Likewise, additional maps are available between dates of those used in this 

 investigation, but their level of accuracy and/or scale were not suitable. 

 Accuracy in original data sets and in their interpretation is an essential 

 ingredient in producing believable shoreline change information. 



5. This study is intended to enhance and explain the accompanying 

 shoreline change maps. The maps were used to establish transects perpendicu- 

 lar to shoreline trend at a 50-m alongshore interval. Shoreline position at 

 each survey date was digitized on the transect allowing linear comparisons of 

 shoreline position to calculate shoreline change. Average and maximum net 

 rate of change and standard deviation of shoreline change are among data pre- 

 sented for each transect. Shoreline change transect data are presented in 

 summary form (a) in short, defined alongshore coastal segments; (b) by Barrier 

 Island/Mainland beach; (c) by defined coastal reach; (d) by geomorphic zones; 

 and (e) for the entire study area. Extremely dynamic changes around inlets 

 and capes were not measurable using this technique and had to be specially 

 treated. Where possible, temporal and alongshore spatial variations in shore- 

 line change rates were compared with physical characteristics of the coast and 

 process information to explain observed variability. 



6. Several important differences exist between this report and the pre- 

 vious two. First, very limited bay side shoreline information was available 

 on the NOS maps, and where it was present, shoreline change was so small as to 

 fall outside accuracy limits of this technique. Consequently, no bay shore- 

 line data are presented, only data from coastlines facing the open ocean. 

 This factor allowed the use of linear measurement of shoreline change, as in 

 Report 3 (Knowles and Byrnes, in preparation), not aerial changes as in 

 Report 1 (Everts, Battley, and Gibson 1983). A second difference is the 

 length of shoreline examined in this report. Report 1 covered 210 km of gen- 

 erally linear barrier island coastline. Report 3 covered 208 km of mixed lin- 

 ear, elongated barriers and short barriers with frequent inlets. This report 

 covers over 336 km of shoreline composed of short barriers with frequent in- 

 lets and a wide range of coastal orientations, shallow open-water bays, and 

 long, arcuate coastal headlands. The length of shoreline required subdivision 

 of the coastline into smaller reaches to allow presentation of data. For this 

 study, the shoreline change maps were produced by NOS in a south- to -north 

 direction, opposite of previous reports. This necessitated some changes in 

 procedures used to obtain quantitative information. 



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