METHODOLOGY

Figure 2. Shoreline grid for Cumberland Island National Seashore.Click on figure for larger image.

In order to develop a database for a park-wide assessment of coastal vulnerability, data for each of the six variables mentioned above were gathered from state and federal agencies (Table 2). The database is based on that used by Thieler and Hammar-Klose (1999) and loosely follows an earlier database developed by Gornitz and White (1992). A comparable assessment of the sensitivity of the Canadian coast to sea-level rise is presented by Shaw and others (1998).

The database was constructed using a 1:70,000-scale shoreline for Cumberland Island that was produced from the medium-resolution digital vector U.S. shoreline provided by the Strategic Environmental Assessments Division of NOAA's Office of Ocean Resources Conservation and Assessment (http://spo.nos.noaa.gov/
projects/shoreline/shoreline.html). Data for each of the six variables (geomorphology, shoreline change, coastal slope, relative sea-level rise, significant wave height, and tidal range) were added to the shoreline attribute table using a 1-minute (approximately 1.5 km) grid (Figure 2). Next each variable in each grid cell was assigned a vulnerability value from 1-5 (1 is very low vulnerability, 5 is very high vulnerability) based on the potential magnitude of its contribution to physical changes on the coast as sea level rises (Table 1).