Return Period
Return period refers to the statistical average interval of time between flood events of a given magnitude, typically expressed in years (e.g. a 1 in 100 year event). Speak with a consultant to understand which return period events your FRA must assess. The technical basis for return period analysis is set out in the Environment Agency river modelling standards.
Case Example
A site in Flood Zone 3 is assessed using the 1 in 100 year return period, meaning there is a 1% chance of flooding in any given year, which triggers the requirement for an FRA and stricter development controls.
Design for correct storms. Rida Reports applies return periods in your FRA.