Flood Barriers will Deflect Water From the Holland Tunnel – But Where will 30 Million Gallons Go?
The Tribeca entrance to the Holland Tunnel is slated to be equipped with a flood protection system, but Community Board 1 has concerns that waters deflected from the passage will swamp the surrounding community.
Chris Lee, director of government and community relations at the Port Authority of New York & New Jersey (the agency that operates the tunnel) says, “this is part of our larger Holland Tunnel-Hurricane Sandy project. During Sandy in 2012, we had severe flooding in the tubes, which necessitated a tunnel closure of ten full days. We had mechanical systems that were out, and there was salt damage to a lot of the systems. And over the last seven or eight years we’ve been closing the tunnel every night, repairing almost all of the tiles and other systems.”
“That’s coming to a close and those overnight closures are now done,” he added, “but this last part is a key part of our emergency preparedness plan going forward, to protect the Holland Tunnel from surges like we saw during Sandy.”
That storm dumped an estimated 30 million gallons into the tube. The solution the Port Authority has selected to protect against a similar disaster in the future is AquaFence, a temporary (and reusable) barrier of interlocking, flip-up panels that are strong enough to resist high winds, and rely on the weight of floodwaters to hold them in place. The actual panels that will protect the tube in the event of a flood are stored at a remote location during normal times, and brought to the site and lined up around the perimeter during flood danger.
“The fence is going up not only in front of the tunnel,” noted Tammy Meltzer, chair of Community Board 1 (CB1) during a July 30 meeting. “It is also going up along Canal Street and down part of Hudson Street.”
This will require installing anchor bolts along each of these thoroughfares, in some cases into the mortar of recently restored cobblestone streets. More urgent, however, are concerns that preventing 30 million gallons of flood waters from entering the Holland Tunnel in a future inundation would heighten risk for adjacent streets, such as Hudson, Laight, Vestry, and Varick. “The downstream impacts on surrounding private properties needs to be analyzed and building owners informed,” said Alice Blank, chair of CB1’s Environmental Protection Committee.
A Port Authority spokesperson responded, “a hydrologic analysis was performed as part of the application process to [the Federal Emergency Management Agency]. The results showed there would be a negligible effect on surrounding properties due to storm surge while the perimeter and portal protection barriers are in place, a 0.007-inch rise.”
At its July 30 meeting, CB1 enacted a resolution saying the Board “supports the Port Authority’s… application to install anchor bolts and covers that will secure flip panels to provide flood mitigation protection as requested, as long as the Port Authority addresses CB1’s concerns by providing information about: (1) their deployment plan, (2) sidewalk access, and (3) analyses to show that diverted water will not flood neighboring buildings more than would occur without the AquaFence.”