Wave Transformation on a Fringing Reef System With Spur and Groove Structures

Abstract

Spurs and Grooves (SAG) are coral forereef structures with their main axis normal to the reef crest. The dimensions of SAG vary considerably on a global scale. Despite being common, there are relatively few studies that relate SAG morphology with wave transformation processes. Measurements of wave transformation are presented from Xahuayxol, Quintana Roo, Mexico, across a SAG zone with larger spurs than in previous studies. An array of pressure sensors and current meters sampling at high frequencies were deployed over 8 days. Our results show that SAG structures are more important for wave transformation than previously reported since a high rate of wave energy flux dissipation (up to 0.077 kW/m2) was found and the corresponding wave dissipation friction factor, fw (1.01), was four times higher as compared to other reefs. We also found that the wave dissipation rate over the spurs can be up to three times higher than the adjacent grooves (0.098 vs. 0.028 kW/m2). This study demonstrates that SAG plays a very important role in wave dissipation over coral reefs.