Coronavirus—Present and Future: Interview with Garry Horvitz

Garry Horvitz

Garry Horvitz, before social distancing was necessary.

We interviewed Garry Horvitz, Vice President and geotechnical engineer at Hart Crowser for his perspective on how the engineering world has changed since the coronavirus arrived and what the future holds. Here are excerpts from that conversation.

The Coronavirus is Hastening a Continuing Trend

I’ve noticed over time that, from an engineering getting-work-done perspective, there has been less and less need for interaction. Less need for proximity. We had developed a habit of video conferencing even before this. The tools have become that good—we can not only see each other, but we can share information virtually: project plans, drawings, white board information. We’d been using tools like Skype, Teams, Zoom, and WebEx to save the time and cost of travel and parking. We already know we can be effective without physically congregating. This is not game-changing in that respect. Things had already been evolving.

The Downside to Meeting Virtually

The downside to this trend is that we need human interaction. Even this conversation with you would be much more comfortable if we could have done it in person. I don’t like working from home—I enjoy social interaction—walking around the office to talk with others. Remote work gives me a little PTSD from when I was convalescing for four weeks after I broke my knee.
As far as marketing and business development, it’s always been “Don’t send an email if you can pick up the phone, and don’t pick up the phone if you can meet in person.” I have also said that there are times when I make up an excuse to meet with a client in person. The more senses you have working when you’re meeting with someone, the easier it is to build and maintain a relationship. But we’ll get back to that. Engineers tend to be introverts, and there will be those who will shy away from making that personal contact when they have the alternative to do that.

The Upside to Meeting Virtually

Personally, I’m happy I can visit with Lynn-dee who is in the other room working. I also like the 20-second commute although I miss stopping at the latte stand on the way in.

What is Essential Work?

People are pushing the definition of essential work to keep the economy going. There’s a natural tendency to call something essential when it’s not. They want to keep people working but it’s overplayed. On the other hand, you can’t just turn everything off just to avoid risk. There needs to be a balance. You can’t decide never to cross a street to avoid being hit by a bus. You have to balance risk and reward.

The Importance of Patience

One thing we can do for each other is to have patience. Don’t expect things to happen as quickly as you’d like. Everybody is exasperated and frightened. Nobody knows what’s going to happen. We’re sailing in uncharted waters on both a business and personal level. Deadlines may need to be extended, although not from a lack of efficiency—because we had already been working virtually. We’re fortunate in the architect/engineering industry that we can do that for design.

Our Real Enemy

When you think of the number of people in this world and how they are all affected by the coronavirus, you see that the threat of pandemic far exceeds external political influences and the threat of war. We seem to like to hate other people but our most important enemy is microscopic. A virus has no soul so you can’t hate it. Our government should have acted on this months ago. We were completely unprepared. That will change. And it ought to change. (“I’m Garry and I approved this message.”)

What Does the Future Hold?

I never thought it would get to this point. Even so, I’m not seeing a lot of architect/engineer firms going out of business (yet). Back in the 2008 recession it was different; the writing was on the wall. Development dropped off a cliff. Hart Crowser’s client base was diverse, which helped us to weather that. Now money will likely be put into infrastructure packages of one sort or another and that will keep us going. I don’t see a huge downturn, but ask me again in two months.

 

A Message from Hart Crowser about Coronavirus (COVID-19)

March 25, 2020

To all our clients, teammates, and friends:

Like all of you Hart Crowser is adapting almost daily to the changing COVID-19 conditions and directives from health officials and local and national leaders. We have taken the following steps:

  1. All staff with the capability of working from home have that option. Most are doing so.
  2. Our offices are open but all internal and project meetings are being conducted in Microsoft TEAMS.
  3. We are actively supporting ongoing projects with you or on your behalf. That includes office/technical work, site exploration and testing, and construction administration. We expect to meet deadlines or work with you to revise expectations.
  4. All non-essential air travel has been stopped.
  5. Our offices and work spaces are regularly cleaned and disinfected.

Above all our goal is to keep our staff healthy. Sometimes we can do this on our own but other times we will need to work together with you to ensure we can all work in safe environments. We remain committed to our clients, teammates, and staff and look forward to strong collaboration as we work through the challenges of stopping this virus.

