Spatiotemporal Evolution of Coastal Dune Systems in the Çukurova Delta Plain: A Multitemporal Analysis Using Historical Aerial Photographs and UAV-Based Photogrammetry

Coastal dune systems are dynamic landforms primarily shaped by aeolian processes, where onshore winds transport and deposit dry beach sediments behind natural or anthropogenic obstacles along the shoreline. The Çukurova Delta Plain, representing Turkey's most extensive deltaic formation along the Eastern Mediterranean coast, encompasses the largest coastal dune fields, extending approximately 100 kilometers. These dune ridges are prominently developed within the eastern sector of the Seyhan Delta and across the Ceyhan Delta. While recent advancements in Unmanned Aerial Vehicle (UAV) photogrammetry and Structure-from-Motion (SfM) techniques have significantly enhanced the generation of high-resolution digital elevation models (DEMs) for geomorphological studies, research focusing on coastal dune dynamics remains notably limited in Turkey. This study addresses this critical gap by presenting the first comprehensive investigation into the spatiotemporal evolution of coastal dunes in the Çukurova Delta Plain, the second-largest delta system in the Eastern Mediterranean after the Nile Delta. The research employs a multitemporal approach, integrating historical aerial photographs and contemporary UAV-derived imagery to analyze both decadal-scale and seasonal morphological changes. For long-term change detection, the study utilizes archival aerial photographs acquired by the General Directorate of Maps (HGM) at 20-year intervals spanning from 1950 to 2016. High-resolution UAV surveys conducted at 3-month intervals during the study period enable the assessment of short-term seasonal variations in dune morphology. The results demonstrate significant spatial and temporal variability in sediment budgets across the study area, with distinct patterns of erosion and accretion observed in different sectors of the Seyhan and Ceyhan Delta dune systems. The analysis reveals that while certain dune segments exhibit remarkable stability over multi-decadal timescales, others show pronounced sensitivity to seasonal variations in wind regimes and sediment supply. This study contributes to the broader understanding of deltaic coastal geomorphology by quantifying the response of dune systems to both long-term and short-term environmental forcings. The findings provide valuable insights for coastal management strategies and highlight the importance of integrated monitoring approaches in vulnerable dune ecosystems facing increasing anthropogenic pressures and climate change impacts.