RESULTS

Figure 5. Relative Coastal Vulnerability for Cumberland Island National Seashore. Click on figure for larger image.

The CVI values calculated for Cumberland Island range from 7.75 to 17.89. The mean CVI value is 12.66; the mode is 16.00 and the median is 13.06. The standard deviation is 3.27. The 25th, 50th, and 75th percentiles are 9.0, 13.0 and 15.5, respectively.

Figure 5 shows a map of the coastal vulnerability index for Cumberland Island National Seashore. The CVI scores are divided into low, moderate, high, and very high-vulnerability categories based on the quartile ranges and visual inspection of the data. CVI values below 9.0 are assigned to the low vulnerability category.

Figure 6. Percentage of Cumberland Island shoreline in each CVI category. Click on figure for larger image.

Values from 9.0 to 13.0 are considered moderate vulnerability. High-vulnerability values lie between 13.01 and 15.5. CVI values above 15.5 are classified as very high vulnerability. Figure 6 shows the percentage of Cumberland Island shoreline in each vulnerability category. Nearly 30 km (19 miles) of shoreline is evaluated along the national seashore. Of this total, twenty-two percent of the mapped shoreline is classified as being at very high vulnerability due to future sea-level rise. Twenty-eight percent is classified as high vulnerability, twenty-eight percent as moderate vulnerability, and twenty-two percent as low vulnerability.