The impact of long-term changes in ocean waves and storm surge on coastal shoreline change: A case study of Bass Strait and south-east Australia

Abstract

Abstract. Numerous studies have demonstrated that significant global changes in wave and storm surge conditions have occurred over recent decades. Climate projections indicate such changes are likely to continue out to at least 2100. As coastlines respond to the environmental forcing of waves and storm surges, the question of whether the observed and projected changes in waves and storm surges, will impact coastlines in the future, is important. Previous global-scale analyses of these issues have been inconclusive. This study investigates the south-east coast of Australia over a period of 26 years (1988–2013). Over this period, this area has experienced some of the largest changes in wave climate of any coastal region, globally. The analysis uses high-resolution hindcast data of waves and storm surge, together with satellite observations of shoreline change. All datasets have been previously extensively validated against in situ measurements. The results show that beaches along this region appear to have responded to the increases in wave energy flux and changes in wave direction. This has enhanced non-equilibrium longshore drift and recession of the coastline, with recession rates of up to 1 m/year.