Managing Coastal Community Vulnerability: An Assessment of the Temporal Dynamics of Community Vulnerability as a Consequence of Coastal Management Decision Making

Abstract

In the context of the climatic changes proposed for the twenty‐first century, effective coastal hazard management strategies are essential so that coastal communities are not exposed to the increased or exacerbated hazard impacts expected to take place along the coastal margin. The coastal planning regime in New Zealand and its approach to coastal hazard risk reduction has undergone significant transformations over the past half‐century. Today, local authorities are required to proactively reduce or avoid coastal hazard risks through the use of ‘soft’ hazard management strategies, recognising the dynamic behaviour of the coastal environment and the potential for increased risk under future climate change. While a wealth of proactive coastal hazard management strategies are now available for local authorities aiming to fulfil their legislative requirements, general principles that guide costal [i.e. coastal] managers in their diverse range of choice are only just beginning to be developed and limited understandings of the effectiveness of such strategies in avoiding coastal hazard risk under future climate change exist. Coastal vulnerability assessments that examine the multi‐dimensional nature of coastal systems, and the complex processes operating within, provide important insights into the policies and strategies associated with coastal use and are considered as pivotal to the development of effective and appropriate coastal management strategies. This thesis develops and applies a combined physical and human asset‐based vulnerability assessment methodology within the local coastal setting of the Omaha community; northern Auckland, to examine the consequences various coastal management decisions have had on the vulnerability of the community. Results indicate that the vulnerability of the Omaha is temporally dynamic and has responded to the various coastal hazard management decisions that have been applied throughout community’s history. In particular, hazard engineering approaches have had limited success in reducing vulnerability, and while the more proactive strategies of coastal hazard zoning, development setbacks and building requirements are effective in avoiding vulnerability to the current regimes of erosion and inundation, such strategies are limited in avoiding the vulnerability of communities to high impact hazards such as tsunamis and accelerated sea level rise.