RESILIENT SHORES: After Sandy, climate scientists and architects explore how to co-exist with rising tides

Coastal Resilience
AFTER THE WIND, RAIN AND WAVES of Hurricane Sandy subsided, many of the modest homes in the Chelsea Heights section of Atlantic City, New Jersey, were filled to their windows with murky water. Residents returned to find roads inundated by the storm surge. Some maneuvered through the streets by boat.

This mode of transport could become more common in neighborhoods like Chelsea Heights as coastal planners rethink how to cope with the increasing risk of hurricane-induced flooding over the coming decades. Rather than seeking to defend buildings and infrastructure from storm surges, a team of architects and climate scientists is exploring a new vision, with an emphasis on living with rising waters. “Every house will be a waterfront house,” said Princeton Associate Professor of Architecture Paul Lewis. “We’re trying to find a way that canals can work their way through and connect each house, so that kayaks and other small boats are able to navigate through the water.”

The researchers aim for no less than a reinvention of flood hazard planning for the East Coast. A new approach, led by Princeton Professor of Architecture Guy Nordenson, rejects the strict dividing line between land and water that coastal planners historically have imposed, favoring the development of “amphibious suburbs” and landscapes that can tolerate periodic floods. These resilient designs can be readily modified as technologies, conditions and climate predictions change.

Discovery2014_CR_textbox1To plan for future flood risks, Princeton climate scientists are using mathematical models of hurricanes to predict storm surge levels over the next century, taking into account the effects of sea level rise at different locations. Four design teams — from Princeton, Harvard University, the City College of New York and the University of Pennsylvania — are using these projections to guide resilience plans for specific sites along the coast: Atlantic City; Narragansett Bay in Rhode Island; New York City’s Jamaica Bay; and Norfolk, Virginia. [See Planning for resilience up and down the coast.]

The designs will serve as a guide for the U.S. Army Corps of Engineers’ North Atlantic Coast Comprehensive Study, a plan to reduce the risk of flood damage to coastal communities, which is due to Congress in January 2015. “The Army Corps understands that they have to revisit what it means to make structures that are resilient,” said Enrique Ramirez, a postdoctoral research associate in architecture at Princeton and the project’s manager. He serves as a liaison between the design teams and Army Corps officials in regional districts.

The idea for the project grew out of Nordenson’s work on a pre-Sandy project to develop creative proposals for adaptation to rising sea levels in New York Harbor. The project culminated in a book, On the Water: Palisade Bay, and a 2010 exhibition, Rising Currents, at the New York City Museum of Modern Art. The proposals included repairing and lengthening existing piers, as well as planting wetlands and building up small islands inside the harbor. “It was forward thinking because we showed that there are benefits to building things in the water,” Nordenson said. Other Princeton contributors to On the Water were engineering professors James Smith and Ning Lin (then a graduate student) and climate scientist Michael Oppenheimer of the Woodrow Wilson School of Public and International Affairs.

Hurricane Sandy heightened the urgency of long-term coastal planning. While advising a New York State commission on future land use strategies, Nordenson began discussing a broader plan for the East Coast with Joseph Vietri of the U.S. Army Corps of Engineers and Nancy Kete of the Rockefeller Foundation. This discussion led to the Structures of Coastal Resilience project, which is funded by the Rockefeller Foundation and began in October 2013. The project is managed by Princeton’s Andlinger Center for Energy and the Environment and will extend resilient design concepts to other coastal regions, as well as integrate hurricane storm surge predictions with projections of local sea level rise.

One of the project’s goals is to encourage a reconsideration of the absolute flood zone boundaries on maps produced by the Federal Emergency Management Agency (FEMA), which determine building code requirements and insurance rates. Climate science shows that the geographical borders of flood risk should be based on the probabilities and outcomes of different storm events, not the placements of artificial levees that may be overtopped by high storm surges. Indeed, many of the homes and businesses ravaged by Hurricane Sandy were not located in flood hazard zones on FEMA’s maps. “Sandy really brought home the message that we have to do a lot better in the future,” said Oppenheimer, the Albert G. Milbank Professor of Geosciences and International Affairs. “Because while we sit here thinking about it, the risk is only increasing.”

