Preserving Eelgrass While Remediating Legacy Contamination


What do you do when the State requires you to take action, yet prohibits that action? It’s a conundrum that takes imagination and determination.

The Setup

For over 100 years, several companies used the nearshore at the former Custom Plywood site for processing and manufacturing wood-related materials that would be used nationwide. They filled the tideland with wood, ash, bricks, metal, and sediment. They left a tug, boiler ash, scrap metal, barrels and drums, aluminum cans, scrap wood, paper, sawdust and creosote-treated pilings. As if that wasn’t enough, in 1992 a fire destroyed the mill, adding dioxin (a carcinogen) to the sediment.

The Conundrum

The Washington State Department of Ecology and Hart Crowser removed most of the contamination from the property and tidelands. Despite this, there are many acres of tidelands that are still peripherally contaminated with dioxins, much of which contains healthy eelgrass habitat. The eelgrass is not affected by the dioxin contamination; the problem is that it serves as a potential pathway for human exposure (i.e., shellfish consumption). By State mandate eelgrass must be protected. (See our earlier post about the importance of eelgrass). This means that the State requires that something be done about the contamination but not at the expense of the valuable eelgrass habitat. Our current options for dealing with dioxin contamination are to either dig up the contaminated material, or immobilize/cover it to prevent the exposure to the benthic community. Either action would potentially destroy the eelgrass. What to do?

The New Approach

The solution? Remediate the sediment in place by covering the eelgrass habitat, but not burying it. Eelgrass, unlike other species of seagrass, can only tolerate a very small level of burial. We needed to determine if the eelgrass at the former Custom Plywood site could withstand deposition of very fine layers of sand that would act as a barrier (cap) to the contamination in order to protect the benthic community and the habitat overall. Our team conducted a two-year pilot study to see whether the eelgrass could tolerate a four- or eight-inch layer of sand (applied two inches at a time), rather than a single layer application that would ordinarily be used for remediation. As part of this study, our team also investigated if adding a layer of carbon could increase the cap performance so that the cap could be as thin as possible.


Diver with eelgrass/sediment sample. Photo courtesy of Research Support Services.

The Result

The data clearly showed that eelgrass at the former Custom Plywood site can survive a four-inch cap if implemented in multiple thin layers. This means that the preferred alternative for cleaning up the residual contamination is potentially feasible. The next step is to design a large scale application using the information and data gathered from the pilot study. Eventually we hope to finally cleanup the former Custom Plywood site while leaving the existing eelgrass habitat in place and functioning.

For more information about eelgrass contact Emily Duncanson or Jason Stutes at (425) 775-4682.


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The Game of Thrones Wall—An Engineering Perspective

Game of Thrones Wall

Photo: HBO

The Game of Thrones (the HBO series based on George R. R. Martin’s books, A Song of Fire and Ice) features a giant wall made of ice. Seven hundred feet high. It’s an imposing structure, but it has to be, in order to keep out the terrifying dead people who inhabit the north.

According to Martin, “You could see it from miles off, a pale blue line across the northern horizon, stretching away to the east and west and vanishing in the far distance, immense and unbroken. This is the end of the world, it seemed to say.”

Such an extraordinary structure couldn’t help but draw attention from our geotechnical engineers and staff, who responded to some of the quotes from the books.

“The wall is a hundred leagues long.”

A league was supposed to be the distance that a person could walk in one hour. An English league, once upon a time was about three miles long, which would make the wall three hundred miles long.

“The wall is 700 feet high.”

This is almost as tall as the 1201 Third Avenue Building in Seattle, a 55-story building, which coincidentally has beautiful blue coloring as well. Certainly it takes a lot of work to design and build a high-rise—imagine building so many adjacent high-rises that they would stretch for 300 miles. That’s never been done.

At a height of 700 feet and a unit weight of 57.4 pounds per cubic foot (pcf) for fresh water ice, the base contact pressure on the underlying soil/rock would be on the order of 40,000 pounds per square foot (psf). (Compare that to a high-rise on glacial till at 14,000 psf).

“The wall has stood for, what, eight thousand years?”

Assuming a coefficient of secondary compression, C-alpha, of 0.02 and assuming that the base upon which the wall is built is comprised of some reasonable thickness of compressible organic muskeg (say ten feet), and assuming the wall was built over a period of one hundered years, the wall will likely have settled about three to five feet under its own weight.

