Geospatial assessment of shoreline dynamics for sustainable policy shifts: Evidence from rapidly developing coastal zones

Coastal zones are dynamic environments. It undergo continuous morphological change due to natural processes and human activities. It is posing significant risks to ecosystems, tourism, and coastal communities. This study investigates shoreline dynamics and coastal morphological changes at Calido Beach, Kalutara, along Sri Lanka's southwestern coastal belt. The primary objective of the research is to identify and visualize shoreline changes and coastal morphological variations using geospatial techniques. The study examines erosion and accretion patterns and their implications for sustainable coastal management and disaster risk reduction. The study employed a quantitative geospatial analysis of historical satellite imagery from Google Earth Pro for 2015, 2017, 2020, and 2022. The results indicate notable shoreline fluctuations over the study period. Moderate erosion was recorded between 2015 and 2017 with an estimated land loss of approximately 68,519 m². A substantial increase in erosion occurred between 2017 and 2020, reaching approximately 425,419 m². It is primarily associated with the artificial cutting of the sandbar during the 2017 flood event, and further factors of sea level rise, monsoon impact, and sand mining were examined with secondary scholarly works. The period between 2020 and 2022 shows partial recovery with an accretion gain of approximately 66,128 m². The findings highlight the importance of geospatial monitoring in understanding coastal dynamics for sustainable decision-making. It emphasizes the need for integrated coastal management strategies with environmental impact assessments and utilizes them in policy decision-making in Sri Lanka. The findings call for improved flood mitigation measures to enhance coastal resilience and sustainable environmental management with informed geospatial techniques.