Keywords: Physical environment, Climate change, Nearshore habitat, Sea level rise, Implementation Strategies, Shoreline armoring

Close to 30% of Puget Sound's shoreline is armored with seawalls and other structures meant to protect beaches against rising tides and erosion. But science increasingly shows that these structures are ineffective and cause significant harm to salmon and other creatures. State and federal agencies have been encouraging private property owners to remove armoring in a race to improve habitat, but why did so much of it start appearing in the first place?


Walk along most Puget Sound shorelines and you’ll encounter armoring. These seawalls, bulkheads, and revetments range from formal rock, concrete, metal, and wood walls that look to be carefully designed and engineered to haphazard piles of boulders, tires, and debris that appear to have been tossed up with little regard for an understanding of wave dynamics. Together they total about 700 miles of human-constructed barriers in greater Puget Sound, or enough to clad the entire Washington and Oregon coasts.

Long a part of the way people dealt with the Sound’s protean shores, armoring was historically justified by industrial and agricultural development for dikes and levees, railroads and roads, and reclamation and reuse. In a 2010 report, Washington Department of Ecology geologist Hugh Shipman wrote that by the 1950s though, large-scale residential communities that required dredging and filling of wetlands had supplanted previous reasons for armoring. More recently, an increase in people building homes along the Sound has led to consequent growth in private landowners constructing relatively small-scale bulkheads. Of the 57 percent of Puget Sound shoreline considered residential, roughly half has been armored. 

Today, property owners are increasingly interested in environmental stewardship and there’s a lot more information on how to build sustainably on the shoreline.

Hugh Shipman, Washington Department of Ecology

Not only has the style of armoring changed, so has the ecological understanding of this massive alteration to the shoreline. Long viewed as relatively benign, shoreline armoring has become more of an “in your face” environmental issue, says Shipman. The obstructions narrow beaches by changing wave dynamics, reducing bluff erosion, and preventing the beach from migrating inland. The smaller, more constrained beaches result in habitat loss for clams and other shellfish, as well as insects, worms, and amphipods, which rely on the steady upper beach accumulation of drift logs and beach wrack (algae, seagrass, leaf litter, and other tide-deposited debris). Studies also show that armored beaches are less hospitable to the key forage fish surf smelt and Pacific sand lance, both of which spawn in beach sediment and require specific conditions harmed by armoring.

The news on armoring, however, is not all bad, says Shipman. In his more than three decades of work as a coastal geomorphologist for the state, he has seen a huge change in the social landscape. “When I began, most people were unaware of the potential problems with bulkheads, nor were they aware that the eroding shoreline is an important element of the coastal ecosystem. Today, property owners are increasingly interested in environmental stewardship and there’s a lot more information on how to build sustainably on the shoreline.”

A long history

People have long been altering the shoreline of Puget Sound and the Salish Sea, says Colin Grier, an anthropologist at Washington State University. The terraforming structures of Coast Salish people date back to 5,000 years before the present. They include clam gardens, or terraces created by building low rock walls, which trapped sediment and created additional habitat on shorelines. Grier points out that some were immense structures that could stretch along kilometers of shoreline. The oldest were built 3,500 years ago and are the earliest evidence for food-based land management in the region. Better known and more widespread are middens. Often thought of simply as shell refuse heaps, they can contain animal bones, artifacts, and other debris. At Shingle Point, on Valdes Island, south of Gabriola, middens date back more than 5,300 years ago, and like the clam gardens, created significant changes to coastal processes.

Human-built clam gardens found in the lower intertidal zone are characterized by a level terrace behind a rock wall. Photo: Amy S. Groesbeck

Human-built clam gardens found in the lower intertidal zone are characterized by a level terrace behind a rock wall. Photo: Amy S. Groesbeck

Grier has concluded that residents over the millennia specifically and consciously altered the shoreline for their own benefit, for domestic, ecological, and perhaps military reasons. “The changes were proactive, iterative, and adaptive and based on the collective oral history about the dynamics of the shoreline,” he says. “They are time-vetted solutions that we can learn from.”

