5.1 Possible approaches

The earlier sections of this Guide have looked at the processes and risks related to beach-dune systems, and have pointed towards the need to treat each site as a unique situation; generic dune management approaches are not appropriate. This Chapter sets out the underlying issues involved in selecting a management approach that will achieve the specific objectives established for each site.

It is assumed throughout this section that all sites being considered have assets at risk from erosion and that protection of these assets will be balanced against impacts on the environment. Most approaches to erosion management are damaging to the environment to a greater or lesser extent. This is particularly so for projects entailing civil engineering operations such as revetment and sea-wall construction or major beach renourishment schemes. The inclusion of such approaches herein does not, therefore, indicate approval or commendation of them from SNH in all circumstances. Rather, they are included to provide a comprehensive guide to the options available to coastal managers and to promote good practice, from an environmental perspective, in the design and implementation of coastal defences, whatever approach is adopted.

Questions to be answered include:

There are four general approaches to managing dune erosion:

There is obviously some overlap between these approaches and some differences of opinion as to what may be short term or long term, and what their impact on the environment may be. Schemes that have a life expectancy (without maintenance) of up to 10 years are considered short term in relation to the natural environment. In addition it should be noted that these approaches are not independent – indeed it may well be advantageous to combine small scale, short term management with engineered schemes to encourage dune systems to redevelop after being damaged.

Selection of the appropriate approach, or combination of approaches depends on the objectives and constraints relevant to the site. Scheme options suitable to each approach are set out in a series of Summaries presented in Appendix 1. These include:

Non-interference

Small scale, short term

Selective frontages

Large scale, long term

(Note. Gabions are often associated with poor shoreline management practice, and should only be used in specific circumstances. If they are regularly exposed to wave attack then they will have a short life before becoming ineffective and an eyesore. However, used as a buried defence or within sheltered areas of an estuary they can be both effective and unobtrusive. Their position in the short-term, small scale category is debatable as they can be used over long frontages, and if well maintained can last for longer than 10 years before needing substantial renovation.)

The Summaries set out sufficient information about each option for the reader to make an informed decision about their appropriate use. The Summaries of small scale, short term operations provide information that will allow implementation, possibly using volunteer or unskilled labour. It is assumed that larger schemes will only be put in place following preliminary appraisal and design studies by a competent coastal consultant; the relevant Summaries present information to allow the proposed designs to be assessed for appropriateness and potential long term impacts.

Appendix 1 also includes a summary of “novel” methods, providing a brief indication of the reasons for not giving them serious consideration.