2B.12B - Policy Decisions

Policy decisions (No Active Intervention, Strategic Realignment and Hold the Line Advance the Line) are based on complex judgements (engineering feasibility, environmental sensibility, land value and political and social reasons.) 
Cost-Benefit Analysis (CBA) and Environmental Impact Assessment (EIA) is used as part of the decision making process. 

In the UK, coastal management is overseen by DEFRA (Environment, Food and Rural Affairs). Since DEFRA introduced Shoreline Management Plans in 1995 there have been only four policies available for coastal management, which differ greatly in their costs and consequences. 

1) No active intervention
  • No investment in defending against flooding or erosion, whether or not coastal defences have existed previously. 
  • The coast is allowed to erode landward and/or flood.
2)  Strategic (managed) realignment
  • Allow the coastline to move naturally (in most cases to recede) but managing the process to direct it in certain areas.
3) Hold the line
  • Build of maintain coastal defences so that the position of the shoreline remains the same over time. 
4) Advance the line
  • Build new coastal defences on the seaward side of the existing coastline. 
  • Usually this involves land reclamation. 

Making decisions about which policy to apply to a particular location is complex. It depends upon:
  • the economic value of the assets that could be protected, e.g. land
  • the technical feasibility of engineering solutions: it may not be possible to 'hold the line' for mobile depositional features such as spits, or very unstable cliffs. 
  • the cultural and ecological value of land: it may be desirable to protect historic sites and areas of unusual diversity
  • pressure from communities: vocal local political campaigning to get an area protected
  • the social value of communities that have existed for centuries. 

SMPs plan for the future using three time periods called 'epochs'. These are:
  • Up to 2025
  • 2025-55
  • 2055+
A hold the line policy applied to an area up to 2025 may become a managed realignment policy after 2025. This is because by 2025 sea level rise is likely to have made 'hold the line' a much more expensive policy to apply. 


Cost-Benefit Analysis

  • Cost-benefit analysis (CBA) is used to help decide if defending a coastline from erosion and/or flooding is economically justifiable. 

An example is Happisburgh in North Norfolk:
  • The policy adapted in this area is 'no active intervention'
  • This is because to defend the village would have an impact on the wider coastal management plan.
  • Happisburgh would end up as a promontory, blocking longshore drift and causing further erosion downdrift. 
  • Longer term, the plan is managed realignment, although this would still involve property being lost to the sea by erosion. 

Costs of erosion:
  •  £160,000 could be available to Manor Caravan Park to assist in relocating to a new site
  • Affected residents could get up to £2000 each (a total costs of £40-70,000) in relocation expenses plus the cost to the council of finding plots of land on which to build new houses. 
  • Grade 1 listed St Mary's Church and Grade 2 listed Manor House would be lost. 
  • Social costs as the village is slowly degraded, including health effects and loss of jobs.

Benefits of erosion:
  • By 2105, between 20 and 35 houses would be 'saved' from erosion, with a combined value of £4 million - 7 million
  • 45 hectares of farmland would be saved, with a value of £945,000
  • The Manor Caravan Park would be saved, which employs local people.

The cost of building coastal defences at Happisburgh is around £6 million, very close to the value of property that could be saved, and much higher than the compensation cost payable to local residents. 
Coastal managers argue that Happisburgh must be seen in the wider context of the whole SMP, further justifying the decision not to defend the village. 


Environmental Impact Assessment (EIA)

Coastal management usually requires an EIA to be carried out. This is quite separate from any CBA, although might inform the final CBA. EIA is a process that aims to identify:
  • the short-term impacts of construction on the coastal environment
  • the long-term impacts of building new sea defences or changing a policy from hold the line to no active intervention or managed realignment

EIA is wide-ranging and includes assessments of:
  • impacts on water movement (hydrology) and sediment flow, which can affect marine ecosystems because of changes in sediment load
  • impacts on water quality, which can affect sensitive marine species
  • possible changes to flora and fauna, including marine plants, fish, shellfish and marine mammals
  • wider environmental impacts such as air quality and noise pollution, mainly during construction