Best Regards to All
David G. Winter, PE, LEED AP Chief Executive Officer

Going Backwards in Time: Layers of the Grand Canyon

As we reported in a recent post, adventure is a way of life for Hart Crowser staff. In January 2018, Geologist Kaelan Hendrickson also proved this by kayaking 226 miles through the Grand Canyon. He triumphed over numerous rapids, scrambled through side canyons, and endured winter conditions on the eleven-day trip. His goal: see and experience the tumultuous 1.8-billion-year geologic history for himself. The experience was like going backwards in time day by day.

Kaelan and the group of six began the adventure at Lee’s Ferry alongside the youngest layer of rock known as the Kaibab Limestone. This layer was formed 270 million years ago (give or take) by the sea that covered much of North America. After two days, they reached the next youngest rock layer, Coconino Sandstone. The mysterious cross-bedding throughout the layer was formed from dune fields much like the Sahara.

As the group descended into one of the darkest sections of the canyon, they reached the 280 million-year-old Hermit Shale layer, formed from low-energy streams. The landscape at this time was a coastal plain, tremendously different than now. Streams drained into the ocean and Permian reptiles roamed the plains. These streams carried fine particles that piled up over many years

The group continued going back in time, to the Supai Group layer, formed 300 million years ago from beach deposits. During this turbulent period, the coastlines changed rapidly: beaches, dunes, and shallow seas left rocks in their wake. An abundance of fossils are found in this layer.

Halfway through the trip, the group reached the Redwall Limestone, formed 340 million years ago when a shallow sea once again dominated North America. The rock here holds fossils of coral, brachiopods (marine animals that resemble clams), and other marine invertebrates. An uninformed traveler might think this layer was red all the way through, but the dramatic surface stain hides drab gray underneath.

Deer Creek Falls

Day 6: Deer Creek Falls flowing out of Redwall Limestone.

After a grueling eight days the group reached Bright Angel Shale, formed from a muddy shallow sea, much like the Mississippi River at the Gulf of Mexico. This layer holds shallow sea fossils such as crinoids (sea lilies and fans) and worms. The crinoid fossils can often be pulled intact straight out of the rock.

On day ten, the group finally reached the Precambrian Basement Rocks, the oldest rock in the Grand Canyon. The granites in this layer were formed 1.8 billion years ago by cooling underground magma. An island chain much like the Hawaiian Islands collided with North America, forcing magma to the earth’s surface. These rocks were under intense heat and pressure and are highly deformed. Today, they form the deepest part of the Grand Canyon including the infamous Lava Falls rapid, named for the lava-formed rock.

Once the group successfully navigated Lava Falls, they had kayaked down the largest rapid on the trip. While another day of paddling remained, the group had now seen 1.8 billion years of geologic history and conquered one of the most remote whitewater stretches in the United States. What they experienced will stick with them forever.

Grand Canyon

Day 8: Supai Group (top) through Bright Angel Shale (bottom).

 

Adventure as a Way of Life

Two Odd Facts

Odd fact one: America’s national forests are not entirely public. They often contain “inholdings,” pockets of private land surrounded by public land. Some 180,000 acres of inholdings are within federal wilderness areas.

Odd fact two: Even in places so remote you can’t get there from here, there is a potential of environmental contamination.

Sometimes these two odd facts intersect. An example is in the Wild Sky Wilderness at Mt. Baker-Snoqualmie National Forest in Washington, where The Wilderness Land Trust (motto: Keeping Wilderness Wild) had the chance to protect 350 full acres of inholdings by acquiring them and giving them to the US Forest Service. By doing transactions like this, the trust helps give access to wilderness areas previously closed to the public and provides intact habitat and unbroken migration corridors for wildlife, including endangered species.

But a Phase I environmental site assessment was needed before the property could change hands; this would give the Forest Service information for a decision whether to accept the property from The Wilderness Land Trust, and it would also help evaluate any risk to the trust. This is especially important in this area, which is spotted with small historic mining claims that could have metals contamination.

Some of the information for this assessment was gleaned by interviewing individuals who were knowledgeable about the area, and by poring over regulatory files, maps, aerial photos, and other historical material, but a site visit was also needed.