With the arrival of European settler that dynamic began to change though Shipman says that the earliest shoreline changes were built more on a scale and in a manner directly related to the environmental conditions. He imagines a family living along the shoreline near a creek in the late 1800s and dumping rocks on the beach to “solve a problem,” such as protection from the highest tides. They then might place some piling to extend a wharf into the water to facilitate shipping their goods. “Next thing you know they’ve got armoring,” says Shipman. “It was primarily a utilitarian response.”

Modern armoring, however, has been more of a discretionary action. As the region’s population grew and became wealthier, property values have risen so that only wealthy people can typically afford to buy and build along the shoreline. What once had been a cabin that families visited seasonally to go clamming or swimming had grown into a mansion where people lived year-round. Now that people were permanent residents on very valuable property, they wanted to make sure their land and home were protected, and to use as much of their property as possible. In order to do so, they felt they had to armor, and they had the resources to do so.

Shoreline armoring at Sunlight Shores in Island County. Photo: Jim Johannessen/Coastal Geologic Services. https://flic.kr/p/2hAgkpB (CC BY-NC 2.0)

Shoreline armoring at Sunlight Shores on Whidbey Island. Photo: Jim Johannessen/Coastal Geologic Services (CC BY-NC 2.0)

For some, their decision may have been influenced by their neighbors. In 1966, economist Alfred Kahn published a landmark paper on what he called the “tyranny of small decisions.” Kahn observed that small, individual transactions could combine to have far reaching, unexpected results. As an example, he showed how the decision by Ithaca, New York, residents to travel by car, bus, and plane ultimately resulted in the loss of passenger train service, a service that residents favored but failed to support. The idea of small decisions can also be applied to armoring.

Very few residential seawalls cover more than a few hundred feet and most animals can adapt to a low-quality beach by finding suitable habitat nearby. The problem is how animals respond in the long run, as every new armored beach has the potential to reduce the availability of suitable habitat. Each of these small decisions to armor is compounded because research has found that whether a homeowner decides to armor or not depends on what a neighbor has built. If the homeowner experiences damage because of adjacent structures, he or she is more likely to modify their property in response. The same study revealed that once they have armored, more than 75 percent of homeowners said they would do it again, even though their experiences revealed that natural shorelines were more durable and less expensive to maintain.

Private homeowners also benefited from loopholes in two of the state’s most far-reaching environmental laws —the Hydraulic Code Act (1949 with subsequent modifications) and the Shoreline Management Act (1971) — both of which address habitat protection along our coasts. Both of the acts also provided exemptions for single family residences (SFR). Although other regulations did apply to SFRs, they had limited effect at preventing bulkhead construction, in part because of limited enforcement. A 2005 report by Washington Department of Fish and Wildlife ecologists noted that the two state biologists focused on Puget Sound each issued approximately 600 permits per year and rarely had time to field check them.

Not until 2019 was the exemption for single family residences repealed for the HCA. It has not happened with the SMA.

Hugh Shipman says that these exemptions could be better characterized as a symptom than a source of the armor problem.  “We (our predecessors) just didn't see residential bulkheads as that big of a deal and letting property owners avoid going through a fairly onerous permitting process was a way of reducing friction to the passage of the SMA,” he says. With the better understanding of the downside of armoring, though, local and state guidelines have become stricter, he adds. In addition, their application has become stricter as the science improves and public awareness increases. “In the current situation, it’s hard to get a bulkhead — exempt or not.”

Resistence from homeowners

The bigger challenge at present is to encourage homeowners to remove their armoring. Most of them are in the middle of a bell curve on motivation to do so, says Nicole Faghin, Coastal Management Specialist for Washington Sea Grant. On the left side of the curve are those adamantly opposed to removing their bulkhead. On the other end of the spectrum are those who have heard of and are concerned about habitat issues and require little incentive to getting rid of their armoring. The bulk of homeowners, who comprise the middle, may also be influenced by habitat concerns but Faghin says another issue could loom even larger: sea level rise. Ironically, according to Faghin, “It may have more traction than habitat issues” for convincing homeowners to move away from traditional armoring.

