Structures of Coastal Resilience

Catherine Seavitt Nordenson,Guy Nordenson,Julia Chapman

• Publisher: Island Press
• Year: 2018
• ISBN:
  9781610918596
• Topic: Architettura
• Subtopic: Architettura generale

Structures of Coastal Resilience presents new strategies for creative and collaborative approaches to coastal planning for climate change. In the face of sea level rise and an increased risk of flooding from storm surge, we must become less dependent on traditional approaches to flood control that have relied on levees, sea walls, and other forms of hard infrastructure. But what are alternative approaches for designers and planners facing the significant challenge of strengthening their communities to adapt to uncertain climate futures?Authors Catherine Seavitt Nordenson, Guy Nordenson, and Julia Chapman have been at the forefront of research on new approaches to effective coastal resilience planning for over a decade. In Structures of Coastal Resilience, they reimagine how coastal planning might better serve communities grappling with a future of uncertain environmental change. They encourage more creative design techniques at the beginning of the planning process, and offer examples of innovative work incorporating flexible natural systems into traditional infrastructure. They also draw lessons for coastal planning from approaches more commonly applied to fire and seismic engineering. This is essential, they argue, because storms, sea level rise, and other conditions of coastal change will incorporate higher degrees of uncertainty—which have traditionally been part of planning for wildfires and earthquakes, but not floods or storms.This book is for anyone grappling with the immense questions of how to prepare communities to flourish despite unprecedented climate impacts. It offers insights into new approaches to design, engineering, and planning, envisioning adaptive and resilient futures for coastal areas.

Chapter 1

Designing for Coastal Resiliency

For months and even years after a hurricane, images of water in the city are haunting. In October 2012, Hurricane Sandy transformed New York City’s subway tunnels into rushing underground canals. Photographs captured fields of taxicabs floating in the water, coastal homes collapsing into the ocean, and floodwaters cresting over the stoops of nineteenth-century townhouses. More than a decade after Hurricane Katrina struck the Gulf Coast and New Orleans in 2005, the aerial surveys of submerged city blocks captured by helicopter overflights remain ingrained in national memory. Photographs on the ground revealed New Orleans residents trudging through chest-deep muddy water and navigating city streets and highways in boats and makeshift rafts. More recently, the trio of massive superstorms of the 2017 hurricane season—Harvey, Irma, and Maria—significantly affected the Texas Gulf Coast and Houston, the Virgin Islands and the Florida Keys, and the entire island of Puerto Rico. Indeed, the hurricanes of 2017 again revealed not only the vulnerabilities of coastal cities but the painful inequities of fragile social and infrastructural systems. Once again, images capture the incomprehensible hardship and loss induced by hurricane-force winds, torrential rainstorms, and massive storm surge flooding. These images are also uncanny; the juxtaposition of water with urban structures is unfamiliar and disquieting.

By contrast, some of the most beautiful portraits of Venice capture the city during the acqua alta, the exceptionally high tides of the Adriatic Sea that bring water into the plazas and streets of this Italian city. For centuries, Venice has flooded on a regular basis. Architectural historian Manfredo Tafuri deemed Venice the first modern metropolis, in part because it was the first city to be built without medieval walls. Instead, the shallow lagoon surrounding Venice secured the city from foreign intruders with its mudflats, hidden channels, tides, and currents. The sea provided a defense system for the Venetians that perimeter walls could not. The safety and security of the city depended on bringing the sea in.¹

Systems of levees, seawalls, and barriers built to defend many coastal cities from flooding diverge from this Venetian approach. Yet as recent flood events have shown, these hard infrastructural defenses are not infallible. Indeed, during massive rain events, coastal defenses—designed to prevent surge flooding from the ocean—prove useless and may even exacerbate inland flood damage. When flood infrastructure fails, disaster often ensues. In addition, sea level rise, one of the many tangible impacts of global climate change, has presented the imperative of thinking differently about coastal flooding. A warming climate leads to rising water levels, with a massive impact on coastal cities. As oceans warm with the increase in global temperature, seawater expands within the ocean basin, causing a rise in water levels. In addition, the warming climate is causing the significant melting of ice over land at higher latitudes, which then adds more water to the ocean. One evident effect of climate change is that hurricanes are causing frequent and costly damage to areas that were historically at low risk of routine flooding. With sea level rise, flooding is likely to occur more frequently, even during average storms or very high tides. The urban neighborhoods, industrial sites, and tourist destinations that have developed in floodplains have often thrived because of their proximity to the water, but rarely have design and planning been used to mitigate potential flood damage in these vulnerable places. The result has been repeated catastrophic damage from strong storms, as well as increased chronic tidal inundation, often called “nuisance flooding.” Coastal cities must adapt to keep pace with the transforming dynamic between ocean, land, and climate. Sea level rise and the increased risk of storm surge demand new solutions to the management of coastal flood hazards. Attempting to keep the water out of these communities is no longer a realistic strategy. Rather, creative planning and design might envision ways to allow water to enter these neighborhoods while reducing the risk of damage to property, livelihood, and health.

