Study of coastal changes in Kiashahr- Dastak region in 1968 to 1994, interval by using GIS

In this research sea-level changes of Kiashahr-Dastak coastal zone in a 26 years old interval (1968-1994) were studied. The arial photographs were studied in a GIS environment utilising Ilwis software and considering field evidences as well as grain- size analysis. The results were shown as erosion and sedimentation maps in this interval. Changes in the position of coast line is indicative of regressive coasts (sedimentation-dominant zones) in the areas where the rivers run in to the sea and transgresive coasts (erosion-dominant or drowned zones) in the eastern part of Sefidrud delta, particularly the northern part of Dastak district. GIS based studies and field investigations show that sea level rise caused progration of coasts with an average of 14 m/year and in the sedimentation area had regreted with an average of 11.3 m/year. In addition, significant changes are also seen in the coastal facies in this time interval; among them avulsion of the Sefidrud and changes in the distribution of facie are the most important