Flood Generation Processes in North Africa

Abstract

Floods and flash floods are among the most frequent and destructive natural hazards worldwide, and North Africa has experienced numerous severe and deadly flood events over recent decades. The magnitude, frequency, and severity of floods in this region exhibit strong spatial and temporal variability, reflecting the combined influence of basin physiography, hydrological processes, and climatic conditions. Ongoing climate change is expected to alter these controls, further complicating the understanding of flood-generation mechanisms and their evolution over time. This study aims to investigate the dominant processes driving flood generation across North Africa and to examine how climate variability and change may influence flood characteristics, trends, and severity. We analyze long-term streamflow records from 163 basins distributed across Morocco, Algeria, and Tunisia, with basin areas ranging from 23 to 20,000 km² and observation periods spanning from 1950 to 2023. Flood events are examined across a wide range of magnitudes, from frequent runoff events to rarer extreme floods, with the objective of identifying dominant flood-generation processes and potential shifts in their relative importance over time.