Tides in Torres Strait

The indigenous communities resident in Torres Strait, a remote multi-island region located off the northern tip of mainland Australia, are exposed to a broad array of natural events that are compounded by the unique tidal influences from both the Pacific and Indian Oceans and, more recently, possible influences of climate change as well. Torres Strait consists of 16 main inhabited islands, which presently have an inadequate mapping capability due to the lack of a suitable co-ordinate, height and tide datum. As a result, existing mapping can not be used for management of and response to predicted events related to tsunami, storm surge and sea level rise. This paper reports on a unique and comprehensive tidal study designed to quantify the tidal properties in Torres Strait, along with the establishment of a co-ordinate, height and tide datum that will establish a fundamental level of spatial infrastructure to support all management and planning functions. Similar spatial infrastructure is already established elsewhere in Australia. Tide data were established from readings derived from sea-bed tide gauges deployed on most of the inhabited islands. The tide gauges were deployed for a minimum of 35 days in order to derive the main tidal constituents. Analysis of the tidal data reveals that highly complex variations occur across this remote island region, and that further studies will be essential to fully surveying the region's bathymetry in order to develop accurate predictive models.