To address key question 2, the USGS authors assembled a committee of coastal scientists to evaluate the potential outcomes of the four sea-level rise scenarios specified in SAP 4.1 and how these might be developed. The members of this group were chosen on the basis of their expertise and long experience in the coastal research community and also their involvement with coastal management within the mid-Atlantic region. Of the 13 committee members who were contacted, all agreed to participate, but three were unable to attend the meeting due to schedule conflicts (see Appendix A). The two-day workshop was held on April 12-13, 2007 in Beltsville, MD at the USGS Patuxent Wildlife Research Center. Prior to the meeting, the committee members were informed of the meeting objectives and provided with background documents. To orient the participants to the scope of the discussion, members were provided with: a) the SAP 4.1 Prospectus, b) a list of questions and topics that the USGS authors needed to address, and c) a report by a panel of wetlands scientists (Reed and others, 2007) developed for SAP 4.1. This report was provided as an example of a committee-based approach to answer other questions posed by the SAP 4.1 Prospectus.

The sea-level rise impact assessment effort was conducted as an open discussion facilitated by the USGS authors. The group of scientists was tasked with discussing the potential changes that could occur over the remainder of this century based on four sea-level rise scenarios:

1. a continuation of the 20^th century rate of sea-level rise,
2. the 20^th century rate + 2 mm/yr,
3. the 20^th century rate + 7 mm/yr, and
4. a 2-m rise over the next few hundred years.

The 20^th century rate refers to the long-term relative sea-level rise rates that have been observed over the last century at east coast tide gauge stations (Table 1; Zervas, 2001). The relative rates include both contributions from the long-term eustatic rate (1.7 mm/yr) and local contributions due to subsidence (See Section E). The second two scenarios assume the acceleration of the local rates will be driven by accelerations in the eustatic rate. The first two scenarios imply changes in sea-level that are within the range of those presented by the recent IPCC report (Bindoff and others, 2007). The third scenario implies a change that could exceed the IPCC model predictions by 0.3 m. These three scenarios are also consistent with a recently conducted wetlands accretion assessment for the mid-Atlantic region between New York and Virginia (Reed and others, 2007). The main topics that the committee discussed were:

1. approaches that can be used to conduct long-term assessments of coastal change;
2. important factors and processes contributing to shoreline change over the next century;
3. key geomorphic settings in the mid-Atlantic Bight;
4. potential responses of these environments to sea-level rise; and
5. likelihood of these responses to the sea-level rise scenarios.

After the meeting, the USGS authors assembled this report to summarize the discussion that occurred during the two day meeting and to synthesize the resulting assessment. Drafts of this report were circulated to the meeting participants soliciting feedback. Participants provided comments and suggested changes to the overall assessment that were incorporated into the final document, which was subsequently approved by all members.