AfA480: 2004 Climate Change Fluvial Flood Depth Grids for England

Modelled fluvial flood depth data for England was created in 2004 using the JFlow two-dimensional hydrodynamic model on a 5x5m grid. The dataset provides a high-level sensitivity analysis for climate change effects, simulating a 20% increase in peak flows for 1% and 0.1% annual chance flood events. Its primary purpose was to fill gaps in detailed local data to define flood zone extents for spatial planning.

Use Cases

• High-level flood zone definition for spatial planning based on modelled flood extents.
• Sensitivity analysis of potential climate change impacts on fluvial flooding using a 20% peak flow increase scenario.
• Initial screening for areas that may require more detailed local flood risk assessment.

Strengths

• Provides national coverage for England, created using a standardized two-dimensional hydrodynamic model (JFlow).
• Offers high spatial resolution data on a consistent 5x5m grid.
• Represents a historically significant, standardized baseline dataset produced for national planning in 2004.

Limitations

• The dataset has not been updated since its creation in 2004, and climate change modelling allowances have since changed.
• Sources conflict on the specific annual chance of flooding, listing both 1% (1 in 100) and 0.1% (1 in 1000) events for the same grid references.
• Critical metadata is missing, including specific column names, row counts, file size, license, and author information.

Provenance

Source

Government Digital Service (from eu_open_data platform), likely originating from the UK Environment Agency's Approval for Access (AfA) product AfA480.

Collection Method

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

Time Range

2004

Freshness

Metadata last updated on 2026-07-06, but the underlying data is from 2004 and has not been revised.

Geography

England, delivered in 100x100km tiles based on Ordnance Survey National Grid references (e.g., SS, SO).