A multi-temporal analysis of shoreline dynamics influenced by natural and anthropogenic factors: Erosion and accretion along the Digha Coast, West Bengal, India

Abstract

This investigation analyzed shoreline evolution along India's Digha Coast from 1992 to 2022, using multispectral Landsat satellite images and the Digital Shoreline Analysis System (DSAS). Methods included identifying zones and transects, shoreline extraction, and applying spatial statistical techniques. The study area, divided into five zones with 587 transects, enabled both short- and long-term analysis. Key findings indicate that the mean long-term rate of shoreline change is -0.54 m per year, with 70.70 % of transects experiencing erosion and 29.30 % accretion. Notably, Zone V had the highest accretion rate (8.55 m/year), while Zone III faced the most erosion (-7.47 m/year). Short-term analysis from 1997 to 2017 indicated significant erosion, contrasting with accretion during 1992-1997 and 2017-2022. Particularly, Zones II, III, and IV underwent major erosion, especially from 1997 to 2002. The study underscores the need for continuous shoreline management strategies and demonstrates geospatial technology's effectiveness in capturing coastal landscape changes.

Keywords: Coastal management; DSAS; Geospatial analysis; Long-to-short term change; Sediment dynamics; Shoreline change.