Surface Water Flood Speed Risk Maps for the United Kingdom

Flood speed risk is modeled across five distinct velocity thresholds: 0m/s, 0.25m/s, 0.5m/s, 1m/s, and 2m/s. This probabilistic dataset from the UK Environment Agency assesses annual likelihoods of flooding events with water travelling at or above these speeds, categorized into High, Medium, Low, and Very Low risk bands. The data was last updated in April 2026.

Use Cases

• Model pedestrian safety and structural impact by analyzing flood extent and speed layers for velocities of 0.25m/s and 0.5m/s.
• Prioritize emergency response planning by identifying areas with a High risk (>=3.3% annual chance) of flooding with water speeds of 1m/s or higher.
• Calibrate local flood models by integrating national-scale probabilistic risk data for speeds >=2m/s with local authority data.
• Assess long-term property risk by mapping the 'Very Low' risk band (below 0.1% annual chance) for all speed thresholds.

Strengths

• Provides five distinct modeled layers for specific flood speed thresholds (0m/s, 0.25m/s, 0.5m/s, 1m/s, 2m/s).
• Risk is quantified with clear annual probability bands: High (>=3.3%), Medium (1-3.3%), Low (0.1-1%), and Very Low (<0.1%).

Limitations

• Data is probabilistic, representing overall risk rather than specific event scenarios, limiting use for real-time flood forecasting.
• The spatial resolution and exact geographic coverage of the modeled extents are not specified in the provided description.

Provenance

Source

Environment Agency (UK)

Collection Method

Produced using national-scale hydrological modeling enhanced with compatible local models from Lead Local Flood Authorities.

Time Range

null

Freshness

Updated as of April 2026.

Geography

United Kingdom