“The top wide enough for a dozen armored knights to ride abreast.”

How wide is an armored knight? Say five feet? 5 x 12 = 60 feet wide? To safely travel, there would need to be at least three feet between riders so the total width (including four feet on either side for shoulders and jersey barriers) would be 101 feet.

“The gaunt outlines of huge catapults and monstrous wooden cranes stood sentry up there, like the skeletons of great birds, and among them walked men as small as ants.”

To anchor the catapults and cranes, it is likely that the overturning and uplift forces on the catapults and cranes would control the design. The overturning forces associated with the action of the catapults and the wind loads on the structures (resulting from the unobstructed exposure to the predominant winds due to the height of the wall) could be resisted by using high-capacity drilled micropiles.

“It was older than the Seven Kingdoms and when he stood beneath it and looked up, it made Jon dizzy. He could feel the great weight of all that ice pressing down on him, as if it were about to topple, and somehow Jon knew that if it fell, the world fell with it.”

One of the Seattle-Tacoma International Airport Third Runway walls (135 feet tall) was built stepped in, in order to avoid this feeling when you stand at the base of it. However, typically, a tall wall looks shorter when looking up than when it does when looking down. Jon is a weenie.

“Eight hundred feet above the forest floor, a good third of that was earth and stone rather than ice.”

It seems that people got creative over the years, sometimes making use of on-site materials, a good practice to save cost, time, and the environment. It also makes sense, when you are building a structure with a contact bearing pressure equal to 40,000 psf, to do overexcavation and replacement with densely compacted (i.e., 95 percent of the maximum dry density, within two percent plus or minus of optimum moisture content, as determined by ASTM D1557 Test Procedure) well-graded sand and gravel with less than five percent passing the U.S. No. 200 sieve based on the minus three-quarter-inch fraction.

Have questions about the geotechnical design of other giant structures? Need a dragon or two? Contact Garry “the Hound” Horvitz.

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Towering Hills for Beauty and Strength

Governors Island

Image courtesy of West 8 / Rogers Marvel Architects / Diller Scofidio + Renfro / Mathews Nielsen / Urban Design +

A dozen years ago an American port representative was asked how his port was preparing for rising sea levels. “Well…we aren’t,” he answered, somewhat sheepishly, because he knew they should be. Back then, the public was skeptical of the controversial topic, and frankly many ports had too many other priorities. But now public officials see the situation in a new light. They are taking advantage of waterfront development projects to make property not only more resilient to climate change, but also more beautiful and beneficial to the public.

A perfect example is the 40-acre Governors Island Park and Public Space in New York. West 8, an urban design and landscape architecture firm, transformed the abandoned former military island into a green oasis with an extraordinary 360-degree experience of water and sky that has won numerous awards. Part of the makeover involved creating four tall, dramatic hills from twenty-five to seventy feet high. This meant overcoming a major challenge involving Governors Island history.

Governors Island hill

Pumice, or lightweight fill (the light colored material) is placed on the water side of the tallest hill. Image courtesy of West 8

From Subway Dirt to Island

Back in 1637, when a Dutch man bought Governors Island for two ax heads, a string of beads, and some nails, the island was only about 72 acres. In 1901, somebody needed a place to discard the dirt from the excavation of New York’s Lexington Avenue subway line. What better place to put it than Governors Island? The dirt widened the island by 100 acres.

Fast forward to the twenty-first century. Now that the island had been sold back to the people of New York for one dollar, it was possible to take advantage of the island’s potential views, which meant building upwards. To create the new hills, West 8 needed to add 300,000 cubic yards of new fill—enough to fill 40 Goodyear blimps. The challenge was to keep that massive amount of dirt from pushing the island built on subway fill out into the harbor.

Hart Crowser worked with the lead civil engineer to make the hills strong yet light. Twenty-five percent of the new fill is from the demolition of structures and parking lots. This made it sustainable and strong. Pumice lightened the load. Some of the fill was wrapped in geotechnical matting, and the steepest slopes used wire baskets. This allowed hills as high as seventy to be built within twenty feet of the shoreline, and allowed for varying slopes and walkways, where the public can safety enjoy the park.

Governors Island reopened to the public on May 28.

