England Flood Depth Model for 1% Annual Chance Flooding, 2004

Modelled fluvial flood depth data was created for the 1% annual chance of flooding situations as a by-product from the 2004 generalised modelling project. The Environment Agency produced this data using the JFlow two-dimensional hydrodynamic model on a 5x5m grid to fill gaps where no detailed local modelled data existed in 2004. This metadata record is for the AfA238 Flood Zone Depth Grid Dataset 2004, covering the Ordnance Survey National Grid reference SX.

Use Cases

• Assessing broad catchment-scale flood risk based on modelled flood depth data.
• Supporting Shoreline Management Plan development based on generalised flood extents.
• Historical comparison of flood zones where detailed local models have since replaced this data.

Strengths

• Data is modelled on a 5x5m grid, suggesting a relatively fine spatial resolution.
• Coverage is available for the whole of England, though this specific file is for grid reference SX.

Limitations

• The dataset was created in 2004 and has not been updated; more recent, accurate local detailed modelling is available for many areas.
• The data is explicitly not suitable for identifying whether an individual property will flood or for detailed decision making.
• Column-level documentation is absent; field semantics must be inferred after download.

Provenance

Source

Environment Agency, with digital spatial data licensed from the Centre for Ecology & Hydrology (CEH).

Collection Method

Created using the JFlow two-dimensional hydrodynamic model.

Time Range

2004

Geography

England, specifically for Ordnance Survey National Grid reference SX.