Effects of Protection Structures on Wave Characteristics in Submerged Reef Platform

Submerged reefs are among the most unique environments for wave reduction globally due to their capacity to generate high bed drag forces. However, constructions on offshore coral reefs, such as sea dikes and sea walls, which serve to protect national sovereignty and foster economic development, have recently altered the wave dynamics of these reefs. This study examines changes in wave characteristics on a coral reef before and after a dike’s construction. A total of 24 experimental scenarios were conducted in a wave flume at Thuy Loi University, Hanoi (Vietnam), including cases with the presence of a dike. The results indicate a significant increase in wave heights attributable to the dike’s presence on the reef, with increases ranging from 10% to 30% due to structural obstacles and the effects of relative shallowness. Additionally, the study provides an empirical formula to predict incoming wave heights, which is intended to aid in the design of structures on submerged reefs.