Click to enlarge. The low-lying barrier island that is home to Atlantic City is particularly vulnerable to storm surges, especially in parts of the city, such as residential Chelsea Heights, that were built on wetlands. Researchers are exploring ways to make existing neighborhoods (Panel A) more resilient in the face of occasional storm surges. By raising houses, using roads as low levees and letting abandoned lots return to wetland conditions, these neighborhoods can become “amphibious suburbs” (Panel B). A similar approach can be applied to existing canal neighborhoods (Panel C), making them more resilient and tolerant of flooding (Panel D).

Click to enlarge. The low-lying barrier island that is home to Atlantic City is particularly vulnerable to storm surges, especially in parts of the city, such as residential Chelsea Heights, that were built on wetlands. Researchers are exploring ways to make existing neighborhoods (Panel A) more resilient in the face of occasional storm surges. By raising houses, using roads as low levees and letting abandoned lots return to wetland conditions, these neighborhoods can become “amphibious suburbs” (Panel B). A similar approach can be applied to existing canal neighborhoods (Panel C), making them more resilient and tolerant of flooding (Panel D).

Smarter building codes are also needed, according to Lin, an assistant professor of civil and environmental engineering, who heads the effort to predict storm surge levels. Current building code books primarily address earthquake risks. “A tiny few chapters are for wind, and very few pages are for flooding,” Lin said. Large-scale, long-term projects such as levees and seawalls have been the standard approach to coastal protection. But the Coastal Resilience team puts forth a different view, one of coping with occasional flooding rather than fighting it. “We will never be able to prevent such hazards. We can only be prepared to reduce their impact,” Lin said.

Resilient designs call for supporting, revitalizing and in some cases reengineering natural features such as wetlands and beach dunes. This so-called “soft infrastructure” can reduce the impact of waves, improve water quality and create new recreational spaces for coastal residents and visitors. Rather than the exclusive construction of barriers, the project’s plans include “layered systems of natural and engineered structures that will respond in different ways to different hazards,” Nordenson said. “It is a more nuanced and more resilient approach.”

Flexible design is also an important component of the project. Ideally, the sizes and arrangements of structures will be adaptable as predictive models improve. Scientists continue to debate how climate change will affect the strength and frequency of storms. “But we are trying to take what we know right now and do the best job we can in accounting for the uncertainties in what we know, and use that to explore how we should be thinking about adaptation,” said Smith, the William and Edna Macaleer Professor of Engineering and Applied Science and chair of the Department of Civil and Environmental Engineering at Princeton.

Meteorological measurements show that the extreme winds of a swirling hurricane transfer energy to the ocean surface. The winds and the storm’s low air pressure cause a dome of water to rise, generating a surge of high water when the storm makes landfall. “When you think of the storm, you think of the wind and the rain. That’s what seems scary,” said Talea Mayo, a postdoctoral research associate who is working with Lin to model storm surges. But the coastal storm surge was the main cause of deaths and property damages from Hurricane Sandy.

To predict future storm surges, Lin and Mayo are using thousands of synthetic hurricanes modeled by Kerry Emanuel, an atmospheric scientist at the Massachusetts Institute of Technology. “Anytime you’re studying hurricanes, especially so far north, your historical data are really limited because there just aren’t enough events,” Mayo said. “So instead of basing our risk analysis on historical data, we use synthetic data.”

Hurricane damage 1944

Storms have caused significant damage to Atlantic City’s iconic boardwalk throughout its existence. Shown here is South Inlet during the Great Atlantic Hurricane of 1944. Image from the archive of the Coastal and Hydraulics Laboratory, Engineer Research and Development Center, Vicksburg.