The Adventure Begins

Miners had somehow clambered their way to the property in the late 1800s and early 1900s. Loggers made it there as well, before the 1960s. But the only way in was by helicopter (too expensive) or by foot.

So, two of Hart Crowser’s intrepid geologists packed their backpacks and camping gear, and headed out for, you could say, a wilderness adventure. Their goal was to explore the possibility that some contaminated mine drainage may discharge from underground workings on or upstream from the property into surface water.

They first consulted National Weather Service mountain forecasts to schedule the visit between a series of strong Pacific weather systems and to reach the site before it became snowed in for the season. On November 9th, they drove the gated Forest Service road up the south fork of the Sauk River valley from the Mountain Loop Highway toward the Monte Cristo Campground trailhead. They were stopped about a mile from the trailhead by a debris flow that had covered the road, so continued on foot to the trailhead and from there to Poodle Dog pass (named after a real dog, we understand) at the head of the Silver Creek valley.

Debris Flow

Debris flow across Monte Cristo road at the beginning of the adventure

As they trudged up the pass, heavy snow began falling, obscuring the landscape. From the pass, the geologists left the established trail and worked their way down into the Silver Creek valley and onto the property, at times following a route marked by old surveyor’s flagging. They located a partially open adit (a mining tunnel entrance) associated with the historical Q.T. Lode claim as well as a waste rock pile on a nearby property associated with the historical Orphan Boy claim.

Heavy snowfall throughout the day increased the adventure factor and kept the geologists from exploring part of the property, and further snowfall closed access until Spring. Even so, they were able to use their reconnaissance information along with their previous research to prepare a Phase I report.

In any case, this summer, soon after snow-melt, was the best time to detect and characterize any mine drainage. A geologist went out one more time accompanied by a Forest Service engineer. He helped the engineer with a different job at a remote mine (volunteering a day of his time) in exchange for assistance at the Silver Creek claims. This time they investigated mine openings along Silver Creek and its tributaries, and looked for any secrets the snow had hidden the first time around, in order to support the mission of The Wilderness Land Trust.

Hart Crowser Hawai‘i Office He‘eia Work Day

He‘eia Stream Estuary

The Hart Crowser Hawai‘i team working at He‘eia Stream Estuary. In the area in the right half of this photo we’ve removed the invasive knot grass. The remaining akulikuli is looking a bit trampled, but will recover quickly and thrive.

On Wednesday, June 27, the Honolulu staff each dedicated a vacation day to volunteer with Hui Ko‘olaupoko (HOK) at He‘eia, O‘ahu. HOK is a non-profit watershed management group established in 2007 to work with communities to improve water quality through ecosystem restoration and storm water management, focusing specifically in the Ko‘olaupoko region on windward O‘ahu. HOK’s mission is to protect ocean health by restoring the ‘āina: mauka to makai (land: mountain to sea).

HOK implements innovative projects that effectively manage and protect water quality and natural resources. Projects have included storm water low-impact development projects such as rain gardens, and other watershed focused projects.

The He‘eia estuary restoration project is a collaboration with several other non-profits to restore the ecosystem of He‘eia Stream. This project is aimed at improving water quality and increasing habitat for native aquatic animal species by removing invasive plants and replanting native Hawaiian species. In the past 3 years, about 4 acres of mangrove have been cleared and native species planted. Our work for the day consisted of removing invasive “knot grass” from the estuary flats where it was overwhelming the native vegetation that was planted following removal of the mangrove.

For the plant nerds among us, the predominant native vegetation we protected in the estuary flats were:

  • Akulikuli (Sesuvium portulacastrum), an indigenous coastal succulent ground cover that has been very successful in the estuary
  • Mau‘u‘aki‘aki (Fimbristylis cymosa), a sedge that forms short, rounded tufts of light green narrow, stiff, erect blades
  • Ahuawa (Mariscus javanicus), a greenish blue rush with beautiful brown spiky umbrella flowers/seed pods

We also got to see many native and rare species that have been planted along the stream bank, including Ilima with its tiny flowers that need about 500 to make a lei!); Lama; Ohai; and Mao hau hele. All of these plants have interesting cultural uses and significance, well explained at these website links by our friends at Hui Kū Maoli Ola, an amazing native plant nursery in upper He‘eia.

