New Bulkhead Construction: Site, Design and Permits

Building a bulkhead where none exists is a different undertaking from replacing an old one. A replacement continues an existing condition. A new wall changes the shoreline, and regulators, neighbors and the shoreline itself respond to that change. The work rewards careful site evaluation and an honest look at alternatives before anyone draws a wall.

This guide covers new construction specifically. For replacing an existing wall, see bulkhead replacement. For the mechanics of how walls retain soil, see how bulkhead walls work.

Start with the site

A good site evaluation answers why the shoreline is eroding and what it will take to manage that. Key questions include:

• What is causing the erosion? Waves from long fetch, boat wakes, groundwater seepage, runoff or a combination. The cause shapes the solution.
• How much wave energy reaches the site? Exposure determines whether a vertical wall, a sloped structure or a nature-based option is realistic.
• How deep is the water, and how high is the bank? These set wall height and the loads it must resist.
• What is the bottom made of? The Virginia Institute of Marine Science notes that soft clays and peats need to be accounted for to prevent settlement, and that a hard marl layer may prevent proper sheet pile penetration for wooden bulkheads.
• What habitat is present? Marsh, oyster beds and submerged vegetation affect both design and permitting.
• What is nearby? FEMA advises careful consideration when building a bulkhead near existing structures, since installation may affect them.

Alternatives, and why regulators ask about them

Shoreline stabilization ranges from vegetation alone, through hybrid approaches such as marsh with a stone sill, to rock revetments and vertical walls. Each has a place.

NOAA Fisheries describes living shorelines as nature-based stabilization that can become more stable as plants and roots grow, notes that they are typically not used on open-ocean beaches, and says technique choice depends on wave energy, tidal range and slope. Storm performance is part of the discussion: a peer-reviewed study of Hurricane Irene in North Carolina found that the storm damaged 76 percent of bulkheads surveyed in the central Outer Banks, while no damage was detected to other shoreline protection types in that survey. That is one storm and one region, but it is the kind of evidence agencies cite.

Regulation reflects this. Under the Clean Water Act Section 404 program, EPA states that no discharge of dredged or fill material may be permitted if a practicable alternative exists that is less damaging to the aquatic environment. Virginia law directs its Marine Resources Commission to permit only living shoreline approaches unless the best available science shows they are not suitable, and to incorporate living shoreline elements to the maximum extent possible when they are not. Maryland generally requires nonstructural stabilization unless an owner obtains a waiver, for example where the shoreline is mapped as appropriate for structural measures or site conditions make a living shoreline unsuitable. The federal Nationwide Permit for bank stabilization also notes that living shorelines may be authorized under a separate nationwide permit.

The practical result: an application for a new wall is stronger when it explains why alternatives were considered and why they do not fit the site. See riprap and living shorelines and shoreline erosion control.

Core design inputs

Two details deserve emphasis. First, water levels need a clear datum. NOAA defines tidal datums such as Mean High Water over a 19-year epoch, and separately cautions that the geodetic datum NAVD88 should not be treated as mean sea level. Second, embedment is calculated, not guessed. VIMS describes a rule of thumb of at least half the sheet length below ground, measured from the existing mean low water line rather than the beach, and notes that a bulkhead in a medium wave-energy environment may need to penetrate deeper still. A licensed engineer should determine the actual depth for your soils and loads.

Permitting

New walls usually need federal, state and local authorization. The federal Nationwide Permit for bank stabilization, NWP 13, lists bulkheads among eligible methods but limits bulkheads to 1,000 feet, a limit that cannot be waived, and requires pre-construction notification above certain thresholds, including more than 500 feet of length. Projects that do not qualify go through individual review. The bulkhead permit guide and permit navigator explain the layers.

Typical construction sequence

1. Mobilization and protection. Equipment staged on land or water; erosion and turbidity controls installed as permit conditions require.
2. Layout. The wall line and elevations set out from the survey and drawings.
3. Sheets or piles. Driven or installed to design depth.
4. Wales and anchors. On anchored walls, wales attached and tie rods connected to deadmen or other anchors. See tieback and anchor repair for how these parts work.
5. Filter fabric and backfill. Fabric placed behind the wall and backfill added in stages, as shown in VIMS's bulkhead schematic.
6. Cap. Timber or concrete cap installed to tie the top together.
7. Toe protection and ends. Stone at the toe where designed, returns and transitions completed.
8. Restoration and closeout. Grading, planting, final inspections and as-built records.

For budgeting, see bulkhead construction costs.