Coastal resilience necessitates not only new infrastructural strategies but also a fundamental transformation in understanding how cities might relate to the water around them. Sea level rise and storm surge may be interpreted not as threats to urban life but as opportunities for re-envisioning new ways of living along the coast. Climate change might trigger new urban paradigms; it could be the inspiration for imagining the transformation of cities into a new condition that is not only resilient to climate hazards but also greener, healthier, and more equitable.

This book seeks to offer information of value to the policymakers, engineers, scientists, planners, architects, and landscape architects who play an enormously important role in rethinking and visualizing a resilient built environment. Developing a comprehensive and integrated approach to coastal resilience will require a greater emphasis on methods of design thinking than has traditionally been allotted to this category of work at the waterfront. Imagining alternative futures for coastal cities and landscapes will require new paradigms of innovative analysis, synthesis, and design—productive methods and creative strategies for considering the complex parameters of both ecological systems and uncertain climate futures. Resilience discourse and disaster management are typically dominated by numerical analysis. Yet the value of visual imagination and spatialized system thinking in this arena cannot be underestimated.

Todd Shallat’s authoritative analysis of the early history of the U.S. Army Corps of Engineers (USACE), Structures in the Stream: Water, Science, and the Rise of the US Army Corps of Engineers, illustrates the ordering of the landscape and its waterways not merely as the result of physical structures but as part of an ongoing process of defining and shaping institutional structures.² This book draws on Shallat’s holistic interpretation of “structures,” emphasizing the connections between physical structures—dams, dunes, seawalls, levees, revetments—and nonphysical structures—laws, policies, institutions, bureaucracies. These two kinds of structures are intertwined and must be understood in tandem. Structures of coastal resilience therefore are broad in both scale and scope; they encompass not only physical proposals but also the conceptual and theoretical constructs that define the complex systems at play along the coastline, including both opportunities and hazards.

The term resilience also carries nuanced associations. In the last decade, resilience and adaptation have entered the vocabulary of city, state, and federal agencies. The pervasiveness of these terms illustrates not only rising awareness that climate change will bring increased and irreversible environmental risks and disturbances but also an increase in the cumulative efforts to take action. At the local level, coastal cities and counties as varied as Portsmouth, New Hampshire; Plymouth, Massachusetts; and Lafourche Parish, Louisiana are developing resiliency and adaptation plans to cope with coastal flood risk, wetland restoration, and emergency management. Federal agencies, including the National Oceanic and Atmospheric Administration (NOAA), the U.S. Geological Survey (USGS), the U.S. Department of Housing and

Urban Development (HUD), the U.S. Fish and Wildlife Service (FWS), and the USACE have all devoted resources to resilience efforts, especially after Hurricane Sandy in 2012. In his 2013 Climate Action Plan, President Barack Obama emphasized the need to prepare communities for climate impacts and increase the resilience of buildings and infrastructure. A 2015 Executive Order requires that new federal investments in floodplains manage risk at a higher standard.

Although the term resilience is rapidly gaining new applications in diverse fields including economics, sociology, and education, its origins are primarily in engineering, psychology, and ecology.³ And although resilience is now a buzzword in contemporary political and planning circles, these multiple origins suggest that resilience carries several different definitions. Engineering and ecological resilience, in particular, have distinct meanings rooted in their respective fields. The development of ecological resilience theory began in the 1960s. By the 1970s, ecologists pioneered ideas surrounding “alternate states” and “regime shifts,” arguing that an ecological system does not maintain a steady-state condition, reacting only to disturbances and then returning to that steady state. Rather, ecosystems are constantly in flux, shifting states or regimes though natural and human-made disturbances.⁴ In his 1996 essay “Engineering Resilience versus Ecological Resilience,” ecologist C. S. Holling distinguished between two types of resilience: After an event or interruption, engineering resilience pursues the return to a steady-state condition, whereas ecological resilience accepts major regime shifts in the system in order to survive or maintain function.⁵ The survival of complex ecological systems depends on the acceptance of, and adaptation to, a fundamentally changed environment.

