4 Summary 



Data were originally obtained for the dolos-armored Manasquan Inlet jetties 

 during a monitoring effort conducted over the time period 1982-1984 under the 

 MCNP Program. Armor unit breakage was documented, and quantitative data 

 regarding armor unit movement were obtained. By means of limited ground- 

 based surveys, aerial photography, and photogrammetric analysis, very precise 

 base-level conditions were established for the dolos-armored jetties at 

 Manasquan Inlet. Similar data were obtained and analyzed for the period 1984- 

 1994 under the Periodic Inspections work unit of the MCNP Program. 



The current monitoring (1998), also obtained under the Periodic Inspections 

 work unit of the MCNP Program, entailed reestablishing targets and conducting 

 limited ground-based surveys, aerial photography, and photogrammetric analysis 

 for comparison with data obtained in 1994. The entire above-water armor unit 

 fields were analyzed and armor unit movement quantified. A broken armor unit 

 survey also was conducted during this effort. During the current monitoring, 

 detailed analyses regarding horizontal and vertical displacements were con- 

 ducted not only for the targets established on the dolosse but for the entire armor 

 unit. Comparisons were made for the 1994 and current (1998) surveys. Also, 

 using photogrammetric techniques, additional (nontargeted) dolosse were 

 selected for analysis of armor unit movement between the 1994 and 1998 sur- 

 veys. In addition, base data were obtained documenting the positions of the 

 recently installed CORE-LOC armor units placed on the jetty heads in late 1997. 



Results of the current monitoring effort indicate that dolosse movement was 

 less dynamic during the period 1994-1998 as opposed to other survey periods. 

 Maximum horizontal movement detected was 0.7 m (2.3 ft), and maximum ver- 

 tical displacement was 0.3 m (1.2 ft). In general, however, most movements in 

 both the horizontal and vertical directions have been less than 0.061 m (0.2 ft). 

 Even though major storms occurred during the period, the dolosse appear to have 

 settled into the structure and are more stable. 



Horizontal movement for the majority of the dolosse was relatively uniform. 

 The entire unit tended to move in the same direction as opposed to rotating. Of 

 the units that rotated, however, the majority of units on the north jetty moved in 

 a clockwise direction, while those on the south jetty rotated in a counterclock- 

 wise direction. 



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Chapter 4 Summary 