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Volunteering with the Children of the Night


Nick Galvin, Hart Crowser environmental scientist, is in Guatemala with his family to volunteer for the Xeroderma Pigmentosum Project.

A bumpy two hours from the nearest “town” of Santa Cruz Barillas, a padlocked chain stretches across the one-lane dirt road. The volunteer team’s diesel Land Cruiser rumbles to a halt. Another Guatemalan road toll. The chain falls and they continue on their way. The small village in the mountainous Huehuetenango department comes into view; the rusting corrugated-steel rooftops of the small village sprawl on the steep mountainsides. The scent of cardamom wafts through the air. Along with maize, cardamom is the local cash-crop.

The volunteer team consists of four. Milo and Dalila, who grew up there and have family in the area, plus Nick Galvin and his wife Bree. Dalila has worked as an un-trained nurse with these families for over fifteen years and Milo is the driver. They serve as translators from Spanish to Canjobal—the native Mayan dialect. Many there know only a few words of Spanish or none at all.

They park on a ridge between two deteriorating wooden school houses. The kids peer between the cracks to get a better look at the two extranjeros (foreigners). They don’t know it yet, but the road to this house will be impassable in two weeks from the incoming rains. From there they walk 15 minutes through hillsides of cardamom, meeting one of the program’s oldest children.

Cardamom fields

Bree en route through the cardamom fields.

At 16 years old, she is hardly a child. But after losing her eyesight and numerous surgeries to remove cancerous growths, she is completely dependent on her family for care. The disease has wracked her body and she suffers daily, but greets the team warmly. Her family’s house consists of two rooms: a smoky cooking area, where an open fire heats a listing metal cooktop surrounded by a couple of plastic chairs; and a sleeping area, where the entire family sleeps on uneven wooden-board beds. The floors are dirt and slope gently with the hillside. There is no electricity, toilet, or running water.

For a little over a month now, the team has been working with several families in this community suffering from Xeroderma pigmentosum or XP. XP is an unimaginably debilitating disease. Those suffering from XP are unable to repair damage from UV-radiation (i.e., the sun). This in turn leads to aggressive skin cancers and extreme photosensitivity, often at a very young age.

XP is an autosomal recessive genetic disease. Think back to freshman-year biology with Punnett Squares and Mendel’s Peas. A person suffering from the condition must have two affected alleles – one from each parent. The inheritance pattern is similar to red hair, blue eyes, or green peas, but with a much more drastic outcome. A person with only one affected allele (a portador, or carrier) can lead a normal life, with no adverse effects.

Punnett Square

Punnett Square showing regular distribution of “regular” (Y) and “affected” (y) alleles and outcome for a recessive trait – green peas. Photo courtesy of Quizlet

The majority of children in Santa Cruz Barillas are not well protected from sun exposure. Often, diagnosis occurs when the child begins to develop hyperpigmentation (darker spots) on the most exposed areas of their body; their face, neck, and arms. Many of these will become skin cancer. Shortly after, if still unprotected, the child will begin to lose his eyesight and exposure to bright light will become extremely painful.

Battling this horrific disease is beyond difficult. The only real “treatment” for those suffering from XP is an early-age diagnosis and vigilant sun protection—avoiding all exposure to sunlight. The only true way to achieve this is to stay indoors in a closed room during all daylight hours. This can have drastic psychological effects. Many houses don’t have electricity or artificial light sources, so this leads to a life sequestered inside, alone and in the dark.

In this village, generations have lived and intermarried, spreading the XP gene throughout the population. However, this is only one reason this disease is so rampant. Many still reject outside aid and chose to believe in archaic explanations; curses, spiritual intervention, or a divine form of punishment. Lack of education about the disease allows these ideas to perpetuate. Some families choose to hide (or worse, abandon) affected children. However, many do not and there is a growing contingent working to eradicate the disease.

Village center

Village center and an omnipresent Land Cruiser shuttle.

In reality, the only true method of prevention is selective reproduction. By knowing who the carriers in the community are, carriers can avoid marrying one another. This slowly dilutes and removes the affected gene from the population. Working with the community, this is a project that their organization has been heavily involved with. Through genetic testing, they have identified the families with the gene and carriers in the village. They have encouraged open communication between the carriers, families, and community, and provided scholarships for carriers to attend college outside of the area. This both elevates the family economically and provides them with an opportunity to find a partner outside of the village. They hope that this information, combined with genetic counselling and education, will allow the village to move closer to eradicating XP from their community.

