Environmental Professionals Radio: munitions, aviation, and Hawaii with Dennis Peters

Dennis Peters, Environmental Manager at Hart Crowser, a division of Haley & Aldrich, joins this episode of the National Association of Environmental Professionals’ (NAEP) Environmental Professionals Radio. NAEP’s podcast covers anything and everything related to being an environmental professional, including career advice, timely topics, policy updates, and more. On this episode, Dennis discusses his work with military ordnances in Hawaii, how the pandemic has impacted the islands, his experience flying planes, and more. Listen to the whole interview below:

The Fate of Supplemental Environmental Projects: Hanging in the Balance

Turtles in waterfront habitat

What is a Supplement Environmental Project (SEP) and How Does it Work?

A Supplemental Environmental Project (SEP) is a federal mechanism used to facilitate settlement of an environmental enforcement action. It allows a polluter to voluntarily take action in place of paying a fine. The business or individual undertakes a project that provides “tangible environmental or public health benefits to the affected community or environment, that is closely related to the violation being resolved, but goes beyond what is required under federal, state or local laws.”

Interestingly, for every dollar the business spends, their fine is only reduced by 80 percent. This means that an SEP costs a company more. If a fine is $1 million, for example, a company could pay $1 million on a habitat restoration project and still owe $200,000 in fines. In spite of the higher cost of implementing an SEP, companies prefer them for the benefits they could achieve: a beneficial restoration for the community, and goodwill for the company.

A Guidance Change Halts Most SEPs

However, in early 2020 the Department of Justice issued guidance saying that they could (for the most part) no longer support this approach. Their stance is that while enforcement of laws is a function of the executive branch, that branch can’t choose how to appropriate federal funds. Instead, the fine must be deposited in the Treasury so that Congress can decide how to appropriate those dollars under its constitutional authority.

What Now?

The guidance doesn’t apply retroactively, and so previously negotiated SEPs shouldn’t be affected.

Given that the 2020 guidance is relatively recent, there is still uncertainty about how it will play out, and a change in administration may affect the future of SEPs.

More information on SEPs

Information about our environmental services

Questions? Contact Mark Dagel, LHG

Marshy habitat

Updated Industrial Stormwater General Permit Sampling Requirements

The new Industrial Stormwater General Permit (ISGP) sampling requirements for Washington State became effective on January 1, 2020.

The ISGP’s goal is to improve stormwater quality (and reduce pollutants in runoff) through management of stormwater at industrial sites. The ISGP originates from a combination of federal (the Clean Water Act) and Washington state (Water Pollution Control Act) law. Under the ISGP, permittees are required to implement Best Management Practices (BMPs) to reduce stormwater pollution, monitor their stormwater discharges, compare the results with benchmark values, and implement an escalating series of corrective actions depending on the number of times the benchmarks are exceeded.

What Stormwater Provisions Changed? Key Updates

Many of the key provisions didn’t change. Here is a brief summary of the key updates.

  • The five core water quality benchmarks—turbidity, pH, oil sheen, copper and zinc—remain the same, and the requirements and deadlines for implementing corrective actions if those benchmarks are exceeded remain unchanged.
  • The new permit proposes to use 2017 North American Industry Classification System (NAICS) groups to classify the sectors required to apply for permit coverage (the previous permit relied on the 1987 Standard).
  • Industrial Classification (SIC) groups to identify the sectors required to apply for permit coverage. The Clean Water Act remains based on SIC codes, and there is a not a one-to-one relationship between the two codes.
  • The Washington State Department of Ecology has changed the groundwater-related provisions with an intention to increasingly regulate infiltration of stormwater under the ISGP. For sites with a discharge point to groundwater (i.e., infiltration systems), the terms and conditions of this permit will apply. There is an exemption to permit coverage for facilities that discharge only to groundwater.
  • Permittees must sample the stormwater discharge from the first fall storm event each year (the start date for the “first fall storm event” sampling requirement has been moved from October 1 to September 1). First fall storm event means the first time on or after September 1 of each year that precipitation occurs and results in a stormwater discharge from a facility. We’ll likely see more 3rd quarter benchmark exceedances as a result, as there are fewer summer storms to sample to average with the first flush.
  • Permittees claiming “consistent attainment of benchmark” for one or more discharge monitoring parameters will now be required to collect a single annual sample in the 4th quarter.
  • Ecology has retained the provision requiring permittees that discharge to Puget Sound Sediment Cleanup Sites, including the Lower Duwamish Waterway, to conduct line cleaning and storm drain solids characterization sampling once during the permit term.
  • The new permit requires that the stormwater pollution prevention plan (SWPPP) be prepared by qualified personnel. Some additional information and details are also to be presented on figures, such as showing the property size/acreage, areas of existing and potential soil erosion that could result in the discharge of a significant amount of turbidity, sediment, or other pollutants, etc.

