Geospatial analysis of short term shoreline change behavior between Subarnarekha and Rasulpur estuary, east coast of India using intelligent techniques (DSAS)

A geospatial analysis of shoreline change pattern is most significant parameter to understand the behavioral interaction between land and sea water. Geospatial analyses using various statistical and quantitative methods which are more applicable, accurate and dependable to measures the spatio-temporal trend of erosion accretion and estimate the change rate of shoreline. Remote sensing and GIS techniques have been used for the identification of shoreline change over the various time scales. To identify the rate Digital Shoreline Analysis System (DSAS) was applied in the current research. The present study aimed to identify the trend of coastal erosion accretion during 43 years (1975–2018) which is divided into four short term period (1975–1988, 1988–2000, 2000–2010 and 2010–2018) between the coastal stretch of Subarnarekha and Rasulpur estuary along Bay of Bengal using multi temporal satellite images. The accurate shoreline position has been delineated by the histogram threshold method using the images of Landsat Multi Spectral Scanner, Thematic Mapper and Enhanced Thematic Mapper. The shoreline change rate has been calculated based on cast transect method through some statistical techniques such as End Point Rate (EPR) and Net Shoreline Movement (NSM) in GIS application. 70.42 km long coastal stretch along Bay of Bengal has been divided into three littoral zones (LZ) to analyze the shoreline shifting on a zone basis. From the analysis it has been observed that maximum erosion occurred between 1988 and 2000 time period in all zones. The result shows that highest rate of net shoreline movement has been found in LZ I (− 1715.71 m) in 1975–1988 and LZ III (− 1719.65 m) in 2000–2010 at Subarnarekha estuary and Junput respectively. The present study reveals that most of the accretive formation is observed in 2000–2010 and 2010–2018. Major accretion is identified in the southern part of Subarnarekha estuary, 23.93 m/year in EPR method. Maximum shades of changes was experienced in LZ I, especially in Subarnarekha estuary area. In the time span of 1975–1988 this area faced the highest erosion and highest accretion with the rate of − 78.54 m/year and 23.93 m/year respectively through EPR method. During 1988–2000, − 37.35 m/year erosional rate was found in the Subarnarekha estuary. The highest erosional rate was − 8.48 m/year in Beguran Jalpai during 1988–2000 by EPR. The maximum rate of accretion has been noticed as 7.7 m/year in LZ II in the time period of 2010–2018.