Other ongoing projects focus on improving the health and quality of life of individuals living with XP. Many of the children have parasitic infections from questionable drinking water sources. Many don’t have sufficient clothing or shoes. All of the children are malnourished. A typical diet consists only of maize tortillas, beans, and the occasional vegetable or fruit. One project the team has spearheaded since they arrived is vegetable gardens. By providing the materials for gardens and classes in fertilizing, composting, and maintenance, they can provide access to a sustainable, healthier diet for the families and children.

Without a doubt, it has been an incredible experience. Staying in the village and working in the families’ homes is a sobering view into their lifestyles and the unimaginable conditions many have to endure. There is an imposing amount of work that could be done to improve the living conditions and quality of life for many of these families. For Nick and his family knowing that they were able to help—even just a small amount—is incredibly rewarding.

Due to the sensitive nature of this disease and the volunteers’ agreement with the community, they could not provide photos of the families or children.

More information about XP

Sources: Up-to-Date, Medscape

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Diving In – The Promise of Social Marketing for Storm Water Education


Kapalua Bay on Maui

Kapalua Bay on Maui. The West Maui Kumuwai campaign uses social marketing to protect a sensitive watershed.

Individuals have a direct influence on storm water quality in their communities, and regulators strongly emphasize public education and involvement campaigns in municipal storm water management programs. But how can leaders convince residents to pick up after pets, reduce lawn pesticide use, and wash cars without getting soapy water in storm drains? And how can they discourage commercial and industrial workers from dumping contaminated liquids down storm drains behind shops, and to use drip pans to keep oil off pavement? These behavior changes would have a direct positive effect on the coastal and inland water resources we enjoy.

In traditional environmental education campaigns, the message is often delivered through newsletters, brochures, public service announcements, and social media. Some effort may be made to reach a specific audience, but the focus is producing a good quality educational tool. The hope is that having a good message and delivering it well will make people listen, learn and act.

But experience in educational campaign history indicates otherwise. Simply handing someone a pamphlet does not mean that a person will act on that information.

Enter social marketing. Social marketing integrates marketing concepts and tools from social psychology to influence behaviors that benefit individuals and communities for the greater social good.  While social marketing campaigns sometimes employ social media, the two are not the same. Social marketing can use a variety of tools to influence behaviors. First used in the public health realm, the practice focuses on a specific community. Research and surveys identify real or perceived barriers to change, and campaigns are designed to overcome those barriers and reward desired behaviors.

A great example of social marketing in action is the West Maui Kumuwai (WMK) campaign in a sensitive watershed on Maui. WMK is a non-profit that shines a spotlight on the actions of everyday people to promote ocean health. Through community surveys, WMK identified landscaping activities as a community concern relative to storm water pollution. WMK’s Reef-Friendly Landscaper campaign invites landscapers and gardeners to “Take the Pledge” by agreeing to a set of ocean-friendly landscaping activities. WMK then promotes those companies on its website and through social media, to keep these companies engaged and committed.

If you’ve heard of other successful social marketing campaigns related to storm water education, please let us know with a comment.

For more information about storm water services for municipalities, construction, and industry, contact Janice Marsters at

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Anchoring the World’s Longest Floating Bridge

SR520 Bridge

Photo: WSDOT


You’re at the bottom of Lake Washington, 200 feet underwater. It’s flat as a pancake here, but the first 50 feet of soil is diatomaceous silt and clay, which is unspeakably unstable. Think microscopic glass Christmas tree ornaments with the consistency of chocolate mousse. Below that is 50 feet of very-soft clay (zero blowcount, to those in-the-know).

Try, just try, to anchor the new SR 520 Bridge in this chocolate mousse (remember, it’s a floating bridge that can’t be left to drift off to Renton or points unknown). And just for good measure, make each of the 58 anchors able to resist a horizontal load of 600 tons—four times what was needed for the old bridge.

Figure out that you’ll need three types of anchors. In areas along the side slopes, where the water is shallower and has competent soil, use a gravity anchor, but call it a box of rocks amongst your workmates.  Build it like a heavily reinforced concrete egg carton with only four compartments. Joke about the kind of eggs that would fit into a 40 foot by 40 foot by 23 foot carton.  Build them on a barge at the concrete plant in Kenmore at the north end of the lake.  Make them so heavy that that the only derrick large enough to lift one is too big to fit through the Ballard Locks. Tow the gravity anchors through the Ballard locks, though they barely fit, while the public looks on in astonishment.

