By Danielle Butsick, Senior Environmental Management Specialist, Port of Seattle
Protecting the critically endangered Southern Resident Killer Whales in Puget Sound is a top priority for the Port of Seattle and its partners throughout the region. Underwater noise, which comes from many sources, including in-water construction, vessel traffic and land-based operations, poses a threat to the health of these iconic marine mammals, an ecologically, economically and culturally important for our region. The noise from these activities can interfere with the southern resident killer whale’s ability to communicate with each other and increases the difficulty for social animals to find mates and hunt for food.
To address these threats, the Port of Seattle and its Puget Sound and Salish Sea partners are conducting research and leveraging technology to better understand and reduce acoustic impacts on Southern Resident Killer Whales and other mammalian species at risk.
Harbor Commissioners authorized investment in underwater noise research, exploration of the potential benefits of new noise reduction technologies, use of “best management practices” and strategic planning to understand more means of reducing the impacts of maritime activities.
“By leveraging research and technology, the Port and our partners can apply lessons learned from around the world to reduce underwater noise and protect the critically endangered Southern Resident Killer Whales that are so iconic of our region”, said Harbor Commissioner Fred Felleman, who conducted his postgraduate research on this population of whales. “I am committed to supporting these efforts to help ensure that commerce and communities can co-exist in these waters.”
Learn about these important port investments to calm the strait and waterways and reduce impacts on marine life.
Pilot study of double-walled piles
In 2021, port contractors installed a public access jetty supported by pilings at the popular Duwamish River Park. Offshore pile driving, which is used to install a deep foundation in water, produces high sound pressure levels in both ambient air and the underwater environment. The Port saw the opportunity to test a new type of double-walled piling in the construction of the pier, designed to reduce the propagation of noise underwater.
The port worked with the pile manufacturer to fabricate steel piles for the project, and conducted underwater noise, airborne noise and ground vibration monitoring to assess how well the piles were working to reduce noise during installation. The data collected through this project has provided valuable insights for improving the technology and understanding how it performs in different environments and will be used to inform recommendations for potential future use of the technology.
Tailor-made “bubble curtain” for the construction of Terminal 5
The Terminal 5 Rehabilitation and Port Deepening Berth Project is investing more than $300 million in infrastructure improvements to develop international maritime freight transport. The facility is currently under construction; phase 1 is complete and construction of phase 2 continues until 2022.
The scale of the project and the amount of pile driving required to rebuild the ships’ northern berth meant that additional safeguards were needed to ensure construction activities did not adversely affect marine mammals and other species. protected.
“Bubble curtains” are often used to absorb noise from underwater construction activities, reducing the distance traveled underwater. Rings of bubbles are continuously released during in-water construction activities and essentially “cancel” noise that can harm marine life. However, they are generally not used for the scale of construction taking place at Terminal 5.
So the port worked with underwater noise experts from the Washington State Department of Transportation and a leading underwater noise consulting firm, JASCO, to design two custom 83-foot bubble curtains. long. This equipment meets the needs of the project and ensures the protection of marine life. We think this is the biggest bubble curtain ever made! Subsequent monitoring of underwater noise near the project showed that the device was successful in reducing noise to levels approved by the United States Fish and Wildlife Service (USFWS) and National Oceanic and Atmospheric Administration (NOAA), Fisheries Division.
Management Best Practices
Marine mammal monitoring
Whenever the Port carries out construction projects in water involving pile driving with a vibrating hammer, one or more biologists are called in to monitor the area (depending on the extent of the activity). These biologists monitor the area for organisms (such as a southern resident killer whale) that could be harmed by underwater noise. If a protected species is sighted, marine mammal monitors – who are often posted both in a small work boat and ashore – immediately call the construction crew to alert them to the sighting and halt work until further notice. until the animal has left the area.
Strategic planning and research
Underwater Noise Mitigation and Management Plan
The port is a member of Green Marine, a voluntary environmental certification program with members from across the North American marine industry, including Canada and the United States. Green Marine encourages its members to take measurable steps to reduce their environmental impact and invest in operational improvements to improve environmental outcomes. One of Green Marine’s certification criteria is underwater noise. The Port is currently certified at Level 2. To achieve Level 3, the Port is developing an Underwater Noise Mitigation and Management Plan (UNMMP) that will help chart the course for setting and achieving noise reduction targets .
The UNMMP will contain a summary of potential impacts on protected species from underwater noise generated by port-related activities, and describe noise reduction and mitigation measures, as well as best management practices to minimize noise submarine. The plan will also outline a potential underwater noise monitoring strategy and the data needed to better understand the underwater noise generated by port-related activities.
Hydrophone Gap Analysis Partnership with University of Washington Applied Physics Laboratory and NOAA
As part of its quest to better understand underwater noise in Puget Sound and the Salish Sea, particularly related to large commercial vessels, the Port is partnering with the University of Washington’s Applied Physics Laboratory and NOAA Fisheries to study deficiencies in the hydrophone array – the technology used to monitor both ships and marine mammals. Researchers will study the existing network to develop recommendations on how the technology can be better leveraged and how to improve how the equipment works together and delivers data to end users. With any remaining study funding, the team will purchase hydrophones or install listening stations (as recommended by the study) to collect underwater noise data from large commercial vessels.
Monitoring of underwater dredgers “in situ”
A deeper berth was required as part of the Terminal 5 rehabilitation and berth deepening project to accommodate the large new modernized freighters. This dredging project, in early January 2022, was an excellent opportunity to document the types, frequencies and amounts of noise generated during dredging activities – as very little data currently exists. The port has assembled and deployed a team of specially trained hydroacoustic technicians and equipment to monitor construction activities in real time. They collected data on underwater noise before, during and after the dredging operations, and at all the different phases of the work to characterize the different sources of noise. The team is preparing a technical note to report on its findings.
Invest in quiet sound
Quiet Sound is a collaborative program officially launched in 2021, aimed at reducing the impacts of underwater noise on Southern Resident Killer Whales from large commercial vessels. The Port of Seattle is a founding member of Quiet Sound and helped lead the planning team that defined the program’s mission and overall structure. Now officially launched, under the operational leadership of Maritime Blue, the port has committed to financially supporting Quiet Sound for the next three years, and port staff will sit on the steering committee to help guide operational decisions. . Staff will also participate in three of the five Quiet Sound Task Forces established to undertake specific technical studies and work on targeted underwater noise reduction efforts. These groups include the Whale Monitoring and Vessel Noise Working Group, the Vessel Operations and Incentives Working Group, and the Whale Reporting System Working Group.
Top photo credit: “Southern Resident Killer Whales” by NOAA Fisheries West Coast is licensed under CC BY-NC-ND 2.0.