Industry Day Project Narrative_SLSJ_20261015_FINAL.pdf

Project Background

Project History:

St. Lucie Inlet is comprised of the navigation channel and four navigation features including the impoundment basin, north jetty, offshore breakwater, and south jetty. The Federal navigation channel requires routine maintenance, primarily to Cut-1 and the impoundment basin. The north jetty, offshore breakwater, and south jetty have not received any routine or emergency maintenance from USACE or the non-federal sponsor (NFS), Martin County. The only known construction efforts for these structures are initial construction (1978-1982) and the north jetty modifications (2009).

The south jetty has experienced continued deterioration resulting from numerous damage drivers, most notably degradation of the asphalt walkway and internal grout, armor stone instability, and slope instability.

The worst deterioration has occurred along the jetty’s head. A breach developed approximately 10 years ago near the seaward limit of the structure head and continues to expand, and new breaches are forming along the head section. The continued degradation threatens to compromise the ability of the jetty to stabilize the inlet and the adjacent shoreline (the northern end of Jupiter Island) and increase the volume of sand entering the inlet system, potentially increasing operation and maintenance (O&M) costs for the federal project.

To date, the Federal navigation channel has experienced no direct service disruptions or increases in maintenance dredging activities directly related to the south jetty condition; however, given the age and continued deterioration of the structure, this is unlikely to continue. Further, a major storm event could significantly damage the south jetty and quickly result in adverse impacts to the Federal project and overall inlet stability. Major maintenance is recommended before the jetty is further damaged, more extensive structure repairs are needed, and repair costs increase.

Project Location:

St. Lucie Inlet is in Martin County on the southeast coast of Florida, about 115 miles north of Miami (Figure 1), serving as the County’s only point of access to the Atlantic Ocean. The Federal project connects the Atlantic Ocean with several key waterways including the Intracoastal Waterway (IWW) and Okeechobee Waterway, both heavily used by recreational and commercial vessels. The nearest coastal inlets are Jupiter Inlet, 17 miles south, and Ft. Pierce Inlet, 22 miles north.

Figure 1: St. Lucie Inlet Federal Navigation Project Location

Project Description:

The work consists of rehabilitation of the head structure of the South Jetty at St. Lucie Inlet. This includes a rebuilt rounded head structure and head-to-trunk transition with a marine mattress foundation and toe protection stones. Rehabilitation will require substantial moving and manipulation of both new and existing stones to obtain the required interlocking. The reworking of existing stones is only for incorporation of new stone. The retrieval of existing stone outside of the design template will not be required and is not part of the necessary rework of existing stone. The originally constructed South Jetty is approximately 1,320 feet in length with a crest height of 5.5 feet NAVD88. The crest width is 10 feet and the north and south slopes of the structure slope at 1V:2H.

There is an asphalt walkway approximately 1,090 feet in length that runs along the existing jetty crest, terminating eastward at approximately Station 12+00 as shown on the approved permit drawings.

Manipulation of stone along the crest may be necessary while completing the required work along the side slopes. The asphalt walkway will need to be removed within the repair area as necessary as work progresses. Any asphalt sections removed, or damaged such that they need to be removed, must be transported and properly disposed of off-site, and will not need to be replaced.

Existing Conditions:

The south jetty consists of a 1- to 2-foot-thick foundation of loose bedding stone (without geotextile fabric or a structured foundation), a uniform gradation core (800 – 1,600 lb stone), and a single layer of 6- to 10-ton armor stone. The upper portion of the structure includes chinking stone and asphaltic concrete grout and a 10-foot-wide asphalt walkway atop the crest. The asphaltic grout and asphaltic concrete walkway were critical to the design by providing a secondary structural feature to bind the single-layer armor stone.

The structure has experienced varying levels of damage due to numerous failure modes. The failure modes primarily consist of 1) asphalt and grout deterioration due to a lack of maintenance; 2) armor stone instability due to undersized stone and/or asphalt and grout deterioration; and 3) slope instability due to toe scour, structure settlement, and/or destabilized (undersized) stone. The structure condition and failure modes vary along the structure’s length but conditions generally degrade progressively seaward with the greatest degradation along the head section. See Figure 2 below and the following photographs of the site.

Figure 2: South Jetty Head Section – Aerial imagery of main breach located at approximately Station 11+50

Project Information

Scope of Work:

The proposed work includes rehabilitation of the head of the south jetty structure (the seaward-most 400 to 500 feet) by restabilizing the structure foundation and placing a second layer of large armor stone. The proposed scope includes:

1. Excavating the existing bed material to place a widened marine mattress foundation, expanding the current structure footprint up to 85 feet on the jetty centerline as shown on the approved permit drawings;

2. Placing 9- to 15-ton toe protection stones to form the structure foundation and provide scour protection;

3. Removing and disposing of the remaining asphalt walkway and other debris off-site;

4. Repairing the existing core and reworking the single layer of armor stone, as needed; and,

5. Placing a second layer of 9- to 15-ton armor stone to stabilize the structure.

Overview of Construction Staging and Access Requirements:

Clearing of access routes and staging areas may be required. Any areas that are disturbed during construction are to be restored to pre-construction conditions or better once jetty rehabilitation work is completed.

