David Proverbs and Jessica Lamond
Flood resilient construction has become an essential component of the integrated approach to flood risk management, now widely accepted through the concepts of making space for water and living with floods. Resilient construction has been in place for centuries, but only fairly recently has it been recognized as part of this wider strategy to manage flood risk. Buildings and the wider built environment are known to play a key role in flood risk management, and when buildings are constructed on or near to flood plains there is an obvious need to protect these. Engineered flood defense systems date back centuries, with early examples seen in China and Egypt. Levees were first built in the United States some 150 years ago, and were followed by the development of flood control acts and regulations. In 1945, Gilbert Fowler White, the so-called “father of floodplain management,” published his influential thesis which criticized the reliance on engineered flood defenses and began to change these approaches. In Europe, a shortage of farmable land led to the use of land reclamation schemes and the ensuing Land Drainage acts before massive flood events in the mid-20th century led to a shift in thinking towards the engineered defense schemes such as the Thames Barrier and Dutch dyke systems. The early 21st century witnessed the emergence of the “living with water” philosophy, which has resulted in the renewed understanding of flood resilience at a property level.
The scientific study of construction methods and building technologies that are robust to flooding is a fairly recent phenomenon. There are a number of underlying reasons for this, but the change in flood risk philosophy coupled with the experience of flood events and the long process of recovery is helping to drive research and investment in this area. This has led to a more sophisticated understanding of the approaches to avoiding damage at an individual property level, categorized under three strategies, namely avoidance technology, water exclusion technology, and water entry technology. As interest and policy has shifted to water entry approaches, alongside this has been the development of research into flood resilient materials and repair and reinstatement processes, the latter gaining much attention in the recognition that experience will prompt resilient responses and that the point of reinstatement provides a good opportunity to install resilient measures.
State-of-the-art practices now center on avoidance strategies incorporating planning legislation in many regions to prohibit or restrict new development in flood plains. Where development pressures mean that new buildings are permitted, there is now a body of knowledge around the impact of flooding on buildings and flood resilient construction and techniques. However, due to the variety and complexity of architecture and construction styles and varying flood risk exposure, there remain many gaps in our understanding, leading to the use of trial and error and other pragmatic approaches. Some examples of avoidance strategies include the use of earthworks, floating houses, and raised construction.
The concept of property level flood resilience is an emerging concept in the United Kingdom and recognizes that in some cases a hybrid approach might be favored in which the amount of water entering a property is limited, together with the likely damage that is caused. The technology and understanding is moving forward with a greater appreciation of the benefits from combining strategies and property level measures, incorporating water resistant and resilient materials. The process of resilient repair and considerate reinstatement is another emerging feature, recognizing that there will be a need to dry, clean, and repair flood-affected buildings. The importance of effective and timely drying of properties, including the need to use materials that dry rapidly and are easy to decontaminate, has become more apparent and is gaining attention.
Future developments are likely to concentrate on promoting the uptake of flood resilient materials and technologies both in the construction of new and in the retrofit and adaptation of existing properties. Further development of flood resilience technology that enhances the aesthetic appeal of adapted property would support the uptake of measures. Developments that reduce cost or that offer other aesthetic or functional advantages may also reduce the barriers to uptake. A greater understanding of performance standards for resilient materials will help provide confidence in such measures and support uptake, while further research around the breathability of materials and concerns around mold and the need to avoid creating moisture issues inside properties represent some of the key areas.
Rapid urbanization and growing populations have put tremendous pressures on limited global housing stocks. As the frequency of disasters has increased with devastating impacts on this limited stock of housing, the discourse on post-disaster housing recovery has evolved in several ways. Prior to the 1970s, the field was largely understudied, and there was a narrow understanding of how households and communities rebuilt their homes after a catastrophic event and on the effectiveness of housing recovery policy and programs designed to assist them. Early debates on post-disaster housing recovery centered on cultural and technological appropriateness of housing recovery programs. The focus on materials, technology, and climate missed larger socioeconomic and political complexities of housing recovery. Since then, the field has come a long way: current theoretical and policy debates focus on the effect of governance structures, funding practices, the consequences of public and private interventions, and socioeconomic and institutional arrangements that effect housing recovery outcomes.
There are a number of critical issues that shape long-term post-disaster housing recovery processes and outcomes, especially in urban contexts. Some of them include the role of the government in post-disaster housing recovery, governance practices that drive recovery processes and outcomes, the challenges of paying for post-disaster housing repair and reconstruction, the disconnect between planning for rebuilding and planning for housing recovery, and the mismatch between existing policy programs and housing needs after a catastrophic event—particularly for affordable housing recovery. Moreover, as housing losses after disasters continue to increase, and as the funding available to rebuild housing stocks shrinks, it has become increasingly important to craft post-disaster housing recovery policy and programs that apply the limited resources in the most efficient and impactful ways. Creating housing recovery programs by employing a needs-based approach instead of one based solely on loss could more effectively focus limited resources on those that might need it the most. Such an approach would be broad based and proportional, as it would address the housing recovery of a wide range of groups based upon their needs, including low-income renters, long-term leaseholders, residents of informal settlements and manufactured homes, as well as those with preexisting resources such as owner-occupant housing.
