Historical information sheds new light on the intensification of flooding in the Central Mediterranean

Abstract

Hydrological disasters, such as floods, can have dire consequences for human societies. Historical information plays a key role in detecting whether particular types of hydrological disasters have increased in frequency and/or magnitude and, if so, they are more likely attributable to natural or human-induced climatic and other environmental changes. The identification of regions with similar flood conditions is essential for the analysis of regional flooding regimes. To this end, we here present the longest existing flood reconstruction for the Eastern Liguria Area (ELA) in northwestern Italy, covering 1582 to 2022 CE, which offers a case study representative of the central Mediterranean region. An Annual Flood Intensification Index was developed to transform the historical data into a continuous annual hydrological time-series contained by a homogeneous data structure for the study-area. We found two change-points (trend breaks) in the reconstructed time-series, in 1787 and 1967, with only occasional heavy floods comparable to present-day disasters occurring before the first change-point, and an increasing intensification of floods after the second change-point up to the present day. The recent intensification of flooding in the ELA, associated with changes in land use and land cover, also appears to coincide with phases in which hydrological hazards have become more changeable and extreme in disaster-affected areas. This is evidenced by river basin responses to human-induced disturbances.

Integrated Hydrological Modeling for Watershed Analysis, Flood Prediction, and Mitigation Using Meteorological and Morphometric Data, SCS-CN, HEC-HMS/RAS, and QGIS

“…Effective water management and disaster mitigation measures are greatly hindered by weather variability, particularly severe events, including extreme rainfall, storm events, and long-ongoing droughts [14,18]. The intensification of the hydrological regimes caused by climate change has substantially impacted intensity, spatial range, duration, and frequency of flood events [8,19,20]. However, as climate change causes more hydro-meteorological extremes, common hydrological modeling methodologies are frequently insufficient for delivering reliable flood predictions and alternatives to mitigation.…”

Rewinding the Tape: Documentary Heritage to (Re)discover “Lost” Natural Hazards—Evidence and Inferences from Southern Italy

“…Recorded data should be used in a complementary way to conduct a more refined and detailed flood analysis, thus getting qualitative and quantitative information on the floods (e.g., hydrometric data, casualties, flooded areas, damages, effects on buildings and infrastructures, institutional response for the rescue intervention) [12,13]. Historical information can also be useful to both improve flood risk management [14] and identify changes in flood frequencies over centuries [15].…”

“…Recorded data should be used in a complementary way to conduct a more refined and detailed flood analysis, thus getting qualitative and quantitative information on the floods (e.g., hydrometric data, casualties, flooded areas, damages, effects on buildings and infrastructures, institutional response for the rescue intervention) [12,13]. Historical information can also be useful to both improve flood risk management [14] and identify changes in flood frequencies over centuries [15]. Since the beginning of the 21st century, past traces have been considered more and more to investigate flood events in different regions of the world such as Russia, Hungary, Czech Republic, Spain, France, and Brazil [16][17][18][19][20][21][22].…”