Urban water infrastructure is designed to provide protection from waterborne disease and hydrological stability for urban citizens to be able to maintain everyday life despite daily and seasonal rainfall variation. Since the emergence of modern forms of urban governance and planning in the nineteenth century, controlling the flow of water through cities has largely been viewed as a technical problem to be solved by professional engineers, who account for hydrological variability in designing and managing water infrastructure. Reservoirs are built to store water for distribution during dry months. Drains are sized for high flow rates to quickly remove water from streets and buildings during storm events. Flood defences are constructed to protect buildings and other assets from water levels which can be anticipated to occur with known probability. Risks associated with the unlikely failure of these systems or extreme events that fall outside their operating conditions have been covered by the insurance industry, providing financial protection to enable citizens and businesses to recover from disasters. Despite its overall success, this approach to managing water in cities is now reaching its limits. Burgeoning urban populations and climate change are increasing the complexity of water management such that it is no longer a technically tractable problem, requiring greater attention from urban planners, designers, politicians and citizens.
Iain White's book Water and the city: risk, resilience and planning for a sustainable future makes the case for the importance of spatial planning within a framework of risk reduction and resilience as the foundation for a new approach to managing water in cities. Although focused on contemporary challenges, his analysis is positioned within a broad historical context of urban planning and water management. The main purpose of this book is to develop a conceptual framework for urban risk and resilience, which may prove applicable to other sectors but emerges from his analysis of the particular nature of urban flooding and water scarcity in modern cities, with emphasis on the UK context.
The book begins by challenging perceptions of drought and flood as ‘natural disasters’, demonstrating the interactions between people and the environment in creating these hazards and adapting to the risks they present. Throughout history, urban form has been shaped by efforts to reduce risks posed by environmental and other hazards. In the modern period this has been dominated by technocentric adaptation based on quantitative assessment of risk and cultural ambitions of mastery over nature. Human activity increasingly exacerbates rather than mitigates the environmental risks, even though disasters such as floods and drought are often designated as natural events beyond the influence of urban planning and engineering. White presents population growth and climate change as the major driving forces further entangling human activity and environmental hazards in enhancing urban risk.
White presents the key problems of flooding and water scarcity in the city, with analysis of how urban planning and engineering have contributed to both mitigating and enhancing these urban risks. Flood risks to cities present a particular challenge to neo-liberal approaches to urban governance which rely on market-driven development and private insurance, which cannot adequately account for the spatially complex causes and impacts of flooding. As a balance to these drivers, White makes the case for a stronger role for spatial planning, drawing on new sources of knowledge about the causes and impacts of flooding. The analysis of water scarcity focuses on drought events and the need for greater attention to managing demand rather than expanding supply. The concept of virtual water is presented to show that cities may be at risk of water scarcity in distant countries through reliance on imports of food and other water-intensive products.
The core of White's thesis is the development of a framework for analysing and managing urban risk and enhancing resilience. Risk is a socially constructed concept composed of three elements – hazard, exposure and vulnerability. Resilience can be enhanced by reducing the magnitude of each component. Hazards are events such as drought and flood, which are caused by human and natural factors. Exposure reflects the number of people, buildings or assets which may be subject to the hazard, which in the case of flooding and water scarcity is spatially determined. Vulnerability refers to susceptibility to the impacts of the hazard and is a function of social as well as physical elements. Spatial planners have a unique capacity to intervene to improve urban resilience by reducing all three components of risk using a variety of policy and planning measures, where conventional engineering approaches have focused on technical interventions which attend to only measurable, physical contributors to risk.
The final section of this book includes chapters that expand and apply the concepts of hazard, exposure and vulnerability to water scarcity and flooding. Each element is developed in detail to further expand the analytical framework, with potential interventions presented as illustrative rather than prescriptive. Such interventions include the use of sustainable urban drainage and green infrastructure to reduce flood hazards; the use of non-potable water supply and demand management to reduce exposure to water scarcity; and the attention to underlying social equity issues in reducing vulnerability to flood events. The concluding chapter draws the framework of risk and resilience back to the sustainable cities agenda, highlighting the potential of water-resilient spatial planning to enhance rather than to constrain urban development.
White's analysis of urban risk and resilience as socially constructed and multifaceted is helpful in moving from a narrow quantitative framing of environmental hazards by technical experts towards a more encompassing and realistic analysis of the issues. Importantly, this opens up the possibility for wider engagement with the complex trade-offs and infrastructure alternatives in managing water in cities. Better understanding of spatial distribution of risk, especially when broken down into its different components, can allow planners, engineers, governments and citizens to identify alternatives and make more robust decisions to improve urban resilience. Within appropriate governance frameworks, wider definition of risk and resilience potentially allows for more open deliberation about incommensurable risks, such as comparing the health risks from recycled water and the risks to supply from water scarcity.
Overall, White's risk and resilience framework is better developed in his analysis of flooding than water scarcity, particularly in regard to the relationship between resilience and sustainability. Drought resilience is currently driving many water utilities to implement energy-intensive desalination and potable recycling schemes, which are mostly unsustainable. Reducing demand for water through implementation of non-potable water supply at household and neighbourhood scale, and driving cultural and technological change to reduce domestic consumption, is the basis for sustainable water systems in cities where supplies are increasingly stressed under ‘normal’ rather than ‘extreme’ conditions. White noted the difference between flood risk as a ‘shock’ and water scarcity as a ‘stress’, which fundamentally changes the nature of management. Whilst urban resilience to drought will be improved by reduced baseline demand resulting from the transition to a more sustainable balance of supply and demand, overemphasis on drought risk management as the key concern for water supply diverts attention for more fundamental reform to flows of water under ‘normal’ conditions.
Managing water in cities is increasingly complex, requiring new approaches that move beyond engineering techniques. Water and the City is important in framing the role of spatial planning in the emerging interdisciplinary landscape of urban water management. White's comprehensive development of the risk and resilience framework is a thoughtful transposition of system concepts into the urban planning discourse and provides a useful tool for analysing urban preparedness and response to extreme events such as drought and flooding. This book is a useful framing of water management for planning academics, professionals and students and will provide established water professionals with a valuable new perspective. It also provides a clear outline of the concepts of urban risk and resilience, which may be of value to researchers and practitioners working to address wider issues of climate change adaptation and other urban shocks and stresses.
Sarah Bell
Department of Civil, Environmental and Geomatic Engineering,
University College London, London, UK
© 2011, Sarah Bell