Table 1 shows the six physical variables described in the Introduction,
which include both quantitative and qualitative information. Actual
variable values are assigned a vulnerability ranking based on value
ranges, whereas the non-numerical geomorphology variable is ranked
qualitatively according to the relative resistance of a given landform to erosion. Shorelines with erosion/accretion rates between -1.0 and +1.0 m/yr are ranked as moderate. Increasingly higher erosion or accretion rates are ranked as correspondingly higher or lower vulnerability. Regional coastal slopes range from very high risk, <0.3 percent to very low risk at values >1.2 percent. The rate of relative sea-level change is ranked using the modern rate of eustatic rise (1.8 mm/yr) as very low vulnerability. Since this is a global or "background" rate common to all shorelines, the sea-level rise ranking reflects
primarily local to regional isostatic or tectonic adjustment. Mean
wave height rankings range from very low (<0.55 m) m to very high (>1.25 m). Tidal range is ranked such that microtidal (<1 m) coasts are very high vulnerability and macrotidal (>6 m) coasts
are very low vulnerability.
Table
1: Ranges for Vulnerability Ranking of Variables on the Atlantic Coast.