THE RELATIVE CONTRIBUTIONS OF WAVE POWER AND SEA LEVEL TO COASTAL EROSION IN REEF-FRONTED SANDY BEACHES

Coastal erosion in sandy beaches can be caused by numerous factors. Examples include wave energy, sea level, riverine runoff, terrain subsidence, and climate oscillations. Fringing reefs impose an additional layer of complexity to the morphodynamics of such systems. They act as rigid structures that can both dampen wave energy and induce intricate wave-induced circulation patterns. It has been hypothesized that, when compared to open-ocean beaches, wave-induced erosion at reef- fronted beaches is more sensitive to changes in the sea level. The reason for this is that fringing reefs can act as a physical barrier that shelters the shoreline from incoming wave energy, thereby leading to lower shoreline variability during periods of low sea level and higher shoreline variability during periods of high sea level. It has not been quantified, however, what are the relative contributions of wave power and sea level on sandy beaches fronted by fringing reefs, nor a systematic comparison between reef-fronted and open-ocean sandy beaches has been conducted. The aim of this research is to compare three distinct beaches with increasing abundances of fringing reefs to quantify such relative contributions to test this hypothesis.