Bulkhead vs. Seawall: What's the Difference?

Ask a dozen waterfront owners what separates a bulkhead from a seawall and you will get several answers. Some say size. Some say material. Many say there is no difference. Each answer has some basis, because the engineering definitions and the everyday vocabulary do not line up neatly.

This guide explains how coastal engineers use the terms, how agencies and homeowners use them in practice, where revetments fit, and why the distinction still matters when a wall is designed, repaired or replaced.

The engineering definitions

The U.S. Army Corps of Engineers (USACE) design manual for coastal revetments, seawalls and bulkheads sets out the classic distinction. It classifies vertical shoreline structures "as either seawalls or bulkheads, according to their function," and calls protective materials laid on slopes revetments.

On function, the manual is direct. The terms "are often used interchangeably. However, a bulkhead is primarily intended to retain or prevent sliding of the land, while protecting the upland area against wave action is of secondary importance. Seawalls, on the other hand, are more massive structures whose primary purpose is interception of waves."

The USACE property owner's guide adds that severe wave action is usually beyond a bulkhead's capacity, and that seawalls are generally not needed in sheltered waters where large waves do not occur. FEMA's shoreline fact sheet follows the same logic: it lists seawalls for ocean and sheltered shorelines, and bulkheads for sheltered shorelines only.

The engineering distinction, then, is about what the wall is designed to resist:

• A bulkhead is designed mainly around earth pressure from the soil it retains.
• A seawall is designed mainly around wave forces, and is typically heavier, with vertical, curved or stepped faces.

How the words are used in practice

Outside design manuals, usage is looser, and agencies acknowledge it.

• North Carolina. The Division of Coastal Management defines a bulkhead as "any shore-parallel vertical structure designed to prevent erosion, overtopping, flooding, or sliding of the land," and lists "Vertical Structure" and "Seawall" as other names for it.
• Chesapeake Bay. A Virginia Institute of Marine Science (VIMS) publication notes that bulkhead and seawall "are two terms often used to denote the same type of shoreline protection structure," then draws a distinction: bulkheads are generally smaller and less expensive, while seawalls are generally poured concrete designed to withstand the full force of waves. The VIMS glossary similarly describes a seawall as usually taller and larger than a bulkhead.
• Florida canal communities. Residential canal walls are commonly called seawalls. The City of Cape Coral's residential permit guideline is titled "Seawall," and its inspection sequence includes a cap and tieback inspection. A tied-back wall retaining a canal bank in sheltered water behaves much like what USACE would call a bulkhead, whatever it is named locally.

None of these usages is wrong. They reflect regional habits and, in some places, the fact that one structure does a bit of both jobs. For clarity, Bulkhead Walls uses "bulkhead" for soil-retaining shoreline walls and uses "seawall" where it is the regional term, as in our guides to seawall repair and seawall replacement.

Where revetments fit

A revetment is not a wall. It is a sloped layer of armor placed on an earthen bank. FEMA describes coastal revetments as durable stone, concrete or other materials placed on a slope, typically with an armor layer, filter layers, geotextile fabric and toe protection.

The slope is the important part. USACE notes that all three structure types can reflect waves and erode the fronting bottom or beach, but that the problem is most prevalent for vertical structures and progressively less so for curved, stepped and rough sloped structures that absorb or dissipate more wave energy. The tradeoff is space and access: a revetment occupies more of the shoreline and, if built of random stone, can hinder access to the water. See riprap and living shorelines for more.

Side-by-side comparison

The table summarizes USACE and FEMA guidance in general terms. Individual structures vary, and many real shorelines combine types, such as a bulkhead with stone toe protection in front of it.

Why the distinction matters

The name on a wall is less important than what it was designed to do. Still, the difference has practical consequences.

1. Design loads. A wall designed to retain soil in a quiet canal is not automatically suited to open-coast storm waves. If exposure changes, for example after a nearby marsh erodes, the original design assumptions may no longer hold.
2. Comparing quotes. Two contractors may use different words for the same scope, or the same word for different scopes. Compare material, height, embedment, anchorage, drainage and toe protection, not the label. Our guide on how to compare contractor quotes explains what to line up.
3. Permits and policy. Agencies may treat vertical walls and sloped structures differently. Maryland's guidelines, for example, describe stone revetments as environmentally preferable to bulkheads. Check the bulkhead permit guide for how terms appear in your state's process.
4. Research. Knowing both terms helps when you search records, permits or technical guidance for your area.

Which term fits your shoreline

A few questions help place a structure, though a licensed professional should confirm what any particular wall was designed for.

• Is the wall mainly holding up a yard or bank that is higher than the water? It is functioning as a bulkhead.
• Does it face open water with a long fetch and regular breaking waves? It may be carrying seawall-type loads, whatever it is called.
• Is the shoreline protected by sloped stone rather than a wall? That is a revetment.
• Is there stone at the base of a vertical wall? That is likely toe protection, a common addition to both bulkheads and seawalls.

For the forces involved, read how bulkhead walls work. For the broader context of shoreline change, see waterfront erosion explained.