Southend Central Area Action Plan (SCAAP) - February 2018
Appendix 4: Flood Risk Management Technical information and Definitions
Flood Risk Definitions:
Flood risk zone 2 – medium risk, 1 in 1,000 to 1 in 200 annual probability Flood risk zone 3 - high risk, 1 in 200 annual probability or more
Design flood event and flood level – based on 1 in 200 annual probability event at the end of the development's lifetime.
Extreme flood event and flood level – based on 1 in 1,000 annual probability event at the end of the development's life.
As an example, the SFRA2 predicts that within the Central Seafront Area, outside of Adventure Island, by 2110, the design and extreme maximum flood depth are approximately 1 metre and 4 metres. Adventure Island is characterised by 5m maximum flood depths under both scenarios.
Lifetime of development – assumed to be 100 years for residential, 60 years for commercial (unless circumstances indicate otherwise)
Flood Risk Vulnerability Classification
Highly Vulnerable
- Emergency services
- Emergency dispersal points
- Basement dwellings
More Vulnerable
- Hospitals
- Residential institutions such as care homes, children's homes, and hostels
- Buildings used for: dwelling houses; student halls of residence; drinking establishments; nightclubs; and hotels
- Health services, nurseries and educational establishments