Gravity anchor

Gravity Anchor on its way to the SR 520 Bridge site. Photo: Kiewit

Flood the 440-ton floating boxes with water to make them sink. Lower them to the lake-bottom and place them on a leveled-out gravel pad. Fill each of them with 1,700 tons of rock to make them heavy enough for lateral frictional resistance, or so they won’t budge.

Don’t stop there. Use a second type of anchor, a drilled shaft, along the shoreline where the lake is shallow enough that the box of rocks would have caused havoc as a navigational hazard. Make them ten feet in diameter and 100 feet tall, not as tall as the original Godzilla, but close enough.

Drilled Shaft

Ten-story-deep drilled shaft anchor. Image: KPFF Consulting Engineers

Then, use fluke anchors, the most technically challenging anchor, for the majority of the project. Make these fluke anchors from reinforced concrete plates three feet by 35 feet wide by 26 feet tall. Cast a steel tetrapod into the side so that the anchor cables can be attached to the I-bar at the end of the tetrapod. Explain that a “tetrapod” is a four-sided shape with triangular faces (not to be confused with a four-limbed vertebrate).

Fluke Anchor

Fluke anchor being jetted into the bottom of Lake Washington. Image: KPFF Consulting Engineers

Place the fluke anchors in a steel frame equipped with water jet tubes to drive them into the mud. Because the mud is chocolate mousse, place mounds of rock above and beside the fluke anchors. And then more rock. And then more rock. Good, that’s enough.

Now, celebrate. The Washington State Department of Transportation’s grand opening of the longest floating bridge in the world will be April 2 and 3, 2016. You can run, bike, or possibly meander across the bridge. Hopefully there will be food. You’re hungry after all that work.

Hart Crowser was the geotechnical engineer-of-record for the anchors for the new SR 520 Bridge. The design-build contractor was a joint venture of Kiewit/General/Manson. The structural engineer was KPFF Consulting Engineers.

Need more detail? Read the technical paper Geotechnical Design: Deep Water Pontoon Mooring Anchors or contact Garry Horvitz, PE, LEG, at

Fluke anchors on barge

Fluke anchors on barge.

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Why an Earthquake Warning System Should Not Be a Priority In The Pacific Northwest

Earthquake_damage_Cadillac_Hotel,_2001_SmallerThe newest and hottest topics when it comes to disaster discussions in Oregon and Washington, as well as on the national level, are an earthquake warning system and earthquake prediction possibilities. They are the new obsession that has come on the heels of the New Yorker articles this summer. While we don’t object to advancing both of these methods to better warn of impending quakes and hopefully save lives, we do think that the discussion is premature, especially here in the northwest.

The first reason is that an earthquake warning system like that in Japan has to be implemented only with a comprehensive, aggressive, and continuous public education program. Without a full understanding of what you should do when your phone emits an ear piercing shriek warning of impending shaking, we risk even greater panic and possibly more casualties. Running out of buildings with unreinforced masonry or weak facades just before the shaking could put people at more risk of falling hazards outside of the buildings. It could also cause major traffic hazards as drivers try desperately to get across or get off bridges and overpasses. Unless we develop a much better awareness of what the public should do when they receive the warning, it may cause more problems than it solves.

But the real issue is that these technologies are acting as the bright shiny objects that are distracting all of us, from the public to the president, from the real issue: our infrastructure is in dire need of upgrades not only to prevent casualties, but also to encourage long term recovery.  We doubt 30 seconds of warning will seem as beneficial when the public doesn’t have wastewater for one to three years.  Further, a warning system that stops surgery or an elevator is not as important as making sure that the hospital or building itself is designed to withstand shaking. Especially in Oregon and Washington, all of our energy and funds need to be focused first on comprehensive and intelligent infrastructure improvements that increase our community resilience. And that needs to happen as quickly as possible. We implore you not to follow the flashing light! Urge our government to focus on the real issues, and encourage your colleagues and neighbors to personally prepare.

For more information contact Allison Pyrch at (360) 816-7398 or

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