Lauren Nassef

Flooding, long dismissed as a problem that happens to someone else, has risen in our national consciousness over the past 15 years thanks to such names as Katrina, Rita, Sandy, and Harvey—a set of the worst houseguests you could ever imagine. Recent flooding has been driven by a variety of causes: hurricanes whose landfall wasn’t in perennially threatened areas, as well as intense rains and snowmelt—manifestations of climate change and malign coincidence.

One linked fact is that flooding has afflicted far more than the usual geographic suspects, with New England and the Gulf Coast experiencing intense onslaughts. The impact has been highly destructive, and the only silver lining might be a greater awareness among architects and experts—and the public—of the need to take action.

Resilience, which until recently was represented by academics or the occasional forward-minded planner, is in the process of vaulting into mainstream consciousness as a result.

Illya Azaroff, AIA, founding principal at +LAB Architect PLLCs and a professor at New York City College of Technology (City University of New York), notes, “Before Hurricane Sandy, every time there was a resilience meeting, we all knew each other. Since then, I’m in meetings all of the time, and I don’t know a majority of the people. That’s a great thing.” (Azaroff ’s #HurricaneStrong home in Breezy Point, Queens, is the subject of the 2019 AIA Film Challenge seed film.)

Among architects and policymakers, a more acute awareness of the risks of flooding is developing—not only because of its increased geographic dispersal, but also because flooding has started to serially outstrip the bounds of outdated flood maps in surges of Neptunian irredentism. While this is an obvious shock to anyone whose home or business has been deluged, it is often chased by a second one: the fact that no one will pay for the damages.

FEMA flood maps, which classify sites into different levels of risks, have been irregularly funded, and many homes and businesses within their current boundaries lack insurance anyway. Prospective changes to FEMA flood insurance policies could prompt considerable changes in the nature of future construction and repairs in vulnerable areas. Assessments to date have been based on comparatively broad classifications of risk; FEMA’s Risk Rating 2.0 update, set to be implemented in 2020, will apply a finer-grained set of evaluations to individual properties, including the elevation of ground on the property, the elevation of a structure’s first-floor distance to water, and potential rebuilding costs.

“If property ownership costs are going to dramatically increase, that will have an affect on architects and the kinds of buildings they design,” says Rachel Minnery, FAIA, the senior director of resilience, adaptation, and disaster assistance at AIA. “Design is not the leader here, economic loss is.”

When it comes to the work of influencing and guiding where to build, how to build, how to protect what’s built, and how to reduce overall flood risks, architects have a vital role to play.

David Waggonner, FAIA, a principal at Waggonner & Ball who has been active with New Orleans flood planning, notes that architects are often merely responding to client specifications and may not have ultimately persuasive capacities, but that it is becoming necessary to take a stronger stance. “Architects are needed,” he says. “If we stay out of this, God help us.”

Storm-Related Ocean Flooding in Boston

There is no single way to foil flooding, and understanding the geographic variables is key. Some parts of New England, unexpectedly ravaged during Hurricane Sandy, feature safe land close to where any building is sited—even next to the ocean.

“The geologic structure of Connecticut is like the fingers of your hand; some of the geological ridges stretch out into the sea. You don’t have to retreat out of the area; you just have to retreat upland to the ridges,” says Donald Watson, FAIA, principal at EarthRise Design in Trumbull, Conn. This means that flood-vulnerable neighborhoods can migrate to higher ground nearby, possibly within the same town.

“Greenwich has done this [by allowing] developers to increase densities in safe zones and decrease densities in unsafe zones,” he says. New housing is permitted in the flood plain if “dry access” is provided, ensuring accessibility under normal flood conditions. One usually doesn’t need to go far to find portions safe from flooding.

There are some exceptions in New England that yield more difficult circumstances, however. “Boston is different,” Watson says.

“It’s essentially built on a mud flat. [As a designer], I have to understand all water from above and below. Water comes from all sides, and it also comes from the ground.”

Packing up and moving uphill is an easy theoretical recommendation, but it’s not a realistic solution for several of the most historic neighborhoods in the United States, such as North End and Seaport, located in just such less-than-propitious spots. As Minnery notes, architects “can’t overlook the cultural and historical significance of places that developed on waterfronts.” Boston is undertaking a wide range of planning solutions, including surge barriers and shorefront zones.

The relative mercy of storm-related ocean flooding is that it is often brief. The trouble is that it can become incredibly forceful as it overwhelms urban water systems—especially when water pours down slopes in dense urban neighborhoods that funnel it into narrow corridors.

Azaroff says that his own historic red brick row house has a water retention capacity of 300 gallons. Graywater systems and green roofs, or even the act of rendering frequently small urban yards permeable, can make a considerable difference. The key is not holding water forever; it’s holding it at designated points when existing systems are near capacity and safely releasing it under more normal conditions.

