dataset · Wales
Saltmarsh Extents
Polygon data layer showing the extent of Saltmarsh in Coastal and Transitional waters for use by both Flood and Coastal Risk Management and the implementation of Water Framework Directive. At the seaward end of the transect, the final demarcation will be where the saltmarsh vegetation cover has become so sparse it only covers 5% whether it is Upper, Mid, Lower or Pioneer saltmarsh.
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Licence: ["There are no access restrictions on this data. NRW may release, publish or disseminate it freely.", "\u00a9 CNC/NRW Data may be re-used under the terms of the Open Government Licence providing it is
Evidence quality: 41.4
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
- saltmarsh extent polygons, including Upper, Mid, Lower and Pioneer saltmarsh
- Coverage docs-verified
- Wales (bounding box 51.24° to 53.51° N, 5.78° to 2.61° W)
- Update frequency docs-verified
- as needed (no fixed schedule)
- Formats docs-verified
- WMS (Web Mapping Service)
- Access docs-verified
- Free and open, no access restrictions; licence per ENTRY is Open Government Licence v3.0 (© CNC/NRW)
Useful for
- Use cases llm-inferred
- Saltmarsh extent baseline for flood and coastal defence scheme appraisal in Welsh estuaries · Saltmarsh extent inputs for WFD coastal and transitional water habitat assessments · Intertidal habitat baseline mapping for ecological constraints or biodiversity net gain work
- Audience llm-inferred
- flood and coastal risk management engineers · water framework directive and coastal ecology consultants · GIS analysts · coastal planners
Limitations
- Constraints llm-inferred
- Dataset reference date is 2017-03-01 (publication), so extents may be dated relative to current conditions · Only a Web Mapping Service is listed in the docs; download format is not stated · Update frequency is as needed, so there is no fixed refresh schedule · Saltmarsh boundary at the seaward end is defined by a 5% vegetation cover threshold, which may affect comparisons with other saltmarsh datasets
Evidence
- https://datamap.gov.wales/capabilities/layer/330/?ows_service=wms
- https://www.data.gov.uk/dataset/aca4bb32-6481-4c9a-8384-83d1cf626e74/saltmarsh-extents3
Check upstream coverage, uncertainty and licence before use. Station observations are not forecasts or design levels.