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Taming the flood: Why it’s crucial to get your flood warning plan right


Two recent appeal decisions illustrate the importance of having an adequate flood warning and evacuation plan where flooding could be an issue in a proposed development, as James Cook explains

Two recent secretary of state (SoS) decisions have considered the use of a flood warning and evacuation plan (FWEP) when applying the exception test under NPPF paragraph 164.

Decision APP/D2510/V/20/3262525 related to the proposed extension of the period of occupancy of three caravan parks in Skegness. Decision APP/Z0166/V/21/3270776 related to the proposed change of use of a former police dog and horse training centre in Bristol to a touring caravan site. The Environment Agency (EA) appeared as a rule 6 party in both proceedings.

Limb (a) of the exception test requires it to be demonstrated that a development will provide wider sustainability benefits that outweigh the flood risk. Limb (b) includes a requirement to demonstrate that a development will be safe for its lifetime. NPPG advises that one of the considerations for ensuring any new development is safe, including where there is a residual risk of flooding, is whether adequate flood warnings would be available to people using the development. An FWEP is a specific requirement for sites at risk of flooding that are used for holiday or short-let caravanning/camping.


The EA contended that a FWEP could not be the sole mitigation against residual flood risk but there were concerns about the adequacy of the FWEPs in any event and they required modifications. The inspector said it was conceivable that failure of an FWEP may result from shortcomings in procedure and/or implementation. If the FWEP failed in any way, such that people were still on site when flooding occurred, they would likely to have been in need of rescue.

Both the Inspector and the SoS concluded that the adequacy of the FWEPs was integral and that it was not appropriate to condition the redrafting of the FWEPs until a later date. It could not be concluded with any reasonable degree of confidence that redrafted FWEPs would ensure that everyone would leave a site before being affected by a flood event. It followed that the proposal had failed to satisfy limb (b) of the exception test as well as the requirements of NPPF 167 (d) and (e) in relation to the management of residual risk and safe access and escape routes.

“Both the inspector and the SoS concluded that the adequacy of the FWEPs was integral”


The SoS concluded that neither the NPPF nor NPPG clearly state whether an FWEP can or cannot be the sole means of dealing with flood risk, but agreed with the EA that design risk and residual risk must be kept as distinct concepts, and that an FWEP should not be seen as a routine way of dealing with design risk. The SoS agreed with the inspector that whether or not an FWEP can be used as the sole means of mitigation would depend on the case and whether the FWEP could be relied upon to make the development safe for its lifetime.

The inspector concluded that the EA’s flood warning system would provide sufficient time for the site to be evacuated in accordance with the FWEP, and that the risk of failure was sufficiently low to conclude that the development would be safe for its lifetime in accordance with limb (b) of the exception test.

But the SoS disagreed, finding the FWEP dependent upon fallible processes which meant a residual risk of failure and that the applicant had no plans for managing those residual risks. The SoS therefore concluded it had not been demonstrated that the proposal failed not only limb (b) of the exception test, but also limb (a).

In brief

  • Two called-in appeals considered the use of an FWEP when applying the NPPF’s exception test
  • Both applicants needed the SoS to agree that the FWEP would ensure the development would be safe
  •  The SoS rejected the first because the FWEP was inadequate, and the second because it did not include plans for residual risks.

James Cook is head of planning law at Blacks Solicitors

Image credit | Shutterstock | Marck Bickerdike 


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