Ecological resilience theory suggests that change in a system is both inevitable and critical. Coasts are dynamic entities, changing shape and form in reaction to powerful forces of water and wind. Cities, too, are always in flux. Gentrification, blight, growth, decay, renewal, and revitalization transform neighborhoods over years and decades. An understanding of resilience as ecological resilience capitalizes on the dynamic processes that make coastal cities vibrant places to live and work. In this book, coastal resilience does not mean restoring coastal communities to preflood conditions or creating a steady state; rather, it means building dynamic systems that can transform, change, and evolve during and after a flood. Ecological resilience readily encompasses climate adaptation, the process of planning for expected yet unknown future environmental conditions.

But coastal resilience goes beyond accepting change; it actively encourages transformation, creating places that embody shared visions for the city. In coastal cities, citizens should be able to see, hear, and smell the water. Rivers, bays, and oceans are critical assets for urban life. Coastal resilience encourages infrastructure that exploits rather than disrupts this connection to water. In some cases, this means expanding notions of infrastructure beyond hard engineered structures to encompass what has come to be known as “green” or “soft” infrastructure: wetlands, islands, forests, parkland, and vegetation but also floodplain management and planning. Incorporating geological, ecological, and biological systems into coastal infrastructure is important not only for mitigating flood risk and preserving vulnerable ecosystems but also for creating novel urban spaces that can withstand change. Coastal resilience transforms the threats of rising seas and more frequent surges into opportunities for building stronger cities.

This understanding of resilience builds on sustainability, another key term of an environmentally conscious age. From building to fishing to farming to manufacturing, sustainable practices aim to minimize environmental impact, reducing natural resource consumption, greenhouse gas emissions, and other pressures on human and natural ecosystems. With its root word sustain, sustainability assumes that the planet might be sustained in a steady-state condition. But with climate change, the nonstationarity of climate, weather, and severe events promises a tumultuous future in which the status quo cannot be maintained, and indeed must adapt. Sustainability also tends to be parceled. A single building or consumer product may be deemed “sustainable” by accrediting parties or even marketing agencies. However, resilience is not so easily compartmentalized. Communities and cities build resilience through collaborative efforts and comprehensive initiatives, considering the relationships between systems, functions, and populations.

Similarly, design thinking, which this book emphasizes, encourages consideration of the relationships between systems, functions, and populations. Multiple scales must be considered, and multiple time horizons. Design thinking requires imagining a different kind of city in a postdisaster context, one that may look and work differently than before. For example, notions of resiliency that prompted a shift toward design thinking in New York City may be traced not only to the impacts of Hurricanes Irene and Sandy on the region in 2011 and 2012 but also to the earlier national crisis of Hurricane Katrina in 2005, when it became clear that some of the greatest future challenges for urban planning and natural disaster mitigation would be compounded by climate change. The cultural heart of the New York region has been rapidly extending beyond the island of Manhattan into the outer boroughs and New Jersey. The New York and New Jersey Upper Harbor is a new center of gravity, pulling development and design attention toward the Manhattan, Brooklyn, Staten Island, Hoboken, and Jersey City waterfronts. This local interest in the harbor—for both its urban potential and its environmental risks—was compounded by the 2005 hurricane season. When Hurricanes Katrina and Rita struck the Gulf Coast in August and September of 2005, sea level rise, storm surge, and the disappearance of coastal wetlands garnered national attention. At that time, the possibility of a hurricane striking New York City was not at the forefront of municipal planning, although the region falls within the zone of possible serious storms. And throughout the twentieth century, several storms had caused severe damage to the New Jersey and Long Island coasts. This context incited not only concern for the impact of climate change on the region but also ideas for how design might simultaneously mitigate risk and transform the metropolitan area.

