Bottom Drag Coefficient on a Shallow Barrier Reef

Abstract

Abstract The present paper reports of a field experiment over a shallow, roughness‐varying barrier reef at Maupiti island, French Polynesia. The depth‐averaged momentum balance is used to estimate the bottom drag coefficient C d , which varies from 0.01 to 0.3, with dependence on both depth and reef structure. The depth effect on C d is well predicted by a log dependency, as used in previous laboratory and fields observations. The present results extend the approach to a system with more wave exposure and higher roughness‐to‐depth ratio. Additionally, the statistical relationship between high‐resolution reef topography and hydrodynamical parameters is discussed.