Spatio-temporal analysis of shoreline changes and future forecasting: the case of Kucuk Menderes Delta, Turkiye

Abstract

A delta coastal area is one of the most important regions for human use owing to its scenic natural beauty and economic value. However, due to the constant interaction between the land and water environments in this region, it is also one of the most rapidly changing landforms in the world under the impact of natural processes as well as anthropogenic activities. Therefore, the determination and the constant monitoring of these changes spatiotemporally are of great significance in terms of the protection, planning, proper usage, effective management, and sustainability of the delta coast. In this study was aimed to determine the short-term and long-term shoreline changes that occurred between the years 1957 and 2020 along the coast of the Kucuk Menderes Delta and its close surroundings. In addition, the underlying causes were explored, and the future of the shoreline position was forecasted. The shorelines were digitized using seven multi-temporal orthophoto maps based on the high water line indicator. The shoreline changes were analyzed using different statistical methods, namely, the Net Shoreline Movement (NSM), Shoreline Change Envelope (SCE), End Point Rate (EPR), and Linear Regression Rate (LRR), by employing the Digital Shoreline Analysis System (DSAS). The future position of the shoreline was estimated using the extended Kalman Filter in the DSAS. The analyses revealed that in a period of 63 years, the maximum accretion distance (NSM) and rates (EPR and LRR) were 248.99 m, 3.96 m/year, and 3.65 m/year, respectively, the maximum erosion distance (NSM) and rates (EPR and LRR) were - 142.37 m, - 2.27 m/year, and - 2.19 m/year, respectively, and the delta coastal area had increased by 37.01 ha. It is forecasted that the delta coastal area will expand by 10.63 ha and 16.16 ha from 2020 to 2030 and 2040. If the current conditions that occurred in the last 63 years continue with similar effects, it was forecasted that by the years 2030 and 2040, significant changes would occur in the shoreline such as retreat into the existing facilities/usage areas and decrease of Eleman Wetland area, which would greatly alter the ecology, hydrography, and spatial usage of the delta region.