Figure 3. Aerial view of deteriorated jetties at Manasquan Inlet, March 1962 



Breaking waves accompanied by storm surge were identified as the principal 

 cause of damage to the structures at the inlet. Unfortunately, no reliable wave 

 data existed at the site. Therefore, the design wave height was based on depth- 

 limited breaking wave criteria. The design water depth at the seaward end of the 

 jetties was calculated to be 8.8 m (29 ft), based on a mlw depth at the structure 

 toe of 5.5 m (18 ft), plus 1.65-m (5.5-ft) maximum spring tide height, plus 

 1.65-m (5.5-ft) storm surge el. Using procedures from the Shore Protection 

 Manual (SPM) (1984) for a range of wave periods from 7 to 15 sec and assum- 

 ing a nearshore bottom slope of 0.01, values of the breaking wave height ranged 

 up to 7.5 m (24.7 ft) for the longer wave periods. The design breaking wave 

 height selected was, therefore, 7.6 m (25 ft). Several alternative designs were 

 considered for the rehabilitation, including 10,885- and 18,145-kg (12- and 

 20-ton) stone and 14,515-kg (16-ton) dolosse. Dolosse were determined to have 

 the lowest annual maintenance cost and were selected for construction. Based 

 on engineering judgment, a decision was made to reinforce the dolosse with 

 epoxy-coated reinforcing rods. 



In 1995, maintenance was performed at the tip of the south jetty where core 

 stone under the jetty cap was exposed. Nylon bags were placed in this area, and 

 concrete was pumped into them as a temporary solution (Figure 9). A total of 

 53.5 cu m (70 cu yd) of concrete was used. This was the first maintenance per- 

 formed on the jetties since the major rehabilitation was completed in 1982. 



In October 1997, void areas in both jetties were rehabilitated with 17,235-kg (19- 

 ton) CORE-LOC armor units. CORE-LOCs were developed by the Corps of 



Chapter 1 Introduction 



