AfA480: 2004 Fluvial Flood Depth Change Under Climate Scenarios

England's 2004 generalised modelling project produced this 5x5m grid data showing the difference in modelled fluvial flood depths between baseline and climate change conditions, assuming a 20% increase in peak flows. It covers the 100x100km Ordnance Survey National Grid reference SP and was generated for both the 1% and 0.1% annual chance flood events using the JFlow two-dimensional hydrodynamic model. The dataset was created to fill gaps in detailed local data for defining Flood Zones for spatial planning, but it has not been updated since 2004.

Use Cases

• Assessing potential changes in flood inundation extent for spatial planning based on a 20% peak flow increase scenario.
• Comparing baseline and climate-adjusted flood depths from the 2004 generalised modelling project at a 5x5m resolution.
• Identifying areas where climate change may exacerbate flood risk for preliminary strategic reviews, prior to seeking detailed local models.

Strengths

• Provides a high-resolution (5x5m grid) comparison of flood depths under two scenarios.
• Covers a specific, large (100x100km) geographic tile (SP) with modelled data for England.
• Derived from a defined hydrodynamic modelling process using the JFlow model.

Limitations

• Data is outdated (from 2004) and climate change allowances have since changed.
• Sources conflict on the annual chance of flooding covered (0.1% vs 1%).
• Metadata is incomplete, with no information on row count, specific columns, license, or author.

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 metadata update recorded as 2026-07-06, but the underlying data is from 2004 and is explicitly stated as not updated.

Geography

Covers the 100x100km Ordnance Survey National Grid reference SP in England. Modelled data for the whole of England exists, but this specific dataset is for tile SP.