In‐channel wood‐related hazards at bridges: A review

Abstract

In-channel wood is a key component in fluvial ecosystems; however, transport of inchannel wood during floods can create hazards in urbanized areas. Among the main problems is wood accumulation at bridges, which reduces flow openings, causes blockage and inundation of nearby areas and, eventually, results in structures collapsing. Increasing awareness of the importance of the ecological role of wood in rivers calls for a compromise between the preservation of river ecosystems and management strategies for the prevention of wood-related hazards. In recent years, knowledge related to in-channel wood dynamics and hazards has notably increased, and a significant body of valuable information can be found in an extensive number of studies. This review provides a comprehensive summary of the most relevant advances regarding in-channel wood-bridge interactions. We review the factors controlling wood accumulation formation and summarize the different approaches used to analyse this process, namely, physical and numerical modelling. Finally, we conclude by highlighting the most important knowledge gaps, addressing particularly underresearched fields and stressing the remaining challenges.

Bridge pier scour under pressure flow conditions

“…This increase is proportional to the upstream wetted area blocked by the deck and thus to the ratio h b / h 0 . The presence of large woody debris accumulations further increases the blockage at the pier section (De Cicco, Paris, Ruiz‐Villanueva, Solari, & Stoffel, ).…”

Wood Jam Dynamics Database and Assessment Model (WooDDAM): A framework to measure and understand wood jam characteristics and dynamics

“…Historic wood removal (Comiti, ; Sedell & Froggatt, ; Wohl, ) has simplified and reduced the ecologic health of river corridors, motivating the reintroduction and active retention of wood in rivers as a mechanism of ecological restoration. However, wood can be hazardous to infrastructure and people (De Cicco, Paris, Ruiz‐Villanueva, Solari, & Stoffel, ; Mazzorana, Zischg, Largiader, & Hübl, ; Wohl et al, ). Balancing the positive ecological effects of wood jams with their potential hazards depends on building or retaining wood jams that will exhibit dynamics (change through time) that are desirable for given management goals (e.g., minimizing wood transport downstream while maximizing heterogeneity in a given reach).…”

Hydrodynamic simulation of the effects of stable in-channel large wood on the flood hydrographs of a low mountain range creek, Ore Mountains, Germany

“…Large wood assemblages and elements are more likely to be stable when their length exceeds the channel width (i.e. Gurnell et al, 2002); this is most likely to occur in small first-order streams and rivers, which in turn are the most abundant order of water courses on the planet (Downing et al, 2012). However, even in small but steep headwater streams, large wood may be transported during hydrogeomorphic events of high magnitude such as debris flows (Galia et al, 2018) or extreme floods.…”