A range of different techniques to predict shoreline change and how these might be applied to assess shoreline change over the next century were discussed. The committee believed that the particular challenges to the application of such techniques are knowledge of how the sediment budget and geologic framework will affect long-term shoreline changes.

The discussion focused primarily on three techniques: a) the Bruun Rule (Bruun, 1962), b) extrapolation of historical shoreline change rates (Leatherman, 1990), and c) the Coastal Vulnerability Index (CVI, Gornitz and White, 1992; Gornitz and others, 1994; Thieler and Hammar-Klose, 1999). The first two approaches were not deemed adequate to form a basis for long-term prediction. The main reason is that there is a lack of consensus in the coastal science community regarding their validity for long-term prediction. In addition, regarding the Bruun model, it was recognized that there is a lack of basic information available over wide stretches of the coast that can be used to adequately define the model input parameters, and that the basic assumptions of the model cannot be satisfied in most real-world applications. Reservations were expressed about shoreline change rate extrapolation due to the quality of historical shorelines that are used and whether these accurately reflect natural processes that contribute to long-term changes. The CVI technique was also discussed but there was no consensus among the group as to whether this tool could be used to inform quantitative long-term assessments.

Given the limited time available for input into the CCSP effort, members of the committee agreed to conduct a qualitative assessment of the potential response of the ocean coast of the mid-Atlantic region to four sea-level rise scenarios described in Section C. Using these scenarios, this effort focused on:

1. defining key geomorphic compartments along the mid-Atlantic coast, and
2. specifying potential responses based on knowledge of their behavior that has been established in the coastal science literature and in the experience of the committee members.

Coastal compartments were defined, and the committee assigned a geomorphic designation to each portion of the mid-Atlantic coast. The potential coastal response for each of the specified outcomes for a given sea-level rise scenario were then evaluated. The results of this assessment are explained below.