Table 7 (Concluded) 



Target 



Easting 



Northing 



Elevation 



South Jetty (continued) 



56 



0.037 (0.12) 



0.012 (0.04) 



0.030(0.10) 



57 



0.030(0.10) 



0.040(0.13) 



0.021 (0.07) 



58 



0.056(0.19) 



0.037(0.12) 



0.034(0.11) 



59 



0.049(0.16) 



0.006 (0.02) 



0.040(0.13) 



60 



0.034(0.11) 



0.012 (0.04) 



0.012(0.04) 



(Sheet 4 of 4) 



were 0.085 m (0.28 ft) and 0.052 m (0.17 ft), respectively, for the north and 

 south jetties. Sixty-four percent of the targeted units on the north jetty and 

 79 percent of those targeted on the south jetty had maximum horizontal 

 movements of 0.061 m (0.2 ft) or less at any point on the targeted dolosse. 



Evaluation of the vertical motions of the targeted dolosse revealed that some 

 units moved upward and some units subsided. A comparison of the vertical data 

 between 1994 and 1998 indicated the average change in elevation of all points 

 on the targeted units was 0.061 m (0.2 ft) and 0.052 m (0.17 ft) for the north and 

 south jetties, respectively. The maximum vertical displacement for any point on 

 a targeted dolos on the north jetty was 0.3 m (1.0 ft), and the maximum displace- 

 ment for any point on a targeted dolos on the south jetty was 0.37 m (1.2 ft). 

 Considering all values obtained for the targeted units, 32 percent of the elevation 

 changes on the north jetty and 56 percent on the south jetty were 0.03 m (0.1 ft) 

 or less. 



In addition to the targeted armor units, additional (nontargeted) dolosse were 

 selected on the north and south jetties for comparison of movement data between 

 the 1994 and 1998 surveys. The locations of these additional armor units are 

 shown in Figures 29 and 30. Thirty-three dolosse on the north and 29 on the 

 south jetty were selected. Outlines of these additional dolosse, as well as eleva- 

 tions at two or three points on each unit, were obtained from the stereo models 

 for the two surveys and compared on photogrammetric maps to determine hori- 

 zontal and vertical motions, similar to the procedures used on the targeted units. 



Evaluation of the horizontal motions of the additional dolosse indicated that 

 movement was relatively uniform for over half of the armor units, in that the 

 entire unit tended to move in the same direction (nonrotational movement). 

 Forty-five percent of the dolosse on the north jetty and 32 percent of those on the 

 south jetty slightly rotated in either a clockwise or counterclockwise direction. 

 Considering the rotated armor units, there was a dominance of clockwise rotation 

 on the north jetty, and counterclockwise rotation was dominate on the south 

 jetty. In general, of the additional (nontargeted) armor units analyzed that 



50 



Chapter 3 Current Monitoring Plan and Data Comparison 



