US Army Corps of Engineers
Wilmington District

Setback Policy for all Federal Navigation Channels

* The Wilmington District Setback Policy was revised on November 13, 2013 *

 

What is a Setback?

The U.S. Army Corps of Engineers (USACE) Wilmington District establishes a setback from all Federal channels.  A setback is a distance from the channel in which construction is prohibited.  Setbacks are intended to serve two primary purposes: 1) they give the USACE and its contractors adequate space and maneuverability to perform dredging throughout a channel, and 2) they provide commercial and private boating traffic a safety margin when navigating Federal channels.  Please be aware that most construction and maintenance activities over, under or within navigable waters, whether affecting the setback or not, require authorization from the USACE Regulatory Program and the North Carolina Division of Coastal Management.  You should contact these organizations directly if proposing to undertake construction in these areas.

 

What Type of Construction does a Setback Prohibit?

The Wilmington District does not allow construction of hardened or permanently fixed structures within the setback.  It is our policy to only allow floating structures within the setback, on a case by case basis.  Construction or placement of structures, whether permanent or hardened in nature, can be built up to the setback line. Floating structures must be anchored outside of the setback limit in order enable complete removal (at owners expense) of the structure during a dredging event.  Whether structures are in compliance with the setback or not, we do reserve the right to seek modification or removal of any structure that is determined to be a hazard to navigation. Any Existing Docks/Piers within the setback maybe required to modify or removal of the structure if we determine that the structure was not authorized by a permit.  

 

Where can the Setbacks be Viewed Graphically?

All Wilmington District navigation setback limits are graphically displayed via a downloadable Google Earth KMZ file. This data is freely available to the public and can also be accessed via the Wilmington District's Navigation webpage.  All of the latest setback information, including coordinates, will be displayed on Navigation Basemap for use in Google Earth.  

How is the Setback Determined?

a.  General.  The following setbacks are designated to ensure that no structures encroach beyond the top edge of the navigation channel, including appropriate side slopes, and that there is sufficient clearance for dredging the navigation channel to its full width and depth, including slide slopes. Additionally, considerations are made for safe passage of commercial vessels through some Federal channels. Absent unusual circumstances, the following guidelines will apply. 

Piers, docks, or waterfront structures should not extend any closer to the near bottom edge of the Federal channel than the sum of the project depth plus two (2) feet overdepth, times three (3), plus ten (10) feet, except as provided in subparagraphs (b.), (c.), and (d.) below. (Example:  6-foot project + 2-foot overdepth = 8 feet x 3 + 10 = 34-foot setback from near bottom edge of channel). This will allow for full maintenance dredging of the Federal project with allowable overdepth and appropriate side slopes (generally a 3:1 slope), and give dredging contractors adequate room to conduct operations without endangering docks and other structures. Additionally, these setbacks should allow for the safe passage of vessels appropriately sized to navigate these Federal channels.

b.  Atlantic Intracoastal Waterway (AIWW).  Piers, docks, or other waterfront structures should not extend any closer to the near bottom edge of the AIWW Federal channel than 80 feet. Additionally, there are four instances when the setback is more than 80 feet, as outlined below.

 

i. Bends in the AIWW Navigation Channel.  Bends are especially dangerous for vessels, especially those pushing barges. Large vessels negotiating turns, particularly when currents are swift, require additional clearance to safely navigate through bends in shallow-draft channels. Accordingly, where the angle of deflection of the centerline of the AIWW channel from straight is 30 degrees or more, the setback will be expanded to 100 feet on the inside of the bend and 100 feet on the outside of the bend from the near bottom edge of the Federal channel for 1,000 feet in length of the centerline of the channel, going both directions from the point of intersection at the channel bend. If these expanded setback ends are within 1,000 feet of one another, the two expanded lengths will be connected, using the smaller of the two setbacks for the intervening distance. All deflections are measured using the centerlines of the channel. All setbacks are measured from the near bottom edge of the channel ( Figure 1).  In certain cases, it is necessary to extend the 100-foot setback beyond 1,000 feet in length for navigational safety and in order to protect navigational servitude. Channels where extensions have been made beyond 1,000 feet are as follows:

 

a.  Entire length of Cape Fear to Little River (CFR-LR) Tangents 17 and 18 (Figure 2).

