TFIP006: Sensitivity of the NSW coastline to wave climate change and the investigation of associated hazard definition schemes
To determine the sensitivity of coastline planform shape and orientation of characteristic beaches on the NSW south, central and north coasts, to variations in deepwater wave climate (direction, significant wave height and period) on interannual and multi-decadal time scales;
To investigate the technical basis for NSW hazard definition schemes to assess the impact of wave climate change on NSW coastline planform.
The project will produce a unique integration of geoscientific and engineering approaches to the problem. This pilot project forms part of a larger research focus on coastlines and climate changing.
We hope this project will form the basis for an external funding application.
Considerable research effort has been directed towards understanding and the gross prediction of shoreline response to sea-level rise (eg. Cowell et al., 2003a and b). In contrast, the sensitivity of coastline planform shape to interannual and multi-decadal changes in wind and wave climates is poorly understood, and has not been included in statutory Coastline Hazard Definition Studies. Initial studies by Goodwin et al. (2006) and Slott et al. (2006) have shown that large-scale coastline shapes change with wave climate, such that sections of coastline erode whilst others accrete.
Research by Short et al. (2000) and Ranasinghe et al. (2004) has demonstrated the statistical relationship between the Troup Southern Oscillation Index (SOI) and embayed beach alignment and shape changes on Sydney's northern beaches, for the past few decades. Goodwin et al., (2006) and Goodwin (unpublished consultancy report, 2006) has taken this further to show that rotation of regional coastline compartments (multiple beaches, such as those in northern NSW) also occurs on multi-decadal to centennial scale, associated with Pacific basin-wide climate changes. This new and emerging work on regional coastline alignment rotation describes a new paradigm for understanding coastal behaviour.
These coastline changes are an order of magnitude greater than for sea-level rise and will increase or ameliorate the regional impacts of sea level rise and produce significant uncertainties for the definition of future coastline hazards and the associated risk management zoning. This pilot project will focus on the development of an applied methodology for assessment of local and regional coastline planform change along Australian coasts. The proposed methodology will form part of the statutory requirements under the NSW Coastal Policy.