upper part of the figure. Waves from sectors 1 or 2 , for instance, approach 

 the shore at an angle north of the shore-normal orientation (sector 3) . 



III. PROCEDURE 



The primary data base of this study is beach profiles obtained from 20 

 profile lines at Ludlam Beach. A series of aerial photos of the area obtained 

 between 1949 and 1974 provides supplementary information. 



1 . Beach Profiles . 



A beach profile is a cross section of the ground surface surveyed at a 

 given time at a profile line. A profile line is identified by one or more 

 fixed points (bench mark and auxiliary mark) across the beach and by a direc- 

 tion. Many beach profiles may be obtained at each profile line. 



a 

 lines 

 4. 



Profile Line Location. The approximate location of the 20 profile 



numbered from 1 to 20 in a north to south direction, is shown in Figure 

 The spacing between profile lines is tabulated in Table 4; the total dis- 

 tance from profile line 1 to 20 is approximately 35,000 feet (93 percent of 

 the length of Ludlam Beach). Only profile line 1, which faces northeast toward 

 Corson Inlet, is not oriented near-perpendicular to the axis of the island. 

 The surveyors' documentation of the profile lines is given in Appendix B. 





Table 4. Profile line 



spacing at 



Ludlam Beach. 



Profile 



line Distance between 



Profile 1 



ine Distance between 





profile lines 





profile lines 





(ft) 





(ft) 



1 





11 



3,648 



2 



720 



12 



600 



3 



1,128 



13 



1,680 



4 



2,200 



14 



1,512 



5 



3,360 



15 



1,128 



6 



1,380 



16 



1,720 



7 



1,584 



17 



1,650 



8 



1,130 



18 



2,280 



9 



1,992 



19 



3,850 



10 



1,260 



20 



2,160 



Profile lines were usually surveyed from behind the frontal dune or the 

 bulkhead to varying elevations between MSL and 2 feet below MSL. The seaward 

 limit of the profiles was regulated by the tidal stage, wave conditions at the 

 time of the survey, and the maximum wading depth for surveyors. Distance and 

 elevations of each survey are referenced, respectively, to the bench mark on 

 each profile line (App . B) and to the 1929 National Geodetic Vertical Datum. 



30 



