Geospatial Assessment of Flood-Prone Areas in Rize Türkiye

Abstract

Flooding constitutes one of the most significant hydrometeorological hazards affecting settlements located along the Eastern Black Sea coast of Türkiye. Rize  is particularly vulnerable because of its exceptionally high precipitation regime, steep topography, dense river networks, and rapid urban expansion occurring within narrow coastal plains. This study investigates the temporal and spatial characteristics of rainfall and evaluates potential flood susceptibility in Rize  by integrating rainfall frequency analysis and Geographic Information Systems (GIS). Monthly precipitation records covering the period between 2015 and 2024 were obtained from meteorological observations and supplemented with Climate Hazards Group InfraRed Precipitation with Stations (CHIRPS) satellite products for spatial analyses. Statistical analyses, including Gumbel frequency distribution and Mononobe rainfall intensity equations, were employed to estimate future rainfall conditions and associated return periods. The results demonstrate that average monthly precipitation in Rize  varies between  81 and 261 mm, indicating persistently humid climatic conditions throughout the year. Peak precipitation occurs during October, November, and December, whereas comparatively lower rainfall is observed during April and May. Rainfall projections indicate that estimated extreme precipitation for 2-, 5-, 10-, and 15-year return periods reaches 370 mm, 520 mm, 618 mm, and 674 mm, respectively. Spatial analyses reveal that low-elevation coastal neighborhoods and valley bottoms exhibit considerably higher flood susceptibility due to the combined effects of intense precipitation and topographic concentration of runoff. The integration of rainfall forecasting techniques and GIS-based spatial modelling provides a reliable framework for flood-risk assessment and supports the development of early warning systems, disaster mitigation strategies, and sustainable urban planning policies in Rize.