For more information, see the Washington State Department of Ecology website’s Industrial Stormwater General Permit page or contact Andrew Kaparos.

Creative Solutions for Marine Construction: Managing Underwater Noise from Pile Driving

Harbor Seal

Balancing Ecological and Industrial Needs

The Snohomish River mouth in Puget Sound is a busy place. Bald eagles, seabirds, salmon, seals, and the occasional whale frequent this area year-round. The area is also a hub of industry with vessels large and small coming and going from the Port of Everett’s International Seaport and recreational marinas, and adjacent US Navy facilities. This convergence of ecological and industrial uses can sometimes lead to conflicts that require careful management.

When the Port of Everett needed to upgrade its South Terminal Wharf to accommodate bigger cranes, it turned to Hart Crowser to assist with Endangered Species Act (ESA) permitting. The project would require partial demolition of the existing wharf, driving hundreds of new steel piles, and reconstructing the wharf deck over water. Pile driving in particular is known to generate high levels of underwater noise that can be a nuisance and cause physical harm to fish, diving birds, and marine mammals. Therefore, the project would need to demonstrate that sufficient precautions would be taken to avoid detrimental effects.

The biological assessment (BA) prepared by Hart Crowser analyzed the potential impacts of the project on southern resident killer whales, marbled murrelet, Chinook salmon, steelhead and bull trout – species that are listed under the ESA and known to occur in the area. Using the best available scientific information, Hart Crowser calculated the noise disturbance and injury zones for these species. In some cases, this zone extended over 9 kilometers from the site!

The US Fish and Wildlife Service and the National Marine Fisheries Service (collectively referred to as the Services) reviewed the BA and concurred with our analysis. The Services issued an “incidental take” statement that allowed the port to continue with the project subject to several terms and conditions. These included working within the “in-water work window” to avoid the salmon outmigration period, a limit of 2,000 blows per day for impact pile driving, acoustic monitoring to verify noise levels, and monitoring to immediately identify any fish kills and shut down if ESA-listed species entered the affected area.

Subsurface Conditions Require a Creative Solution

Port of Everett dock

Given these constraints, the construction contractor, Advanced American Construction, commenced work in September but soon realized that the subsurface conditions in several areas required significantly more blows with the impact hammer to install each pile. On many days, they were required to stop work early to avoid exceeding the daily blow count limit. This led to concern that an extended construction timeline might push past the in-water work window. If this were to occur, it would likely require shutting down for several months and returning for a second construction season, which would add considerable cost to the project.

In the meantime, The Greenbusch Group conducted the acoustic monitoring and recorded site-specific noise levels for the type of hammer, pile, and substrate. While they confirmed that the underwater noise from pile driving of 24-inch diameter piles matched the assumed levels, they also noted that in certain situations – such as when 18-inch diameter piles were driven, or when piles were driven in areas above the waterline – the noise was several decibels less.

