Beitrag
When flood inundates a tectonically active area
Andriopoulou-Mounteanou, Stefania A.; Skilodimou, Hariklia D.; Bathrellos, George D.
Zeitschrift für Geomorphologie (2025)
Online veröffentlicht: Nov 8, 2025
Manuskript akzeptiert: Sep 30, 2025
Manuskript-Revision erhalten: Sep 24, 2025
Manuskript-Revision angefordert: Jun 12, 2025
Manuskript erhalten: Jun 5, 2025
DOI: 10.1127/zfg/0837
Abstract
Flooding is a recurrent and severe natural hazard in urban areas, impacting infrastructure and public safety. This study examines flood events and their impacts across eight separate drainage basins within the city of Patras, in southern Greece, from 1909 to 2024. The studied drainage basins are Glafkos, Diakoniaris, Tritaki, Meilichos, Tholopotamos, Haradros and Selemnos rivers and unnamed stream. The elongation ratio (Re), was calculated to evaluate flood hazard and tectonic activity across the drainage basins. The flooded area during each event within each drainage basin was estimated and correlated. Moreover, the flooded area and the current urban pattern within each drainage basin were associated. The flood-affected areas of the studied drainage basins were grouped by year, and the number of buildings submerged during each event was analyzed. The data were combined and analyzed by using Geographical Information System (GIS). The drainage basins of Selemnos and Haradros rivers present the lowest Re values, and are considered highly elongated and tectonically active. While the Tritaki drainage basin with the highest Re has an oval shape. The remaining drainage basins have elongated shape, as indicated by their Re values, and exhibit tectonic influence. Among the study area Glafkos and Diakoniaris drainage basins are the most flood-prone. Indicated by repeated flood events in the region near the mouth of both rivers that has been affected, with considerable overlap in the flooded areas. High percentage of impacted urban pattern and numerous of flooded buildings in each drainage basin were calculated. Both of the drainage basins, exhibit low elevation, dense urban pattern and a high value of Re associating the susceptibility to flooding. The Meilichos River experienced two flood events with noteworthy affected area, urban pattern and buildings. The Tritaki, Selemnos, Haradros rivers and the unnamed stream each experienced one flood event of low-impact area. The Tholopotamos River is unaffected by flooding. During the years 1909 to 2024, there were 18 flood incidents in the study area. The one that was marked as the most catastrophic was in 1962, when four rivers overflowed leading to the flooding of 4,000 buildings. This study can guide local authorities, engineers and communities on flood risk and spatial planning.
Schlagworte
elongation ratio • flooded area • flooded buildings • drainage basin • GIS • city of Patras • southern Greece