 

b.  Entire length of the west side of CFR-LR Tangent 6 (Figure 3). 

 

c.  Along the east side of CFR-LR Tangent 6 for approximately 1,500 feet from the intersection of Tangents 6 and 7. The remaining east side of Tangent 6 reverts to an 80-foot setback (Figure 3). 

 

d.  The widener at the intersection of CFR-LR Tangents 5 and 6 (Figure 3).

 

e.  Entire length of Section 5 Tangent 2 through Section 5 Tangent 4A, Snows Cut (Figure 4). 

 

f.  Entire length of Section 2 Tangent A (Figure 5). 

 

g. The south side of Section 3 Tangent 3 for 1,000 feet from the intersection of Section 3 Tangents 2 and 3, but only an 80-foot setback along the north side of Section 3 Tangent 3 (Figure 6).

 

 

ii. Inlet Crossings.   AIWW setbacks are expanded at inlet crossings based on the current centerline of the inlet connecting channel to the AIWW. These setbacks vary by location, to accommodate for increased traffic around inlets, faster and stronger currents, to account for the more dynamic nature of shorelines and shoal features adjacent to inlets, and to allow for maintenance dredging of approved channel widener segments adjacent to inlets.  Specific AIWW Inlet Crossing setbacks are defined as follows:    

 

a.  Shallotte Inlet Crossing – a 100-foot setback along both sides of CFR-LR Tangent 20 for 1,000 feet from the intersection of CFR-LR Tangents 19 and 20. A 200-foot setback along both sides of Tangent 19 for 2,000 feet from the intersection of Tangents 19 and 20. The remainder of Tangent 19 has a 100 foot setback along both sides to the intersection of Tangent 18 (Figure 7).

 

b.  Lockwoods Folly Inlet Crossing – a 200-foot setback along both sides of CFR-LR Tangent 11 for approximately 3,400 feet, centered on the intersection of Lockwoods Folly Inlet and AIWW (Figure 8).

 

c.  Carolina Beach Inlet Crossing – a 200-foot setback along both sides of Section 4 Tangent 1 for approximately 2,200 feet, centered on the intersection of Carolina Beach Inlet and AIWW (Figure 9).

 

d.  Masonboro Inlet Crossing – a 200-foot setback along both sides of Section 4 Tangent 3 for approximately 3,000 feet from the intersection of Section 4 Tangent 3 and Section 4 Tangent 4 (Figure 10). 

 

e.  Mason’s Inlet Crossing – a 100-foot setback along the west side of Section 3 Tangent 12 for approximately 2,000 feet and a 200-foot setback along the east side of Section 3 Tangent 12 for approximately 2,000 feet, centered on the intersection of Mason’s Inlet and AIWW (Figure 11). 

 

f.  Topsail Creek / Topsail Inlet Crossing – a 200-foot setback along both sides of Section 3 Tangent 8 for approximately 2,000 feet, centered on the intersection of Topsail Creek and AIWW (Figure 12).

 

g.  New River Inlet Crossing (Cedar Bush Cut) – a 200-foot setback along both sides of Tangent J. A 200 foot setback along both sides of Tangent I for approximately 1,500 feet from the intersection of Tangents I and J (Figure 13). 

 

h.  Brown Inlet Crossing – a 200-foot setback along both sides of Section 2 Tangent F for approximately 7,800 feet, centered on the intersection of Brown Inlet with the AIWW (Figure 14). 

 

i.  Saunders Creek Crossing (Bear Inlet) – a 200-foot setback along the south side of Section 2 Tangent C for approximately 2,000 feet from the intersection of Section 2 Tangents C and D. A 200-foot setback along the south side of Section 2 Tangent D for approximately 1,000 feet from the intersection of Section 2 Tangents C and D (Figure 15).

 

j.  Bogue Inlet Crossing – a 200-foot setback along the south side of Section 1 Tangent G. A 100-foot setback along the north side of Section 1 Tangent G (Figure 16).

