Risk of Flooding from Surface Water Direction: 1 Percent Annual Chance

A GIS layer showing the dominant flow direction of flooding from surface water, based on a 2-meter grid and grouped into eight compass directions. It models maximum speed flow resulting from a flood with a 1% annual chance, produced by the UK Environment Agency as part of the Risk of Flooding from Surface Water (RoFSW) mapping. The dataset was last updated on 2026-07-06.

Use Cases

• Model regional surface water flood propagation based on dominant flow direction.
• Assess flood hazard corridors for strategic planning based on 2-meter grid data.
• Integrate flow direction data with other flood risk layers for composite hazard mapping.

Strengths

• Based on a 2-meter resolution grid, providing detailed spatial data.
• Groups flow direction into eight distinct compass bands for simplified analysis.
• Part of a formal Risk of Flooding from Surface Water (RoFSW) mapping program.

Limitations

• Description metadata is limited; actual data quality requires manual inspection after download.
• The dataset is not suitable for identifying flooding at individual property level.
• Last updated 2026-07-06; freshness should be verified.

Provenance

Source

Environment Agency

Collection Method

Produced as part of the Risk of Flooding from Surface Water (RoFSW) mapping, previously known as the updated Flood Map for Surface Water (uFMfSW).

Freshness

Last updated 2026-07-06.

Geography

United Kingdom