Tide Gage 



30. Water level data were obtained from a NOAA/MOS control tide station 

 (No. 865-1370) located at the seaward end of the research pier (Figure 2), by 

 using a digital tide gage manufactured by Leupold and Stevens, Inc., Beaver- 

 ton, Greg. The Leupold-Stevens' analog-to-digital recorder is a float- 

 activated, negator-spring, counterpoised instrument that mechanically converts 

 the vertical motion of a float into a coded, punched paper tape record. The 

 below-deck installation at pier sta 19+60 consisted of a 30.5-cm-diam stilling 

 well with a 2.5-cm orifice and a 21.6-cm-diam float. 



31. This tide gage was checked daily for proper operation of the punch 

 mechanism and for accuracy of the time and water level information. The ac- 

 curacy was determined by comparing the gage level reading with a level read 

 from a reference electric tape gage. Once a week, a heavy metal rod was low- 

 ered down the stilling well and through the orifice to ensure free flow of 

 water into the well. During the summer months, when biological growth was 

 most severe, divers inspected and cleaned the orifice opening as required. 



32. Quarterly, a National Oceanic and Atmospheric Administration 

 (NOAA)/NOS tide field group familiar with the installation and equipment 

 inspected the tide station. The tide gage elevation was checked using ex- 

 isting NOS control positions, and the equipment was checked and adjusted as 

 needed. NOS and FRF personnel also reviewed procedures for tending the gage 

 and handling the data. Any specific comments on the previous months of data 

 were discussed to ensure data accuracy. 



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