maintained by alinement of two separated, fixed objects. Readings were taken 

 every 15 meters or at each break in the beach slope, then continued to 

 -0.6 meter MSL by a rodman . Surveys were timed to coincide with low tide to 

 extend to that depth. Occasionally, however, extreme water levels or surf 

 conditions prohibited seaward extension of the profiles. Readings were taken 

 to the nearest 1.0 foot (0.3 meter) horizontally and 0.1 foot (0.03 meter) 

 vertically. Occasionally it was necessary to move the level, so care was 

 taken to document the elevation and new location. 



b. Survey Frequency . The distributions of the profile line measurements 

 by year and season and by month and season are shown in Figures 10 and 11, 

 respectively. Each season is represented by at least one survey with autumn 

 and winter being the seasons of the least and most surveys, respectively. 



Survey data were recorded in field notebooks. Range and elevation were 

 computed by the note man in the field and then doublechecked by another member 

 of the survey team. The detailed procedures for transcribing coding forms 

 for computer processing are given in DeWall (19 79, p. 15). All data were 

 meticulously hand checked, and spurious points were either corrected or dis- 

 carded. Profile data are shown in tabulated form in Appendix B. 



c. Profile Analysis . Surveys of profile lines were analyzed by CERC 

 and computer plots were generated for (1) change in MSL shoreline intercept 

 (App. C) , (2) above MSL change in unit volume between surveys (App. D) , and 

 (3) profile envelopes (App. E) . Changes in the MSL intercept position 

 were referred to the MSL position on the first survey of the study. 

 Volume changes were referred to the mean above MSL volume over the study 

 period. The distance-elevation coordinates of the MSL contour intercept 

 with the initial survey on each profile line are defined as the origin of 



a coordinate system to which all subsequent surveys are referred. Nega- 

 tive distances indicate stations landward of the MSL intercept with the 

 initial profile; positive distances indicate seaward stations. 



The cross-sectional area of each profile was computed and bounded by 

 three coordinate lines: (1) a vertical line projected from the landwardmost 

 distance common to all surveys on a given profile line, (2) a horizontal 

 line at the MSL elevation, and (3) the surveyed profile. The calculation was 

 accomplished by summing 30.0-centimeter horizontal slices through the area 

 from the highest elevation to MSL. The area change was then computed by sub- 

 tracting the previous profile area from the measured profile area (Fig. 12) . 

 Note that the change in area (and volume) is referred to the previous survey 

 and not the original survey. Cross-sectional areas were computed in sauare 

 feet and then converted to unit volume in cubic meters per meter of shoreline. 



Appendix E provides a profile envelope for each profile line. Each plot 

 shows two lines drawn through the upper and lower extremes of the surveyed 

 sand elevations on each profile line. The envelope of extremes contains 

 points from different surveys, rather than trace a particular eroded or 

 accreted profile found during one survey. This profile "sweep zone" is use- 

 ful for designing the required depth of footings for coastal structures, 

 burial depth for pipelines, and for other beach protection or improvement 

 considerations . 



The temporal and spatial variability of each profile was also evaluated 

 using empirical eigenfunction analysis. This technique has been used in a 



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