Stock photo (Unsplash), not a job photo.
People use these words interchangeably, but contractors, permit offices and insurers don’t. Here’s what each one is, in plain English.
The short version
| Structure | What it does | Where you see it on Long Island |
|---|---|---|
| Bulkhead | A vertical wall at the water’s edge that holds the land behind it in place, anchored back into the yard | South Shore canals and lagoons, creeks, harbors |
| Seawall | A heavier wall built to stand up to open-water waves | Exposed bayfronts and some Sound frontage |
| Retaining wall | Holds back soil on land, for grade changes, not tidal water | Yards, driveways, bluffs above the waterline |
| Revetment | Sloped armor stone that absorbs and breaks wave energy | Open bays, Sound beaches, erosion-prone shores |
| Living shoreline | Marsh plants, low stone sills, natural materials | Gentle shorelines with existing marsh |
What is a bulkhead, exactly?
A bulkhead is a wall of timber, vinyl or steel sheeting driven into the bottom along the shoreline. It’s held up by tie-backs anchored to deadmen buried in the yard, topped with a cap, and backed by filter fabric and fill. Its job is to keep your land from washing into the water and to give you a straight edge to dock a boat against. On Long Island canals, it’s the default.
Bulkhead vs seawall
The difference is mostly wave energy. A canal bulkhead faces boat wakes and tides. A seawall faces storm waves on open water and is built heavier, often steel or concrete, sometimes with armor stone in front. DEC’s fast-track bulkhead general permit specifically excludes high-energy wave areas and Coastal Erosion Hazard Areas, so exposed shorelines usually need individual review whichever structure you choose.
Bulkhead vs retaining wall
A retaining wall holds soil on land, and the water never touches it. A bulkhead is a retaining wall built for tidal water, with materials and anchoring to match. Don’t let a landscaper build a “retaining wall” at the waterline. Permit offices treat waterfront structures separately. The Town of Southampton, for example, lists bulkheads, revetments and retaining walls in the beach area as structures that each need a Town Trustees permit.
Revetments and living shorelines
Where a vertical wall isn’t allowed, or would make erosion worse by reflecting waves, a sloped stone revetment or a living shoreline may be the better option. Some towns push you toward these. Brookhaven’s wetlands code states a policy of using non-structural erosion control wherever practicable, and it prohibits new South Shore bulkheads unless the Town finds one necessary to protect safety or prevent significant property damage.
Which one do you need?
- Existing bulkhead on a canal: replace it in kind. See bulkhead replacement and the permit guide.
- Open bay or Sound frontage taking a beating: talk to a contractor about seawalls, revetments or a hybrid. See seawalls & storm repair.
- Retaining a slope above the water: that’s landscaping, not marine work, unless it’s in a regulated beach or wetland area. Check with your town.
Need it done? See seawalls, revetments & storm repair on Long Island.