Assessing the Evolution of Intensity – Duration – Frequency Curves over Greece: A Comparative Study between 2016 and 2023

The development and regular revision of the Greek National Flood Risk Management Plans (FRMPs) serve as direct response to the guidelines introduced by the Floods Directive (Directive 2007/60/EC) of the European Parliament and of the Council, in order to effectively mitigate and manage potential risks related to extreme precipitation events. The current study presents a comparison between: a) the Intensity-Duration-Frequency (IDF) curves obtained in 2016 over Greece using the Koutsoyiannis et. al (1998) methodology, and b) their 2023 revised version using a more recent approach (Koutsoyiannis, 2022; Iliopoulou et al., 2022).

Through a comparative analysis of the two distinct IDF sets, we assess the inherent statistical variability of rainfall fields and its probable influence on extreme rainfall estimation. Focus is on determining both the nature and extent of potential spatiotemporal alternations, while identifying emerging trends and possible abnormalities that indicate substantial shifts in precipitation patterns, thus enhancing understanding of the evolution of flood risk over Greece.

As the IDF curves form the cornerstone of Flood Risk Management Plans, it is crucial to identify significant variations in their profiles over short periods of time. Consequently, the current work highlights the necessity for regular updates of the national Flood Risk Management Plans, in accordance with the Floods Directive guidelines, while identifying areas that exhibit substantial statistical variability. Ultimately, the obtained results will allow for the development of robust decision-making frameworks, enabling stakeholders and policymakers to develop flexible and compliant mitigation strategies against potential hydrological hazards to protect the community and infrastructural assets.

 References

Iliopoulou, T., Malamos, N. and Koutsoyiannis, D. (2022) Regional ombrian curves: design rainfall estimation for a spatially diverse rainfall regime, Hydrology, 9(5), 67, https://doi.org/10.3390/hydrology9050067.

Koutsoyiannis, D., Kozonis, D. and Manetas, A. (1998) A mathematical framework for studying rainfall intensity-duration-frequency relationships, Journal of Hydrology, 206 (1-2), pp 118-135, https://doi.org/10.1016/S0022-1694(98)00097-3.

Koutsoyiannis, D. (2022) Stochastics of Hydroclimatic Extremes - A Cool Look at Risk, 2^nd Edition, ISBN: 978-618-85370-0-2, 346 pages, Kallipos Open Academic Editions, Athens, 2022, https://doi.org/10.57713/kallipos-1.