Houston, City on a 100-Year Flood Plain

While Boston faces brief, sustained flooding risks, it’s the nagging persistence of floodwaters that complicate planning in another location. Houston, which was battered by Hurricane Harvey in 2017, is perhaps the most difficult urban site in the country, given that there are no bedrock ridges: the majority of the city, and surrounding Harris County, rests squarely on the 100-year or 500-year flood plain. During Harvey, however, nearly three-quarters of all flood-damaged homes and apartment buildings were outside of a FEMA-designated flood plain.

The trouble is that there’s simply no rapid way for this bathtub to drain. As Shawn Gillen, AIA, vice president of DFD Architects, notes, “In north Texas, FEMA’s maps are based on terrible data. They show culverts and roads and bridges that don’t exist, and others that exist weren’t on them. In many locations, risks were known but ignored.”

The risks of this lengthy inundation are different than those of short-term flooding, as in Boston, and call for different solutions. Water will erode around and under foundations, destorying them through upheaval or settling. It can be especially damaging to wooden framing, which can be ruined after several days of flooding.

Gillen took note of a widely circulated and shocking image of the La Vita Bella Nursing Home in Dickinson, Texas, where residents were inundated with several feet of water during Hurricane Harvey. After checking its location, he immediately discovered that the nursing home was across the street from a stream, a short distance from Dickinson Bayou. “It was in the flood plain,” he says. “This was going to happen at some point. It should not have been a surprise.”

Most homes can’t escape flood risk altogether; they can only mitigate it, or address the distinction between dry floodproofing—in which structures are entirely impermeable— and wet floodproofing, which allows water to move in enclosed parts of a home’s lower area, such as a crawl space, and then out when the water recedes. Last year, Houston increased required elevation levels for new buildings to be 2 feet above the 500-year flood plain, replacing a prior standard of 1 foot above the 100-year flood plain. Implementing this earlier would have protected 84 percent of the hundreds of thousands of homes that flooded.

Building above a flood plain can’t always be accomplished just by piling up dirt, which will either get swept away by water or shift the problem to a neighbor. “If you want to raise your site, you’re altering the hydraulics of everything,” Gillen says. “If you bring your house up by 36 inches, you’re going to flood the house next to you even worse.”

The key is to elevate the building structurally, usually with concrete, steel, or stone, and to elevate living spaces, mechanical elements, and wood above this level. “All materials below the floor level have to be water resistant or super easy to replace,” Gillen says.

The common practice of building homes on stilts, time-honored elsewhere, is mysteriously absent in American construction, but would make ample sense. In Southeast Asia, Gillen notes, buildings are designed to let the waters flow beneath them.

Waggonner, whose work in New Orleans in an exceptionally challenging deltaic condition resembled the challenges of Houston, says, “The good news is, you have an incredible ecosystem if you just use it.” For decades, the philosophy of New Orleans was to pump and cover water, which ultimately proved work-intensive and unsuccessful.

“The earth is like our skin,” he says. We put too many bandages on our skin, and [it] doesn’t absorb anymore.”

A Recurring Problem

In some cases, the most sensible architectural solution is simply ceasing to build. AIA’s Minnery criticizes the “substantial damage” standard in the National Flood Insurance Program (NFIP), which has administered all flood insurance in the United States since 1968. It’s meant to assess when structures are simply in too risky an area to be reasonably repaired, but the trouble is that it establishes a bar that does not prevent repeat repairs to structures that are perennially flooded in significant ways.

“Unless it triggers substantial damage of over 50 percent, they’ll just repair it over and over again,” she says. “I’ve actually heard of structures that have gone through the process 10 times or more.”

Roy Wright, former head of the NFIP, notes that one of the programs he encouraged was an “extreme repetitive loss” category to end payments for such serially afflicted properties. He stresses that these were a statistically small portion of cases, and that most of the program’s problems were less individually dramatic, but systemically severe. According to Wright, the trouble is most often not those houses that flood every few years, but the homes that flood infrequently—and are likely to flood again.

Residents living in flood plains, and their bipartisan elected representatives, pose a substantial obstacle. “I don’t think there is an appetite to deal with fundamental issues in the NFIP,” he says.

Some homeowners in high risk areas simply don’t have the resources to improve their homes, or the means to relocate. Flood risks are a hassle and expense for anyone, but failing to prepare is sure to be worse. Many at every stage of the process prefer to ignore the problem.

“There’s a fear of data because there’s this presumption of responsibility and liability,” Minnery says. “It’s the kiss of death to find out that your property has a flood risk.” In many cases, faulty data in the past encouraged avoiding the issue, but with the increased occurrence of flooding outside of established flood areas and more accurate LIDAR and satellite FEMA mapping, there’s a fresh and more accurate awareness of extant risks.

As EarthRise Design’s Watson observes, “Before you sit down and build, you should figure out the worst thing that could happen to your site—and then think of something worse. There’s phenomenal opportunity for innovation if you understand the risks.”