(arrows indicate the chronological order of the data points) . Attempts 

 to correlate changes in sand elevations between Jones Beach and Ludlam 

 Island gave results which, at best, resembled the two correlations plotted 

 near the origin in Figure 9. Correlation between beaches was usually poor. 



5. Profile Fluctuations 



The histograms of sand level changes (Appendix E) show that the 

 greatest fluctuations in sand level usually do not occur at the most sea- 

 ward pipe. As typical examples, on Jones Beach at profile 07, pipes 3 and 

 4 show a greater range of sand level changes than pipe 5, the most seaward 

 pipe, and on Ludlam Island at profile 18, pipes 7 and 8 show more variable 

 sand levels than pipes 9 and 10 (Appendix E) . Probably the greatest 

 fluctuations occur at the pipe intermittently located in the beach face, 

 since here is the steepest segment of the profile where vertical changes 

 due to any erosion will be most exaggerated. 



Section IV. WAVE OBSERVATIONS 



1. Procedure 



In addition to the weekly observations of sand levels at the 

 pipes, visual observations of wave height, period, direction, and breaker 

 type were made approximately daily during January, February, and March, 

 1968. These observations are tabulated in Appendix F. Since the main 

 purpose of this paper is to present data, this appendix contains, as far 

 as possible, exact duplication of data reported, with no attempt at 

 evaluation. 



The instructions for making the observations, and the forms for 

 recording them are shown in Figure 10. These forms, which were adapted 

 from those used in the CERC-USCG Cooperative Surf Observation Program 

 (Darling, 1968), were filled out by unpaid local observers and mailed 

 weekly to CERC where they were tabulated. Wave observations were taken 

 on the five beaches containing pipe profiles, as well as at localities on 

 Plum Island, Massachusetts, and Watch Hill (near Misquamicut Beach), Rhode 

 Island. All Plum Island data were obtained on the northern half of the 

 island, but well south of Merrimack River Inlet. 



The data near Misquamicut Beach were taken at the U. S. Coast Guard 

 Station at Watch Hill, Rhode Island, west of Misquamicut Beach, but because 

 Watch Hill is a rocky promontory, waves observed there may differ somewhat 

 from waves on the sand beach at Misquamicut. 



2. Height Histograms 



The most characteristic feature of a wave is its height. Figure 

 11 contains wave-height histograms compiled from Appendix F for the seven 



16 