One of the delights of working on this project was getting to visit the adjacent He‘eia Fishpond. Paepae o Heeia, another non-profit, has been restoring the 88-acre, 800-year-old fishpond since 2001. He’eia Fishpond was likely constructed by hundreds, if not thousands, of Hawaiians who passed and stacked rocks and coral for approximately 2-3 years to complete the 1.3-mile wall. Fishponds helped Hawaiians practice sustainable aquaculture long before western contact. There are only a few fishponds remaining of the approximately 100 that are known to have existed on O‘ahu, as most have been destroyed by development. Restoration of remaining fishponds has been a big part of the Hawaiian cultural renaissance over the past 25 years. While we didn’t work on the fishpond itself, we were able to cross the stream to walk on the fishpond walls (which are dry stacked!), to view the functioning sluice gates, and to learn more about fishponds.

We had a fun team-building day that successfully cleared invasive species from a large area, and learned a bit more about native plants and Hawaiian culture around fishponds. Thanks to HOK for hosting us, and kudos to our Hawai‘i team for being adventurous and volunteering their own time to take on this project!

Ko‘olau mountains

The beautiful Ko‘olau mountains in the distant background, a portion of the fishpond wall and sluice hale in the midground, and our team working hard in the foreground.

Walking on Fishpond Wall

Walking on the fishpond wall after a long day of work; the enclosed fishpond is to the left, with the open waters of Kāne‘ohe Bay to the right.

Hawaii team

Our Hawaii team is all smiles visiting He‘eia Fishpond after a long day of work helping to restore He‘eia Estuary.

Sluice gates

The working mākāhā (sluice gates) of He‘eia Fishpond.

Ilima,official flower of O‘ahu

The beautiful native Ilima, the official flower of O‘ahu. The little flowers are treasured for lei – it takes more than 500 of these flowers to make a delicate and special lei.

 

You Shall Not Pass

Chinook Salmon

Removing Fish Barriers

In 1969, a burning river helped draw attention to the polluted state of many United States waterways. Since then, much progress has been made to clean them up, allowing wildlife to thrive in habitats that were once dead. It’s only more recently that attention has migrated (pun intended) to fish passage problems.

According to NOAA, In the United States, more than 2 million dams and barriers block fish from migrating upstream to spawning and rearing habitat. The Washington State Department of Transportation (WSDOT) says that a little under two thousand culverts block fish passage along Washington highways. As of last year, WSDOT completed 319 fish passage projects, but there is still much to accomplish.
Read on for an example of a recent project, what services are needed to clear the way, and information about Washington, Oregon, Hawaii, and Alaska organizations that are trying to make a difference.

Example of a Fish Passage Project—Rue Creek

Before construction

Rue Creek before construction.

After construction

Rue Creek after construction.

The Pacific Conservation District received a Washington Coastal Restoration Initiative grant from the Washington State Recreation and Conservation Office. Hart Crowser supported the Pacific Conservation District with design and development of two culvert replacements on Rue Road in Pacific County.

Fish passage and flow conveyance capacity were restored by removing the existing culverts and overlying fill, and installing a 50-foot bridge that met design requirements in the Washington Department of Fish and Wildlife’s Water Crossing Design Guidelines and Washington State Department of Transportation’s Standard Specifications for Road, Bridge and Municipal Construction and Design Manual. Staff then used the stream simulation approach (one of the methods to size and design culverts that is an option in the Washington Department of Fish and Wildlife’s Water Crossing Design Guidelines) to design the pattern, dimensions, and other features of the stream channel at the crossing, which would enable safe passage of juvenile and adult salmonids both upstream and downstream. An added benefit was that the replacement should prevent the creek from flooding Rue Creek Road and nearby residences.

Services Needed for Fish Passage Projects

These projects can require:

  • Hydraulic engineering
  • Geotechnical engineering
  • Stream reach assessment
  • Wetland delineation
  • Permit applications to comply with Section 404 of the Clean Water Act, Section 7 of the Endangered Species Act, and other federal, state, and local permit requirements. For the Rue Creek example above, this included preparation of a JARPA, SEPA checklist, ESA Section 7 Biological Assessment, Essential Fish Habitat assessment, and Stewardship Plan.

