Author(s): Nick Wallerstein; Scott Arthur; Dian Sisinnggih

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Keywords: Culvert; Trash screen; Urban flooding; Blockage; Fly-tipping

Abstract: There are over 300,000 culverts in the UK which must be and maintained effectively to minimize flood risk. A key part of managing this risk is to reduce the likelihood of culvert blockage by natural or anthropogenic debris and culverts are often protected from becoming blocked internally by the fitting of a trash screen (grille) at the inlet. However, grilles can become a hazard in themselves if they are not maintained properly. In this research a large data-set obtained from grilles in Northern Ireland was used to determine monthly and annual trends in blockage frequency and the type of material causing blockage. Annual and monthly blockage trends were strongly positively correlated with precipitation. Discharge from three gauge sites was compared with blockage frequency but the relationships were found to be weak. Blockage material was broken down into classes by size and origin and it was found that the sum of monthly counts of small vegetation (such as leaves and twigs) strongly corresponded to changes in the average monthly blockage frequency. Counts of domestic and industrial material remained fairly constant through the year indicating there to be no temporal anthropogenic driver to blockage.

DOI:

Year: 2010