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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

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.

eDNA: A Powerful Tool for Scientists and Managers

Sampling eDNA in a stream

Using a pump to filter stream water to get an eDNA sample to determine whether salmon are in the stream.

Detecting the presence or absence of a species of interest is a common challenge for scientists and fisheries managers. Whether you’re interested in protecting an endangered species or removing an invasive species, knowing where they are or are not is crucial. Many techniques can be time-consuming or damaging to the local environment, and they don’t always work on more cryptic species. An emerging technique has the potential to address some of these pitfalls: environmental DNA, or eDNA.

eDNA is DNA fragments found in the environment (usually in soil or water) that come from an animal. Animals shed cells from their bodies through routes such as mucous, feces, or skin flakes. Each cell contains a full set of nuclear DNA and many copies of mitochondrial DNA. As these cells break down, the DNA is released into the environment. A researcher can collect samples (such as water or soil samples) and analyze any DNA present (typically mitochondrial DNA) for a match with the target species.

A useful application of this technology is to learn when and where endangered/threatened salmonids are present. Knowing which drainage systems these fish spawn and rear in is essential to managing and restoring their populations. Scientists can take water samples along river and creek systems where they suspect salmon will be. They then analyze the water samples for salmon DNA, and generate maps of fish distribution. If sampling is repeated over time, temporal trends along with spatial trends in salmon populations can be mapped, providing powerful information to managers and policy-makers.

In the future, eDNA may also help determine how many of each species of interest are in a given area. Research into the relationship between quantity of eDNA obtained and population numbers is ongoing.

For more information on eDNA methodologies, see this USGS factsheet.

Effects of the Proposed Steelhead Critical Habitat Listing

Steelhead Habitat

Example of Critical Steelhead Habitat

The National Marine Fisheries Service has proposed designating a few thousand miles of freshwater and estuarine habitat in Washington and Oregon as critical habitat for Puget Sound steelhead and lower Columbia River coho salmon. Both are listed as “threatened” under the federal Endangered Species Act.

If the designations come to pass, the extent of critical habitat protected from construction or other development activities under the proposed rule will substantially increase in the Puget Sound region. Many more miles of critical habitat will be protected from activities associated with forestry, grazing, agriculture, road building and maintenance, mineral extraction, sand and gravel mining, and dams. It will become increasingly important for anybody involved with these activities to accurately identify and classify the presence of listed fish species and associated critical habitats within a project’s impact area. This information must then be properly incorporated into a biological assessment that applies established criteria in a specific manner to assess and document project effects and measures taken to avoid, minimize, or mitigate those effects.

Developers who educate themselves about the Endangered Species Act and use design strategies to reduce habitat impact will better navigate the regulatory review process and be more likely to avoid needless permitting delays or denials.

The NMFS will accept public comments on the proposed rule through April 15, 2013.

Additional information, including maps of the proposed areas, are in the Federal Register announcement (78 FR 2725).