Hydrodynamics of spur and groove formations on a coral reef

Journal of Geophysical Research C: Oceans
By: , and 

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Abstract

Spur and groove (SAG) formations are found on the fore reefs of many coral reefs worldwide. Although these formations are primarily present in wave‐dominated environments, their effect on wave‐driven hydrodynamics is not well understood. A two‐dimensional, depth‐averaged, phase‐resolving nonlinear Boussinesq model (funwaveC) was used to model hydrodynamics on a simplified SAG system. The modeling results show that the SAG formations together with shoaling waves induce a nearshore Lagrangian circulation pattern of counter‐rotating circulation cells. The mechanism driving the modeled flow is an alongshore imbalance between the pressure gradient (PG) and nonlinear wave (NLW) terms in the momentum balance. Variations in model parameters suggest the strongest factors affecting circulation include spur‐normal waves, increased wave height, weak alongshore currents, increased spur height, and decreased bottom drag. The modeled circulation is consistent with a simple scaling analysis based on the dynamical balance of NLW, PG, and bottom stress terms. Model results indicate that the SAG formations efficiently drive circulation cells when the alongshore SAG wavelength allows for the effects of diffraction to create alongshore differences in wave height without changing the mean wave angle.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Hydrodynamics of spur and groove formations on a coral reef
Series title Journal of Geophysical Research C: Oceans
DOI 10.1002/jgrc.20225
Volume 118
Issue 6
Year Published 2013
Language English
Publisher AGU
Contributing office(s) Pacific Coastal and Marine Science Center
Description 15 p.
First page 3059
Last page 3073