Assessing the effects of sea level rise on ocean waves and surge events along the victorian coast

• High-res wave-hydrodynamic hindcast developed for Victoria under SLR scenarios. • Captures cross-scale dynamics from open ocean to enclosed coastal bays. • SLR amplifies water level extremes; wave height response is spatially varied. • Dataset supports erosion, inundation, and shoreline hazard assessments. This study investigates nonlinear surges and extreme wind-wave patterns off the coast of Victoria by simulating sea level rise (SLR) scenarios of 0.5, 0.8, 1.0 and 1.4 meters alongside a 31-year hindcast (1990–2020) using the validated SCHISM-WWMIII coupled wave-circulation model. Model simulations were compared with observational data, confirming the accuracy of the results. Our findings indicate that sea levels along the Victorian coast have been rising at a rate of 1.46 × 10⁻ 2 cm/year, while wave heights in the Southern Ocean have also increased over time. However, the rate of wave height increase is lower along the Victorian coast compared to the Southern Ocean. Due to island blocking, mean wave heights in Bass Strait remain lower than those in the Southern Ocean, yet extreme water levels in the strait exceed those in the open ocean. The impact of SLR is most pronounced in the waters south of Tasmania, where maximum elevations exceed 1.2 meters under the 1.0-meter SLR scenario. SLR contributes to higher mean water levels and increased wave heights off the coast of Victoria, underscoring the complex interactions between rising sea levels and coastal wave dynamics. Wave direction and peak period were also examined, but their changes under SLR scenarios were found to be minimal. These findings highlight the importance of incorporating both SLR and wave dynamics into coastal hazard assessments to better understand future risks.