Six Decades of Morphodynamic Evolution Around Ashdod Port, Southeastern Mediterranean Coast of Israel

Long-term morphodynamic responses to large ports are difficult to quantify when historical observations cover different periods, spatial domains, and engineering interventions. At Ashdod Port, on the Mediterranean coast of southern Israel, previous studies documented individual stages of coastal change, but the cumulative response to six decades of port development remained unresolved. This study reconstructs the Ashdod coastal system from 1957 to 2025 using historical and modern bathymetric–topographic surveys, shoreline analysis, and intervention-adjusted sediment balances. During 1965–1995, approximately 4.50 × 106 m3 of sand accumulated within the ~2.5 km sector immediately south of the main breakwater (MBW), while a comparable deficit developed north of the port. Following construction of Ashdod Marina (1995–1997), accumulation became distributed across the southern sectors, while erosion persisted north of the port and extended farther downdrift. For 1965–2021, intervention-adjusted balances were +7.859 × 106 m3 south and −7.208 × 106 m3 north of the port, corresponding to +140 and −129 × 103 m3/yr, respectively. Their similar magnitude and opposite signs constrain the long-term morphological response to interruption of the predominantly northward sediment-transport system but do not constitute a direct LST estimate. Successive port expansions extended the MBW head from ~15 to ~25 m water depth, across most of the sandy inner-shelf domain extending to ~30 m. North of the port, substantial sediment losses were accompanied by limited shoreline retreat, showing that shoreline change alone underrepresents the submerged response. Despite artificial northward transfer of ~1.457 × 106 m3 since 2000, the downdrift deficit persisted. Historical accumulation south of the port should therefore not be equated with a presently available sand reserve. The record demonstrates the value of multi-decadal volumetric analysis for resolving cumulative port impacts and supporting sediment management on engineered sandy coasts.