The permanent flood risk of culverts and the impact of increasing debris blockage

Luke Fallowfield*, Davide Motta

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Hydraulic modelling of culverts relating to the flood risk posed by debris in watercourses has previously only assessed the impact of fixed culvert blockage levels, without analysing the change in flooding as blockage levels increase. With increasing flow rates in rivers during flood events, there is concern that existing culverts may be undersized and therefore already posing a substantial flood risk regardless of them becoming blocked by debris. In this article, two‐dimensional (2D) flood modelling is used to produce flood maps detailing the change in flood area and property flooding as culverts become increasingly blocked at several sites in the Northwest of England. The results show a clear distinction between sites where the accumulation of blockage is the key contributing factor towards local flood risk, and sites where the presence of the culvert itself is the predominant flood risk factor. The blockage induced flood risk metric is introduced to characterise the contribution of culvert blockage to the overall flood risk.
Original languageEnglish
Article numbere13021
Number of pages12
JournalJournal of Flood Risk Management
Early online date27 Jun 2024
Publication statusE-pub ahead of print - 27 Jun 2024

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