhabiting the ecologically sensitive deltaic tracts of the Sunderbans in India.
Abstract: Rising sea levels and the increasing intensity of storm surges and tropical cyclones due to climate change and the resulting dynamic shifts in shoreline positions have dramatically increased the exposure risk and vulnerability of local communities inhabiting the ecologically sensitive deltaic tracts of the Sunderbans in India. The impacts arising from such hazard events on this fragile ecosystem need to be gauged to ameliorate the lives and livelihoods of these residents. This article examines the spatial distribution of vulnerability to coastal hazards within the Sundarban Biosphere Reserve (SBR) in India. For this, we have utilized several structural and process variables, which were integrated to construct a coastal vulnerability index (CVI), using the square root equation. The coastlines of the islands located within the SBR were overlain by 543 grids, each of 2 × 2 km dimension, to assign the risk rank for each considered variable. This revealed that of the total shoreline length (754 km), nearly one-fourth was very highly vulnerable, followed by highly vulnerable (27.8%), moderately vulnerable (27.9%) and low vulnerability (18.8%). Of the total islands located in these grids (27), the coastline of eleven islands was found to have very high vulnerability, five experienced high vulnerability, eight recorded moderate vulnerability while only three had low vulnerability status. The ambient geomorphological characteristics, coastal area slope, the rate of shoreline change and sea level rise were significant variables that accorded high and very high vulnerability to the islands. The CVI helped in identifying islands that require immediate attention for lessening the impact of climate change induced hazards in the SBR and also aided the assessment of the physical and coastal vulnerability conditions of these islands. This approach can be effectively utilized for assessing coastal vulnerability and for creating a holistic approach towards coastal conservation and management.
54 citations
TL;DR: In this paper, the authors used the Revised Universal Soil Loss Equation (RUSLE) model to analyze the assessment of soil erosion uncertainty using open source digital elevation models (SRTM, ASTER and CARTOSAT) and their increasing grid space (pixel size) from the actual.
Abstract: Digital Elevation Model (DEM) is one of the important parameters for soil erosion assessment. Notable uncertainties are observed in this study while using three high resolution open source DEMs. The Revised Universal Soil Loss Equation (RUSLE) model has been applied to analysis the assessment of soil erosion uncertainty using open source DEMs (SRTM, ASTER and CARTOSAT) and their increasing grid space (pixel size) from the actual. The study area is a part of the Narmada river basin in Madhya Pradesh state, which is located in the central part of India and the area covered 20,558 km2. The actual resolution of DEMs is 30 m and their increasing grid spaces are taken as 90, 150, 210, 270 and 330 m for this study. Vertical accuracy of DEMs has been assessed using actual heights of the sample points that have been taken considering planimetric survey based map (toposheet). Elevations of DEMs are converted to the same vertical datum from WGS 84 to MSL (Mean Sea Level), before the accuracy assessment and modelling. Results indicate that the accuracy of the SRTM DEM with the RMSE of 13.31, 14.51, and 18.19 m in 30, 150 and 330 m resolution respectively, is better than the ASTER and the CARTOSAT DEMs. When the grid space of the DEMs increases, the accuracy of the elevation and calculated soil erosion decreases. This study presents a potential uncertainty introduced by open source high resolution DEMs in the accuracy of the soil erosion assessment models. The research provides an analysis of errors in selecting DEMs using the original and increased grid space for soil erosion modelling.
52 citations
References
More filters
TL;DR: This article showed that 10,000-13,500 km2 of the Mississippi Delta could be submerged by AD 2100 due to global sea-level rise, reduced sediment supply and subsidence.
Abstract: Global sea-level rise, reduced sediment supply and subsidence threaten the stability of the Mississippi Delta. Calculations of riverine sediment load and storage indicate that 10,000–13,500 km2 of the delta could be submerged by AD 2100.
861 citations
"Shifting shoreline of Sagar Island ..." refers methods in this paper
...Work on the delta shoreline detection has also been performed for the Mississippi delta by Coleman, Huh, and Braud (2008) and Blum and Roberts (2009)....
[...]
01 Feb 2006
TL;DR: In this paper, the authors made an assessment of contemporary effective sea-level rise (ESLR) for a sample of 40 deltas distributed worldwide and found that direct anthropogenic effects determine ESLR in the majority of the studied, with a relatively less important role for eustatic sea level rise.
