AfA480: 2004 Fluvial Flood Depth Grids with Climate Change

A 2004 generalised modeling project produced 5x5m grid fluvial flood depth data for England, simulating a 20% increase in peak flows to assess climate change effects. The dataset covers two flood probabilities: a 0.1% annual chance (1 in 1000) and a 1% annual chance (1 in 100) event. It is intended for high-level sensitivity analysis and spatial planning but is not updated and unsuitable for site-specific assessments.

Use Cases

• High-level sensitivity analysis of climate change impacts on flood zones based on a 20% peak flow increase.
• Defining extents of Flood Zones for spatial planning where no detailed local modeled data existed in 2004.
• Comparing generalized flood risk scenarios across England using a standardized 5x5m grid model.

Strengths

• Provides national-scale coverage for England, modeled on a standardized 5x5m grid.
• Uses a specific two-dimensional hydrodynamic model (JFlow) for flood depth simulation.
• Includes data for two distinct flood probability scenarios (0.1% and 1% annual chance).

Limitations

• The dataset is not updated; modeling assumptions and climate change allowances from 2004 are outdated.
• Sources conflict on the specific flood probability covered, listing both 0.1% and 1% annual chance events.
• Metadata completeness is low; column names, row counts, license, and author information are unknown.

Provenance

Source

Environment Agency (via Government Digital Service and Approval for Access product AfA480)

Collection Method

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

Time Range

2004

Freshness

2026-07-06 07:15:26.775656

Geography

England, specifically for the Ordnance Survey National Grid reference SX (100x100km tile). Data is available for other grid references across England.