Coastal hazards and associated management issues on South Pacific Islands

An understanding of natural coastal hazards is essential for the safe and sustainable development of the small island states in the South Pacific. This paper describes the roles of coastal geology and oceanography in the analysis of impacts due to fluctuating water levels and wave damage from cyclones. The examples include coastal erosion, flooding and wave damage in a range of island settings. As seen in Tarawa, rapid erosion and accretion can result from both short-lived storms as well as transient sub-decadal water-level changes related to El Niٌo and the Southern Oscillation (ENSO). Cyclone waves are responsible for extensive damage in low-lying atolls and on the coastal fringes of high islands. Observed cyclone wave impacts in Niue demonstrate that even infrastructure perched on 20 m cliffs may not be immune during severe storms. These examples demonstrate that integrated coastal management (ICM) plans, to be successful, must explicitly incorporate a realistic range of coastal processes and responses based on an understanding of the physical environment. It should be noted that much ICM begins with institutional and policy issues and incorporates science as a secondary component. When science is introduced, much emphasis is placed on biological issues and on infrastructure development, while non-living resources and physical shore processes are sometimes overlooked. As we hope the examples in this paper demonstrate, the geological oceanographic context may be absolutely fundamental to the recognition of hazards, delineation of risk, and prediction of changes that may occur from any manipulation in the coastal system.