August 2022 Update to the National Planning Practice Guidance: Flood Risk and Coastal Change

There has been a major update to the Flood Risk and Coastal Change section of the Planning Practice Guidance, which is expected to have a significant affect on planning applications.

The update is packaged as a necessary move in the face of the impacts of climate change, but the knock-on effect means less land available to develop and harder to get planning permission.

The update places a fair amount of responsibility on Local Councils and their Strategic Flood Risk Assessments.  How these changes are implemented and when they will come into effect at local level are yet to be confirmed by each authority.  However, it should be assumed that any application that has not been submitted would be subject to this updated guidance.

The update is extensive, with various updates to technical requirements and definitions.  Therefore, the below provides a summary which covers the main changes which we consider the most relevant to our colleagues and Clients: 

Sustainable Drainage Systems (SuDS)

  • There is a strong emphasis that preference should be given to multifunctional SuDS features in accordance with the CIRIA defined “4 Pillars of SuDS”: enhancing water quality, improving biodiversity, providing amenity benefits, and reducing volumes of surface water runoff.
  • Authorities are encouraged to make use as much as possible of opportunities presented by new developments to reduce the causes and impacts of flooding, through the use of Natural Flood Management techniques.  This could include de-culverting watercourses or catering for off-site flood flows.
  • Environmental permits may be required for SuDS features discharging potential pollutants.

The Sequential Test

  • Flooding from all sources is to be considered as part of the Sequential Test, including an allowance for climate change.  The test is to be applied for any level of flood risk, with the aim to “steer new development to areas with the lowest risk of flooding.”
  • Table 2: Flood Risk Vulnerability and Flood Zone ‘Incompatibility’ has been updated to reflect the above, with the stricter replacement of ‘Development is appropriate’ with ‘Exception Test is not Required’:
Table 2: Flood Risk Vulnerability and Flood Zone ‘Incompatibility’
  • The area of consideration for alternative sites as part of the test is to be defined by local circumstances.  Sites not within the Client’s ownership are to be considered ‘reasonably available’.  In addition, alternative sites could include a series of smaller sites or part of larger developments.
  • SHLAAs and ELAAs are to utilised as part of the test but can also include sites available on the open market.
  • Where other ‘reasonably available’ sites are identified, demonstrating clear reasons for refusing development at these sites in relation to wider sustainable development objectives and local and national policies would need to be accomplished for the Sequential Test to be passed.

The Exception Test

  • The application of the Exception Test remains the same.  However, the requirements have become stricter with the removal of the use of planning conditions/obligations should a site fail to score positively against the aims of the sustainability appraisal.
  • The developer will still need to demonstrate wider sustainable benefits, this should be in relation to the impacts of flood risk on social, economic and environmental factors.
  • Examples of wider sustainability benefits have been provided, which includes:
    • The re-use of suitable brownfield land as part of a local regeneration scheme;
    • An overall reduction in flood risk to the wider community through the provision of, or financial contribution to, flood risk management infrastructure;
    • The provision of multifunctional Sustainable Drainage Systems that integrate with green infrastructure, significantly exceeding National Planning Policy Framework policy requirements for Sustainable Drainage Systems.

Functional Floodplain & Definitions

  • The functional floodplain, Flood Zone 3b, has been redefined as land having a 3.3% (1 in 30 year event) or greater annual probability of flooding.  This will increase the extent of the functional floodplain from the 5% annual probability (1 in 20 year event).
  • The ‘design flood event’, on which site specific FRAs are to assess developments against, has been redefined to include climate change.   The events are now as follows:
    • River flooding with a 1 in 100 year annual probability of occurring plus an allowance for climate change.
    • Tidal flooding with a 1 in 200 year annual probability of occurring plus an allowance for climate change.
    • Surface water flooding with a 1 in 100 year annual probability of occurring plus an allowance for climate change.
  • The design lifetime of residential developments remains at a minimum of 100 years.  However, the lifetime of non-residential developments has increased to at least 75 years.


  • A hierarchal approach to mitigation has been added, with developments required to reduce flood risk through:
    • Avoidance through plan/decision making (in tandem with the Sequential Test),
    • Control risk within and off site, through liaison with LLFA/EA,
    • Mitigate risk on-site with flood resistance and resilience measures,
    • Manage residual risk through management measures.
  • Flood risk activity permits may now be required for works within a floodplain, this is likely to include any form of works that raise levels above existing. 
  • Flood compensatory storage is now permitted off-site, provided level-for-level compensation on-site is proven not to be possible, and that the off-site location is hydraulically and hydrologically linked.

Access and Egress

  • There is now a set requirement to assess the ability of users to evacuate before a 1 in 1000 year storm event, plus an allowance for climate change.  This would likely require a reasonably appropriate Flood Evacuation Plan for any development at risk of flooding.
  • There is also a focus on emergency response and evacuation routes, particularly to less mobile users and also where there is potentially a large number of users.

Community Infrastructure Levy (CIL) & Section 106 Contributions

Within several subcategories, the update states that the developer should be expected to cover potential additional costs incurred, with reference to the NPPF Paragraph 187 as an ‘agent of change’.  The details of this have not been provided, but early indications show that it is likely that any costs would be through the CIL or Section 106 contributions.  Notable inclusions as part of the update are as follows:

  • In relation to increasing the number of people living or working within an area which would increase the scale of evacuation needed, and where suitable mitigation cannot be provided, it states that developers need to cover the full cost of any additional emergency service provision needed.
  • Developments downstream of reservoirs are required to cover potential costs of improving the dam design to reduce the flood risk, operation and general maintenance. 
  • It states that it may be appropriate for Local Planning Authorities to use the CIL or Section 106 contributions to fund strategic area-wide flood management improvements and Natural Flood Management techniques.

There have been further updates to the extent of assessment required and also the technical requirements and definitions in relation to Change of Use, Flood Resilience, Off-site Impacts, Residual Risks, and several more subcategories.

If you would like to find out how these changes may affect your project, please get in touch with Stomor and we’ll be happy to discuss further.

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