Flood prediction remains one of the central challenges in hydrology, due to the intrinsic complexity of the processes governing runoff generation and their strong dependence on climate, soil, and geomorphological conditions. The body of research presented here develops a coherent framework aimed at bridging process understanding and probabilistic modelling, with a particular focus on theoretically derived flood frequency distributions.

From Conceptual Understanding to Theoretical Modelling

Early contributions (e.g., Gioia et al., 2007; Fiorentino et al., 2006) focused on identifying the key variables controlling flood generation, highlighting the role of runoff contributing areas, soil moisture, and rainfall variability as fundamental drivers of flood peaks.

A major step forward was the development of theoretically derived flood frequency distributions, based on the concept that flood peaks can be described as the product of runoff per unit area and the dynamically varying contributing area. This approach, initially formalized in the IF model and later extended, provides a physically-based alternative to purely statistical methods.

The work by Gioia et al. (2008) introduced a generalized framework incorporating multiple runoff generation mechanisms, showing that flood distributions can be interpreted through the coexistence of different threshold processes.

Dual Mechanisms and the TCIF Model

A key advancement of this research line is the recognition that flood generation is governed by two distinct mechanisms:

  • ordinary events associated with limited contributing areas and infiltration excess
  • extreme events associated with widespread basin saturation and storage exceedance

This conceptualization led to the development of the TCIF (Two-Component IF) model, which explicitly accounts for these dual processes.

The TCIF model (Gioia et al., 2012; Iacobellis et al., 2011) demonstrated how the interaction between climatic forcing and basin properties controls not only the magnitude of floods but also the shape and skewness of flood frequency distributions  .

Moreover, regional applications showed that model parameters can be related to geomorphoclimatic descriptors, enabling prediction in ungauged basins and supporting regionalization approaches.

Publications

  • Gioia, A., Iacobellis, V., Manfreda, S., Fiorentino, M. (2017). Comparison of different methods describing the peak runoff contributing areas during floods. Hydrological Processes. https://doi.org/10.1002/hyp.11169
  • Gioia, A., Iacobellis, V., Manfreda, S., Fiorentino, M. (2012). Influence of infiltration and soil storage capacity on flood peaks. Hydrology and Earth System Sciences. https://doi.org/10.5194/hess-16-937-2012
  • Iacobellis, V., Gioia, A., Manfreda, S., Fiorentino, M. (2011). Flood quantiles estimation based on theoretically derived distributions. Natural Hazards and Earth System Sciences. https://doi.org/10.5194/nhess-11-673-2011
  • Fiorentino, M., Gioia, A., Iacobellis, V., Manfreda, S. (2011). Regional analysis of runoff thresholds behaviour. Advances in Geosciences. https://doi.org/10.5194/adgeo-26-139-2011
  • Gioia, A., Iacobellis, V., Manfreda, S., Fiorentino, M. (2008). Runoff thresholds in derived flood frequency distributions. Hydrology and Earth System Sciences. https://doi.org/10.5194/hess-12-1295-2008
  • Manfreda, S., Fiorentino, M. (2008). A stochastic approach for the description of the water balance dynamics. Hydrology and Earth System Sciences. https://doi.org/10.5194/hess-12-1189-2008
  • Fiorentino, M., Manfreda, S., Iacobellis, V. (2007). Peak runoff contributing area as hydrological signature. Advances in Water Resources. https://doi.org/10.1016/j.advwatres.2006.11.017
  • Gioia, A., Iacobellis, V., Fiorentino, M., Manfreda, S. (2007). Influence of climatic and soil factors on flood frequency distributions. WSEAS Transactions.
  • Fiorentino, M., Gioia, A., Iacobellis, V., Manfreda, S. (2006). Analysis on flood generation processes by means of a continuous simulation model. Advances in Geosciences. https://doi.org/10.5194/adgeo-7-231-2006

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About the author

He is Full Professor of Hydrology and Hydraulic Constructions at the University of Naples Federico II. He is currently chair of the IAHS MOXXI working group. His research primarily centers on hydrological modeling and monitoring. Recognizing the challenges posed by the complexity and limitations of traditional hydrological observations, he actively explores advanced and alternative monitoring techniques, such as the utilization of Unmanned Aerial Systems (UAS) coupled with image processing.