Joanne Stevenson, Ilan Noy, Garry McDonald, Erica Seville, and John Vargo
The economics of disasters is a relatively new and emerging branch of economics. Advances made in analysis, including modeling the spatial economic impacts of disasters, is increasing our ability to project disaster outcomes and explore how to reduce their negative impacts. This work is supported by a growing body of case studies on the organizational and economic impacts of disasters, such as Chang’s in-depth analysis of the Port of Kobe’s decline following the 1995 Great Hanshin earthquake, and the evolving studies of the workforce trends during the ongoing recovery of Christchurch, New Zealand, following a series of earthquakes in 2010 and 2011.
The typical view of post-disaster economies depicts a pattern of destruction, renewal, and improvement. Evidence shows, however, that this pattern does not occur in all cases. The degree of economic disruption and the time it takes for different economies to recover varies significantly depending on characteristics such as literacy rates, institutional competency, per capita income, and government spending.
If the impacts are large relative to the national economy, a disaster can negatively affect the country or sub-national region’s fiscal position. Similarly, disasters may have significant implications for the national trade balance. If, for example, productive capacity is reduced by disaster damage, exports decrease, the trade balance may weaken, and localized inflation may increase.
Studies of individual, household, industry, and business responses to disasters (i.e., microeconomic analyses) cover a broad range of topics relevant to the choices actors make and their interactions with markets. Both household consumption and labor markets face expansion and contraction in areas affected by disasters, with increased consumption and employment often happening in reconstruction related industries.
Additionally, the ability of businesses to absorb, respond, and recover in the face of disasters varies widely. Characteristics such as size, number of locations, and pre-disaster financial health are positively correlated with successful business recovery. Businesses can minimize productivity disruptions and recapture lost productivity by conserving scarce inputs, utilizing inventories, and rescheduling production.
Assessing the progress of economic recovery and predicting future outcomes are important and complex challenges. Researchers use various methodologies to evaluate the effects of natural disasters at different scales of the economy. Surveys, microeconomic models, econometric models, input-output models, and computable general equilibrium models each offer different insights into the effect of disasters on economies.
The study of disaster economics still faces issues with consistency, comprehensiveness, and comparability. Yet, as the science continues to advance there is a growing cross-disciplinary accumulation of knowledge with real implications for policy and the private sector.
As an urbanized river-dominated delta, New Orleans, Louisiana, ranks among the most experimental of cities, a test of whether the needs of a stable human settlement can coexist with the fluidity of a deltaic environment—and what happens when they do not.
That natural environment bestowed upon New Orleans numerous advantages, among them abundant fresh water, fertile soils, productive wetlands and, above all, expedient passage between maritime and continental realms. But with those advantages came exposure to potential hazards—an overflowing Mississippi River, a tempestuous Gulf of Mexico, sinking soils, eroding coasts, rising seas, biotic invasion, pestilence, political and racial discord, conflagration—made all the worse by the high levels of social vulnerability borne by all too many members of New Orleans’ population. More so than any other major metropolis on the North American continent, this history of disaster and response is about the future of New Orleans as much as it is about the past.
This article examines two dozen disasters of various types and scales, with origins oftentimes traceable to anthropogenic manipulation of the natural environment, and assesses the nature of New Orleans’ responses. It frames these assessments in the “risk triangle” framework offered by David Crichton and other researchers, which views urban risk as a function of hazard, exposure, and vulnerability. “Hazard” implies the disastrous event or trauma itself; “exposure” means human proximity to the hazard, usually in the form of settlement patterns, and “vulnerability” indicates individuals’ and communities’ ability to respond resiliently and adaptively—which itself is a function of education, income, age, race, language, social capital, and other factors—after having been exposed to a hazard.
Emergency and disaster planning involves a coordinated, co-operative process of preparing to match urgent needs with available resources. The phases are research, writing, dissemination, testing, and updating. Hence, an emergency plan needs to be a living document that is periodically adapted to changing circumstances and that provides a guide to the protocols, procedures, and division of responsibilities in emergency response. Emergency planning is an exploratory process that provides generic procedures for managing unforeseen impacts and should use carefully constructed scenarios to anticipate the needs that will be generated by foreseeable hazards when they strike. Plans need to be developed for specific sectors, such as education, health, industry, and commerce. They also need to exist in a nested hierarchy that extends from the local emergency response (the most fundamental level), through the regional tiers of government, to the national and international levels. Failure to plan can be construed as negligence because it would involve failing to anticipate needs that cannot be responded to adequately by improvisation during an emergency.
Plans are needed, not only for responding to the impacts of disaster, but also to maintain business continuity while managing the crisis, and to guide recovery and reconstruction effectively. Dealing with disaster is a social process that requires public support for planning initiatives and participation by a wide variety of responders, technical experts and citizens. It needs to be sustainable in the light of challenges posed by non-renewable resource utilization, climate change, population growth, and imbalances of wealth. Although, at its most basic level, emergency planning is little more than codified common sense, the increasing complexity of modern disasters has required substantial professionalization of the field. This is especially true in light of the increasing role in emergency response of information and communications technology. Disaster planners and coordinators are resource managers, and in the future, they will need to cope with complex and sophisticated transfers of human and material resources. In a globalizing world that is subject to accelerating physical, social, and economic change, the challenge of managing emergencies well depends on effective planning and foresight, and the ability to connect disparate elements of the emergency response into coherent strategies.