May 2011
Halcrow has played a crucial role in delivering Exercise Watermark, the UK’s largest civil protection exercise for over 60 years.
Following the 2007 floods, which cost the UK economy an estimated £3.2 billion and caused 13 fatalities, an independent review was carried out by Sir Michael Pitt. One of his recommendations called for a national flooding exercise at the earliest opportunity, to test new arrangements put into place to deal with flooding and infrastructure emergencies.
As one of the Environment Agency’s partners on the project, Halcrow supported the planning, design and successful delivery of this unprecedented flooding exercise.
Halcrow’s knowledge and expertise in flood risk, covering all sources of flooding, was employed to design and map a realistic four-day flooding scenario. The team also helped engage local resilience forums by attending their meetings and providing advice to ensure local objectives would be adequately tested by the national exercise.
Halcrow led the production, coordination and quality assurance of a vast set of information – including e-mails, texts, telephone calls, weather updates, news clips and travel information – used to simulate public responses during a flood event. During the actual exercise, three Halcrow employees took up technical roles in the control centre, making a further valuable contribution to this large and hugely successful flooding exercise.
Exercise Watermark required a large amount of GIS flood mapping to animate the hourly development of the flood extent over the four-day exercise. Halcrow brought a number of innovations to the project, as flood risk management director Richard Crowder explained: “Typically, only maximum extent flood maps were available as output from existing models, so we used our experts to develop practical assumptions about how the maximum extent of flooding from different sources would develop over time. We then prepared bespoke GIS scripts to buffer the flood extents out from their assumed source, such as coastal defence line or the centre of a surface water pond, to provide approximate hourly extents, adding a realistic temporal dimension to the flood scenario.”
Some of Halcrow’s clients also used Exercise Watermark to successfully test the company’s innovative FloodViewer tool, which serves to support decision making during flood emergencies.