U.S. Geological Survey
Coastal and Marine Geology
Woods Hole Field Center

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National Assessment of Coastal Vulnerability to Sea-Level Rise: Preliminary Results for the U.S. Gulf of Mexico Coast

Table of contents
Web Site Title Page
Introduction
Risk Variables
Data Ranking
Coastal Vulnerability Index
Results
Discussion
Summary
References


Table 1.

Ranking of coastal vulnerability index variables for the U.S. Gulf of Mexico.

Figure 1.

Map of the Coastal Vulnerability Index (C.V.I.) for the U.S. Gulf coast. The C.V.I. shows the relative vulnerability of the coast to changes due to future rise in sea-level. Areas along the coast are assigned a ranking from low to very high risk, based on the analysis of physical variables that contribute to coastal change.

Figure 2.

Histograms showing the frequency of occurrence and cumulative frequency of C.V.I. values for the U.S. Gulf of Mexico coast. The vertical red lines delineate the chosen ranges for low, moderate, high, and very high risk areas.

Figure 3.

Bar graph showing the percentage of shoreline along the U.S. Gulf of Mexico coast in each risk category. The graph also shows the total length of shoreline (in kilometers) in each risk category. The total length of mapped shoreline in this study is 8058 km.

Low: 647 km
Moderate: 2968 km
High: 1056 km
Very High: 3387 km

Figure 4.

Map of the geomorphology variable for the U.S. Gulf of Mexico coast. The shoreline is composed predominantly of very high-risk barrier island complexes, lagoons, marshes and deltas.

Figure 5.

Map of the tide range variable for the U.S. Gulf of Mexico coast. The tide ranges are less than 1.0 m over the open-ocean coast, thus, the entire coast has a very high risk ranking.

Figure 6.

Map of the wave height variable for the U.S. Gulf of Mexico coast. The wave height variable displays a regional trend of high wave heights ( >.8 m) to the west and lower wave heights <.4 m) to the east.

Figure 7.

Map of the relative sea level rise variable for the U.S. Gulf of Mexico coast. The highest rates of sea-level rise in the Gulf of Mexico (and in the United States) are in the Mississippi delta region (>10 mm/yr).

Figure 8.

Map of the coastal slope of the U.S. Gulf of Mexico coast. The slope is the least,<0.02%, in the region of the Mississippi delta. The slope is the highest (>.0435 %) south of Corpus Christi, along the western panhandle of Florida, and in the greater Tampa - St.Petersburg region.

Figure 9.

Map of the erosion rate variable for the U.S. Gulf of Mexico coast. Most of the Gulf of Mexico coast receives a moderate to very high risk ranking, meaning the coastline is either stable or is eroding. There are few accreting areas.


Contents > Back to Top

Introduction > Risk Variables > Data Ranking > C.V.I. > Results > Discussion > Summary > References
This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.

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