Culvert Blockage Assessment and Management

Recent fluvial flood events have highlighted the issue of river culvert blockage and the devastating impacts of flooding on development such as Letterkenny Hospital, Douglas and Dundrum Shopping Centres.

If you are part of an organisation responsible for the management of culverts and pipes, or the management of a significant development or number of developments the issue of flooding, blockage and effective asset management will be a priority for you.

Screen Blockage Picture

Unlike other sources of flood risk, culvert blockage is not being investigated as part of the OPW CFRAM Programme.  It is therefore the responsibility of operators and managers in both private and public sectors to review and address risks associated with culvert blockage.  We are pleased to provide a bespoke service which allows for a fully predictive and risk based approach to asset management that is trusted by public authorities in Ireland and the UK.

Service Outline 

Our bespoke service allows for a fully predictive and risk based approach to asset management that is trusted by public authorities in Ireland and the UK.

  • How – through advanced 2D modelling using LiDAR DTM;
  • Why – to identify and manage blockage flood risk to people and property;
  • Who – used by the NRA, Dun Laoghaire Rathdown County Council and a host of UK Local Authorities to manage risk.

The approach is based on a three step procedure that identifies and logs the assets (with client assistance), models the impacts of blockage and reports on flood risk from each asset.  An overarching report provides a summary of the exposure to flood risk from asset blockage.  This information can be used to implement an appropriate asset management strategy.

Analysis Procedure

In summary;

  • JScreen is a JBA developed software tool that simulates flooding caused by blockages in pipes, culverts or at bridges.  It also defines the extent of any such flood using an award winning 2 dimensional hydraulic model developed by JBA, that is capable of producing rapid results for multiple locations and multiple return periods.  
  • In addition, JScreen also analyses the consequences of the flood, by taking into account all of the properties (An Post Geodirectory information) within each flood area.  It produces an individual report for each asset, which clearly identifies the flood risk associated with blockage and generates a simple database that can be used for asset management purposes to help prioritise operation and maintenance programmes.
  • There are a large number of structures, particularly culverts many of which were not designed using modern day calculations, are infrequently inspected and as a result are falling into disrepair.  The capacity of these culverts is often inadequate and the assets contribute to the causes of flooding of nearby homes, businesses and transport links. 

For more information there are pdf fact sheets and an example report available by clicking on the links to the right.  For one to one discussions please contact or call on 061 345 463.

To understand how culvert and trash screen design can influence flood risk then click below for a video demonstration of the JBA Trust flume by Rob Lamb and Jeremy Benn.

The flume is a scale model of the flow of water in a simple channel, driven by a system of recirculating pumps and featuring scale models of typical engineered structures such as weirs, bridges, culverts and debris screens. 

The flume appeals equally to those with a keen interest in hydraulics and to those for whom it is an unknown science. It is particularly useful in helping to understand some of the causes of flooding and how good design and maintenance of rivers and drainage channels can help to manage flood risk.