The FRA for this scale of development will vary from a relatively minor nature to a more thorough investigation / report depending on the type, location and scale of development.
Examples of what will or may need a more substantial Flood Risk Assessment (not a complete list)
- Anything in an area known to flood.
- Infill development in developed areas.
- Increased impermeable/hard areas.
- Anything that discharges to a watercourse.
- Development at the bottom of a hill or slope.
- Development on a hill (reference flooding others).
The FRA should assess:
- Surface water measures already in place, their state of maintenance and performance.1
- Likely run-off that would be generated from the proposal.2,3
- Residual risks after any sustainable drainage system has been constructed.5
- The source of potential flooding - rivers, tidal, coastal, surface flow, highway or a combination. 1
- How surface water that falls on the site will be dealt with on site.3,4
- The name and details of the body that will be responsible for the future maintenance of the system.
- A location plan will be required usually at a scale of 1:1250 sufficient to identify the site and show watercourses in the vicinity of the site.
- A plan of the site showing existing and proposed development.
- As most watercourses in the New Forest District Council area are at capacity it is unlikely that more water will be permitted to be discharged to a watercourse than occurred prior to development - plans and where necessary, calculations will be required to show compliance.
- Surface water from highways floods property and highway drains outfall to watercourses that are generally at capacity so no water from the development site including driveway and access roads are to be drained to existing highway. Proposed finished levels are to be shown on the proposed development drawing.
- In many locations where a FRA is required and a sustainable drainage system or water retention scheme is required a 1 in 100 year storm will need to be designed for. The flood flow route when this storm is exceeded will also need to be shown.
4 copies of this information should be submitted with your planning application to New Forest District Council.
Further information and advice is available from:
New Forest District Council
Telephone 023 8028 5333
E mail email@example.com
Planning Liaison Team
Wessex Business Park
Environment Agency (West)
Sunrise Business Park
Higher Shaftesbury Road