A Danish urban-planning firm is proposing a radically innovative solution to a pair of problems that plague Lower Manhattan: vulnerability to extreme weather events, and a chronic shortage of parking. Copenhagen-based architects Tredje Natur (which translates as “Third Nature”) wants to create in St. John’s Park — the four-acre, circular green space enclosed by the Holland Tunnel Rotary, and bounded by Laight, Varick, Beach and Hudson Streets — a submersible parking garage with a public park on top. Beneath the garage would be a vast underground cavity, into which storm water would vent when they cause local sewers to overflow. Their plan is called “Pop-Up.”
During normal weather, the parking garage would be submerged, and the park above it would be flush with ground-level.
When this empty “reservoir” filled, it would cause the garage and park above to begin rising out of the ground, floating to a height of as much as four stories, as a result of what engineers calls “hydrostatic buoyancy.” As first noted in ArchDaily, an urban-design website that serves as a clearinghouse for innovative planning proposals, the Third Wave team has designed a series of stabilizers and tracks that would ensure the structure always remained horizontal, while also guaranteeing that it ascended and descended at a safe speed. Additionally, because it could be made to stop only at preset levels, one floor of the structure would always remain flush with the surrounding ground, in the same way that elevators stop only at heights that correspond with each story of a building, and never between floors.
“We sat down with a map showing where the biggest problems with water handling will occur and another map showing where there are the biggest problems with parking,” explains Ole Schroder, a partner in Third Nature. “When you put the two maps on top of each other you can see some places where there is potential for solving the two problems with the same concept.” One of these places was Lower Manhattan, and the open space within the Holland Tunnel Rotary was large enough to accommodate the structure they had in mind.
Moreover, building Third Wave’s proposed garage would entail no loss of park space for Lower Manhattan. Quite the opposite: although St. Johns Park is legally mapped as park land, it has been closed to the public for more than a decade, as part of the security measures designed to protect the Holland Tunnel from terrorist attack. Indeed, the 2010 edition of American Institute of Architects Guide to New York City described the interior space as, “a circular wasteland,” and observed that, “our ancestors preserved many a New York treasure, but blew it here.”
Whether the garage was submerged to elevated, the park above it would remain open to the public.
In place of this fenced-off no man’s land, Third Wave hopes to build a multi-acre public amenity that would restore the area to Tribeca’s surrounding streetscape. At the same time, the facility would create the capacity to store many hundreds of thousands of gallons of water that, during heavy rainfall, would otherwise flood local streets.
“There is a battle for urban space. Often the choice comes down to financials and open spaces lose to developments,” reflects Jonathan Asbjorn, another designer who worked on plan. “By combining several solutions into one, the Pop-UP enables cities to ensure their economic vitality whilst becoming resilient. They can maximize the economic return by creating dense and vibrant neighborhoods, and ensure resilient and liveable urban spaces for the local population.”