Analyzing Ogurja Island’s shoreline changes in response to the Caspian Sea water level decline

Shorelines are vital and dynamic components of the coastal zone, constantly changing due to various environmental factors. These areas hold significant recreational, economic, and ecological importance, making the understanding of shoreline alterations critical. Unlike open oceans, the Caspian Sea (CS) has experienced a noticeable decline in water level since the late 1990s due to a combination of climatic variability, reduced riverine inflow, increased evaporation, and anthropogenic factors. This decline in water level is expected to drive morphological changes in the shorelines, with an overall trend of shorelines retreating seaward. In this study, the shoreline changes of Ogurja Island, the largest island in the CS, were analyzed using Sentinel-2 satellite imagery from 2015 to 2023, covering a total of 9 images, and the Digital Shoreline Analysis System tool. The study aimed to establish a relationship between these shoreline changes and the decline in the Caspian Sea water level (CSL). The results reveal a strong correlation, with shoreline movements reaching up to 80 m/year in some areas, and significant changes are expected with the projected CSL decline. This research offers an initial attempt to connect shoreline dynamics with water level fluctuations, highlighting the importance of considering shoreline changes in future water level predictions. The study recommends that future research focus on integrating advanced models, such as hydrodynamic simulations and machine learning techniques, to refine shoreline predictions and enhance understanding of the CS’s dynamic coastal environment.