2 3 4 5 7 



Percent Greater Than Indicated 

 a. Daily highest high-water levels 



20 30 



50 70 90 



^-120 





~ ~^^^^^ 



1-100 



^^^■v^^^ 



_] 



^ 



5 -80 



— ■- -. 







5 



' 



i -60 



— ~ .^_^ 



o 



^^*'^*«,,^^ 



-1 



^^*^^ 



£ -''0 



^*\ 



1 



>v 



° -20 



1 1 II 1 1 1 1 1 1 II III 



O.i 0.3 0.5 08 I 2 3 4 5 7 10 20 30 50 70 90 



Percent Lower Than Indicated 



b. Daily lowest low-water levels 



Figure 21. Distribution of 1980 daily highest and lowest 

 tide levels, referenced to NGVD 



of the daily highest tides, the level exceeded 111 cm (NGVD) (i.e., 102 cm 

 above the 1980 msl); likewise, for 1 percent of the time the daily lowest 

 tides were less than 98 cm below NGVD or 107 cm below msl. 



119. The following tabulation identifies times during the winter storm 

 season months of 1980 when spring tides caused by perigee-syzygy alignment of 

 the planets could be expected to produce extreme tidal heights: 

 Date (Mean Epoch) Type of Tide 



18 January, 2200 hours EST 

 16 February, 1600 hours EST 

 16 March, 1500 hours EST 

 23 October, 1230 hours EST 

 21 November. 1100 hours EST 



Pseudo-perigean spring 

 Perigean spring 

 Perigean spring 

 Proxigean spring 

 Perigean spring 



58 



