Residual UNCERTAINTY Allowance - an update approach to freeboard

Sayers and Partners has been working with the Environment Agency and Royal HaskoningDHV to update the freeboard guidance as part of the joint Environment Agency/Defra Research and Development Programme. The existing fluvial freeboard guidance is now well over 10 years old. The guide does not reflect the Environment Agency’s risk based approach to Flood and Coastal Risk Management. This project aims to ensure the consideration of freeboard when designing and appraising assets is consistent, and advice to developers is fair and well evidenced. We are also aiming to extend the guidance to other sources of flood risk (coastal, surface water). The overall objective of this project is to produce:

 “An updated, practitioner focused, guide for establishing freeboard allowances for design of new flood and coastal defences and assessment of existing defences, and development control.”

The project is now complete and the report is here