Figure 7. Location of study area tide gages 



calibrated or verified to a surge plus tide event. Consequently, two periods 

 during the summer of 1985, one at spring tide and the other at neap tide, were 

 chosen for calibration and verification of the model. 



30. A 29-hour period from 0800 29 July to 1300 30 July 1984 was chosen 

 for calibration. During this period data were available from all five study 

 area tide gages, and both the highest tide and the largest range of the month 

 occurred (6.7 and 13.0 ft NGVD, respectively, at Boston). Data from each gage 

 are plotted against data from the N0S gage at Boston (Figures 8-12). The gage 

 at Simpson's Pier went dry at -4.2 ft NGVD resulting in the horizontal lines 

 at low tide in Figure 8. Several facts can be immediately seen from these 

 figures. The range, phase, and MSL of the study area gages are very close to 

 those of the Boston gage. The water levels at high tide are all within 

 several tenths of a foot, and the phases at high tide are all within several 

 minutes. It is interesting that Broad Sound Tuna, a river gage, has the 

 highest tides resulting from a small upward shift in MSL. The largest dif- 

 ferences occur at low water where the river gages show a distinctly higher and 

 later low tide, relative to Boston. During the calibration process, adjust- 

 ments were made in the following items so that the numerical results would 



26 



