QUANTITATIVE ASSESSMENT OF COASTAL DYNAMICS FOR HAZARD MANAGEMENT: SMALL ASSOCIATED ISLANDS OF PUERTO RICO

The island of Puerto Rico is highly vulnerable to the effects of imminent sea-level rise. The lack of awareness amongst public officials regarding coastal dynamics and sea-level rise has contributed to an overwhelming demand for accurate and cost effective coastal hazard management. We are responding to this demand by developing a model that (1) quantifies the extent of vulnerability in a given area (CVI) and (2) projects the effects of sea-level rise on small associated islands using digital elevation models (DEM) generated using ground-based Light Detection and Ranging (LiDAR) and Real Time Kinematic Global Positioning System (RTK GPS). Studying coastal dynamics of small islands provides a more thorough understanding of the shoreline’s response to sea-level rise in general. The study’s parameters being evaluated are island topography, land cover, nearshore bathymetry, shoreline change, and potential sea-level rise. This knowledge is shared with public officials in Puerto Rico that are vulnerable to coastal hazards, and is applied to a modified Coastal Vulnerability Index (CVI) in order to provide an easy to use, low cost, yet quantitative shoreline hazard assessment method. Projected rates of sea-level rise will be applied to DEMs in order to visually and quantitatively constrain potential land loss associated with a global rise in sea level. Maps of each island will be generated in GIS with public land use classification, geologic substrate, and vulnerability level delineated. A pilot survey was conducted in 2011 on two small islands, Cayo Ratónes and Arecife Media Luna offshore of southwestern PR. Modified CVI tables for each, and DEMs for Arecife Media Luna are presented. The project is devoted to raising awareness and conducting risk assessment using the modified CVI, aerial photos, public land use classification, and geoindicators checklist evaluations.