Jeomorfolojik Araştırmalar Dergisi

Öz

Coasts undergo different changes due to natural dynamic processes and anthropogenic interventions to the coast. Changes in the shoreline play an important role in understanding the dynamic development processes of coasts. In addition, the determination of the changes in the coasts where human pressure is concentrated due to the attractive feature of the coasts reveals data that can be used in terms of coastal use, geomorphological, ecological, anthropogenic planning and sustainable development for the future. In this respect, various techniques are used to determine the coastline change in the world and Turkey. In this study, the long-term (1963-2023) change in the Riva coast, which is located in the north of Istanbul and hosts different coastal geomorphological units and anthropogenic interventions, was analysed with DSAS tool. Orthophoto and satellite images of 1963, 1970, 1982, 1990, 1990, 2000, 2005, 2015 and 2023 were used in the study. Geographical Information Systems (GIS) and Remote Sensing (RS) techniques were used and shoreline change analyses were performed with DSAS tool. In the study, the Net Shoreline Movement (NSM) and End Point Ratio (EPR) analyses in the DSAS tool were performed for the change of the shoreline in 7 different short-term and 3 different long-term periods. Afterwards, the distance analyses were also examined geometrically by using Union analysis on GIS. According to the DSAS analyses, the highest coastal change in terms of distance and annual rate of change in Riva coasts in 7 different periods occurred in the period 2000-2005, and the lowest coastal change occurred in the period between 1990-2000. In 2003, the intervention to the mouth of Riva Stream by anthropogenic factors affected the shoreline and areal change. In the period between 1963-2023, according to the NSM statistics, the maximum distance in coastal advancement is 147,78 metres, while the extreme value in coastal retreat is -29.37 metres. The average distance of shoreline change in this long-term period is 8,67 metres. According to the EPR statistics, the maximum rate of coastal accretion in the period between 1963-2023 is 2.48 m/year, while the minimum rate of coastal erosion is -0.49 m/year. The average EPR value in the 60-year period was calculated as 0.14 m/year. In the 60-year period, it was determined that coastal accretion occurred around the mouth of Riva Creek and towards Soğan Tombolo under the joint influence of natural and anthropogenic factors, while coastal erosion was observed to the east of the tombolo.