Assessment of Coastal Zone Changes and Relative Bathymetry in Dingalan, Aurora Using Remote Sensing Techniques

Abstract. This study examines the coastal dynamics of Dingalan, Aurora, Philippines, using geospatial tools such as remote sensing and GIS for evaluating land cover changes, shoreline movement, and relative bathymetry. Analysis of Sentinel-2 imagery reveals significant transitions in land cover classes over the years, indicative of the impacts of natural processes and human activities on the coastal landscape. Notably, built-up areas expanded by 175,975.34 m² (33.12%) from 2016 to 2020 and by another 32,365.52 m² (4.58%) from 2020 to 2024. During the same periods, vegetation cover experienced a decrease of 13.01% and 10.22%, respectively. These trends underscore the importance of balanced land use planning to mitigate the environmental impacts of rapid urbanization in coastal zones. Shoreline change detection using Landsat imagery reveals that the eastern portion has been stable throughout the years. In contrast, central and western portions show sediment accumulation, with mean Endpoint Rate and Linear Regression Rate values of 0.97 and 0.98 in the central portion, and 0.79 and 0.82 in the western portion. This highlights the diverse dynamics of shoreline evolution in the area. The relative nearshore bathymetry was calculated using the natural logarithm ratio of blue-to-green spectral bands, yielding values from -0.28 to 0.22, which provide insights into the underwater topography and supports the characterization of shallow-water regions. This study contributes to a deeper understanding of coastal dynamics, providing information essential for effective coastal management and resilience planning in Dingalan and similar regions. It highlights the need for proactive measures to address ongoing environmental changes and underscores the significance of informed coastal management strategies in promoting sustainable development.