Historical coastal evolution of the ancient harbor of Aegina in relation to the Upper Holocene relative sea level changes in the Saronic Gulf, Greece

•Identification of three distinct sea levels on the coast of Aegina island•Dating of three sea levels, based on archeological evidence and historical sources•Sea level stability for at least 2100 years, from Middle Bronze Age to Roman times•Paleogeographical reconstruction of the ancient harbor facilities•Differences between the resulting curve of sea level change and the predicted model

The extensive ancient harbor installations — today submerged — on the seafront of Kolona in Aegina are associated with the great trading and maritime development of the island from the Middle Bronze Age to the Middle Classical period.Based on geomorphological and archeological indications, three distinct relative sea levels can be defined at depths of 3.17 ± 0.05 m, 0.97 ± 0.05 m and 0.52 ± 0.05 m. The dating of the sea level changes based on archeological evidence and historical sources shows that the initial sea level change in Aegina occurred certainly after AD 170 and most likely after AD 250. The intermediate change is dated between AD 1586 and AD 1839, and the most recent change occurred between 1839 and 1999. A transgression followed a long period of sea level stability that lasted at least 2200 years, from the Middle Bronze Age (ca. 3900 yr BP) to the Late Roman period (ca. 1700 yr BP).According to the paleogeographical reconstruction of the coast, the ancient harbor installations stretch along 1600 m of coastline. The north harbor is bounded by the north breakwater, the riprap on the once wide sandy coast, the detached west breakwater, and the uplift morphology of the west end of Kolona Hill. On the south coast, the harbor installations comprise the fortified “closed harbor” with the shipsheds, the commercial harbor, which is entirely destroyed by the modern port, the anchorage area that is bounded by the west breakwater and built of cone-shaped piles of stones, the tops of which once projected above the sea level, and the south curved breakwater at its southernmost boundary.