AfA480: 2004 Climate Change Fluvial Flood Depth Grids for England

Environment Agency's AfA480 product provides modelled fluvial flood depth data for England, created in 2004 as part of a generalised modelling project. The data, generated using the JFlow hydrodynamic model on a 5x5m grid, offers a high-level sensitivity analysis of climate change effects based on a 20% increase in peak flows. It covers specific 100x100km Ordnance Survey grid squares (e.g., SK, SE) for both 1% and 0.1% annual chance flood scenarios.

Use Cases

• High-level flood zone definition for spatial planning based on modelled extents.
• Sensitivity analysis of potential climate change impacts on fluvial flooding using a 20% peak flow increase scenario.
• Regional-scale flood risk screening prior to commissioning detailed local studies.

Strengths

• High spatial resolution from a 5x5m grid produced by a two-dimensional hydrodynamic model (JFlow).
• Nationwide coverage for England, with data available for multiple 100x100km grid squares.
• Explicitly defined modelling scenario for climate change sensitivity (20% increase in peak flows).

Limitations

• Dataset has not been updated since its creation in 2004, and climate change allowances have since changed.
• Data is explicitly flagged as unsuitable for property-level assessment, detailed decision-making, or site-specific flood risk assessments.
• Metadata completeness is low, with no information on row count, specific columns, file size, or license provided across platforms.

Provenance

Source

Environment Agency (UK)

Collection Method

Produced as a by-product of the 2004 generalised modelling project using the JFlow two-dimensional hydrodynamic model.

Time Range

2004

Freshness

Last updated metadata dates range from 2026-07-06, but the underlying data is from 2004 and is stated as not updated.

Geography

England, covering specific 100x100km Ordnance Survey National Grid squares (e.g., SK, SE).