Lord Taylor of Holbeach (Shadow Minister, Environment, Food & Rural Affairs; Conservative) | Hansard source

asked Her Majesty's Government:

Whether the flood risk maps established by the Environment Agency take account of existing flood defences and assess the risk of flooding accordingly.

Lord Hunt of Kings Heath (Minister of State (Sustainable Development, Climate Change Adaptation and Air Quality), Department for Environment, Food and Rural Affairs; Labour) | Hansard source

The Environment Agency flood map indicates the location of some flood defences, but work is currently taking place to extend this. Some of the areas which benefit from these defences are shown on the Environment Agency website by a hatched shading. Defences can be overtopped if a flood occurs which is higher than the defences are designed to withstand.

A national flood risk assessment of the likelihood of flooding from rivers and the sea has been undertaken that uses a risk-based probabilistic approach that takes into account the location, type and performance of flood defences in the assessment.