NaFRA2: implications for planning applications

The Environment Agency’s (EA) updated National Flood Risk Assessment (NaFRA) aims to provide more accurate and comprehensive data for flood risk management and planning. 

Data suggests that around 6.3 million properties are at risk from at least one source of flooding — rivers, seas, and surface water — which is a 15 per cent increase from 2018 figures of 5.5 million. The majority of those at risk are due to surface water flooding. What’s more, approximately 3,500 properties are situated in areas currently identified as being at risk of coastal erosion between now and 2055.

Due to the ongoing impacts of climate change, the number of properties at risk of flooding is expected to rise further, to 8 million by mid-century, with the majority still at risk from surface water flooding. The volume of properties affected by coastal erosion is also predicted to increase to 19,700 by 2055, a significant increase due to rising sea levels and climate change’s effect on coastal erosion processes. These figures include areas covered by Shoreline Management Plans (SMPs) and without considered investment the risk could be even higher.

Changes explained

One of the pitfalls of the previous NaFRA was that it didn’t offer future flood risk estimates based on climate change, and it suffered from a backlog of local updates. Plus it relied on outdated national models in some cases, without incorporating local datasets.

NaFRA2 resolves these issues by combining a greater range of information including smaller watercourses, updated lidar and hydrology information, more regular updates (quarterly), and combining local flood risk models with up to date national datasets. It provides a single picture of current and future flood risk, considering the potential impact of UK Climate Projections (UKCP18). 

Higher resolution maps depicting potential flood depths are also included. The system integrates various flood scenarios, considering both defended and undefended areas, to provide a more accurate representation of potential risks. The biggest benefit of these changes is the enhanced decision making ability it enables for investment and development.

In terms of flood zones, further changes are expected in March 2025. These are anticipated to be minimal in the overall zone mapping, particularly for zones 2 and 3. The updated flood maps will be more consistent, incorporating new layers such as those that reflect both the presence and absence of flood defences, current conditions, and potential climate change scenarios.

Implications for planning applications

NaFRA2 will continue to be fundamental in informing decisions regarding flood risk management and mitigation. With the EA as the statutory consultee on development in flood zones two and three, and because the flood zones don’t account for climate change, local authorities should apply the standing advice process set out on gov.uk to determine whether or not the EA should be consulted. In some rarer development types, such as essential infrastructure and highly vulnerable development, local authorities are asked to consult environmental consultancies such as GeoSmart.

Additionally, NaFRA2 will not be used to map the functional floodplain (Flood Zone 3b). It will however help in more consistently mapping this area and keeping flood zone designations updated. In the absence of current strategic flood risk assessment (SFRA) data, the 1-in-30 defended scenario may be used to assess the risk of flooding in these areas.

The updated climate change scenarios reflect the current allowances set by the EA, planning for a 4-degree Celsius warmer world by 2100. These scenarios are consistent with UKCP-18 and guide most planning applications. However, some developments may require further climate change assessments, especially nationally significant infrastructure projects or developments with unusually long or short lifetimes.

Further updates

Further updates to NaFRA are anticipated, to prioritise up-to-date flood risk information to enable more informed decision-making: 

• March 11: New flood risk data will be distributed to Local Planning Authorities (LPAs).
• March 25: Flood zone changes anticipated. Older data will be retired, although it will remain available for download for one month after the release of new data.
• Summer 2025: NaFRA2 will begin updates, prioritising locations with outdated or incomplete data.

To find out more about environmental reports to support planning applications, visit: geosmartinfo.co.uk/environmental-reports-for-planning/