Wave direction found to be significant factor of beach erosion under climate change

Most coastal flood models highlight the impact of sea-level rise, but our latest research suggests we've historically been understating the importance of wave direction. 🌊 Our new research published in Coastal Engineering shows that wave direction exerts significant control on beach erosion response under climate change, which changes how we should perform coastal risk assessments. Using MIKE 21 process-based modelling across 35 storm scenarios at Port Fairy, Victoria, we found that:

• 📐 ±10° shifts in wave approach produce opposing erosion–accretion patterns. Storms from the south erode, storms from the south-west retain sediment through alongshore redistribution

• ⚡ A critical threshold at Hs ≈ 4–4.6 m marks the transition from localised eastern sector response to full embayment-wide sediment mobilisation

• 🌊 Mid-century SLR (+0.21 m) doesn't simply amplify erosion, it reorganises sediment pathways, converting previously stable zones into erosional areas under modal wave conditions

This work was made possible by world-class Australian data infrastructure:

• 📡 Integrated Marine Observing System AusWaves buoy network providing continuous nearshore wave observations at Port Fairy

• 🚁 Victorian Coastal Monitoring Programme (VCMP) UAV surveys for beach topography

• 🌐 ERA5 reanalysis for long-term offshore wave climate characterisation

  
  

For coastal managers and engineers on high-energy embayed coasts, we conclude that linear extrapolations of historical retreat rates and static design parameters are not enough; directional wave climate change must be on the table.