Paper No. 85
Presentation Time: 6:00 AM
A COASTAL VULNERABILITY INDEX FOR SMALL ISLANDS OF PUERTO RICO AND THE UNITED STATES VIRGIN ISLANDS
PERISON-PARRISH, Elizabeth M.1, JACKSON Jr., Chester W.
2, RUNYAN, Ryann M.
3, BUSH, David M.
3, SIEMER, Kyle W.
4, LLERANDI-ROMÁN, Pablo A.
5 and NEAL, William J.
6, (1)Geosciences, University of West Georgia, Carrollton, GA 30118, (2)Department of Geology and Geography, Georgia Southern University, Statesboro, GA 30460, (3)Department of Geosciences, University of West Georgia, Carrollton, GA 30118, (4)Department of Environmental Science, University of Toledo, 2801 W. Bancroft, Toledo, OH 43606, (5)Geology Dept, Grand Valley State University, 118 Padnos Hall of Science, One Campus Drive, Allendale, MI 49401-9403, (6)Department of Geology, Grand Valley State University, Allendale, MI 49401, eperiso1@my.westga.edu
A Coastal Vulnerability Index (CVI) incorporates geologic and physical process variables that are dominant in the coastal system, and provides a relative yet quantitative measure of vulnerability. The CVI accounts for the dynamic nature of the coast and reflects its sensitivity to change with respect to rising sea level. A CVI helps provide a scientific basis for coastal management. There are well over 100 small islands and cays surrounding Puerto Rico and the U. S. Virgin Islands. Twenty islands were selected for inclusion in the study because they exhibit either historical, cultural, recreational, or scientific importance, or some combination of factors. The CVI presented here is modified based on previous work of Gornitz and Kanciruk (1989), Shaw et al. (1998), and Thieler and Hammar-Klose, (1999), Wood (2009), and others.
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).
