Effects of Roughness Loss on Reef Hydrodynamics and Coastal Protection: Approaches in Latin America

Abstract

Reefs are known to provide coastal protection and important ecosystem services for many coastlines around the world. Physical processes such as wave damping, sediment transport and nearshore hydrodynamics are closely related to the coastal protection services provided by reefs. The steep-fronted bathymetries of reefs cause abrupt wave transformations and wave damping alongshore, while reef roughness has an important contribution to coastal protection. Five Latin-American case studies are presented to illustrate the coastal protection offered by reefs and their contribution to wave damping. The methodologies applied (e.g. numerical modelling, field measurements) and reef conditions (e.g. reef degradation scenarios and contribution of reef roughness) are listed. Considerable efforts have been made towards diagnosing, understanding and modelling the hydrodynamic transformations induced by reefs. Based on physical and field surveys, roughness and friction parameters were derived in order to implement calibrated and validated numerical models. Discussion on the advantages and disadvantages of the different models applied in the study cases is provided as well as on the needs of highlighting physical processes and the analysis of reef hydrodynamics for supporting appropriate ecosystem-based management.