The West Wales shoreline is divided up into 309 short sections called ‘Policy Units’. For each section, one of the following four policy options is recommended:


No active intervention (NAI)

No investment in the construction of new defences, maintenance or upgrade of existing defences

Hold the line (HTL)

Keeping the line of defence in approximately the same location as it is now. Existing defences are maintained, replaced or upgraded along their current alignment. This may or may not include upgrades to counter climate change and sea level rise

Managed realignment (MR)

Landward retreat of defences, giving up some land to the sea to form a more sustainable defence in the long-term

Advance the line (ATL)

Reclaim land from the sea by building new defences further seaward


A policy option is provided for each of the three epochs (20, 50 and 100 years) for each stretch of coast. Policy options may change for different epochs for the same stretch of coast.   For example, the policy option for a particular policy unit could be ‘hold the existing line’ for the first epoch (0 – 20 years), changing to ‘managed realignment’ for the next epoch (20 – 50 years).

It should be noted that the policies in the SMP do not contain specific details for schemes – either what they will be made of or the standard of protection.