Computer on Table at Sunrise
At the Port of Everett’s request, and in partnership with Greenbusch, Hart Crowser reviewed the acoustic results and dissected the Services’ analyses of incidental take due to noise. The daily blow count limit was driven by the threshold for injury to ESA-listed fish such as Chinook salmon, steelhead and bull trout as defined by the cumulative sound exposure level, or cSEL. The calculation of cSEL incorporates the source noise level and a logarithmic function of the number of blows. Therefore, Hart Crowser biologists determined that by substituting a lower source level into the equation based on pile size, the blow count could be increased and still maintain the same authorized cSEL limit. Hart Crowser and Greenbusch developed a spreadsheet calculator to allow the contractor real-time management of the cSEL based on driving different pile sizes , and prepared a technical memorandum explaining this proposed approach to the Services and US Army Corps of Engineers.

The negotiation was successful, and the contractor was allowed to proceed with a higher blow count if the calculator was used to carefully track the number of blows per pile-type . The creative approach, availability of site-specific data, detailed technical justification, and demonstration of how the new tool would be used resulted in approval without the need for time-consuming formal reinitiation of consultation. Hart Crowser marine mammal monitors on site kept a running tally of the blow counts for different pile diameters and advised the contractor when approaching the cSEL limit. The project is currently on track for completion in 2020.

Orca

Photo: Tim Cole from Unsplash

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.

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.

Recent Guidance on Vapor Intrusion – EPA, Washington State, Hawaii, and Oregon

Vapor intrusion occurs when there is a migration of vapor-forming chemicals from any subsurface source into an overlying building. The vapors can enter buildings through cracks in basements and foundations, or through conduits and other openings. Examples of vapor-forming chemicals that are hazardous to human health include methane (from landfills), tetrachloroethene (PCE) and trichloroethene (TCE) from dry cleaners, benzene (from petroleum products), and radon.

Soil Vapor Migration

Migration of Soil Vapors to Indoor Air
This figure depicts the migration of vapors in soil gas from contaminated soil and groundwater into buildings. Vapors in soil gas are shown to enter buildings through cracks in the foundation and openings for utility lines. Atmospheric conditions and building ventilation are shown to influence soil gas intrusion. (source: EPA)

 

Since 2000, research has shown that exposure to toxic vapors has much greater health risks than previously known. Long term exposure to even very low concentrations can result in cancer. In response, the federal and state governments have lowered the safe exposure limits, and regulators have recently updated guidance for assessing vapor intrusion.

EPA published new guidance for assessing vapor intrusion in June 2015. (OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air; OSWER Pub 9200.2-154). The document provides guidance on conducting investigations, including collecting samples; interpreting risk assessments; and mitigating vapor intrusion.

Washington State subsequently updated their guidance for vapor intrusion in February 2016 (Washington State Department of Ecology, Guidance for Evaluating Soil Vapor Intrusion in Washington State: Investigation and Remedial Action, Pub 09-09-047). This document describes Tier I Screening assessments and Tier II sampling assessments.

Hawaii published their VI guidance in 2014 (Technical Guidance Manual for the Implementation of the Hawai’i State Contingency Plan, Section 7: Soil Vapor and Indoor Air Sampling Guidance). This document provides good information on different types of sampling equipment, with photos.

The state of Oregon is using vapor intrusion guidance published in 2010 (Guidance for Assessing and Remediating Vapor Intrusion in Buildings).  The guidance describes how to perform risk-based evaluations, and the state periodically publishes updated risk-based concentrations for chemicals.

In the state of Minnesota, vapor intrusion concerns have significantly affected the real estate market. Starting in 2017, if a building is suspected of having contaminated soil below or around it, the state has asked the owners to test for vapors and fix vapor problems before the property can be sold. This can significantly add to the costs of property transfers and delay sales or even scare off buyers.

Here in the Pacific Northwest, the states are not requiring soil vapor testing, although near landfills methane vapor testing is often required.  Also, areas with known radon often require vapor mitigation systems. But your environmental consultant should be considering vapor intrusion risks during Phase I Environmental Site Assessments, and might recommend soil vapor tests during Phase II investigations. Vapor intrusion is complicated – vapors move more easily than soil or groundwater contamination. It takes careful evaluation and interpretation of the guidance and test results to help property owners and purchasers make knowledgeable decisions.

Questions? Contact Anne Conrad, (425) 775-4682

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.