Coastal Erodibility in Relation to Sand-Mud Sediment Properties

Abstract Coastal erosion in areas with both cohesive (mud) and non-cohesive (sand) sediments presents challenges in understanding shoreline behavior. This study investigates how sand-mud sediment properties influence coastal erodibility along the shoreline of Pantai Punggor, Batu Pahat, Johor, Malaysia. Profiles of shoreline and elevation changes were produced using UAV photogrammetry techniques. The data was processed by the Pix4D and Global Mapper application tools, over a one-year period. Erosion and accretion zones were identified, reflecting the coastline’s varied response to hydrodynamic forces. Geotechnical testing of sediment samples collected across different tidal zones revealed distinct variations in sediment properties. Sediments in the high-tide zone were typically sandier, more compact, and exhibited greater strength, while those in the mid- and low-tide zones contained higher proportions of silt and clay, with lower strength and density. Shear strength declined progressively from the backshore to offshore, aligning with observed changes in sediment texture and grain composition. These variations influence the erosion resistance of each zone. The study highlights the importance of integrating morphological and geotechnical data to better understand coastal processes in mixed-sediment environments. The findings emphasize how variations in sand-mud sediment properties directly influence coastal erodibility across tidal zones.