Changes in the Shoreline of the Gorganroud and Sefidroud Deltas Using the Digital Shoreline Analysis System (DSAS)

The shoreline is a very dynamic environment. Its situation is influenced on sea level changes, erosion and sedimentation processes, and its displacement has overshadowed human life, communications, and coastal facilities. The purpose of this study is to measure and compare the shoreline changes in the Gorganroud Delta and Sefidrouad Delta by The Digital Shoreline Analysis System (DSAS). In this study, after applying NDWI Index and high pass filtering, the shorelines extracts from the TM and OLI sensors for the years 1986, 2000, and 2015. In order to measure the shoreline changes, transects are considered at intervals of 50 meters perpendicular to the baseline. This step is done in Arc GIS software by DSAS extension.
The results show that the effect of sea level changes on displacement of shoreline is not the same in the both of studied areas. By the increase of sea level in 2000, the shoreline moved landward, while in 2015, due to the drop in sea level, shoreline moved seaward. During this 30-year period, the total rate of change are estimated in Gorganroud Delta and Sefidroud Delta 104/85 and -2/1 in meters/year respectively. With respect to these measurement, the Gorganroud Delta has shown remarkable retrogression and the Sefidroud Delta has shown little change. Also, the shoreline changes in the two above mentioned deltas indicate that the amount of sediment load transported by rivers plays an important role in controlling the shoreline.