were computed. The monthly or annual mean sea level (MSL) reported is the av- 

 erage of the hourly heights, while the mean tide level (MTL) is midway between 

 mean high water (MHW) and mean low water (MLW) which are the averages of the 

 daily high and low water levels, respectively, relative to NGVD. 



Results 



Present year 



68. Tide height statistics for 1985 are presented in Table 9. Tides at 

 the FRF are semidiurnal with both daily high and low tides approximately 

 equal. The annual mean range was 96 cm while MSL was 11 cm above NGVD. The 

 highest water level (136 cm) occurred on 14 December during moderate 10 m/sec 

 winds from the north coincident with the monthly spring tide. 



Present versus past years 



69. Figure 32 shows the monthly tide statistics for 1985 and the previ- 

 ous years. Although MSL increased during the first 11 months of the year, the 

 sharp fall in December kept it within 1 cm of the 12-cm average for previous 

 years. Figure 33 compares the distribution of daily high and low water levels 

 and hourly tide heights for the current year versus previous years. Except 

 for the lack of extremely high or low water levels during 1985, the distribu- 

 tions are essentially equivalent. 



All years 



70. Based on the distribution of the tide heights for all years (Fig- 

 ure 34), the tide can be expected to exceed 110 cm for 0.27 percent of the 

 time (24 hr) . Likewise, the heights can be expected to be less than -80 cm 

 for 0.22 percent of the time (19 hr) . 



54 



