North Solent Shoreline Management Plan

View of Southampton water

What is the North Solent Shoreline Management Plan (SMP)?

The North Solent SMP is a high level, non-statutory, policy document that sets out a framework for the management of over 386km of coastline and coastal defences. The SMP utilises multiple Policy Units along the coast that help to implement more relevant strategies in localised areas. The Policy Units apply one of four management policies, as listed below:

  • Hold The Line (HTL) – Maintain or upgrade the level of protection provided by existing coastal defences
  • Advance The Line (ATL) - Build new defences seaward of the existing defence line
  • Managed Realignment (MR) - Allow the shoreline to move backwards, with management to control or limit movement
  • No Active Intervention (NAI) - A decision not to invest in providing or maintaining defences

Southampton policy units

There are three policy units that cover Southampton, leading from Netley Castle to Redbridge. These management policies are implemented for a certain timeframe known as an epoch. The epoch’s allow the Policy Units to change in accordance with expected future changes such as climate change. 


Policy 5C10  

Epoch 1 (2011-2025) – Hold The Line

Epoch 2 – (2025-2055) – Hold The Line 

Epoch 3 (2055-2105) – Hold The Line


Policy 5C11 

Epoch 1 (2011-2025) – Hold The Line

Epoch 2 – (2025-2055) – Hold The Line 

Epoch 3 (2055-2105) – No Active Intervention


Policy 5C12

Epoch 1 (2011-2025) – Hold The Line

Epoch 2 – (2025-2055) – Hold The Line 

Epoch 3 (2055-2105) – Hold The Line