Emanuel’s team uses existing models of global climate circulation patterns to generate 3,000 synthetic, physically possible storms for nine different climate change scenarios at each of the four study sites — a total of more than 100,000 storms. These hurricanes exist only in computer code, but their wind speeds, air pressure levels and patterns of movement are based on physical laws and information from recorded storms. Mayo and Lin plug these parameters into algorithms that work like sophisticated versions of high school physics problems: solve the equations for conservation of mass and momentum to estimate maximum water levels at each site. Variations in tide levels, coastline shapes and seafloor topographies add additional layers of complexity.

To make reasonable projections of future flood hazards, the models must also account for sea level rise. According to geoscientist Chris Little, an associate research scholar working with Oppenheimer, storm surges are a short-term version of sea level rise. “They both contribute to coastal flooding,” Little said. “Climate change will be felt through the superposition of changes in long- and short-term variations in sea level.”

And when it comes to sea level rise, local projections are crucial for planning efforts. A constellation of factors influence regional differences in sea levels, including the vertical movement of the Earth’s surface, changes in ocean circulation and the melting of glacial ice. Little and Oppenheimer were among the authors of a study published in June 2014 in the journal Earth’s Future, which used model-based and historical tide gauge data for sites around the globe to project local sea levels over the next two centuries.

“We live in a hotspot, where the local sea level rise has been higher in the past than the global mean, and we expect it to continue to be higher in the future,” Oppenheimer said — as much as 40 percent higher than the worldwide average. One reason for this is that the land along the East Coast is slowly sinking (by a millimeter or two each year), a legacy of the ice sheet that covered much of North America until about 12,000 years ago. The ice sheet depressed Earth’s crust over present-day Canada, causing the liquid mantle beneath to bulge southward. Now that the glaciers have melted, the mantle is being gradually redistributed, flowing out from under the East Coast of the United States.

Sea levels respond slowly to changes in climate, including the current warming trend, caused in part by increased carbon dioxide levels from human activity. Because future carbon emissions depend on human decisions, predictions of sea level rise come with built-in uncertainty. This project attempts to meet this challenge head-on: “A major purpose of the project is to think about doing a more thorough job of assessing the uncertainty in these flood zones,” Little said. “I think it’s difficult but worthwhile.”

Resilient designs call for planning and reengineering natural features such as salt marshes, submerged aquatic vegetation and wetlands, as in this imagined coastline for Staten Island, south of Manhattan.

Resilient designs call for planning and reengineering natural features such as salt marshes, submerged aquatic vegetation and wetlands, as in this imagined coastline for Staten Island, south of Manhattan.

Because of this uncertainty, climate scientists deal in probabilities. The Princeton team has projected flood levels for storms with return periods of 100, 500 and 2,500 years. A return period of 100 years is akin to a “100-year flood” — this means that in any given year there is a 1 percent chance of that flood level occurring. These forecasted flood risks are key to making smart building and design decisions in the face of climate change. “Every decision-maker is going to look and decide what risk is tolerable for their region in the context of how much it would cost to defend against that risk,” Oppenheimer said.

The design teams are beginning to test their plans against the climate scientists’ predictions. Simulated local water levels will reveal which structures may be inundated by future storms and at what probabilities. These analyses may prompt the designers to adjust the heights of buildings, roads or beach dunes in their blueprints. And as the science improves, this process will repeat itself. “Over time, others can start to add things that we haven’t been able to include, like the relationship of the wind and the flood,” Nordenson said.

True resilience necessitates a change in outlook. In Atlantic City, the focus area for Lewis and the Princeton group, a narrow channel of water separates the Chelsea Heights neighborhood from the city’s famous boardwalk and high-rise casinos, where many residents work. “You have extensive areas of suburban neighborhoods that are built on wetlands,” said Lewis. “Two binary positions are retreat, where you return these to wetlands, and fortification, which is the seawall approach. And both of them are problematic.”

