AfA480: 2004 Fluvial Flood Depth Change Under Climate Change

England's 2004 generalised modelling project produced this 5x5m grid showing the difference in modelled fluvial flood depths with and without a 20% increase in peak flows, representing a climate change scenario. The data covers the SE 100x100km Ordnance Survey National Grid tile and was generated using the JFlow two-dimensional hydrodynamic model. It was created to define Flood Zone extents for spatial planning in areas lacking detailed local models at the time.

Use Cases

• Assessing potential changes in flood inundation extent for strategic spatial planning based on 2004 climate projections.
• Comparing baseline and climate-adjusted flood depths for the 1% annual chance event (or 0.1% in some sources) from the 2004 national modelling project.
• Identifying areas where generalized model data suggests increased flood risk due to a 20% peak flow increase, prompting further local investigation.

Strengths

• Provides a high-resolution (5x5m grid) spatial comparison of flood depths under two scenarios.
• Based on a standardized national modelling project (2004 generalised modelling) using the JFlow hydrodynamic model.
• Covers a specific, large (100x100km) geographic tile (SE) with consistent methodology.

Limitations

• The dataset is outdated (created in 2004) and climate change allowances have since changed; it has not been updated.
• Sources conflict on the specific annual chance of flooding modeled (0.1% vs 1%).
• Metadata for rows, columns, size, license, and author is consistently missing or listed as 'unknown'/'None' across all platforms.
• Explicitly not suitable for property-level assessment or detailed site-specific decision-making.

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

2026-07-06 07:13:09.645664

Geography

England, specifically the Ordnance Survey National Grid 100x100km tile reference SE.