dataset · England
Overland Flow Pathways
The Most Probable Overland Flow Pathway dataset is a polyline GIS vector dataset that describes the likely flow routes of water along with potential accumulations of diffuse pollution and soil erosion features over the land. It is a complete network for the entire country (England) produced from a hydro-enforced LIDAR 1-metre resolution digital terrain model (bare earth DTM) produced from the 2022 LIDAR Composite 1m Digital Terrain Model. Extensive processing on the data using auxiliary datasets
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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: 60.7
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
- Probable Overland Flow Pathways (polyline) · Detailed Watersheds (polygon) · Ponding and Errors (polygon)
- Coverage docs-verified
- England
- Resolution docs-verified
- 1 m source DTM; flow network based on theoretical one-hectare flow accumulations
- Update frequency docs-verified
- As needed (per publisher metadata)
- Formats docs-verified
- GeoJSON (zipped) · GeoPackage (zipped) · File Geodatabase (zipped) · OGC API - Features · WFS · WMS
- Access docs-verified
- Free and open; no public access constraints; Open Government Licence
Useful for
- Use cases llm-inferred
- Identifying likely overland flow routes and accumulation areas for flood risk screening · Locating exceedance flow paths to inform a drainage strategy · Screening catchments for diffuse pollution and soil erosion risk · Mapping slope along flow pathways for site-level surface water assessment
- Audience llm-inferred
- flood consultants · drainage engineers · hydrologists · GIS analysts · civils engineers
Limitations
- Constraints docs-verified
- Does not consider infiltration; assumes no absorption of water through the soil · Unresolved blockages such as culverts and bridges can create false pathways; flagged with Ponding = 1 and should be disregarded · Use with caution in very flat areas and highly modified drainage systems such as fenlands and the Somerset Levels · Errors may occur at bridges, viaducts and culverts · England only
Evidence
- https://environment.data.gov.uk/api/file/download?fileDataSetId=3ab8a114-961b-4d7a-b712-50b93accec96&fileName=Overland Flow Pathways Technical Information Guidance.docx
- https://www.data.gov.uk/dataset/c9dd994d-9649-4041-96d4-cdc0f1a53152/overland-flow-pathways
Check upstream coverage, uncertainty and licence before use. Station observations are not forecasts or design levels.