Designing for resilience
Developers and some elected officials disagree with arguments that development in floodplains is too risky. They contend that major floods are rare and that repeated successful evacuations actually show that buildings in flood-prone areas meet safety guidelines while satisfying demand for housing in scenic riverside neighborhoods. When Dranoff’s Venice Lofts apartments were evacuated by raft in 2010, he told the Inquirer, “The buildings are performing exactly as planned. Every precaution was taken in the design of the buildings. There’s no harm to people.”
Lippert agreed that good building design, combined with use of flood insurance policies, can mitigate the risks from storms. New structures in flood zones often have “wet” floodproofing, with entryways, garages, and storage spaces on the ground floor that can handle occasional inundation without incurring structural damage. He cited a cluster of new townhomes PMC recently built across the street from its Riverwalk complex.
“You’ll see flood vents on the front and the rear of those structures, across the garage door and in the front of the structures as well. That’s a great example of areas that are designed to have water come in and come out. You just hose them off and then you should be great,” said Lippert, who was hired as Philadelphia’s first floodplain manager in 2018.
He noted that the design does not protect objects on the ground level, as shown by the submerged cars in a number of riverside parking garages. “When you get a warning, you don’t just leave your car in those areas that have flood vents. You would move it to higher ground. Unfortunately, I don’t think there’s enough potential education or understanding of that when you’re located in the floodplain,” Lippert said.
Some commercial structures that are required to have “dry” floodproofing use waterproof gates, which are put in place around a building before a storm to create a bathtub effect. Both the Riverwalk tower and the Aramark building a few blocks to its south have gate systems, but at both buildings the gates appear not to have been installed before last week’s storm, Lippert said. The Aramark building is co-owned by PMC and Lubert-Adler Real Estate Funds, and houses the swanky Fitler Club hotel and spa on its lower levels.
Dry waterproofing can work, but only if the building management acts quickly to install the gates, which can be a laborious process. Scott Erdy, a Northern Liberties-based architect who has designed flood-mitigated buildings in the Navy Yard and Hoboken, as well as the rain-absorbing Cira Green rooftop park in West Philadelphia, said he’s currently working on a residential building in Hoboken with façade panels that can be lowered into place like garage doors.
“We’re trying to incorporate them as part of the architecture so they’re visible,” he said. “On a cruise ship, everybody sees the lifeboats all day long and knows where they are. If the lifeboats are down in the bottom of the basement and there’s a big emergency, no one’s going to know where they are. I really want people to see and understand these resilience issues, not just when there’s a hurricane.”
Erdy, who is also a visiting lecturer in architectural design at the University of Pennsylvania, said local architects and developers are very willing to be proactive about flood resiliency and sustainability generally in their buildings. That’s in part because potential tenants want those features, he said.
“A lot of clients now are more educated on this issue and they ask for these things,” Erdy said. “If you’ve got a big company that’s got corporate shareholders and they’re going to choose between this building which is not environmentally sustainable versus one that is, that’s another selling point. Public awareness is key.”
But Erdy and Lippert both said there are limits to the power of building design. Despite the perception that last week’s storm was unusually rare and intense, the flooding actually matched predictions on FEMA maps and a similar event could occur again next month or next year, Lippert said. He said federally subsidized insurance partially shields landlords and residents from the full economic impact of flooding, but the sheer frequency of indundations in the region may force decision-makers to enact more stringent restrictions on development in high-risk areas.
“There needs to be some kind of ‘come to Jesus’ moment where we really understand the risk and the economics and this pressure to build a tax base,” Lippert said.
“It would be very difficult in an urban city to solve flooding. You can try your hardest to fight back, but especially with climate change and sea-level rise and higher tides, what we build today to ‘solve flooding’ could actually not work in a few years,” he said. “These are natural floodplains, or wetlands, or environmentally sensitive land. It’s where the water wants to go.”