Tappan Zee Bridge demolition: Riverkeeper monitoring plan to use explosives
January 7, 2019
Riverkeeper Team
‘East anchor span” to be dropped onto network of chains on riverbed; timing precedes fish spring migrations.
Photo: John Lipscomb / Riverkeeper
Riverkeeper is watching carefully as plans move forward for demolition of the ‘east anchor span,’ one of the remaining sections of the old Tappan Zee Bridge.
[UPDATE, January 10: The work had been scheduled for Saturday, January 12, but has since been postponed to a later date to be determined.]
According to the contractors, the “east anchor span” has become structurally unstable, and can no longer be safely removed piece by piece as planned. Instead, explosives will be detonated above the water on the “east anchor span” support columns, generating high heat (like a cutting torch) which will cut through the steel supports, causing the structure to drop into the Hudson and onto a network of heavy chains already laid on the river bottom.
After the structure collapses, the plan calls for barges to winch the structure up above the the surface of the water, and for the steel to be cut apart and shipped away by barge.
“They've gone to great lengths to research this and try to make it safe first and of little impact, second,” said John Lipscomb, Riverkeeper Patrol Boat Captain and Vice President of Advocacy.
• A storage tank holding a large amount of fuel has been removed from the old span and spill response vessels and personnel will be on site in an effort to capture any fuel that leaks into the river from equipment remaining on the span, according to the contractor.
• Fortunately, this emergency demolition will avoid the migration season for shad, river herring, striped bass, Atlantic sturgeon and other species, which return and travel up the Hudson in spring.
“It’s unfortunate that the east anchor span must be demolished in this manner. However, we understand that this is an extraordinary situation which requires extraordinary actions,” Lipscomb said.
“There will certainly be environmental impacts that would not have occurred otherwise. However, it’s important to keep this event in context. The specialized explosives used will be above the surface of the River, and will not generate shock waves. The volume of sediments and contaminants stirred up in this operation will probably be minor compared with the disturbance caused by earlier construction activity – including extensive dredging conducted prior to new bridge construction; project vessel activity in shallow areas, and ongoing demolition and removal of all the old support columns and caissons. Also, other projects throughout the Hudson Estuary, such as recurring maintenance dredging of the ship channel farther north, stir up more sediment and contaminants than this one-time event is likely to do.
“We are grateful, on behalf of the River, that this event will occur at the quietest time biologically for the river. We’ll be glad when this is behind us and the remaining demolition can proceed as planned.”
News coverage:
The Journal News / LoHud.com
FiOS1 News
News12 Hudson Valley
CBS New York
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