Abstract: An assessment is made of contemporary effective sea-level rise (ESLR) for a sample of 40 deltas distributed worldwide. For any delta, ESLR is a net rate, defined by the combination of eustatic sea-level rise, the natural gross rate of fluvial sediment deposition and subsidence, and accelerated subsidence due to groundwater and hydrocarbon extraction. ESLR is estimated under present conditions using a digital data set of delta boundaries and a simple model of delta dynamics. The deltas in this study represent all major climate zones, levels of population density, and degrees of economic development. Collectively, the sampled deltas serve as the endpoint for river basins draining 30% of the Earth's landmass, and 42% of global terrestrial runoff. Nearly 300 million people inhabit these deltas. For the contemporary baseline, ESLR estimates range from 0.5 to 12.5 mm yr −1 . Decreased accretion of fluvial sediment resulting from upstream siltation of artificial impoundments and consumptive losses of runoff from irrigation are the primary determinants of ESLR in nearly 70% of the deltas. Approximately 20% of the deltas show accelerated subsidence, while only 12% show eustatic sea-level rise as the predominant effect. Extrapolating contemporary rates of ESLR through 2050 reveals that 8.7 million people and 28,000 km 2 of deltaic area in the sample set of deltas could suffer from enhanced inundation and increased coastal erosion. The population and area inundated rise significantly when considering increased flood risk due to storm surge. This study finds that direct anthropogenic effects determine ESLR in the majority of deltas studied, with a relatively less important role for eustatic sea-level rise. Serious challenges to human occupancy of deltaic regions worldwide are thus conveyed by factors which to date have been studied less comprehensively than the climate change–sea-level rise question. © 2005 Elsevier B.V. All rights reserved.
754 citations
"Shifting shoreline of Sagar Island ..." refers background in this paper
...Change in local sea level is considered one of the major contributors to the change in shorelines (Ericson et al., 2006; Syvitski & Saito, # 2014 Sananda Kundu ∗Corresponding author....
[...]
01 Jun 2007
TL;DR: In this article, a consistent database was established to characterize key environmental factors known to control delta morphology, including the location, basin morphology, fluvial and sediment discharge to the deltas, delta morphology and ocean energy, and shelf depth reached by the subaqueous delta.
Abstract: A consistent database was established to characterize key environmental factors known to control delta morphology. The database includes the location, basin morphology, fluvial and sediment discharge to the deltas, delta morphology, ocean energy, and shelf depth reached by the sub-aqueous delta. Fifty-one deltas were selected to cover the global parameter range of rivers entering all major oceans and coastal seas. Seasonal satellite images of the deltas were processed (IKONOS, SPOT, LANDSAT, and MODIS). Predictive statistical relationships were obtained, suitable for hypothesis testing or to constrain/verify numerical models used to simulate the evolution of coastal systems. The area of a delta is best predicted from average discharge, the total sediment load feeding the delta, and the offshore accommodation space. The gradient of a delta plain, measured from the apex of the delta to the coast along the main channel, is best predicted with a ratio of sediment supply to sediment retention, sediment concentration used as a proxy of delta plain sedimentation, and mean water discharge. Widths of distributary channels form a lognormal distribution, with the cumulative width of the river mouths directly related to the maximum discharge, tidal and wave energy. The grain size of topset deposits scales with the river length. Hundreds of millions of people occupy deltas and human engineering is now a major influence on the growth and evolution of many deltas, through control of the flow path of distributary channels, and mitigation of the seasonal flood wave with concomitant change in the delivery of sediment load. More and more deltas are moving away from their pre-Anthropocene morphology, as influenced by pristine sediment supply and sediment dispersal.
590 citations
TL;DR: In this article, a supervised classification was applied to four Landsat images collected over time (1984, 1999, 2005, and 2009) that provided recent and historical LULC conditions for the western Nile delta.
321 citations
TL;DR: In this article, a cost-effective methodology involving satellite remote sensing images and statistics has been discussed, where multidimensional satellite images have been used to demarcate shoreline positions, from which shoreline change rates have been estimated using linear regression.
296 citations
"Shifting shoreline of Sagar Island ..." refers background in this paper
...Automatic shoreline extraction is complex because of the presence of the saturated water zone near the coast or land and water boundary (Maiti & Bhattacharya, 2009)....
[...]