dataset · England
Reservoir Flood Extents - Dry Day (National)
This data shows the individual flood extents for all large raised reservoirs in the event that they were to fail and release the water held on a “dry day” when local rivers are at normal levels. It represents a prediction of a credible worst case scenario, however it’s unlikely that any actual flood would be this large. The data gives no indication of the likelihood or probability of reservoir flooding. Flood extents are not included for smaller reservoirs or for reservoirs commissioned after th
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Licence: ["There are no public access constraints to this data. Use of this data is subject to the licence identified.", "There are no public access constraints to this data. Use of this data is subject to the
Evidence quality: 67.7
Listed in data.gov.uk public catalogue API on 2026-10-16; relevance/value screened (haiku).
Metadata checked: 2026-10-14T13:20:00.000Z
What's in it
- Data offered docs-verified
- individual flood extents for large raised reservoirs, dry-day failure scenario
- Coverage docs-verified
- National (bounding box lat 49.943 to 55.816, lon -6.236 to 2.072; EPSG:27700)
- Update frequency docs-verified
- quarterly
- Formats docs-verified
- GeoJSON (zipped) · GeoPackage (zipped) · File Geodatabase (zipped) · OGC API - Features · WMS · WFS · layer file (.lyr)
- Access docs-verified
- Free and open: Open Government Licence v3.0, no public access constraints
Useful for
- Use cases llm-inferred
- Screening sites near large raised reservoirs for reservoir-failure flood extent constraints in FRA · Reservoir-failure flood risk context for planning and development site selection · Mapping reservoir inundation extents for emergency planning and resilience assessments
- Audience llm-inferred
- flood consultants · hydrologists · planners · GIS analysts
Limitations
- Constraints docs-verified
- Dry-day worst-case credible scenario; the data is not a prediction of a likely flood · No likelihood or probability of reservoir flooding is given · Excludes smaller reservoirs and reservoirs commissioned after the October 2016 modelling programme start
Evidence
- https://environment.data.gov.uk/api/file/download?fileDataSetId=7edac58e-e2d7-4421-801b-c18a580e7210&fileName=Data Version.txt
- https://www.data.gov.uk/dataset/2e0f68b1-70df-43cc-ad61-ed5ef0e585d1/reservoir-flood-extents-dry-day-national
Check upstream coverage, uncertainty and licence before use. Station observations are not forecasts or design levels.