This feature class was created using the OS boundary line High Water dataset, OS Open Map Local dataset and UKHO Open Data 3 nautical mile limit. The original data was created for the Water Framework Directive (2000/60/EC).

Article 2, clause 6 of the WFD defines Transitional waterbodies as ‘…bodies of surface water in the vicinity of river mouths which are partly saline in character as a result of their proximity to coastal waters but are substantially influenced by freshwater flows’. These are also referred to as estuaries. Derived from the OS Boundary Line High Water line dataset and Scottish Environment Protection Agency estuarine boundaries defined for the Urban Waste Water Treatment Directive (UWWTD) with the addition of Loch Etive.

Dataset includes the most recent overall classification information.