Abstract :
: In recent years, the coastline of Caspian Sea in Guilan province especially the mouth of big rivers such as Sefidroud delta has changed increasingly due to the environmental, continental and marine factors. The changes in position of these coastlines have made some damages. The changes of water level that come from the land, the differences in the land sediment levels, the situation of erosion in coastlineʹs sediments such as continental factor, changes of sea level, patterns of current and Caspian Sea waves are some changes that occurs in Caspian Seaʹs coastlines. Purpose of this study was to investigate causes of these factors in different regions of Guilanʹs coastlines. Using of aerial photos in two periods of years in 1967 and 1994 with the scale of 1/20000 and using of softwareʹs such as Ilwis, and Photoshop, sediment levels was estimated. Some geographic maps and topography with the scales of 1/20000, 1/50000, and space measurement used in order to complete information in this research. The sedimentary units that studied were Quaternary units including Qt1, Qt2 and QM, which are related to land environment Qts and Qsp units are belonged to land and Qt1, Qt2, Qt3 are related to rivers environment and finally the Q2be, Q2b, and Qbm units are related to middle and under coastline. The Guilanʹs coastline progress under the sea erosion was estimated in Astaneh-Ashrafiye 84.08 ha, Talesh, 49.52 ha, Anzali, 45.87 ha, Lasko-kelaye, 1430.69 ha and Roudsar, 678.5 ha. Retrograde under the coastlineʹs sediment was estimated in Astaneh-Ashrafiye, 276.99, Talesh, 48.31, Anzali. Has not retrograde, Lasko-kelaye, 2.04, and Roudsar 5.46 ha.
