Modernizing Greece’s flood defenses: learning from past disasters and leveraging advanced hydrological tools

Climate change is intensifying the hydrological cycle, leading to more frequent and severe flood events worldwide. In Greece, recent disasters have exposed the vulnerability of aging infrastructure: bridges, drainage networks, flood protection structures, and river buffer zones seem to fail repeatedly because they were designed to outdated rainfall patterns. To build resilience, flood protection design must be updated to reflect current and future climates, and factors that were previously ignored, must be incorporated into the respective regulations.

This study presents examples of disasters that lead us to this suggestion, such as the Storm Girionis (2019), Cyclone Ianos (2020), Storm Daniel (2023). It analyzes causes of failures, and discusses an overlooked factor, the role of Intermittent River and Ephemeral Streams (IRES) in increased flash-flood risks, arguing that they must be properly mapped and integrated into flood protection planning.

Moreover, to enhance the suggested redesign of critical infrastructure, this work presents a novel Python‑based tool that automates the generation of design storm hyetographs from watershed shapefiles using Greece’s official gridded intensity‑duration‑frequency (IDF) parameters (Ministry of Environment, 2023). For a chosen storm duration, return period, and time interval, it computes ready‑to‑use hyetographs. Its application is demonstrated at the national scale (10,773 sub‑catchments).

By rapidly producing site‑specific design storms compatible with national standards, Catchment2Storm empowers engineers and planners to redesign flood protection works, bridges, culverts, drainage systems, and buffer zones, based on up‑to‑date climate data. Integrating holistic mapping and updated storm profiles to routine practice, can transform reactive repair approaches to proactive resilience.