AfA480: 2004 Fluvial Flood Depth Grids with Climate Change

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 uses the JFlow hydrodynamic model on a 5x5m grid to simulate flood depths for 0.1% and 1% annual chance events, incorporating a high-level climate change sensitivity analysis based on a 20% increase in peak flows. This dataset is intended for high-level planning and sensitivity analysis but is not updated since its creation and is not suitable for site-specific assessments.

Use Cases

• High-level sensitivity analysis of climate change impacts on flood risk based on a modelled 20% increase in peak flows.
• Strategic spatial planning to define approximate flood zone extents where detailed local models were unavailable in 2004.
• Preliminary assessment of potential flood depth patterns at a 5x5m grid resolution for large-scale studies.

Strengths

• Provides national coverage for England, filling data gaps where detailed local models were absent in 2004.
• Uses a specific two-dimensional hydrodynamic model (JFlow) on a defined 5x5m spatial grid.
• Includes a defined climate change scenario (20% increase in peak flows) for sensitivity analysis.

Limitations

• The dataset has not been updated since its creation in 2004, and climate change allowances have since changed.
• Sources conflict on the specific annual chance of flooding, describing both 0.1% and 1% events.
• Metadata completeness is low, with no information on row count, specific columns, file size, or license.

Provenance

Source

Environment Agency (UK)

Collection Method

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

Time Range

2004 (modelling date)

Freshness

Last updated metadata dates are from July 2026, but the underlying modelled data is from 2004 and is explicitly stated as not updated.

Geography

England, specifically for the 100x100km Ordnance Survey National Grid reference NZ, with data available for other grid references covering the whole country.