St.  Lucie Inlet Jetties and Detached Breakwater

St.  Lucie Inlet, Florida

 Dredging Records

 

Date(s)         Construction and Rehabilitation History

 

1892            St. Lucie Inlet, located at the south end of Hutchinson Island, is reported to have been cut through the barrier island by local residents.  Initially, the inlet was 30 ft wide and 5 ft deep.

 

1909            Federal interest in a navigation project recommended Federal funding of a 18-ft channel as well as a jetty along the north side of the channel.

 

1913            The 1913 River and Harbor Act provided initial appropriation of funds for experimental dredging of a channel 18 feet deep across the reef and ocean bar.

 

1916            Federal construction of the channel seaward from the mouth of the inlet began.   The dredged portion of the project rapidly shoaled with sand and abandonment was recommended in 1917 and again in 1933, but no action was taken.

 

1926-1929     Local interests constructed the north jetty out of coquina rock to a length of 3,325 ft.  The maximum dimension of the rock was 6 to 7 ft with a density of about 120 pcf.  The offshore 100- to 200-ft portion of the jetty was partly covered with granite blocks.  Martin and St. Lucie Improvement District dredged a turning basin at Port Sewall and an 18-ft deep by 150-ft wide by 10,000 ft long channel.

 

1966            Federal legislation was passed modifying the St. Lucie Inlet project to include maintenance of a 6 by 100-ft channel along the best natural deep water alignment between the Federal bar-cut channel and the Intracoastal Waterway.

 

1974            An extension of the north jetty and modification to it for a weir section, excavation of a sand impoundment basin, construction of a south training jetty with a fishing walkway, a 10 by 500-ft channel through the bar-cut tapering to 150 ft through the inlet, and a 7 by 100-ft channel to the Intracoastal Waterway were authorized by Congress.

 

1979-1982     This Federal project consisted of extension of the north jetty 650 ft (350 ft south-southeasterly and then 300 ft southeasterly), construction of a 1,400-ft south jetty with fishing walkway and a connecting rock bulkhead, construction of a 400-ft detached breakwater directly south of the north jetty extension (700 ft apart at their outer ends), an entrance channel 16 feet deep by 300 feet wide, an inlet throat channel 10 feet wide, and the dredging down to rock of a 2,500 foot long by 450 foot wide impoundment basin.  Capstone was to be 6 to 10 tons (at least 75 percent to be 8 tons or more), except on the outer ends of the jetties and the detached breakwater, where the capstone would weigh 10 to 12 tons.  Estimated quantities for completion of the improvements were 64,800 tons of capstone, 8,000 tons of core stone, and 28,600 tons of foundation stone.  The fishing walkway was built using asphaltic concrete cap and grouting mixes.  During construction there was a severe problem with scour, and large apron blankets had to be added (no details on apron or jetty cross sections).

 

1994            Construction by non-Federal interests of a sand tight groin about 450 feet long at an elevation of about 4 feet NGVD located about 50 feet north of and parallel to the north jetty.