Analysis of changes in the coastline of the western shore of the Caspian Sea within the framework of coastal cells (Talesh to Anzali)

Neglecting coastal erosion and its changes can lead to environmental hazards, which are among the main factors affecting human communities and facilities. Paleontological research demonstrates tens of meters of fluctuation in the water level of the Caspian Sea. The shores of the Caspian Sea have variable topography and land use, including lowlands (estuaries of rivers, gulfs, and progradation) and sandy uplands. In lowlands, there is a slight slope that causes flooding of lands when the sea level rises, as well as an increased piezometric level of coastal aquifers. This study investigates changes in the coastal line from Talesh to Anzali over a period of 45 years using spatiotemporal analysis in the form of coastal cells. For this purpose, ArcGIS software was used to extract the coastal lines of 1975, 1997, and 2020. Then, using DSAS software, the amount of changes in the coastline was determined. The research results showed that changes in the coastal line in the study area were entirely influenced by the fluctuations of the Caspian Sea level, with 77% of the coastal line experiencing more than 30 meters of retreat. Human activities have somewhat prevented the instability of the coastline due to changes in the water level of the Caspian Sea.