Expansion and/or improvements of access routes may be required. Maximum limits of access routes and staging areas are shown on the approved permit drawings.

Additional Environmental Considerations:

Construction will be permitted all year round and confined to daylight hours only. Construction that occurs during turtle and shorebird nesting seasons or has the potential to impact other Endangered Species Act (ESA) Protected Species, is subject to environmental restrictions and monitoring requirements. Refer to Table 1 below for a list of protected species.

Access from the water is allowed, but material cannot be dredged outside of the construction limits.

All material excavated must pass through a 2-inch screen prior to use as backfill around the jetty structure or on the beach. All screened material must be disposed of off site. Excavated material may be used to build up the east staging area within the limits shown on the approved permit drawings. After jetty rehabilitation work is complete, the staging area must be graded to the beach fill template and native vegetation restored as shown on the approved permit drawings.

Table 1: Endangered Species Act (ESA) Protected Species

Common Name Scientific Name Federal Status Agency

Birds

Eastern Black Rail Laterallus jamaicensis jamaicensis

Threatened USFWS

Florida Scrub-jay Aphelocoma coerulescens Threatened USFWS

Piping PloverD Charadrius melodus Threatened USFWS

Mammals

Florida Bonneted BatD Eumops floridanus Endangered USFWS

Southeastern Beach Mouse Peromyscus polionotus niveiventris

Threatened USFWS

West Indian (Florida) ManateeD

Trichechus manatus latirostris Threatened USFWS

Tricolored Bat Perimyotis subflavus Proposed USFWS

Reptiles

Eastern Indigo Snake Drymarchon couperi Threatened USFWS

Green Sea TurtleP Chelonia mydas Threatened USFWS & NMFS

Hawksbill Sea Turtle Eretmochelys imbricata Endangered USFWS & NMFS

Kemp’s Ridley Sea Turtle Lepidochelys kempii Endangered USFWS & NMFS

Leatherback Sea Turtle Dermochelys coriacea Endangered USFWS & NMFS

Loggerhead Sea TurtleD Caretta caretta Threatened USFWS & NMFS

Plants

Beach Jacquemontia Jacquemontia reclinata Endangered USFWS

Four-Petal Pawpaw Asimina tetramera Endangered USFWS

Tiny Polygala Polygala smallii Endangered USFWS

Mollusks

Queen Conch Aliger gigas Threatened NMFS

Elasmobranchs

Smalltooth Sawfish Pristis pectinata Endangered NMFS

Giant Manta Ray Mobula birostris Threatened NMFS

Corals

Mountainous Star CoralD Orbicella faveolata Threatened NMFS

Site Photographs:

Captured February 26, 2026.

Figure 3: Upland access road near west end of jetty, facing southeast.

Figure 4: Existing asphalt walkway, facing west.

Figure 5: Existing asphalt walkway, facing east.

Figure 6: Breach located near the head of the jetty structure, facing east.

Figure 7: Eastern edge of breach near end of jetty head structure.

Figure 8: Jetty head structure, facing east.

Figure 9: Jetty head structure, east of the large breach, facing west.

Figure 10: Dislodged armor and core stone at the breach, facing north.

Figure 11: Dislodged armor and core stone at the breach on the south side of jetty, facing north.

Figure 12: Location of east staging area located adjacent south to the jetty, facing north.

Figure 13: East staging area and east access route, facing south.

Figure 14: East access route, facing south.

Figure 15: Intersection of south access route and east access route at the beach, facing west.

Figure 16: South access route near the beach, facing east.

Figure 17: Upland access route near western end of jetty, facing east.

Figure 18: Large scarp on the north side of the upland access route located on the west end of the jetty, facing east.

Figure 19: Large scarp on the north side of the upland access route located on the west end of the jetty, facing west.

Figure 20: Upland access route from the west staging area, facing east.

Figure 21: West staging area, facing east.

Figure 22: West staging area, facing west.

Requests for Information:

Industry is asked to consider the following questions and provide input at the Industry Day:

1) Company/Contractor name, address, point of contact, phone number and e-mail address.

2) Does the Contractor plan to submit a proposal for this contract?

3) Describe the proposed construction methods and equipment needed to rehabilitate the jetty. Address, at a minimum, excavation of existing grade, maintaining open excavation areas, debris removal, and installation of marine mattresses and armor stone.

4) Would temporary earth-retention or water-control measures, such as a cofferdam or similar system, be required to complete the work? Would dewatering be completed if this is the proposed construction methodology?

5) If a cofferdam or other earth-retention system that also excludes all swimming ESA-listed species is not proposed, describe the measures that would be used to prevent the swimming ESA-listed species from entering the active work area during construction, including proposed turtle deterrent measures.

ESA-listed species present in the area are included in Table 1 above.

6) Describe the turbidity control measures that would be incorporated into the proposed construction methodology. If it is not feasible, describe the limitation or restrictions for why not.

7) What safety constraints or hazards could limit the practicality of potential construction methods?

8) What temporary protections or operational measures would be needed to perform the work during winter months, given the inlet’s elevated coastal conditions during that period?