Sunlight Shores in Island County in July 2019 after armoring removal and restoration the previous year. Photo: Jim Johannessen/Coastal Geologic Services (CC BY-NC 2.0)

Sunlight Shores (Whidbey Island) in July 2019 after the removal of 350 feet of armoring and restoration in the fall of 2018. Photo: Jim Johannessen/Coastal Geologic Services (CC BY-NC 2.0)

For some homeowners, sea level rise may actually seem like a reason to add, supplement, or leave in place exist armoring. After all, isn’t the goal of armoring to stop erosion? The problem is that higher seas result in higher waves and tides, which are more effective at weakening and overtopping bulkheads. In addition, climate change will lead to more and more intensive storms with consequent effects. If it turns out that armoring is ineffective against sea level rise, homeowners may need to find different approaches.

Still, coastal planners such as Faghin acknowledge that the science on bulkheads and sea level rise remains a matter of debate. Studies on the east coast have shown that creating more natural, or sometimes referred to as “living,” shorelines can provide better protection than armoring against erosion caused by rising seas. But little similar research has taken place around Puget Sound. That’s going to require more studies in our region. “We need to be able to demonstrate that bulkheads and armoring are not going to hold up with increased winter storms and that living shorelines work well at withstanding increased storm events to better be able to make an argument for removing a bulkhead,” says Faghin.

Homeowners face an additional problem. Space is essential for a soft shoreline to be effective, but many properties are sandwiched between the road and the water, in part because people replaced small homes with bigger ones on small lots. There is simply no space for them to either move their house away from the shoreline or adapt their shoreline to be more resilient to erosion. “As seas and waves are rising and creating faster and faster erosion, property owners are going to be faced with difficult decisions,” Faghin says.

One result is that people are selling their properties, says Andrea MacLennan, a coastal geomorphologist at 

Herrera Environmental Consultantsin Bellingham who has worked for more than two decades with private property owners on shoreline armoring. “Buying their property was an emotional issue. They fell in love with it and then coastal erosion starts. It’s a heartbreak to have to tell people that there is little they can do.” More often though says MacLennan she can offer practical solutions, backed by science, and tailored specifically to homeowners who have the inclination and space, and the money, to change their shoreline.

Like MacClellan, Karin Strelioff of the Thurston County Conservation District also works with private owners. The pair are part of a wave of private and public agency specialists working with the state’s Shore Friendly program. Administered by the Washington Department of Fish and Wildlife and Natural Resources with funding from the Environmental Protection Agency, the Shore Friendly-associated staff conduct site visits, listen to a homeowner’s questions, help them understand how shorelines work, and provide a report on how to manage their property.

A key issue Strelioff has encountered, she says, is people who have moved to the shoreline from urban and suburban areas and are used to meticulous lawns. These new homeowners don’t realize how their management contributes to erosion whether they have armoring or not. Strelioff encourages them to prune for better views and not to clear cut. She points out how roots, shrubs, and trees act like rebar holding together soils. Her goal is to help homeowners create more natural shorelines. “I try to help homeowners become more comfortable with messy,” she says.

Strelioff also notes the challenges of what she calls solutions “in quotes.” “People are living in a very dynamic space. Even if they do everything right, they could still have landslides. But ultimately, our goal is to help property owners work with the land and not against it.”

Policymakers recognize that armor removal may not always be a practical solution. There may be exceptions. We may not need to remove all armor to see ecological benefits but clearly the more bulkheads that are removed the better the impact on the shorelines and shoreline processes.

They also make one additional point. In Puget Sound, armoring is neither effective nor infallible. Years of research on both large -scale structures and individual bulkheads have shown that they tend to fail, which further exacerbates the problem. “We need to change the perception that retreat is losing the battle. We can’t let the alarmist view that armoring is necessary to prevail. The more people see shorelines without armoring, the more they will understand that they don’t need it,” says Andrea MacLennan.


About the author: David B. Williams is a naturalist, author, and educator whose award-winning book Too High and Too Steep: Reshaping Seattle’s Topography explores the unprecedented engineering projects that shaped Seattle during the early part of the twentieth century. He is also the author of "Seattle Walks: Discovering History and Nature in the City," "The Street-Smart Naturalist: Field Notes from the City," and co-author of "Waterway: The Story of Seattle’s Locks and Ship Canal." David’s next book, "Homewaters: Human and Natural History in Puget Sound," is scheduled for publication in April 2021. Williams is a curatorial associate at the Burke Museum and you can find him on Twitter at @geologywriter.

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