Tools and techniques for flood risk management planning

Under the large European R&D project FLOODsite, a wide range of integrated flood risk analysis and management methodologies were investigated and developed. Over 35 organisations under the leadership of HR Wallingford were involved in this EU 6th Framework Programme (FP6) project. The Environment Agency, who provided essential partnership funding during FLOODsite, are working with HR Wallingford to ensure the benefits of this research feed into industry practice. The FLOODsite work, which was completed in 2009, ranged from basic science through to detailed methods and prototype tools.

Typical Humber Estuary flood defences
Ferriby sluice gate provides key flood protection at the River Ancholme’s confluence with the Humber Estuary

The flood management research outputs delivered by FLOODsite were substantial (see www.floodsite.net). HR Wallingford is now working closely with the Environment Agency, a key FLOODsite sponsor, to ensure the knowledge and outputs are drawn through to realise the true benefit of this work. An important first step has been the demonstration, in the context of the Humber Estuary, of the tools and techniques for pre-incident flood risk management planning.

The reliability and breach modelling techniques are being demonstrated on the earth embankment defences along the Stallingborough to Immingham coastline on the south bank of the Humber.

The reliability prototype tool, RELIABLE, developed under FLOODsite and available at http://www.floodsite.net/html/toolkit.asp, enables generation of structure-specific fragility curves. These performance curves are based on a reliability analysis of multiple potential failure modes linked together. The breach model (HR Breach) incorporates a detailed physics-based approach, which predicts breach growth through flood embankments of different material types and construction, combining hydraulics, soil mechanics and structural analysis into a single breach prediction model.

In addition, an estuary-wide risk-based strategy study is exploring flood risk management strategies through to 2115. It is utilising many of the risk-based and long-term planning methods developed during FLOODsite and now embedded in the Environment Agency’s Modelling and Decision Support Framework 2 (MDSF2).

These tools are providing a rich, consistent evidence base of risk information for the whole estuary. They provide a powerful tool for decision-makers to better understand the behaviour of the flood risk system both now and in the future.

For further information, please contact either Caroline McGahey, Principal Engineer, Floods Group, HR Wallingford (01491 822226; E-mail: C.McGahey@hrwallingford.co.uk), or
Dr S Surendran, Principal Scientist, Evidence Directorate, Environment Agency (01189 535259; e-mail suresh.surendran@environment-agency.gov.uk).