Effect of Sea Level Rise on Nearshore Waves and Wave Energy

Sea level rise presents significant challenges for the stability and sustainability of coastal regions. This study examined how sea level rise affects nearshore waves and wave energy. Previous research derived the changes in wave characteristics by expressing sea level rise as a relative change in water depth. Based on this general framework, earlier work was extended by incorporating wave energy and related parameters into the analysis and providing an intuitive way to examine the wave responses across varying depths, beach slopes, and degrees of nonlinearity. The results suggested that under sea level rise, the wave height decreases in the shoaling and transition zones but increases in the surf zone. Nevertheless, sea level rise leads to an overall increase in wave height in strongly nonlinear wave fields, where wave breaking occurs farther offshore. Wave energy displays similar patterns but with an amplified magnitude, while energy flux is influenced further by group velocity. The bottom orbital velocity decreases in deeper water but increases in shallow regions, with the transition zone between decreasing and increasing values shifting offshore as the nonlinearity intensifies. The framework offers a practical tool for understanding a nearshore wave transformation and supports improved hazard assessment and coastal planning under future climate change.