Interest in resilient design in New York was heightened by the aftermath of Hurricane Sandy in 2012. Coastal resilience gained sudden urgency. Projects previously received by the public as speculative gained renewed interest as critical and feasible. Moreover, projects that presented a systemic approach to resilience that would work with natural processes, rather than against them, gained traction. This significant paradigm shift must continue in the devastating aftermath of Hurricanes Harvey, Irma, and Maria in 2017. Innovative design work reconsiders traditional flood control practices, exploring the potential for a Venetian-influenced adaptation of “controlled flooding.” It embraces water currents and tidal exchange as part of the design and construction process, not as obstacles to a new vision of urbanism. It prioritizes ecologically sound waterways as part of a resilient coast. Vegetation—in the form of designed wetlands, mangrove forests, and maritime forests—attenuates waves and reduces the impact of storms on coastal landscapes. These softer infrastructural strategies and systems are appealing every day of the year, not only during times of flood or surge, and are adaptable to uncertain climate futures. They also highlight the power of design and planning to transform the relationship of a place to the dynamic systems of water that interact with it. Much of what design thinking engenders in future communities will rely on creative techniques, but Venice remains a reminder that visionary humans have adapted to the unpredictable influxes of natural systems for centuries.

The design projects presented in this book provide tangible visions of what urban coastal adaptation could look like, from the Palisade Bay research project, to the creative New York City waterfront projects it engendered at the Museum of Modern Art’s workshop and exhibition Rising Currents. The research project Structures of Coastal Resilience, developed by four universities working in parallel with the USACE, examined the coastal embayments affected by Hurricane Sandy at Norfolk, Virginia; Atlantic City, New Jersey; Jamaica Bay, New York; and Narragansett Bay, Rhode Island. Beyond the North Atlantic coast of the United States, collaborative design studies addressing coastal protection and wetland restoration through sediment diversions along the Mississippi River and its delta are presented, along with new ideas for improving water capture, storage, and release at the Yangtze River Delta in China based on historic agricultural techniques. These projects illustrate an approach for creating storm-resilient landscapes by integrating engineered ecologies with traditional storm protection infrastructures. The design of layered systems allows for controlled flooding but also reduces the risk of damage from storm surge, enhances ecologies, and improves the quality of daily life for local residents.

This book’s approach to the planning and design of resilient coastal communities draws on innovative research, partnerships, and projects conducted over the past decade—local, national, and international in scope. Although each coastal resilience project addresses a specific site and its parameters, they all share a common method and embrace design thinking. All the projects are transdisciplinary in scope, involving design thinkers and scientists from many fields, as well as policymakers and government organizations. Working comprehensively and holistically across urban, ecological, and engineered systems, these projects provide a humanist impulse to a field typically dominated by technical expertise, bureaucratic regulation, and hard data. Each initiative demonstrates the capability of resilient design to build robust and adaptive cities through urban planning and landscape design strategies. And each illustrates the role that architects, landscape architects, and planners can play in addressing climate change at a large scale.

The organization of this book follows the working method of many of these projects, from site analysis to design to evaluation. Throughout, it explores the productive exchange and interaction between the design process and scientific method. The second chapter examines the ways innovative designers have begun to interpret coastal sites by combining the representational methods of art and architecture (plan and section drawings, collage, scale models) with tools of coastal engineering and geospatial analysis (wave flumes, hydrodynamic models, and digital elevation topographic and bathymetric data). Research into these ideas was initiated with the Palisade Bay project analyzing the Upper Harbor of New York and New Jersey in 2007–2010 and continued with the Structures of Coastal Resilience projects of 2013–2015. Pushing the conventional boundaries of representational techniques not only reveals the hidden conditions of familiar sites, it also generates inspiration for new design interventions. Visualizing dynamic processes so that they become both accessible and easily understood is critical to communicating how climate change will affect coastal environments. Representation and visualization is the first step toward creating the novel designs and plans that will reflect the dynamic futures of coastal communities.

The third chapter moves beyond visual representation into examples of the collaborative process of interdisciplinary design thinking applied to the projected futures of a resilient coastal condition. It explores coastal projects at a range of scales, from small landscape interventions to urban design initiatives to regional planning efforts targeting an entire river delta. The chapter examines how two kinds of structures—both physical infrastructure and the processes by which institutions operate—might complement each other in the context of planning for coastal resilience. Each project imaginatively combines the three key principles of attenuation, protection, and planning. Attenuation and the dissipation of wave energy offshore reduces the demands on barriers and levees with wetlands, breakwaters, islands, or of...