Changing capacity of beaches of Kusadasi, Turkiye considering sea level rise

The irreversible physical, environmental and socio-economic damages of uncontrolled and intense recreational activities on coastal use have reached an alarming level. Shoreline evolution caused by climate change, sea level rise and rapid growth of coastal communities has also been drastically affecting tourism quality and available recreational areas which should be considered in implementation of adequate and correct management strategies to prevent further damage (Zacarias, Williams, and Newton 2011). It is recommended that the uncontrolled usage of beaches should not exceed a certain level, defined as carrying capacity, considering the long-term protection of coastal areas. In this study, it is mainly aimed to determine the carrying capacities of natural beaches of Dilek Peninsula-Buyuk Menderes national park (Karasu, Aydinlik, Kavakliburun and Icmeler), urban (Kadinlar, Davutlar and Guzelcamli) and non-urban (Pamucak) coasts of city of Kusadası using the Cifuentes (1992) method. The region-specific physical features and climatic conditions limiting the beach use are analysed and temperature (excessive sunshine), precipitation, wind speed, cloud cover and shoreline evolution correction factors are applied to assess the present Real Carrying Capacities (RCC). Also, scenarios of different climate models are adapted to the study area to predict the possible future impacts of climate change on recreational use. Since the beach area is a dynamic and time-dependent parameter changing under the climatic factors and human activities; the Coastal Area Vulnerability Model (CVI-SLR) is integrated into the existing methodology to consider the physical parameters (sea level rise rate, coastal slope, wave height, tidal range and sediment budget) and parameters formed by human effects (coastal protection structures and reduction of sediment supply) in the evaluation of the coastline (Ozyurt, G., 2007; Ozyurt & Ergin  2010). Two time scales are considered to assess shoreline evolution. Satellite images of the beaches are processed by Digital Shoreline Analysis System (DSAS) software to assess the shoreline evolution for years between 2004 and 2018. By applying the measured Weighted Linear Regression Rate (WLR) values to the current beach widths, erosion and accretion correction factors are calculated. Secondly, available beach areas as a result of shoreline retreat are calculated using depth of closure, berm heights and dimensions of active beach profiles and sea level rise of different scenarios during 2000-2100 years with 25-year intervals. Landward and upward movement of cross-shore beach profile and possible future shoreline evolution in coming 100 years are estimated using the Bruun Rule principle for sandy beaches (Davutlar, Guzelcamli, Kadinlar and Pamucak) based on sea level rise trends of East Mediterranean as RCP 4.5 and RCP 8.5 (Vousdoukas et al. 2017) and Mentes coast (Alper 2009). According to the results, the carrying capacities of all of the beaches are decreased by a ratio of two thirds mostly caused by excessive sunshine. Future predictions shows that almost all of the Kadinlar beach and a large part of the Pamucak and Davutlar beaches will be lost in the next 100 years as a result of sea level change and therefore coastline evolution both caused by climate change and uncontrolled recreational use.