This study aims to assess the vulnerable zone of embankment breaching in Gosaba Island using geospatial and quantitative techniques. In this study, multi-temporal Landsat data from 1972 to 2017 were used for delineating shoreline change rate, net shoreline movement (NSM), erosion and accretion area and net areal change for each Gram Panchayats (GP) of the island. The shoreline change rate was calculated using end point rate (EPR) for each GP, and the uncertainty of the shoreline change rate was adjusted by measuring the positional error (± 3.58 m yr⁻¹). Near about, 704.39 ha of lands in Gosaba Island was highly erosion-prone and almost 303.33 ha of lands was completely washed out in the last 45 years. Gosaba (63.35 ha), Kumirmari (58.09 ha), Bally I (66.82 ha), Bally II (16.29 ha), Lahiripur (51.80 ha) and Satjelia GP (52.98 ha) were facing intensive land loss during 1972–2017. For validation of the result, a rigorous field survey during 2017–2018 was conducted and different forms of riverbank erosion were identified and presented in this study. Besides, GP-wise coastal vulnerability was delineated using three parameters, such as EPR, NSM and area under erosion. The statistical analysis revealed that the southern and eastern parts were highly vulnerable to coastal erosion as compared to the northern part of the island. The temporal tidal fluctuations of Sundarbans’ rivers also influence the intensity of coastal erosion. Therefore, the construction and management of embankment in this part of the island is highly challenging and needs a proper strategic framework for the longevity of the embankment. The present research work also suggests some planning measures for the protection of embankments. This research study may help to understand the degree of spatial vulnerability of Gosaba Island to erosion hazards and also encourage coastal planners for strategic planning of coastal zone management and its implementation for better resilience of the island against environmental extremes.

本研究旨在使用地理空间和定量技术评估 Gosaba 岛堤防破坏的脆弱区域。在这项研究中，1972 年至 2017 年的多时陆地卫星数据用于描绘该岛每个 Gram Panchayats (GP) 的海岸线变化率、净海岸线运动 (NSM)、侵蚀和吸积面积以及净面积变化。使用每个GP的终点率（EPR）计算海岸线变化率，并通过测量位置误差（± 3.58 m yr ^-1）。在过去的 45 年中，Gosaba 岛大约有 704.39 公顷的土地高度易受侵蚀，近 303.33 公顷的土地被完全冲刷干净。Gosaba（63.35 公顷）、Kumirmari（58.09 公顷）、Bally I（66.82 公顷）、Bally II（16.29 公顷）、Lahiripur（51.80 公顷）和 Satjelia GP（52.98 公顷）在 1972-2017 年期间面临严重的土地流失。为了验证结果，在 2017-2018 年期间进行了严格的实地调查，并在本研究中确定并呈现了不同形式的河岸侵蚀。此外，使用三个参数，如 EPR、NSM 和侵蚀面积，描绘了 GP-wise 海岸脆弱性。统计分析显示，与岛屿北部相比，南部和东部地区极易受到海岸侵蚀的影响。孙德尔本斯河流的时间潮汐波动也会影响海岸侵蚀的强度。因此，岛内这一部分路堤的建设和管理具有很高的挑战性，需要一个适当的战略框架来延长路堤的寿命。目前的研究工作还提出了一些保护路堤的规划措施。这项研究可能有助于了解戈萨巴岛对侵蚀灾害的空间脆弱性程度，并鼓励沿海规划者对沿海地区管理及其实施进行战略规划，以提高岛屿抵御极端环境的能力。岛上这一部分的堤防建设和管理极具挑战性，需要一个适当的战略框架来延长堤防的寿命。目前的研究工作还提出了一些保护路堤的规划措施。这项研究可能有助于了解戈萨巴岛对侵蚀灾害的空间脆弱性程度，并鼓励沿海规划者对沿海地区管理及其实施进行战略规划，以提高岛屿抵御极端环境的能力。岛上这一部分的堤防建设和管理极具挑战性，需要一个适当的战略框架来延长堤防的寿命。目前的研究工作还提出了一些保护路堤的规划措施。这项研究可能有助于了解戈萨巴岛对侵蚀灾害的空间脆弱性程度，并鼓励沿海规划者对沿海地区管理及其实施进行战略规划，以提高岛屿抵御极端环境的能力。