IAHR Document Library

« Back to Library Homepage « Proceedings of the 37th IAHR World Congress (Kuala Lumpur, 2...

Large Wood Accumulation Probability at a Single Bridge Pier

Author(s): Isabella Schalko

Linked Author(s): Isabella Schalko

Keywords: Accumulation probability, flood protection, flood risk assessment, large wood (LW), river engineering


During flood events, transported large wood (LW) can accumulate at river infrastructures, reduce the flow cross-section, lead to backwater rise and eventually to flooding of the adjacent area. In addition, LW accumulations can damage the river infrastructure itself. To predict the risk of LW accumulations, the estimation of the accumulation probability is essential, especially for an integrated flood hazard assessment. Previous studies on LW accumulation probability focused mainly on the influence of a bridge deck or on the effect of bridge pier shapes. The results are partially contradictory, and the existing design equations for LW accumulation probabilities are only available for bridge decks. Therefore, a series of flume experiments was conducted to analyze the LW accumulation probability as a function of (1) the approach flow conditions, (2) the bridge pier roughness, and (3) the LW characteristics, involving various log lengths, LW with and without branches, and uncongested versus congested LW transport. The LW accumulation probability increases with increasing log length, decreasing approach flow velocity, and for congested LW transport. The approach flow Froude number, the water depth, the bridge pier roughness, and the availability of branches had a negligible effect on the accumulation probability. The results for uncongested LW transport were summarized in a novel design equation to estimate the accumulation probability at a single bridge pier and to identify critical bridge cross-sections prior to a flood event. To upscale the experimental results, and to improve the general process understanding, innovative prototype tests will be conducted in spring 2017.

 (2650, 91, 330)


Year: 2017

Copyright © 2024 International Association for Hydro-Environment Engineering and Research. All rights reserved. | Terms and Conditions