Table 22 

 Green Harbor Jetties 

 Green Harbor, Mass. 



Date(s) Construction and Rehabilitation History 



1898- Two rubble-mound jetties were constructed by the Commonwealth of 

 1899 Massachusetts at the entrance to Green Harbor and have been repaired 

 periodically since that time (Figure 25, present plan view). Infor- 

 mation on the original jetty lengths was not found. 



1931 The state constructed 196 ft of concrete wall at the east jetty's 

 landward end. 



1965 The Federal government adopted the project under authority of the 

 River and Harbor Act of 1960. 



1968- Repairs were made to seaward sections of both jetties, and the west 



1969 jetty was extended 200 ft seaward (Figure 25, insets). The east and 

 west jetty repair sections were 494 and 650 ft long, respectively, 

 and consisted of placing a 3- to 4-ft-thick seal blanket of 1- to 50- 

 lb quarry spalls on the seaward slope of the jetties followed by a 2- 

 to 4-ft-thick layer of cover stone. The cover stone was from 4 to 



7 tons and 0.5 to 4 tons on the east and west jetty repair sections, 

 respectively. The design geometry, including the west jetty exten- 

 sion, called for a 6-ft crown width, 1V:1.5H side slopes, and crown 

 elevations of +14 and +12 ft mlw on the east and west jetties, 

 respectively. The west jetty extension was built up on a core and 2- 

 ft-thick bedding layer of 1- to 50-lb stone, followed by a 3-ft-thick 

 underlayer of 500- to 1,000-lb stone, and covered with 4- to 7-ton 

 armor stone. The jetties' seaward ends had 1V:2H side slopes. A 

 175-ft-long dike of 0- to 25-lb stone was placed at the landward end 

 of the west jetty repair section. The stone was placed to a 4-ft top 

 width, 1V:2H side slopes, and a crown elevation increasing from +12 

 to +14 ft mlw in the landward direction. Prior to the repairs, crown 

 elevations varied from +8 to +11 ft mlw and +6 to +13 ft mlw on the 

 east and west jetty repair sections, respectively. The majority of 

 the east jetty was in a severely unraveled state. Improvements cost 

 $149,000 using a total of 14,900 tons of stone. 



1970 Approximately 335 ft of stone revetment was placed at the landward 

 end of the east jetty. The contract price for placing 3,400 tons of 

 stone was $37,400. 



1972 Inspection reports indicate the east jetty was in good to excellent 

 1974 condition. West jetty inspections showed the outer 350 ft was 



severely unraveled and other void areas existed landward of this 

 section. A 1974 topographic survey showed crest elevations in the 



(Continued) 



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