profile. These maximum changes are compiled in Table II, along with the 

 dates between which the changes occurred, and the sand elevations at the 

 pipes just before the maximum change occurred. The single-pipe maximums 

 from the two profiles on each beach are averaged and plotted as four bar 

 graphs in Figure 7 . 



For the five beaches during January, February, and March, 1968, the 

 data in Table II show the following: 



(1) The maximum of all 1-week changes for all pipes on the 10 pro- 

 files was 5.7 feet of erosion and 4.7 feet of accretion, both occurring 

 on profile 07 of Jones Beach, and on successive weeks. 



(2) The maximum of all 3-month changes for all pipes was 3.0 feet 

 of erosion on profile 05 of Atlantic City, and 3.6 feet of accretion, 

 again on profile 07 of Jones Beach. 



(3) Maximum 1-week erosion appears correlated with the sand eleva- 

 tion at the start of the 1-week interval (Figure 8). 



(4) For 10-profile averages of the maximum erosion and accretion, 

 the 1-week average changes exceed the 3-month average changes by 55% for 

 erosion and by 77% for accretion. (See bottom of Table II.) 



(5) On the average, the two Long Island beaches significantly ex- 

 ceeded the three New Jersey beaches in 1-week erosion, and 1-week and 

 3-month accretion, but the Long Island beaches were somewhat less than 

 the New Jersey beaches in 3-month erosion. 



(6) Of the two Long Island beaches, Jones Beach had somewhat greater 

 maximum changes in sand level than Westhampton Beach, both for 1-week and 

 for 3-month intervals. 



(7) Between the three New Jersey beaches, there appeared to be no 

 significant difference in maximum erosion or accretion. 



(8) Of the 10 values of maximum 1-week erosion, five occurred in 

 January, five occurred in February, and none occurred in March. Of the 

 10 values of maximum 1-week accretion, two occurred in January, five 

 occurred in February, and three occurred in March. 



4. Correlation of Data 



To test qualitatively whether changes in sand elevations could 

 be correlated from place to place, sand elevations at one pipe, as plotted 

 in Appendix B, were visually compared with sand elevations at pipes on the 

 same profile, on the other profile of the same beach, and on different 

 beaches. There was little consistent evidence of positive correlation of 

 sand level changes, and some of the best correlation was in the negative 

 sense. Examples of the better observed correlations are shown in Figure 9 



