Data Ranking System

Table 1 shows the six variables described in the Introduction, which include both quantitative and qualitative information. The five quantitative variables are assigned a change-potential ranking based on their actual values, 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 zero and +1.0 m/yr are ranked as being of low change potential. Increasingly higher erosion/accretion rates are ranked as correspondingly higher change potential. Regional coastal slopes range from very high change potential, <0.30 percent, to very low change-potential at values >1.20 percent. The rate of relative lake-level change is ranked such that zero change in lake level is very low change potential and greater than six mm of rise or fall per year is very high change potential. Mean wave height contributions to change potential range from very low (<.55 m) to very high (>1.25 m). Mean annual ice cover values were ranked such that regions with no annual ice cover were very high change potential and areas with greater than 130 days of ice cover were very low change potential.

Table 1: Ranges for Coastal Change Potential Ranking of Variables on the Great Lakes shores.