Action on the Local Level

Washington

In 2014, the Washington State Legislature created the Fish Passage Barrier Removal Board to develop a coordinated barrier removal strategy and provide the framework for a fish barrier grant program. Its stated mission is to “identify and expedite the removal of human-made or caused impediments to anadromous fish passage in the most efficient manner practical through the development of a coordinated approach and schedule that identifies and prioritizes the projects necessary to eliminate fish passage barriers caused by state and local roads and highways and barriers owned by private parties.”
The board has monthly meetings; agenda and meeting handouts are available on its website. It advanced its first project list to the legislature, which has been funded.

Oregon

The Oregon Department of Fish and Wildlife has a nine-member Fish Passage Task Force, which “advises the Oregon Department of Fish and Wildlife and the Fish and Wildlife Commission on matters related to fish passage. These matters include, but are not limited to, rulemaking to implement statutes, funding and special conditions for passage projects, and exemptions and waivers.” The most recent agendas and minutes are at the link above; older ones are here.

Hawaii

The Pacific Islands Fish and Wildlife Office of The US Fish and Wildlife Service says that the Hawaii Fish Habitat Partnership “is composed of a diverse group of partners that have the capacity to plan and implement a technically sound statewide aquatic habitat restoration program. The partnership is committed to implementing aquatic habitat restoration in the appropriate landscape scale to achieve conservation benefits.”

They list “instream structures and barriers including stream diversions, dams, channel alteration, and road crossings” as one of eight key threats to freshwater species and habitat.
See the Pacific Islands Fish & Wildlife Office annual report for fiscal year 2017 for more information.

Alaska

The Alaska Department of Fish and Game has a fish passage inventory database with information about 2,500 stream crossings. They have partnered with other organizations to complete at least 33 culvert replacements.

You Shall Pass

A blocked river isn’t as dramatic as a burning river, which makes it harder to draw attention to the plight of the remaining blocked fish. But the hope is that continued effort will forward the progress that is already being made.

STEM for Future Generations

Jessica teaching about salmon

Science, Technology, Engineering, and Mathematics (STEM) schools in our area and across the country are working to improve the way our students learn in these subject areas. These STEM-focused schools offer a more hands-on approach to teaching, from using objects students can physically manipulate to working with resources and companies in the area to bring in experts to teach the students more about these fields.

This is why Jessica Blanchette, a marine biologist at Hart Crowser, volunteered her time to educate the 4th graders of Odyssey Elementary on the life cycle of salmon, a crucial element of the ecological community of the Pacific Northwest.

Using multiple instructional strategies, including hands-on activities and colorful presentation materials, Jessica captivated Mukilteo School District students with her knowledge of fry, parr, and smolt—the salmon life cycle. Students had many questions and Jessica had plenty of answers!

Jessica led a thoughtful discussion about the human relationship with salmon, our impacts on them, and ways in which we can promote a successful co-existence. There was excitement in the classroom as the lesson wrapped up: not only because of the activities and new knowledge, but also because the students were beginning to see that one day they, too, can be scientists.

When scientists like Jessica share their time to promote STEM, it has a positive and lasting impact in the community. Hopefully, with more endeavors such as this, local scientists will make a positive difference in our world and for future generations.

Salmon Life Cycle

Mussels Reveal Impact of Puget Sound Stormwater

Bay Mussels

Native mussels (Mytilus trossulus) like these were used to evaluate the degree of contamination in Puget Sound nearshore habitats. Photo: Brewbooks

The mission of the Washington Department of Fish and Wildlife (WDFW) is to preserve, protect and perpetuate fish, wildlife and ecosystems while providing sustainable fish and wildlife recreational and commercial opportunities. An important initiative is evaluating the impacts to nearshore aquatic areas from stormwater discharges. Mussels sieve the water as they feed, and their tissues absorb and retain chemicals and pathogens, so the WDFW led a study using mussels as an indicator organism. They got help from so many organizations and volunteers, the list fills nearly an entire page. It includes the Snohomish County Marine Resources Council (Mike Ehlebracht, Hart Crowser geochemist, volunteers for the MRC), the Washington State Department of Ecology, other governmental agencies, native American tribes, and various non-governmental organizations. The work was funded under the new Stormwater Action Monitoring (SAM) program that is paid for by municipal stormwater permit holders.

