Table 2 



Position Data Obtained During the 1994 Survey 



Monument 



1994 Coordinates 



1994 el, m (ft) 



Northing 



Easting 



North Jetty Cap 



MN-1 



N462562.20 



E21 77592.77 



+4.27 (+14.00) 



MN-2 



N462623.88 



E21 7751 6.50 



+4.22 (+13.85) 



MN-3 



N462680.17 



E21 77433.89 



+4.26 (+13.99) 



South Jetty Cap 



MS-3A 



N462232.84 



E21 77320.33 



+4.25 (+13.95) 



MS-4A 



N4621 76.24 



E21 77403.29 



+4.24 (+13.91) 



MS-5 



N4621 07.30 



E21 77503.96 



+4.26 (+13.99) _j 



Table 3 



Differences Between Horizontal and Vertical Positions of 



Monuments 



Monument 



Northing 



Easting 



Elevation 



Difference from 1994 to 1998, m (ft) 



MN-1 



0.015 (0.05) 



0.021 (0.07) 



-0.006 (-0.02) 



MN-2 



0.006 (0.02) 



0.012 (0.04) 



-0.061 (-0.02) 



MN-3 



0.003(0.01) 



0.024 (0.08) 



-0.009 (-0.03) 



MS-3A 



0.009 (0.03) 



0.012 (0.04) 



0(0) 



MS-4A 



0(0) 



0.003(0.01) 



0(0) 



MS-5 



0.014(0.04) 



0.073 (0.24) 



0.003(0.01) 



0.03 ft). On the south jetty, vertical changes in monuments ranged from to 

 0.003 m (0 to 0.01 ft). 



In addition to the monuments, targets were reestablished on the dolosse that 

 corresponded with those established in previous surveys. A total of 111 dolosse, 

 distributed over the two jetties, were initially targeted with 0.3-m (1.0-ft) painted 

 black crosses to ensure visibility in the aerial photography. Of these, 51 targets 

 were established on the north jetty with 60 targets on the south jetty. For the 

 current (1998) survey, 44 of the original 51 targets on the north jetty and 57 of 

 the original 60 targets on the south jetty were recovered and reestablished with 

 the 0.3-m (1.0-ft) black crosses. Some of the unrecovered targets were on armor 

 units located at the edge of the water and could not be reestablished during 

 ground surveys because of the slippery algae growing on the dolosse. Others 



Chapter 3 Current Monitoring Plan and Data Comparison 



25 



