Coastal systems are very dynamic and active, and the transformation in them occurs relatively quickly due to the collision of two dynamic environments, land and sea, and they are not stable in general. Coasts and inter-oceanic areas are one of the important marine ecosystems that have special environmental, ecological and economic importance.
Coastal environments are among the most sensitive environmental systems that change and evolve relatively fast under the influence of the prevailing hydrodynamic processes.Studying the changes of coastlines is important for updating maps of coastal changes and managing natural resources.
The purpose of this research is to investigate the changes of coastlines in the estuaries of Bushehr province (Khor Bidkhon, Khor Ziarat, Khor Shif) during a period of 30 years (1990 to 2020). The boundary of the blue zone on the coasts was extracted using Landsat satellite data and using the MNDWI index. Modified Normalized Difference Water Index (MNDWI) is one of the most suitable and practical indicators for identifying open waters and dams. Quantitative analysis of coastline changes was also estimated using the Coastline Analysis System (DSAS) plugin. The ability of DSAS extension in ArcGIS software not only increases the efficiency of this software, but also provides the calculation of scales and rates of statistical changes from multiple positions and sources of coastlines. A quantitative comparison of the amount of changes has been made using two methods: net shoreline displacement (NSM) and linear regression rate (LRR).
The use of the DSAS extension has shown the capabilities of spatial analysis compared to mere statistical analysis, because in statistical tables only by summarizing, we finally reach limited numbers, but with the use of the DSAS extension, the differences along the coastline and with more details Is visible. The comparison between the time periods in the three studied areas shows significant changes and changes during t