 

iii. Channels Connecting with the AIWW. Channel connections are especially dangerous for vessels, especially those pushing barges. Additional setbacks in these areas will allow for adequate line-of-sight for vessel captains and adequate space for turning vessels and generally increased traffic. Accordingly, the setback has been expanded to 100 feet on each side of the connection. The length of the expansion will extend from the near bottom edge of each intersecting Federal channel for a distance of 750 feet along the centerline of the connecting channel from the centerline intersection. One exception is the connecting channel between the Cape Fear River and AIWW Section 5 Tangent 3. This channel has an 80 foot setback along both sides. Setbacks for some AIWW channels have been expanded where they intersect other connecting channels.  The expansions are required for navigational safety and increased traffic, and are as follows:

    1. Shallotte River  – a 92-foot wide setback along Shallotte River for approximately 950 feet from the intersection of CFR-LR Tangent 17 and Shallotte River.  An additional widener exists at the intersection of the Shallotte River and CFR-LR Tangent 17 setbacks (Figure 17.1).
    2. Lockwoods Folly River Crossing – a 100-foot setback along the entire southern side of CFR-LR Tangent 8. A 100-foot setback along the northern side of CFR-LR Tangent 8 for approximately 2,000 feet from the intersection of Tangent 8 and Lockwoods Folly River towards Tangent 7 (Figure 17).
    3. Nixon Channel Crossing – a 100-foot setback along the west side of Section 3 Tangent 11 for approximately 2,000 feet and a 200-foot setback along the east side of Section 3 Tangent 11 for approximately 2,000 feet, centered on the intersection of Nixon Channel and AIWW (Figure 18).
    4. Butler Creek Crossing – a 100-foot setback along the west side of Section 3 Tangent 11 for approximately 2,000 feet and a 200-foot setback along the east side of Section 3 Tangent 11 for approximately 2,000 feet, centered on the intersection of Butler Creek and AIWW (Figure 19).
    5. Green Channel Crossing – a 200-foot setback along both sides of Section 3 Tangent 10 for approximately 2,000 feet, centered on the intersection of Green Channel and AIWW (Figure 20).

 

c.  Inlet Navigation Projects. Many of the Federal navigation projects involving channel maintenance within ocean inlets and some side channels and river channels follow the deepest water at the time of maintenance, as opposed to established project limits defining a fixed Federal channel. Due to the dynamic nature of these areas, structures should generally not be constructed within the inlet area, defined as the area from the ocean limits of the Federal navigation project through the natural deep water of the gorge to its intersection on the AIWW or other fixed Federal channel. On other channels that follow the deepest water, piers, docks, or other waterfront structures may only be constructed, if approved by the Chief of Navigation, since they have an unlikely chance of being included in the anticipated migration limits of the channel. 

d.  Small Boat Harbors and Harbors of Refuge.  Small harbors or basins are the terminus point of a navigation channel and do not contain any through channel, but does not include turning basins. Piers, docks, and other waterfront structures should not extend any closer than 15 feet from the near bottom edge of the Federal channel. Dredging of these areas will not include any sideslopes. The 15 foot setback applies to the following small harbors:

    1. Manteo Harbor
    2. Stumpy Point Basin
    3. Rodanthe Harbor
    4. Far Creek Basin
    5. Swanquarter Basin
    6. Wrights Creek Basin
    7. Avon Harbor
    8. Hatteras Harbor
    9. Silver Lake Harbor
    10. Oriental Harbor
    11. Atlantic Harbor of Refuge
    12. Atlantic Harbor
    13. Marshallberg Harbor
    14. Town Creek Harbor of Refuge
    15. Morgan Creek basin
    16. Peltier Creek basin
    17. Swansboro basin
    18. Carolina Beach Harbor
    19. Southport Boat Basin
    20. NCSPA Southport Small Boat Harbor

For channels connecting small basins or harbors to larger waterbodies, piers, docks, and other waterfront structures should not extend any closer to the near bottom edge of the Federal channel than the sum of the project depth plus two (2) feet overdepth, times three (3). (Example:  6-foot project + 2-foot overdepth = 8 feet x 3 = 24-foot setback from near bottom edge of channel).

