AfA480: 2004 Fluvial Flood Depth Grid Climate Change Difference

A 2004 depth grid shows the difference in modelled fluvial flood depths under a 20% increase in peak flows, representing a climate change scenario. This 5x5 meter resolution dataset was produced using the JFlow hydrodynamic model to fill gaps in detailed local flood data for spatial planning. It covers specific 100x100km Ordnance Survey grid squares in England for both 1% and 0.1% annual chance flood events.

Use Cases

• Assessing potential changes in flood zone extents for spatial planning based on a 20% peak flow increase scenario.
• High-level comparison of baseline and climate-adjusted flood depths using the 5x5m grid data.
• Informing preliminary strategic flood risk assessments where detailed local models are unavailable.

Strengths

• Provides a consistent, England-wide modelled baseline for climate change impact on fluvial flooding from 2004.
• Offers high-resolution geospatial data on a standardized 5x5 meter grid.
• Based on outputs from the JFlow two-dimensional hydrodynamic model.

Limitations

• The dataset has not been updated since its creation in 2004, and official climate change allowances have since changed.
• Metadata is incomplete across platforms, with no information on row count, specific columns, file size, or license.
• The data is explicitly not suitable for site-specific property-level assessments or detailed decision-making.

Provenance

Source

Environment Agency (UK), Approval for Access product AfA480.

Collection Method

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

Time Range

2004

Freshness

Last updated metadata dates from July 2026, but the underlying data is from 2004 and is noted as not updated.

Geography

Specific 100x100km Ordnance Survey National Grid squares (e.g., SD, NX, SZ) within England.