Integrity assessment procedure for buffer dune systems on the Cape South Coast, South Africa

[摘要] ENGLISH ABSTRACT: The hypothesis postulated in this research, namely that the effectiveness of natural andconstructed buffer dune systems can be assessed by a set of indicators that defines theintegrity of the dune system and triggers informed management decisions, was evaluatedand proved to be essentially true.Two key objectives, namely (1) the identification of key indicators that define the bufferdune integrity; and (2) the development of a scientifically defendable and practicalchecklist-based method of gathering qualitative information on the identified key indicatorsso as to guide decision-making at municipal level formed the core of the study.The six dune integrity indicators that collectively define the risk profile of a particular sitealong the Southern Cape coastline are (1) the degree of protection from prevailing waveenergy, (2) the characteristics of the dominant winds and sand supply during the dryseason, (3) the relative height of the foredune, (4) the degree of pressure on the bufferdune due to humans, (5) the vulnerability of the type of coastline to erosion, and (6) thecoastline stability considering the prevailing coastal processes.The first two indicators relate to the natural (permanent) characteristics of the site and canbe defined by experts and presented in the form of a risk and vulnerability atlas layer fordirect use by non-experts. The third and fourth indicators relate directly to theimplementation of proactive assessment and appropriate management actions to ensure ahigh level of buffer dune integrity. The last two indicators allow for managementintervention to reduce the vulnerability but may entail costly engineering solutions andrequire expert input.A conceptual risk profile assessment procedure and a decision support guidelineincorporating these indicators were developed and evaluated for relevance and practicalitythrough a series of workshops with municipal officials along the south coast of South Africa.It was seen that although some initial basic training may be required, carrying out rapidassessments of the environmental status of key components of an identified human–naturesystem, such as a buffer dune, is practical and achievable by non-experts.

[发布机构] Stellenbosch University