 

e.       Lockwoods Folly River.  Downstream from the intersection of Lockwoods Folly River Tangents 13 and 14, piers, docks, or waterfront structures should not extend any closer to the near bottom edge of the Federal channel than 34 feet (the sum of the project depth (6)  plus two (2) feet overdepth, times three (3), plus ten (10) feet. Due to the narrow width of Lockwoods Folly River upstream (north) of the intersection of Tangents 13 and 14, exceptions to the setback policy will be permitted on a case by case basis. Navigation Branch has approved a designated dock structure layout for this portion of the river. Minor modifications to the approved design may be considered based upon specific site conditions and variations. For a copy of the approved configuration, please contact the Wilmington District Chief of Navigation.

f.  Harborlines. The setback policy will not apply to Federal projects that have established harbor and pierhead lines or where setbacks have been established by law. Harbor and pierhead lines have been established in the following areas: 

                            i.  Cape Fear River/Wilmington Harbor

                            ii.  Morehead City Harbor and Waterfront

                            iii.  Beaufort Harbor and Waterfront

                            iv.  Neuse River/New Bern

                            v.   Pamlico River/Washington

What if my Dock is currently within the Setback?

Existing piers, docks, or other waterfront structures destroyed beyond repair by a storm, act of nature, or other sudden event, will only be replaced in accordance with the current Wilmington District setback policy, as well as any USACE Regulatory and North Carolina Division of Coastal Management permit requirements.  The redevelopment or expansion of existing piers, docks, or other waterfront structures, (e.g., the conversion of commercial seafood docks to a residential marina), will be subject to current setback policy and any required regulatory permit action. The general maintenance and repair of existing piers, docks, or other waterfront structures located in the Federal channel setback may be authorized provided the work does not increase the footprint of the existing structure or results in additional encroachment into the setback. No new structures, and no reconstruction or redevelopment of existing structures, will be allowed within the authorized boundaries of any Federal channel.

 

What if I am Building a New Dock?

When submitting your permit application, you will need to identify where the setback line is and if you plan to cross it.  If your construction plans cross the setback limit, then you will need to provide detailed documentation regarding your building materials, in order for us to ensure that you will not be using any hardened/permanent structures that will be anchored within the setback.

 

Definitions

-Shallow Draft Navigation Channels are Federally maintained navigation channels with project depth dimensions equal to or less than 14 feet mean low water (M.L.W.).
-Waterfront Structures include any relatively permanent structure placed below mean high water (M.H.W.) of a waterway. This includes, but is not limited to bulkheads, seawalls, groins, revetments, rip rap, or other hardened stabilization structures, dolphins, piles, boat lifts, piers, and mooring buoys.
-Channel Intersections are defined as the point of intersection of two or more channel centerlines.
-A Setback is defined as the distance between a structure and a Federally-authorized and constructed channel (i.e., the distance that a structure must be “set back” from the edge of the channel). All setbacks are measured from the near bottom edge of the channel to the nearest point of the structure, whether that point is fixed or floating.  
-Maintenance and Repair is the fixing of any structure that becomes out of order or broken, as well as performing routine actions to keep its operation in a functional and serviceable capacity. Maintenance does not include any modification that changes the character, scope, size, or footprint of the original structure.
-Redevelopment is the re-building or re-assembling of any structure that is no longer functional or serviceable in its original capacity, specifically pertaining to its framing and structural components. This would include beams, girders, joists, stringers, and/or pilings. Structures severely damaged or destroyed by natural or man-made events, including normal deterioration are considered in this category.

 

If you have Questions about the Setback?

If you need to discuss your particular setback issue, contact a member of the USACE Wilmington District office (call or Email):

Contact Information
Land Use Coordinator

(910) 251-4196

Chief of Geospatial Services (910) 251-4067

Chief of Navigation

(910) 251-4822

 

US Army Corps of Engineers
Attn: Land Use Coordinator
69 Darlington Ave
Wilmington, NC 28403

Or Email questions to:

SAWWEB-WILLandUse@usace.army.mil

If you have any questions, please feel free to contact any staff member listed above.

Last Revised: 03 December 2013