AfA480: 2004 Climate Change Fluvial Flood Depth Grids for England

Environment Agency's AfA480 product provides modelled fluvial flood depth data for a 0.1% annual chance event under a 2004 climate change scenario. The data was generated using the JFlow two-dimensional hydrodynamic model on a 5x5m grid as part of a generalized national modelling project. It serves as a high-level sensitivity analysis based on a 20% increase in peak flows and is available for 100x100km Ordnance Survey grid squares across England.

Use Cases

• High-level sensitivity analysis of climate change impacts on flood extents based on a 20% peak flow increase.
• Preliminary definition of Flood Zones for spatial planning in areas lacking detailed local models.
• Assessing regional-scale flood depth patterns under a specific historical climate change scenario.

Strengths

• Provides national coverage for England, synthesized from multiple grid-specific datasets.
• Based on a specific, documented modelling methodology (JFlow 2D hydrodynamic model) and a 5x5m grid resolution.
• Represents a standardized historical baseline (2004) for climate change sensitivity analysis.

Limitations

• The dataset has not been updated since its creation in 2004, and climate change allowances have since changed.
• Explicitly not suitable for property-level assessment, detailed decision-making, or site-specific flood risk assessments.
• Metadata completeness is low, with no information on row counts, specific columns, file size, or license.

Provenance

Source

Environment Agency (UK)

Collection Method

Modelled using the JFlow two-dimensional hydrodynamic model.

Time Range

2004 (modelling project date)

Freshness

Metadata records show updates in July 2026, but the core modelled data is from 2004 and has not been updated.

Geography

England, available in 100x100km Ordnance Survey National Grid squares (e.g., TA, TM, TR, TG, TV, TQ).