To shield aquatic life from the noisy construction of a new Tappan Zee Bridge, New York officials are considering an accessory for the megaproject: bubble curtains.
Rising walls of bubbles would surround the metal pilings for the bridge as they are pounded into the bed of the Hudson River. Compressed air would be pumped through tiny holes in a sleeve running the length of the new pilings, disrupting the sound waves caused by all that hammering and protecting the local fish.
State officials hope to highlight such precautions as they unveil the final environmental impact statement for the bridge project, which released Wednesday by the Federal Highway Administration and published on a state website.
Project managers have also juggled concerns for humans, state officials said this week. Steps will be taken to mitigate dust and noise for nearby residents in Rockland and Westchester counties, and local stakeholders will “weigh in” on the aesthetics of the bridge.
But planners have taken extraordinary care to protect wildlife in and around the river, the state says. Those efforts are so extensive that planners have joked about doing “everything to protect these fish but give them earmuffs,” one high-ranking state official said.
Left unmuffled, some studies have found that pile-driving damage fishes’ swim bladders, the organ that allows them to float.
Scientists blamed noisy underwater work on the Bay Bridge between San Francisco and Oakland for widespread fish death in 2001, and bubble curtains appeared to mitigate the damage, according to a later report by the California Department of Transportation. The report wasn’t conclusive about the severity of the threat to fish.
Without bubble curtains, “you’d have a whole bunch of dead fish floating down the river,” said Bernie Jebson, a project manager at Fraser River Pile and Dredge [GP] Inc., a Canadian contracting firm that specializes in pile-driving work.
Even with the 10 decibel noise reduction the curtains would deliver on the Tappan Zee, the builders still anticipate the construction could harm hundreds of sturgeon, said Josh Verleun, the chief investigator and staff attorney for the Riverkeeper, a nonprofit environmental-advocacy group. Cuomo’s office disputes the group’s estimates.
The environmental impact statement for the Tappan Zee Bridge is the latest milestone on a project of preeminent importance to New York Gov. Andrew Cuomo, who has pledged to fast-track its construction after years of contemplation and delay. The massive report will be available for public review over the next 30 days, after which time the Federal Highway Administration can issue formal approval and clear the way for the next steps.