Surface water and flood risk maps
The Environment Agency provides a wide range of datasets to support the planning process from a flood risk management perspective. In January 2025, the Agency released a significant update to its technical mapping service, known as NaFRA2 (National Flood Risk Assessment 2). This represents a major step forward in flood modelling, offering higher-resolution data and improved modelling techniques.
NaFRA2 incorporates detailed local information, including topography, infrastructure, flood defence assets, and updated hydrological inputs. For the first time, the dataset also includes climate change modelling, based on short- to medium-term projections from the RCP 8.5 emissions scenario. Although NaFRA2 is not intended for use in planning applications, it provides valuable insight into current and future flood risks across England, including in North Lincolnshire.
On 25 March 2025, the Environment Agency released a major update to the Flood Map for Planning (FMfP), integrating data from the newly launched National Flood Risk Assessment 2 (NAFRA 2). This update marked a significant improvement in flood modelling resolution and accuracy, increasing the grid resolution from 50m to 2m, and incorporating enhanced national and local flood models, updated hydrology, and refined topographic data
The August 2025 update to the FMfP further streamlined the planning process by simplifying how climate change scenarios are represented. Previously, planners were required to assess defended and undefended flood scenarios separately, often using multiple layers and datasets. The updated FMfP now presents a single unified layer for Flood Zone 3, which includes climate change allowances based on the UKCP18 RCP 8.5 emissions scenario, specifically using the 2080s epoch for fluvial and coastal modelling.
This change allows for a more consistent and accessible interpretation of flood risk, particularly for strategic planning and site-specific assessments. However, it remains essential that both defended and undefended scenarios are still considered during site-specific Flood Risk Assessments (FRAs), especially in areas with complex flood defence infrastructure or residual risk.
Key improvements in the August 2025 FMfP include:
- Revised Flood Zones 1, 2, and 3, reflecting more accurate flood extents and depths.
- Integrated climate change modelling within Flood Zone 3, reducing the need for separate scenario analysis.
- Improved surface water flood mapping, incorporating updated land use and permeability data, and accounting for SuDS features where applicable.
While the new mapping provides a more refined national overview, it is not a substitute for detailed site-level analysis. Developers and consultants should continue to undertake site-specific FRAs, supported by hydraulic modelling, topographic surveys, and local drainage assessments, to ensure compliance with planning policy and flood resilience standards.
However, it is important to note that surface water mapping remains subject to modelling limitations and should only be used as a broad indicator of site conditions. It is not accurate enough for detailed planning purposes, and site-specific assessments should always be undertaken where surface water flooding is a concern.