4.2 Risks

Having considered whether erosion is a short term fluctuation or an ongoing problem, and whether the affected area is localised or widespread, the manager must consider what assets may be at risk and over what timescales losses may occur. These assets may be natural, such as a rare habitat or unusual landform, or they may be human, ranging from a footpath to a major residential or industrial development. Protection of natural assets is contentious, as erosion is a natural process and management operations may be more damaging than the erosion itself.

The risk to human assets must be balanced against many considerations, including the inevitable damage to the environment. At one end of the risk scale it may be considered better or more cost effective to lose or move an asset rather than invest effort and money into erosion management operations. At the other end it may well be obvious that further erosion is totally unacceptable and that the costs and consequences of defences are fully justified (Plate 23).

Plate 21

Plate 21 If there is a long term erosion trend, hard defences on dunes may need to be extended in due course to avoid outflanking. At Ruby Bay, Elie, defences have been extended at least six times.

Attempts to interfere with natural processes within any dynamic natural environment can lead to the creation of more problems than are solved. Beach-dune management can often be seen as successful at a local level, with the risk to backshore assets being reduced. However this success may either be short term or it may be achieved at the cost of damage to adjacent areas. If shoreline erosion is both long term and widespread, schemes to protect the dunes will face ever increasing attack from waves and currents as the foreshore continues to recede (Plate 21). Alternatively, if erosion is cyclical and there is a reasonable expectation of natural recovery, expenditure on schemes may well be wasted.

Management of dunes within a small embayment can often be undertaken without consideration of a wider area, as sediment transport processes may well be restricted to the limits of the bay. Where the dunes are within an estuary or along a stretch of open coast the impacts of operations can be more widespread. In these situations, common along much of the Scottish east and south west coasts, managers must be aware that the defence of one section of shoreline may result in accelerated erosion elsewhere.

From an understanding of the coastal processes the manager can make an informed prediction of the risks and costs associated with allowing coastal processes to proceed unhindered. If these risks and costs are considered unacceptable, or at least undesirable, consideration must turn to the effectiveness, costs, consequences and sustainability of possible management operations.