Shoreline Management Plans (SMPs)
In England and Wales, coastal management is guided by Shoreline Management Plans (SMPs). Local councils and the Environment Agency develop these. SMPs use scientific data on coastal processes and also consider the needs of local communities.
SMPs look at the most sustainable ways to manage flood and coastal erosion risks over different time scales:
- Short term: 1–20 years
- Medium term: 20–50 years
- Long term: 50–100 years
There are four main coastal management strategies:
- No active intervention (do nothing) – no coastal defences are built.
- Hold the line – maintain and strengthen existing coastal defences.
- Advance the line – build new defences further out to sea.
- Managed retreat (realignment) – allow the sea to flood inland to a new, more sustainable position.
What is Managed Retreat?
Managed retreat, also called coastal realignment, is when the coastline is deliberately moved further inland. In practice, this means breaching existing defences and allowing the sea to flood low-lying land. New embankments may be built further inland to protect key areas.
This strategy is employed in the UK to address sea level rise, coastal erosion, and storm surges. Instead of trying to ‘hold the line’ at all costs, it works with natural processes.
Managed retreat often involves:
- The relocation of people and property away from high-risk areas.
- The creation of intertidal habitats, such as mudflats and salt marshes, can absorb wave energy.
Examples of Managed Retreat in the UK
- Donna Nook, Lincolnshire Coast
- Wallasea Island, Thames Estuary
- Medmerry, West Sussex (2013) – one of the largest managed retreat projects in Europe.
Costs and Benefits of Managed Retreat
Costs
- Social: Relocation can be stressful and disruptive. For example, proposals in North Norfolk could result in the loss of six villages being lost and hundreds of people over the next 20–50 years. Communities often feel let down.
- Economic: Short-term costs can be very high. The Medmerry scheme cost £28 million, even though maintaining the old shingle beach cost only about £200,000 a year.
- Environmental: Productive farmland may be lost. Some species, such as marsh harriers and cranes, may initially decline until new habitats are established.
Benefits
- Social: Reduces flood risk for nearby communities, giving people greater long-term security.
- Economic: Over time, it is cheaper than constantly repairing hard engineering defences.
- Environmental: Creates valuable new habitats. At Wallasea, 38 species of birds have been recorded on newly created mudflats, including ringed plover, dunlin, Brent geese, and shelduck.