The team recognizes the social and economic importance of maintaining the neighborhood. But barricading it behind a seawall may be prohibitively expensive, not to mention unattractive. More important, metal or concrete seawalls can actually exacerbate flooding when areas behind them are inundated by heavy rain. Lewis and his team have a fundamentally different vision for places like Chelsea Heights: “We’re looking at developing an amphibious suburb,” he said. “We want water to come in. If there are berms [earthen seawalls] that are put in, they should be built with a series of valves.”

The plans for Chelsea Heights include raised homes and roads interspersed with canals and revitalized wetlands. Lewis hopes these ideas will be useful to policymakers and to the Army Corps of Engineers, which may apply the Princeton team’s concepts to Chelsea Heights and other similar communities along the New Jersey shore. By the end of this century, grassy suburban lawns may be transformed into salt marshes.

PLANNING FOR RESILIENCE UP AND DOWN THE COAST

Natural features play a pivotal role in the designs for two of the project’s other focal regions, New York’s Jamaica Bay and Rhode Island’s Narragansett Bay.

  • The plan for Jamaica Bay includes the use of local dredged materials to build up land for marsh terraces, which can serve to reduce wind fetch as well as improve water quality and encourage sediment deposition, according to Catherine Seavitt, an associate professor of landscape architecture at the City College of New York. In particular, her team hopes to expand the restoration of a native wetland grass, Spartina alterniflora, an effective attenuator of wind and waves that also provides valuable ecological habitat.
  • Michael Van Valkenburgh and Rosetta Elkin lead the Harvard design effort for Narragansett Bay. One of their plans involves relocating two critical reservoirs that supply drinking water to the city of Newport. The reservoirs are currently vulnerable to coastal flooding; the proposed project would use dredged material from the original reservoir to fill in and extend the existing maritime forest, now a rare ecosystem along the New England coast. The larger forest, designed by the team, would mitigate coastal erosion, attenuate wave action, and become a valuable recreational area for surrounding communities.
  • The project’s other site, the Norfolk, Virginia, area of Chesapeake Bay, calls for a more extensive reshuffling of settlement and infrastructure, according to Dilip da Cunha, an adjunct professor of landscape architecture at the University of Pennsylvania. Of the four sites, Norfolk is expected to see the most dramatic sea level rise, and is home to the world’s largest naval station and a vital commercial port. The UPenn team’s designs stem from the natural network of fractal-like interfaces where land and water meet. The plan seeks to bolster “fingers of higher ground” that will be more robust to gradual sea level rise as well as storm surges. “The higher grounds could be for housing, schools and other facilities, and the low grounds could accommodate various things, from marsh grasses to football fields,” da Cunha said. “Things that can take water in the case of a storm event, but will not endanger lives.”

-By Molly Sharlach

Shell Structures for Architecture: Form Finding and Optimization

Shell Structures for Architecture

Shell Structures for Architecture

Edited by: Sigrid Adriaenssens, Philippe Block, Diederik Veenendaal and Chris Williams, with a foreword by Pritzker Prize Winner Shigeru Ban
Publisher: Routledge: Taylor and Francis, 2014

This book presents contemporary design methods for shell and gridshell structures, covering formfinding and structural optimization techniques. Edited by experts including Princeton Assistant Professor of Civil and Environmental Engineering Sigrid Adriaenssens, the book introduces architecture and engineering practitioners and students to structural shells and provides computational techniques to develop complex curved structural surfaces, in the form of mathematics, computer algorithms and design case studies.

The City Lost and Found: Exhibition examines creative responses to urban changes in ’60s, ’70s America

Chicago 1969

Kenneth Josephson, “Chicago,” 1969. Photo collage. The Art Institute of Chicago. Gift of the School of the Art Institute of Chicago. Copyright Kenneth Josephson.

THE AMERICAN CITY OF THE 1960S AND 1970S witnessed seismic physical changes and social transformations, including shifting demographics and political protests as well as the aftermath of decades of urban renewal. In this climate of uncertainty, a host of different actors — including photographers, architects, filmmakers, planners and activists — transformed these conditions of crisis into provocative and visually compelling statements about the culture, urban landscape and politics of New York, Chicago and Los Angeles.

