A COASTAL VULNERABILITY INDEX FOR SMALL ISLANDS OF PUERTO RICO AND THE UNITED STATES VIRGIN ISLANDS
CVI parameters are weighted on a 1-5 scale. For each parameter, 1 denotes a very low probability of coastal change, and 5 the highest probability of coastal change. The beauty of a CVI is that it can incorporate a wide range of types of input parameters, but as long as they are weighted, their relative importance is shown. Our CVI incorporates four parameters: shoreline composition, sea level change, slope, and shoreline change. Although developed with Puerto Rico and the U. S. Virgin Islands in mind, it should be applicable to any island setting.
AMBUR software (Jackson et al., 2012) was used to analyze shoreline change and the newly developed AMBUR-HVA tool was used to calculate the CVI, defined as the square root of the product of the ranked variables divided by the total number of variables. After analyzing the 106 km of shoreline contained within the 20 study islands, the three islands rated most vulnerable to coastal change are Isla Morrillito (mean CVI = 2.65), Cayo Ratón (2.74), and Isla de los Palomas (2.81). The three least-vulnerable rated islands are Cayo Río (mean CVI = 6.32), Cayo Ratones (6.35), and Palominitos (6.95).