You’ll be 2 feet higher when boarding the Mukilteo ferry

MUKILTEO — Climate change is a significant factor in the design of two landmark projects here — the new Mukilteo Ferry Terminal and the new Northwest Fisheries Science Center Research Station.

The first ferry arrivals at the new terminal are scheduled for Dec. 29. Contract proposals for the research center are being reviewed, with opening day at least two years away.

Since 2014, Washington State Ferries has required sea level rise to be incorporated into terminal design, according to state bridge engineer Tom Bertucci. That is the year design work began for the Mukilteo terminal, which will serve the state’s busiest ferry route and lies north of the existing terminal.

Engineers added 13 inches to historic high-tide data to account for the expected rise in sea level over the next 75 years. That is the specified design life for many vehicle and pedestrian loading structures. The 13-inch increase was based on recommendations included in a 2011 Washington State Department of Transportation climate vulnerability assessment, based on a medium level of risk.

While tide levels most clearly affect getting vehicles and pedestrians on and off ferries, Bertucci noted that sea-level rise could affect the terminal in other ways. For example, higher water exposes more of the structures to the corrosive effects of saltwater and to damage from storm-driven waves. It could also inundate the system that carries treated stormwater into Puget Sound.

To limit damage, loading structures and other systems were elevated, Bertucci said. The bridge that vehicles drive on to reach to the ferries is 19.5 feet high, 2.11 feet higher than the existing Mukilteo terminal bridge, and will be highest among all the state’s terminals. Structures were also designed to be raised if water levels rise more than 13 inches. A University of Washington 2015 report estimates an increase of 15 to 54 inches in Puget Sound this century. The passenger terminal, which resembles a Coast Salish longhouse, was designed to minimize the greenhouse gas emissions that cause climate change. It features radiant floor heating, a south-facing shed roof covered with solar panels and windows that open to let in cool sea breezes.

Just southwest of the new terminal, scientists are removing the last of their equipment from the sagging and long-neglected former Air Force building that has served as the Mukilteo Research Station, which is part of the National Oceanic and Atmospheric Administration. They will be working out of the Montlake (Seattle) and Manchester (Port Orchard) stations until the new one is built, said Paul McElhany, chief of research in Mukilteo.

Sea level rise and the potential for tsunamis will be factored into design of a new energy-efficient station, McElhany said. In addition to the elevation of the building, he is concerned about protecting wildlife habitat on the shoreline below.

Much of the research done in Mukilteo involves ocean acidification, which is the evil twin of global warming. About half of the carbon dioxide that drives climate change ends up in the atmosphere, McElhany explained. Up to a third of it is absorbed in the ocean. The carbon overload makes it hard for some sea animals to survive, especially those with calcium carbonate shells, such as oysters and crabs. Researchers are also finding that carbon dioxide may disrupt a salmon’s ability to detect threats in its environment.

The public will be able to learn about the latest research when the new facility opens. Along with state-of-the-art laboratories and a home base for research vessels, the Mukilteo Research Station will include an outreach and education center on its elevated waterfront promenade.

Everett writer Julie Titone can be reached at julietitone@icloud.com.