Shoreline Change Detection and Analysis in Kochi, Kerala Using Digital Shoreline Analysis System (DSAS)

Abstract

This study presents a comprehensive assessment of shoreline dynamics along the Kochi Corporation coastline, India, by quantifying rates of erosion and accretion over a 35-year period (1989–2024). Multi-temporal Landsat satellite imagery, encompassing data from the MSS, TM, ETM+, and OLI/TIRS sensors, was integrated within a Geographic Information Systems (GIS) framework. Shoreline change rates were statistically derived using the Digital Shoreline Analysis System (DSAS), employing multiple metrics including Net Shoreline Movement (NSM), End Point Rate (EPR), Linear Regression Rate (LRR), and Weighted Linear Regression (WLR). The analysis reveals a net erosional trend along the study area, with a mean regression rate of 1.16 m/yr. This trend is attributed to a combination of natural processes and anthropogenic drivers. A critical erosion hotspot was identified in the Fort Kochi region, exhibiting a markedly higher rate of 6.36 m/yr, which has precipitated significant damage to coastal infrastructure. The findings are contextualized with a contemporary land use map of a 500-meter coastal buffer, providing critical insights for integrated coastal zone management and underscoring the urgency for targeted mitigation strategies in vulnerable urban coastal locales.