Monitoring Beach Shape Development and Sediment Dynamics on a Sandy Beach with Low Anthropogenic Influence

Abstract

This study examined the evolution of the beach profile and sedimentary balance in Playa del Coco, Mexico, during one year (September 2013–September 2014) to monitor these conditions at a site with little or no anthropogenic influence. The type of beach profile was determined according to the energy profile of the geomorphology, resulting in three types of profiles: low, medium, and high energy. In addition, sediment volumes were quantified, and erosion or accumulation at each study site was described. The results showed that the medium-energy profile was characteristic of the beach most of the time. High-energy conditions were recorded only once due to the influence of a high-category hurricane (Odile, III) during the hurricane season. The dominant sediment size was medium, moderately well-classified to well-classified, coinciding with the medium-energy profile. Coarse, well-sorted sand was recorded at the end of the study, coinciding with the highest loss of sediment on the beach. Playa del Coco showed a state of quasi-equilibrium before the end of the annual cycle, recovering the characteristics of the beach at the beginning of the study. After that time, there was a great loss of sedimentary material influenced by Hurricane Odile (III), modifying the beach’s state of recovery. Therefore, the stability of this beach could be cyclical and respond to the self-organization principle rather than to seasonal parameters. However, the duration of the cycles that influence Playa del Coco seems to be determined by the hurricane season, especially the combination of two main factors: the proximity to the coast of the hurricane and the amount of rainfall associated with the hurricane.

Keywords

• beach profile
• sedimentation
• erosion
• quasi-equilibrium