Welsh National Marine Plan Areas

Welsh Government is a marine plan authority and is responsible for preparing marine plans for Wales. The marine plan area in Wales comprises the inshore and offshore marine planning regions. The inshore region extends from the mean high water spring tides (MHWS) to the 12 nautical mile (12 nm) limit of the UK territorial sea, and the offshore region from 12nm UK limit of territorial sea to the limit of the Welsh zone.

The sea has a maximum tidal elevation (and land reach) during spring tides and the level of mean high water spring tides (MHWS) is usually used to describe the limits of the sea area. MHWS are not defined. The current OS based map may be used as a general guide and shows Normal Tidal Limits (NTL) which is the average point to which a body of water is affected by the ebb and flow of tides. MHWS will extend further shoreward than this depending upon the gradation of the land. MHWS may be further upstream than this point depending upon the presence of obstructions, such as weirs, which may impede further tidal flow on average tides but become overtopped on larger tides.

NRW marine licensing can provide advice as to the location of MHWS for marine licence applications.