Cliffed coasts of new zealand: Perspectives and future directions

Abstract

About one‐quarter of New Zealand’s shoreline is composed of cliffs. In some areas erosion rates are sufficiently rapid to be of concern to planners, whereas other cliffs have eroded imperceptibly slowly over human timescales. This paper reviews work conducted on New Zealand’s cliffed coasts, from the pioneering studies of Sir Charles Cotton, who used Davisian theoretical methods to elucidate the evolution of hard‐rock coasts, to Jeremy Gibb’s nationwide benchmark measurements of historical erosion rates. This review is augmented with a description of state‐of‐the art methods in use globally for investigating processes of cliff evolution. Key methods identified include detailed measurements using the micro‐erosion meter as well as novel geophysical methods of studying cliff movement under wave loading. Such process‐based studies build on previous research that has been largely confined to explanatory description and observation. It is recognised that the combined impact of such studies has been relatively muted, owing particularly to the difficulty of unravelling ambiguous process‐form interactions. However, the increasingly widespread availability of terrestrial and aerial remote laser scanning systems now provides an opportunity to re‐invigorate such studies by extending the scale from local to regional. The paper concludes by outlining prospects within New Zealand for further research. In particular, the development and use of numerical models is seen as an important avenue both for clarifying some basic behaviours observed on cliffed coasts, and for studying the likely response of eroding cliffs to future climate change. © 2002 Taylor & Francis Group, Ltd.