Tropical and extratropical storms can rapidly mobilize large amounts of sediment over large lengths of coastline, leading to coastal erosion. Morphological impacts of extreme storms on sandy beaches have received substantial attention, in part because of the increasing risk of coastal hazards and growing popularity of a coastal lifestyle. Prior research has focused on storm-induced nearshore morphological changes under erosive conditions. However, less attention has been paid to post-storm recovery or accretive processes, where the time scales are much longer. The results from this rapid response project could have wide-reaching benefits in future work related to beach management strategies and could help understand better how beaches respond and repair following storm activity. The study will also provide a baseline dataset for future numerical modeling efforts to enhance predictive capabilities regarding beach recovery and for comparison to post-storm beach recovery at other location with similar characteristics. Based upon the findings of this field study, a much better understanding of the coastal dynamics of Rincon, Puerto Rico, will be achieved. This is a first step towards a better understanding of possible shoreline protection projects for the area. This information will also allow personnel from state and federal agencies to inform coastal residents and stakeholders about the sediment transport pathways and possible causes leading to the severe erosion. The methodology applied in the present study could be readily implemented in other areas of Puerto Rico in which hydrodynamic and morphodynamic processes information are needed. This effort will also aid in the development of local expertise by providing training to a graduate student with the goal of developing a thesis stemming from results of this project. High school teachers and students, college students and the general public will be involved in hands-on learning experiences related to this natural coastal process. The project investigators will also develop presentations (signs and posters) and will be available to talk to the public, people living in coastal regions, and coastal resource managers about this natural coastal process.
The field study will focus on the collection of field data and remote sensing to assess the impact of Hurricane Maria on coastal morphology and quantify post-storm beach recovery dynamics in Rincon, Puerto Rico. Wave and current meters will be deployed at multiple locations along the coast of Rincon to capture the wave-induced currents in the nearshore region. Nearshore measurements will be complemented by two remote sensors to capture the hydrodynamic and morphodynamic processes associated with the post-storm recovery. The sensors will be installed on a retractable tower/tripod, and will help to identify the physical state of the beach and provide spatially resolved and accurate estimates of beach elevation. Live video feed and acquisition will be through a dedicated computer. Furthermore, topographic and bathymetric profile data will be collected with a jet ski-based bathymetric system and a real-time kinematic (RTK) Leica GPS system to measure the beach morphological changes. The single beam echo sounder mounted on the bottom of the watercraft hull has the capacity to measure depth up to 450 meters. Beach profile elevations will be obtained using a handheld antenna, with the surveyor walking offshore. Efforts will be performed to overlap the topographic profiles with the bathymetric profiles. These field observations will enable a quantification of the impact of the hurricane and the immediate post-storm recovery in Rincon and test the hypotheses that after Hurricane Maria's catastrophic impact on the site, beach recovery will be dictated by the hydrodynamics resulting from this year's swell season; and that a full beach recovery will not be completed prior to the next hurricane season.
