Hydrodynamic Impacts on Shoreline Stability: A 40-Year Assessment of Erosion and Accretion Trends in Jepara, Central Java

The shoreline of Jepara Regency, the northern coast of Java, is undergoing transformation due to the incessant movement of oceanic hydrodynamic forces. This study investigates the impact of hydrodynamic conditions on the stability of the Jepara coast over 40 years (1985-2025) and aims to quantify the magnitude and rate of shoreline alterations. Changes along the shoreline were analyzed using satellite images and the interval transect method. EPR, NSM, and SCE methods were used. Monthly average data were collected from the European Center for Medium Range Weather Forecasts satellite to look at the tide, height, and wave period. The study results show that the shoreline is mostly losing land, with a total loss of 12.18 hectares. The land area lost due to cumulative abrasion was -22.33 hectares, which is much greater than the land area gained through accretion, which was only 10.15 hectares. The Ujungtumpuk area on the headland of the northern area is where the coast is most damaged. On the other hand, accretion happens in the middle and southern parts of the country, where the coast looks like a bay. The sea surface temperatures are rising, the water expands and the sea level rises, which makes this abrasion worse. It has been demonstrated that natural land development processes are significantly weaker than detrimental external forces.