Friday 12 November 2010

Flood Risk - Five Steps to Success

Flood risk isn't a black box science, you can scope your sites out easily using the following  five steps.

1. Identify the Flood Zone which the site lies within, insert the sites postcode into the EA website CLICK HERE. This will identify if the site is in flood zone 1, 2 or 3a/b.

At this stage you should also contact the local Environment Agency ‘Development Control Officer’ and hold informal confidential discussions about the site in terms of flooding to determine if there are any show stoppers. The local officers can identify these and provide information which you may not be aware of. They can be contacted via 08708 506 506 then select option 2

2. Residential development is classed as ‘more vulnerable’ within PPS25, therefore it is only acceptable within Flood Zone 3a subject to a ‘sequential and exception test’. Sites within Flood Zone 1 would only require drainage assessments; Flood Zone 2 is acceptable subject to a satisfactory FRA. Development would not be allowed within zone 3b.

3. If the site is within Flood Zone 3, check the SFRA to determine local advice and if the site has been reviewed/allocated within the SFRA. e.g. Greater Manchester SFRA CLICK HERE. If the site is allocated then review the constraints, if it is not allocated a more robust FRA is required


4. If the site is within Flood Zone 3, and not an allocated SFRA site, then a more robust FRA is required, as the site may not be suitable for development.

5. The next stage from this would be to contact a FRA consultant [EMAIL ENZYGO] in order to determine if there are any reasons to challenge the SFRA’s assumptions. This may require 1D or 2D flood modelling, or more detailed drainage assessments.


More details on the following can be found from the links below
  1. flood risk modelling
  2. Sequential and exception tests
  3. drainage assessments
  4. business continuity and flood risk plans
  5. frequently asked questions about flood risk