UK Surface Water Flood Flow Speed at 3.3% Annual Chance

A retired GIS dataset from the UK Environment Agency maps the maximum speed of flood flow from surface water for a 3.3% annual probability event. The data groups flow speed into five bands and is part of the broader Risk of Flooding from Surface Water mapping. It is based on digital spatial data from multiple UK government and research bodies, including the Centre for Ecology & Hydrology.

Use Cases

• Model regional flood hazard scenarios based on flow speed bands.
• Conduct broad-scale environmental risk assessments based on indicative flood mapping.
• Analyze surface water flood dynamics based on maximum speed data separate from depth.

Strengths

• Data is derived from multiple authoritative UK sources, including the Environment Agency and Centre for Ecology & Hydrology.
• Flow speed is categorized into five distinct bands for analysis.
• Specifically models a 3.3% annual chance flood event.

Limitations

• The dataset is explicitly retired and superseded by a newer version.
• Description metadata is limited; actual data quality requires manual inspection after download.
• The dataset carries strong warnings against use at property-level or for specific planning decisions without supporting evidence.

Provenance

Source

UK Environment Agency, Centre for Ecology & Hydrology (NERC), and other UK government and research bodies.

Collection Method

Produced as part of the Risk of Flooding from Surface Water (RoFSW) mapping.

Time Range

Data copyright and database right is noted as 2015.

Freshness

Last update date is unknown; freshness unverified.

Geography

Likely covers the United Kingdom, given the source organizations.