2025/12/16 by Llanos Valera-Prieto, Marcos Sanz-Ramos, Ernest Bladé +1 · 1 voice
Agricultural and Biological Sciences · Environmental Science · #Flood Risk Assessment and Management #Hydrology and Sediment Transport Processes #Soil erosion and sediment transport
paper · doi:10.1016/j.ejrh.2025.103032
openalex publication_date 2025/12/16 · openalex created_date 2025/12/17 · openalex updated_date 2026/07/23
Study region The upper Francolí River catchment (Spain) in the Mediterranean region. Study focus In October 2019, the upper Francolí River experienced extreme rainfall (293 mm in 24 h), triggering devastating flash floods that caused six fatalities, impacted infrastructures (e.g., four bridges collapsed), and led to significant bio-geomorphological changes along the river corridor, including the erosion and transport of large amounts of large wood (LW). This study investigated the effects of this flood, particularly the LW transport and accumulation, combining post-flood observations and numerical modeling over a 1.6 km reach near the L’Espluga de Francolí village (Catalonia, Iberian Peninsula). Using the Iber-Wood, a coupled two-dimensional (2D) hydrodynamic and LW transport model, 31 scenarios were simulated to analyze water flow, sediment transport, and large wood dynamics, focusing on wood-related accumulation and blockage of bridges. New hydrological insights for the region Results demonstrate the model’s ability to replicate observed water depths, flooded area, morphological changes, sediment erosion and deposition, and wood accumulation. LW retention at bridges was found to depend strongly on hydraulic conditions and hydrograph shape. Retention efficiency decreased with increasing discharge, and simulations revealed that wood jams can temporarily block flow, delay the hydrograph, and generate sudden surges when the jam breaks. This blockage–breakage cycle, captured through modeling and field evidence, is critical to understanding how LW contributes to rapid shifts in flood hazard. The findings emphasize the need to consider LW dynamics, hydrograph complexity, and tributary inputs in flood risk assessments, and support the development of more resilient infrastructure and mitigation strategies in mountainous Mediterranean rivers.