摘要:Ghoramara island is situated at 18.36 nautical miles away from Haldia dock in Hooghly estuary, Eastern India. It is a rhombic shaped island covering an area of around 4.8 km² with a total shoreline length of 8.5 kms. This sparingly populated sensitive ecosystem is rapidly changing its morphology due to extensive coastal erosion on the northwestern coast and marginal accretion on the southeastern side. The degradation of the system due to natural and anthropogenic causes leads to the total areal reduction of the island. There is a major loss of agricultural land and fisheries. The two islands Lohachara and Supribhanga lying to the southwest of Ghoramara have already been submerged. The vulnerability and stability of the island is the major fear of the inhabitants. In the present study, multi-resolution and multi-temporal satellite images of Landsat have been utilized to understand the erosion accretion pattern of the island over past four decades (1972-2010). The rate of change in shoreline positions have been estimated using statistical linear regression, end-point rate and net shoreline movement method and cross-validated with regression coefficient (R²) method. Land use land cover map has been prepared for all these years to understand how the erosion-accretion affected the island. It has been shown that the island is constantly shrinking over time and lost almost 50% of its area.
关键词:Hooghly estuary;Ghoramara Island;shoreline change rate;regression coefficient (R²);land use land cover