How Was the Study Done?

As part of this study, the WDFW and volunteers placed “clean” caged mussels at over seventy locations across Puget Sound, including highly industrial areas (such as Smith Cove and Salmon Bay), urban areas like the Edmonds waterfront, and rural areas (such as the San Juan Islands). They left the caged mussels in the water for several months, then retrieved them, often in the dark, in cold and blustery weather. They tested them for stormwater-related contaminants including PAHs (produced by burning coal, fossil fuels, wood, and garbage), PCBs (used in electrical apparatuses, surface coatings, and paints; banned in the US in 1979), metals, PBDEs (used in flame retardants), DDTs (insecticides; banned in the US since 1972), and others.

And the Results…

The study showed that stormwater discharges continue to impact the nearshore aquatic environment, particularly in industrial and highly urbanized (paved) areas. PAHs and PCBs were the most ubiquitous, problematic chemicals detected in the mussels, with some of the highest concentrations found in Elliott Bay (particularly Smith Cove).

Puget Sound is a large, complex, and diverse estuary. This data will be critical in determining best management practices and providing recommendations for environmental remediation. The next round of sampling will occur this fall, with updated data available in another year or two.

Download a copy of the Stormwater Action Monitoring 2015/16 Mussel Monitoring Survey: Final Report.

Questions? Contact Mike Ehlebracht.

Placing caged mussels

Snohomish County Marine Resources Council volunteers and staff place caged mussels.

There’s a Volcano on our Project Site

Water is the life blood of any city, but its systems are not always pretty. So the two-million-gallon Forest Park Low Tank was embedded into the hillside to preserve the natural character of the area and leave unfettered views. However, this presented engineering challenges. Overcoming those challenges helped us win a 2017 Grand Award from the American Council of Engineering Companies (ACEC).

Wait—What’s Down There?

The subsurface conditions were quite unusual. Maps showed them as hard volcanic rock, but our geotechnical explorations discovered a new volcanic vent, as yet unmapped. Although of great interest to geologists, volcanic vents are rarely built on. A search of case histories did not find any information to guide the process. We embarked upon an exploration and laboratory testing program to determine if the 100-foot plus pile of cinders would support the tank. We determined that the cinders were fairly uniform across the area, resulting in uniform support for the tank. Our testing further determined the magnitude of loading the cinders could support. With this information we were able to design a foundation that did not require expensive subgrade improvements or pile foundations.

Our high-tech analyses confirmed a low-tech approach would work.

Burying Infrastructure to Preserve the Natural Beauty

In many places, water tanks are constructed within large cuts that many may view as eyesores and which permanently remove natural habitat. This has been accepted over decades as a necessary compromise to provide a robust water supply to our cities. However, this compromise does not need to be accepted. Much like the trend of burying power, communications, and other utilities that were once also overhead, the Forest Park Low Tank demonstrates that water infrastructure can be adapted similarly.

Making the Water Supply Safe

Water is a critical resource in any disaster that disrupts our infrastructure. It’s common knowledge that we cannot survive for more than three days without water. During any natural disaster, it is imperative that our water remain safe and accessible. We completed a site specific seismic hazard (SSSH) as part of our work, so the tank and appurtenant facilities will withstand the next “Big One.”

Defining Ingenuity

Sometimes ingenuity is not devising something new, but applying simple methods to solve a problem. We used performance-based results to guide changes in shoring design, and confirmed landslide mitigation approaches during construction. We avoided designing expensive foundation alternatives, installing bulletproof (and expensive) secant shoring walls, and over-analyzing slope stability prior to construction. And then we buried our best work.

The one thing to remember about this project is that we did not blow our top over an unexpected volcanic vent; instead, we persevered and worked with the design and construction teams to build a successful project…and then buried it out of “site.”Finished project

Preserving Eelgrass While Remediating Legacy Contamination

Eelgrass

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

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.