A groundbreaking exhibition, The City Lost and Found: Capturing New York, Chicago and Los Angeles, 1960-1980, examines creative responses to dramatic urban changes through the intersection of photography, film, architecture and urban planning. On view from Feb. 21 to June 7, 2015, at the Princeton University Art Museum, the show focuses on the interconnections of art practices and lived realities in these three major American cities, with accompanying print and digital materials.

Catalogue

The exhibition is accompanied by a richly illustrated 272-page catalogue, with contributions from more than 20 noted scholars in art history, urban planning, architecture and cultural studies.

More than 150 objects — including photographs, photo-based work, film, architectural renderings, planning documents and publications — are highlighted across four galleries in the museum. The exhibition reframes work by renowned artists and architects, such as Martha Rosler, Paul Rudolph, Ed Ruscha, Mierle Laderman Ukeles, Garry Winogrand and the firm of Skidmore, Owings and Merrill, while also showcasing pivotal works by underrepresented artists, including Ralph Arnold, Oscar Castillo, Jonas Dovydenas, Arthur Tress and Shadrach Woods.

Though arranged by city, the exhibition focuses on major themes framing common directions of creative response and artistic engagement, including demonstration, preservation and renewal. For example, The New York Times photographer Barton Silverman captured protestors at the 1968 Democratic National Convention in Chicago occupying the public space in Grant Park opposite the convention hotel and taking over a public monument. The speed at which such images circulated in print and in television news coverage resonates with the use of social media in documenting contemporary life.

The exhibition is organized in collaboration with the Art Institute of Chicago, where it opened in October 2014. Katherine Bussard, the Peter C. Bunnell Curator of Photography at the Princeton University Art Museum, coorganized the show with Alison Fisher, the Harold and Margot Schiff Assistant Curator of Architecture and Design at the Art Institute of Chicago, and Greg Foster-Rice, associate professor of film at Columbia College Chicago.

A major scholarly catalogue accompanies the exhibition to further explore the connections between critical practices in art and architecture and the political, social and geographic realities of American cities during this transformational period. For example, Bruce Davidson’s two-year study of a single block, East 100th Street (1966- 68), and Romare Bearden’s photo collage The Block II (1971-72) reveal complex portraits of race, poverty and community in Harlem. With more than 300 illustrations, the book features contributions from more than 20 scholars in art history, urban planning, architecture and cultural studies. The catalogue is published by the Princeton University Art Museum and distributed by Yale University Press.

As a digital component, self-guided walking tours of each city are available to view online and access on mobile devices. Each walking tour connects up to 10 objects from the exhibition with their respective sites of engagement in the city. For example, on the New York City tour, users are directed to the former residence of artist Vito Acconci in Greenwich Village. There, starting at the front stoop, Acconci performed the conceptual work Following Piece for a month in 1969 to “follow [a] different person every day until person enters private place.” In this way users can see and experience firsthand how vital these cities were and remain to artistic and everyday life.

Visit artmuseum.princeton.edu/the-city

–By Erin Firestone

First Princeton-Fung Global Forum held in Shanghai

Shanghai skyline

Shanghai skyline (Photo by Dan Day)

Architects, engineers and other scholars gathered in February in Shanghai for the inaugural Princeton-Fung Global Forum to discuss population growth, social trends, climate change and other factors determining “The Future of the City.”

A $10 million gift from Princeton Trustee William Fung, Class of 1970, established the forum and the Fung Global Fellows Program, which is administered by the Princeton Institute for International and Regional Studies and brings international early-career faculty members working in the social sciences and the humanities to Princeton for a year of research, writing and collaboration. Fung is chairman of the Hong Kongbased Li & Fung group of export and retailing companies.  The 2014 Princeton-Fung Global Forum will be held in Paris.

-By Dan Day